// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 */

#include <linux/delay.h>
#include <linux/sched/types.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <media/cec-pin.h>
#include "cec-pin-priv.h"

/* All timings are in microseconds */

/* start bit timings */
#define CEC_TIM_START_BIT_LOW           3700
#define CEC_TIM_START_BIT_LOW_MIN       3500
#define CEC_TIM_START_BIT_LOW_MAX       3900
#define CEC_TIM_START_BIT_TOTAL         4500
#define CEC_TIM_START_BIT_TOTAL_MIN     4300
#define CEC_TIM_START_BIT_TOTAL_MAX     4700

/* data bit timings */
#define CEC_TIM_DATA_BIT_0_LOW          1500
#define CEC_TIM_DATA_BIT_0_LOW_MIN      1300
#define CEC_TIM_DATA_BIT_0_LOW_MAX      1700
#define CEC_TIM_DATA_BIT_1_LOW          600
#define CEC_TIM_DATA_BIT_1_LOW_MIN      400
#define CEC_TIM_DATA_BIT_1_LOW_MAX      800
#define CEC_TIM_DATA_BIT_TOTAL          2400
#define CEC_TIM_DATA_BIT_TOTAL_MIN      2050
#define CEC_TIM_DATA_BIT_TOTAL_MAX      2750
/* earliest safe time to sample the bit state */
#define CEC_TIM_DATA_BIT_SAMPLE         850
/* earliest time the bit is back to 1 (T7 + 50) */
#define CEC_TIM_DATA_BIT_HIGH           1750

/* when idle, sample once per millisecond */
#define CEC_TIM_IDLE_SAMPLE             1000
/* when processing the start bit, sample twice per millisecond */
#define CEC_TIM_START_BIT_SAMPLE        500
/* when polling for a state change, sample once every 50 microseconds */
#define CEC_TIM_SAMPLE                  50

#define CEC_TIM_LOW_DRIVE_ERROR         (1.5 * CEC_TIM_DATA_BIT_TOTAL)

/*
 * Total data bit time that is too short/long for a valid bit,
 * used for error injection.
 */
#define CEC_TIM_DATA_BIT_TOTAL_SHORT    1800
#define CEC_TIM_DATA_BIT_TOTAL_LONG     2900

/*
 * Total start bit time that is too short/long for a valid bit,
 * used for error injection.
 */
#define CEC_TIM_START_BIT_TOTAL_SHORT   4100
#define CEC_TIM_START_BIT_TOTAL_LONG    5000

/* Data bits are 0-7, EOM is bit 8 and ACK is bit 9 */
#define EOM_BIT                         8
#define ACK_BIT                         9

struct cec_state {
        const char * const name;
        unsigned int usecs;
};

static const struct cec_state states[CEC_PIN_STATES] = {
        { "Off",                   0 },
        { "Idle",                  CEC_TIM_IDLE_SAMPLE },
        { "Tx Wait",               CEC_TIM_SAMPLE },
        { "Tx Wait for High",      CEC_TIM_IDLE_SAMPLE },
        { "Tx Start Bit Low",      CEC_TIM_START_BIT_LOW },
        { "Tx Start Bit High",     CEC_TIM_START_BIT_TOTAL - CEC_TIM_START_BIT_LOW },
        { "Tx Start Bit High Short", CEC_TIM_START_BIT_TOTAL_SHORT - CEC_TIM_START_BIT_LOW },
        { "Tx Start Bit High Long", CEC_TIM_START_BIT_TOTAL_LONG - CEC_TIM_START_BIT_LOW },
        { "Tx Start Bit Low Custom", 0 },
        { "Tx Start Bit High Custom", 0 },
        { "Tx Data 0 Low",         CEC_TIM_DATA_BIT_0_LOW },
        { "Tx Data 0 High",        CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_0_LOW },
        { "Tx Data 0 High Short",  CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_0_LOW },
        { "Tx Data 0 High Long",   CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_0_LOW },
        { "Tx Data 1 Low",         CEC_TIM_DATA_BIT_1_LOW },
        { "Tx Data 1 High",        CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_1_LOW },
        { "Tx Data 1 High Short",  CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_1_LOW },
        { "Tx Data 1 High Long",   CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_1_LOW },
        { "Tx Data 1 High Pre Sample", CEC_TIM_DATA_BIT_SAMPLE - CEC_TIM_DATA_BIT_1_LOW },
        { "Tx Data 1 High Post Sample", CEC_TIM_DATA_BIT_TOTAL - CEC_TIM_DATA_BIT_SAMPLE },
        { "Tx Data 1 High Post Sample Short", CEC_TIM_DATA_BIT_TOTAL_SHORT - CEC_TIM_DATA_BIT_SAMPLE },
        { "Tx Data 1 High Post Sample Long", CEC_TIM_DATA_BIT_TOTAL_LONG - CEC_TIM_DATA_BIT_SAMPLE },
        { "Tx Data Bit Low Custom", 0 },
        { "Tx Data Bit High Custom", 0 },
        { "Tx Pulse Low Custom",   0 },
        { "Tx Pulse High Custom",  0 },
        { "Tx Low Drive",          CEC_TIM_LOW_DRIVE_ERROR },
        { "Rx Start Bit Low",      CEC_TIM_SAMPLE },
        { "Rx Start Bit High",     CEC_TIM_SAMPLE },
        { "Rx Data Sample",        CEC_TIM_DATA_BIT_SAMPLE },
        { "Rx Data Post Sample",   CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_SAMPLE },
        { "Rx Data Wait for Low",  CEC_TIM_SAMPLE },
        { "Rx Ack Low",            CEC_TIM_DATA_BIT_0_LOW },
        { "Rx Ack Low Post",       CEC_TIM_DATA_BIT_HIGH - CEC_TIM_DATA_BIT_0_LOW },
        { "Rx Ack High Post",      CEC_TIM_DATA_BIT_HIGH },
        { "Rx Ack Finish",         CEC_TIM_DATA_BIT_TOTAL_MIN - CEC_TIM_DATA_BIT_HIGH },
        { "Rx Low Drive",          CEC_TIM_LOW_DRIVE_ERROR },
        { "Rx Irq",                0 },
};

static void cec_pin_update(struct cec_pin *pin, bool v, bool force)
{
        if (!force && v == pin->adap->cec_pin_is_high)
                return;

        pin->adap->cec_pin_is_high = v;
        if (atomic_read(&pin->work_pin_num_events) < CEC_NUM_PIN_EVENTS) {
                u8 ev = v;

                if (pin->work_pin_events_dropped) {
                        pin->work_pin_events_dropped = false;
                        ev |= CEC_PIN_EVENT_FL_DROPPED;
                }
                pin->work_pin_events[pin->work_pin_events_wr] = ev;
                pin->work_pin_ts[pin->work_pin_events_wr] = ktime_get();
                pin->work_pin_events_wr =
                        (pin->work_pin_events_wr + 1) % CEC_NUM_PIN_EVENTS;
                atomic_inc(&pin->work_pin_num_events);
        } else {
                pin->work_pin_events_dropped = true;
                pin->work_pin_events_dropped_cnt++;
        }
        wake_up_interruptible(&pin->kthread_waitq);
}

static bool cec_pin_read(struct cec_pin *pin)
{
        bool v = call_pin_op(pin, read);

        cec_pin_update(pin, v, false);
        return v;
}

static void cec_pin_insert_glitch(struct cec_pin *pin, bool rising_edge)
{
        /*
         * Insert a short glitch after the falling or rising edge to
         * simulate reflections on the CEC line. This can be used to
         * test deglitch filters, which should be present in CEC devices
         * to deal with noise on the line.
         */
        if (!pin->tx_glitch_high_usecs || !pin->tx_glitch_low_usecs)
                return;
        if (rising_edge) {
                udelay(pin->tx_glitch_high_usecs);
                call_void_pin_op(pin, low);
                udelay(pin->tx_glitch_low_usecs);
                call_void_pin_op(pin, high);
        } else {
                udelay(pin->tx_glitch_low_usecs);
                call_void_pin_op(pin, high);
                udelay(pin->tx_glitch_high_usecs);
                call_void_pin_op(pin, low);
        }
}

static void cec_pin_low(struct cec_pin *pin)
{
        call_void_pin_op(pin, low);
        if (pin->tx_glitch_falling_edge && pin->adap->cec_pin_is_high)
                cec_pin_insert_glitch(pin, false);
        cec_pin_update(pin, false, false);
}

static bool cec_pin_high(struct cec_pin *pin)
{
        call_void_pin_op(pin, high);
        if (pin->tx_glitch_rising_edge && !pin->adap->cec_pin_is_high)
                cec_pin_insert_glitch(pin, true);
        return cec_pin_read(pin);
}

static bool rx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
                         int arg_idx, u8 *arg)
{
#ifdef CONFIG_CEC_PIN_ERROR_INJ
        u16 cmd = cec_pin_rx_error_inj(pin);
        u64 e = pin->error_inj[cmd];
        unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;

        if (arg_idx >= 0) {
                u8 pos = pin->error_inj_args[cmd][arg_idx];

                if (arg)
                        *arg = pos;
                else if (pos != pin->rx_bit)
                        return false;
        }

        switch (mode) {
        case CEC_ERROR_INJ_MODE_ONCE:
                pin->error_inj[cmd] &=
                        ~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
                return true;
        case CEC_ERROR_INJ_MODE_ALWAYS:
                return true;
        case CEC_ERROR_INJ_MODE_TOGGLE:
                return pin->rx_toggle;
        default:
                return false;
        }
#else
        return false;
#endif
}

static bool rx_nack(struct cec_pin *pin)
{
        return rx_error_inj(pin, CEC_ERROR_INJ_RX_NACK_OFFSET, -1, NULL);
}

static bool rx_low_drive(struct cec_pin *pin)
{
        return rx_error_inj(pin, CEC_ERROR_INJ_RX_LOW_DRIVE_OFFSET,
                            CEC_ERROR_INJ_RX_LOW_DRIVE_ARG_IDX, NULL);
}

static bool rx_add_byte(struct cec_pin *pin)
{
        return rx_error_inj(pin, CEC_ERROR_INJ_RX_ADD_BYTE_OFFSET, -1, NULL);
}

static bool rx_remove_byte(struct cec_pin *pin)
{
        return rx_error_inj(pin, CEC_ERROR_INJ_RX_REMOVE_BYTE_OFFSET, -1, NULL);
}

static bool rx_arb_lost(struct cec_pin *pin, u8 *poll)
{
        return pin->tx_msg.len == 0 &&
                rx_error_inj(pin, CEC_ERROR_INJ_RX_ARB_LOST_OFFSET,
                             CEC_ERROR_INJ_RX_ARB_LOST_ARG_IDX, poll);
}

static bool tx_error_inj(struct cec_pin *pin, unsigned int mode_offset,
                         int arg_idx, u8 *arg)
{
#ifdef CONFIG_CEC_PIN_ERROR_INJ
        u16 cmd = cec_pin_tx_error_inj(pin);
        u64 e = pin->error_inj[cmd];
        unsigned int mode = (e >> mode_offset) & CEC_ERROR_INJ_MODE_MASK;

        if (arg_idx >= 0) {
                u8 pos = pin->error_inj_args[cmd][arg_idx];

                if (arg)
                        *arg = pos;
                else if (pos != pin->tx_bit)
                        return false;
        }

        switch (mode) {
        case CEC_ERROR_INJ_MODE_ONCE:
                pin->error_inj[cmd] &=
                        ~(CEC_ERROR_INJ_MODE_MASK << mode_offset);
                return true;
        case CEC_ERROR_INJ_MODE_ALWAYS:
                return true;
        case CEC_ERROR_INJ_MODE_TOGGLE:
                return pin->tx_toggle;
        default:
                return false;
        }
#else
        return false;
#endif
}

static bool tx_no_eom(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_NO_EOM_OFFSET, -1, NULL);
}

static bool tx_early_eom(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_EARLY_EOM_OFFSET, -1, NULL);
}

static bool tx_short_bit(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_BIT_OFFSET,
                            CEC_ERROR_INJ_TX_SHORT_BIT_ARG_IDX, NULL);
}

static bool tx_long_bit(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_BIT_OFFSET,
                            CEC_ERROR_INJ_TX_LONG_BIT_ARG_IDX, NULL);
}

static bool tx_custom_bit(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_BIT_OFFSET,
                            CEC_ERROR_INJ_TX_CUSTOM_BIT_ARG_IDX, NULL);
}

static bool tx_short_start(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_SHORT_START_OFFSET, -1, NULL);
}

static bool tx_long_start(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LONG_START_OFFSET, -1, NULL);
}

static bool tx_custom_start(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_CUSTOM_START_OFFSET,
                            -1, NULL);
}

static bool tx_last_bit(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LAST_BIT_OFFSET,
                            CEC_ERROR_INJ_TX_LAST_BIT_ARG_IDX, NULL);
}

static u8 tx_add_bytes(struct cec_pin *pin)
{
        u8 bytes;

        if (tx_error_inj(pin, CEC_ERROR_INJ_TX_ADD_BYTES_OFFSET,
                         CEC_ERROR_INJ_TX_ADD_BYTES_ARG_IDX, &bytes))
                return bytes;
        return 0;
}

static bool tx_remove_byte(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_REMOVE_BYTE_OFFSET, -1, NULL);
}

static bool tx_low_drive(struct cec_pin *pin)
{
        return tx_error_inj(pin, CEC_ERROR_INJ_TX_LOW_DRIVE_OFFSET,
                            CEC_ERROR_INJ_TX_LOW_DRIVE_ARG_IDX, NULL);
}

static void cec_pin_to_idle(struct cec_pin *pin)
{
        /*
         * Reset all status fields, release the bus and
         * go to idle state.
         */
        pin->rx_bit = pin->tx_bit = 0;
        pin->rx_msg.len = 0;
        memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
        pin->ts = ns_to_ktime(0);
        pin->tx_generated_poll = false;
        pin->tx_post_eom = false;
        if (pin->state >= CEC_ST_TX_WAIT &&
            pin->state <= CEC_ST_TX_LOW_DRIVE)
                pin->tx_toggle ^= 1;
        if (pin->state >= CEC_ST_RX_START_BIT_LOW &&
            pin->state <= CEC_ST_RX_LOW_DRIVE)
                pin->rx_toggle ^= 1;
        pin->state = CEC_ST_IDLE;
}

/*
 * Handle Transmit-related states
 *
 * Basic state changes when transmitting:
 *
 * Idle -> Tx Wait (waiting for the end of signal free time) ->
 *      Tx Start Bit Low -> Tx Start Bit High ->
 *
 *   Regular data bits + EOM:
 *      Tx Data 0 Low -> Tx Data 0 High ->
 *   or:
 *      Tx Data 1 Low -> Tx Data 1 High ->
 *
 *   First 4 data bits or Ack bit:
 *      Tx Data 0 Low -> Tx Data 0 High ->
 *   or:
 *      Tx Data 1 Low -> Tx Data 1 High -> Tx Data 1 Pre Sample ->
 *              Tx Data 1 Post Sample ->
 *
 *   After the last Ack go to Idle.
 *
 * If it detects a Low Drive condition then:
 *      Tx Wait For High -> Idle
 *
 * If it loses arbitration, then it switches to state Rx Data Post Sample.
 */
static void cec_pin_tx_states(struct cec_pin *pin, ktime_t ts)
{
        bool v;
        bool is_ack_bit, ack;

        switch (pin->state) {
        case CEC_ST_TX_WAIT_FOR_HIGH:
                if (cec_pin_read(pin))
                        cec_pin_to_idle(pin);
                break;

        case CEC_ST_TX_START_BIT_LOW:
                if (tx_short_start(pin)) {
                        /*
                         * Error Injection: send an invalid (too short)
                         * start pulse.
                         */
                        pin->state = CEC_ST_TX_START_BIT_HIGH_SHORT;
                } else if (tx_long_start(pin)) {
                        /*
                         * Error Injection: send an invalid (too long)
                         * start pulse.
                         */
                        pin->state = CEC_ST_TX_START_BIT_HIGH_LONG;
                } else {
                        pin->state = CEC_ST_TX_START_BIT_HIGH;
                }
                /* Generate start bit */
                cec_pin_high(pin);
                break;

        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
                pin->state = CEC_ST_TX_START_BIT_HIGH_CUSTOM;
                /* Generate start bit */
                cec_pin_high(pin);
                break;

        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
                if (pin->tx_nacked) {
                        cec_pin_to_idle(pin);
                        pin->tx_msg.len = 0;
                        if (pin->tx_generated_poll)
                                break;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_NACK;
                        wake_up_interruptible(&pin->kthread_waitq);
                        break;
                }
                fallthrough;
        case CEC_ST_TX_DATA_BIT_0_HIGH:
        case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
        case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
        case CEC_ST_TX_DATA_BIT_1_HIGH:
        case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
        case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
                /*
                 * If the read value is 1, then all is OK, otherwise we have a
                 * low drive condition.
                 *
                 * Special case: when we generate a poll message due to an
                 * Arbitration Lost error injection, then ignore this since
                 * the pin can actually be low in that case.
                 */
                if (!cec_pin_read(pin) && !pin->tx_generated_poll) {
                        /*
                         * It's 0, so someone detected an error and pulled the
                         * line low for 1.5 times the nominal bit period.
                         */
                        pin->tx_msg.len = 0;
                        pin->state = CEC_ST_TX_WAIT_FOR_HIGH;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
                        pin->tx_low_drive_cnt++;
                        wake_up_interruptible(&pin->kthread_waitq);
                        break;
                }
                fallthrough;
        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
                if (tx_last_bit(pin)) {
                        /* Error Injection: just stop sending after this bit */
                        cec_pin_to_idle(pin);
                        pin->tx_msg.len = 0;
                        if (pin->tx_generated_poll)
                                break;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_OK;
                        wake_up_interruptible(&pin->kthread_waitq);
                        break;
                }
                pin->tx_bit++;
                fallthrough;
        case CEC_ST_TX_START_BIT_HIGH:
        case CEC_ST_TX_START_BIT_HIGH_SHORT:
        case CEC_ST_TX_START_BIT_HIGH_LONG:
        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
                if (tx_low_drive(pin)) {
                        /* Error injection: go to low drive */
                        cec_pin_low(pin);
                        pin->state = CEC_ST_TX_LOW_DRIVE;
                        pin->tx_msg.len = 0;
                        if (pin->tx_generated_poll)
                                break;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_LOW_DRIVE;
                        pin->tx_low_drive_cnt++;
                        wake_up_interruptible(&pin->kthread_waitq);
                        break;
                }
                if (pin->tx_bit / 10 >= pin->tx_msg.len + pin->tx_extra_bytes) {
                        cec_pin_to_idle(pin);
                        pin->tx_msg.len = 0;
                        if (pin->tx_generated_poll)
                                break;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_OK;
                        wake_up_interruptible(&pin->kthread_waitq);
                        break;
                }

                switch (pin->tx_bit % 10) {
                default: {
                        /*
                         * In the CEC_ERROR_INJ_TX_ADD_BYTES case we transmit
                         * extra bytes, so pin->tx_bit / 10 can become >= 16.
                         * Generate bit values for those extra bytes instead
                         * of reading them from the transmit buffer.
                         */
                        unsigned int idx = (pin->tx_bit / 10);
                        u8 val = idx;

                        if (idx < pin->tx_msg.len)
                                val = pin->tx_msg.msg[idx];
                        v = val & (1 << (7 - (pin->tx_bit % 10)));

                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
                                         CEC_ST_TX_DATA_BIT_0_LOW;
                        break;
                }
                case EOM_BIT: {
                        unsigned int tot_len = pin->tx_msg.len +
                                               pin->tx_extra_bytes;
                        unsigned int tx_byte_idx = pin->tx_bit / 10;

                        v = !pin->tx_post_eom && tx_byte_idx == tot_len - 1;
                        if (tot_len > 1 && tx_byte_idx == tot_len - 2 &&
                            tx_early_eom(pin)) {
                                /* Error injection: set EOM one byte early */
                                v = true;
                                pin->tx_post_eom = true;
                        } else if (v && tx_no_eom(pin)) {
                                /* Error injection: no EOM */
                                v = false;
                        }
                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_LOW :
                                         CEC_ST_TX_DATA_BIT_0_LOW;
                        break;
                }
                case ACK_BIT:
                        pin->state = CEC_ST_TX_DATA_BIT_1_LOW;
                        break;
                }
                if (tx_custom_bit(pin))
                        pin->state = CEC_ST_TX_DATA_BIT_LOW_CUSTOM;
                cec_pin_low(pin);
                break;

        case CEC_ST_TX_DATA_BIT_0_LOW:
        case CEC_ST_TX_DATA_BIT_1_LOW:
                v = pin->state == CEC_ST_TX_DATA_BIT_1_LOW;
                is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
                if (v && (pin->tx_bit < 4 || is_ack_bit)) {
                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE;
                } else if (!is_ack_bit && tx_short_bit(pin)) {
                        /* Error Injection: send an invalid (too short) bit */
                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_SHORT :
                                         CEC_ST_TX_DATA_BIT_0_HIGH_SHORT;
                } else if (!is_ack_bit && tx_long_bit(pin)) {
                        /* Error Injection: send an invalid (too long) bit */
                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH_LONG :
                                         CEC_ST_TX_DATA_BIT_0_HIGH_LONG;
                } else {
                        pin->state = v ? CEC_ST_TX_DATA_BIT_1_HIGH :
                                         CEC_ST_TX_DATA_BIT_0_HIGH;
                }
                cec_pin_high(pin);
                break;

        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
                pin->state = CEC_ST_TX_DATA_BIT_HIGH_CUSTOM;
                cec_pin_high(pin);
                break;

        case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
                /* Read the CEC value at the sample time */
                v = cec_pin_read(pin);
                is_ack_bit = pin->tx_bit % 10 == ACK_BIT;
                /*
                 * If v == 0 and we're within the first 4 bits
                 * of the initiator, then someone else started
                 * transmitting and we lost the arbitration
                 * (i.e. the logical address of the other
                 * transmitter has more leading 0 bits in the
                 * initiator).
                 */
                if (!v && !is_ack_bit && !pin->tx_generated_poll) {
                        pin->tx_msg.len = 0;
                        pin->work_tx_ts = ts;
                        pin->work_tx_status = CEC_TX_STATUS_ARB_LOST;
                        wake_up_interruptible(&pin->kthread_waitq);
                        pin->rx_bit = pin->tx_bit;
                        pin->tx_bit = 0;
                        memset(pin->rx_msg.msg, 0, sizeof(pin->rx_msg.msg));
                        pin->rx_msg.msg[0] = pin->tx_msg.msg[0];
                        pin->rx_msg.msg[0] &= (0xff << (8 - pin->rx_bit));
                        pin->rx_msg.len = 0;
                        pin->ts = ktime_sub_us(ts, CEC_TIM_DATA_BIT_SAMPLE);
                        pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
                        pin->rx_bit++;
                        break;
                }
                pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE;
                if (!is_ack_bit && tx_short_bit(pin)) {
                        /* Error Injection: send an invalid (too short) bit */
                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT;
                } else if (!is_ack_bit && tx_long_bit(pin)) {
                        /* Error Injection: send an invalid (too long) bit */
                        pin->state = CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG;
                }
                if (!is_ack_bit)
                        break;
                /* Was the message ACKed? */
                ack = cec_msg_is_broadcast(&pin->tx_msg) ? v : !v;
                if (!ack && (!pin->tx_ignore_nack_until_eom ||
                    pin->tx_bit / 10 == pin->tx_msg.len - 1) &&
                    !pin->tx_post_eom) {
                        /*
                         * Note: the CEC spec is ambiguous regarding
                         * what action to take when a NACK appears
                         * before the last byte of the payload was
                         * transmitted: either stop transmitting
                         * immediately, or wait until the last byte
                         * was transmitted.
                         *
                         * Most CEC implementations appear to stop
                         * immediately, and that's what we do here
                         * as well.
                         */
                        pin->tx_nacked = true;
                }
                break;

        case CEC_ST_TX_PULSE_LOW_CUSTOM:
                cec_pin_high(pin);
                pin->state = CEC_ST_TX_PULSE_HIGH_CUSTOM;
                break;

        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
                cec_pin_to_idle(pin);
                break;

        default:
                break;
        }
}

/*
 * Handle Receive-related states
 *
 * Basic state changes when receiving:
 *
 *      Rx Start Bit Low -> Rx Start Bit High ->
 *   Regular data bits + EOM:
 *      Rx Data Sample -> Rx Data Post Sample -> Rx Data High ->
 *   Ack bit 0:
 *      Rx Ack Low -> Rx Ack Low Post -> Rx Data High ->
 *   Ack bit 1:
 *      Rx Ack High Post -> Rx Data High ->
 *   Ack bit 0 && EOM:
 *      Rx Ack Low -> Rx Ack Low Post -> Rx Ack Finish -> Idle
 */
static void cec_pin_rx_states(struct cec_pin *pin, ktime_t ts)
{
        s32 delta;
        bool v;
        bool ack;
        bool bcast, for_us;
        u8 dest;
        u8 poll;

        switch (pin->state) {
        /* Receive states */
        case CEC_ST_RX_START_BIT_LOW:
                v = cec_pin_read(pin);
                if (!v)
                        break;
                pin->state = CEC_ST_RX_START_BIT_HIGH;
                delta = ktime_us_delta(ts, pin->ts);
                /* Start bit low is too short, go back to idle */
                if (delta < CEC_TIM_START_BIT_LOW_MIN - CEC_TIM_IDLE_SAMPLE) {
                        if (!pin->rx_start_bit_low_too_short_cnt++) {
                                pin->rx_start_bit_low_too_short_ts = ktime_to_ns(pin->ts);
                                pin->rx_start_bit_low_too_short_delta = delta;
                        }
                        cec_pin_to_idle(pin);
                        break;
                }
                if (rx_arb_lost(pin, &poll)) {
                        cec_msg_init(&pin->tx_msg, poll >> 4, poll & 0xf);
                        pin->tx_generated_poll = true;
                        pin->tx_extra_bytes = 0;
                        pin->state = CEC_ST_TX_START_BIT_HIGH;
                        pin->ts = ts;
                }
                break;

        case CEC_ST_RX_START_BIT_HIGH:
                v = cec_pin_read(pin);
                delta = ktime_us_delta(ts, pin->ts);
                /*
                 * Unfortunately the spec does not specify when to give up
                 * and go to idle. We just pick TOTAL_LONG.
                 */
                if (v && delta > CEC_TIM_START_BIT_TOTAL_LONG) {
                        pin->rx_start_bit_too_long_cnt++;
                        cec_pin_to_idle(pin);
                        break;
                }
                if (v)
                        break;
                /* Start bit is too short, go back to idle */
                if (delta < CEC_TIM_START_BIT_TOTAL_MIN - CEC_TIM_IDLE_SAMPLE) {
                        if (!pin->rx_start_bit_too_short_cnt++) {
                                pin->rx_start_bit_too_short_ts = ktime_to_ns(pin->ts);
                                pin->rx_start_bit_too_short_delta = delta;
                        }
                        cec_pin_to_idle(pin);
                        break;
                }
                if (rx_low_drive(pin)) {
                        /* Error injection: go to low drive */
                        cec_pin_low(pin);
                        pin->state = CEC_ST_RX_LOW_DRIVE;
                        pin->rx_low_drive_cnt++;
                        break;
                }
                pin->state = CEC_ST_RX_DATA_SAMPLE;
                pin->ts = ts;
                pin->rx_eom = false;
                break;

        case CEC_ST_RX_DATA_SAMPLE:
                v = cec_pin_read(pin);
                pin->state = CEC_ST_RX_DATA_POST_SAMPLE;
                switch (pin->rx_bit % 10) {
                default:
                        if (pin->rx_bit / 10 < CEC_MAX_MSG_SIZE)
                                pin->rx_msg.msg[pin->rx_bit / 10] |=
                                        v << (7 - (pin->rx_bit % 10));
                        break;
                case EOM_BIT:
                        pin->rx_eom = v;
                        pin->rx_msg.len = pin->rx_bit / 10 + 1;
                        break;
                case ACK_BIT:
                        break;
                }
                pin->rx_bit++;
                break;

        case CEC_ST_RX_DATA_POST_SAMPLE:
                pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
                break;

        case CEC_ST_RX_DATA_WAIT_FOR_LOW:
                v = cec_pin_read(pin);
                delta = ktime_us_delta(ts, pin->ts);
                /*
                 * Unfortunately the spec does not specify when to give up
                 * and go to idle. We just pick TOTAL_LONG.
                 */
                if (v && delta > CEC_TIM_DATA_BIT_TOTAL_LONG) {
                        pin->rx_data_bit_too_long_cnt++;
                        cec_pin_to_idle(pin);
                        break;
                }
                if (v)
                        break;

                if (rx_low_drive(pin)) {
                        /* Error injection: go to low drive */
                        cec_pin_low(pin);
                        pin->state = CEC_ST_RX_LOW_DRIVE;
                        pin->rx_low_drive_cnt++;
                        break;
                }

                /*
                 * Go to low drive state when the total bit time is
                 * too short.
                 */
                if (delta < CEC_TIM_DATA_BIT_TOTAL_MIN && !pin->rx_no_low_drive) {
                        if (!pin->rx_data_bit_too_short_cnt++) {
                                pin->rx_data_bit_too_short_ts = ktime_to_ns(pin->ts);
                                pin->rx_data_bit_too_short_delta = delta;
                        }
                        cec_pin_low(pin);
                        pin->state = CEC_ST_RX_LOW_DRIVE;
                        pin->rx_low_drive_cnt++;
                        break;
                }
                pin->ts = ts;
                if (pin->rx_bit % 10 != 9) {
                        pin->state = CEC_ST_RX_DATA_SAMPLE;
                        break;
                }

                dest = cec_msg_destination(&pin->rx_msg);
                bcast = dest == CEC_LOG_ADDR_BROADCAST;
                /* for_us == broadcast or directed to us */
                for_us = bcast || (pin->la_mask & (1 << dest));
                /* ACK bit value */
                ack = bcast ? 1 : !for_us;

                if (for_us && rx_nack(pin)) {
                        /* Error injection: toggle the ACK bit */
                        ack = !ack;
                }

                if (ack) {
                        /* No need to write to the bus, just wait */
                        pin->state = CEC_ST_RX_ACK_HIGH_POST;
                        break;
                }
                cec_pin_low(pin);
                pin->state = CEC_ST_RX_ACK_LOW;
                break;

        case CEC_ST_RX_ACK_LOW:
                cec_pin_high(pin);
                pin->state = CEC_ST_RX_ACK_LOW_POST;
                break;

        case CEC_ST_RX_ACK_LOW_POST:
        case CEC_ST_RX_ACK_HIGH_POST:
                v = cec_pin_read(pin);
                if (v && pin->rx_eom) {
                        pin->work_rx_msg = pin->rx_msg;
                        pin->work_rx_msg.rx_ts = ktime_to_ns(ts);
                        wake_up_interruptible(&pin->kthread_waitq);
                        pin->ts = ts;
                        pin->state = CEC_ST_RX_ACK_FINISH;
                        break;
                }
                pin->rx_bit++;
                pin->state = CEC_ST_RX_DATA_WAIT_FOR_LOW;
                break;

        case CEC_ST_RX_ACK_FINISH:
                cec_pin_to_idle(pin);
                break;

        default:
                break;
        }
}

/*
 * Main timer function
 *
 */
static enum hrtimer_restart cec_pin_timer(struct hrtimer *timer)
{
        struct cec_pin *pin = container_of(timer, struct cec_pin, timer);
        struct cec_adapter *adap = pin->adap;
        ktime_t ts;
        s32 delta;
        u32 usecs;

        ts = ktime_get();
        if (ktime_to_ns(pin->timer_ts)) {
                delta = ktime_us_delta(ts, pin->timer_ts);
                pin->timer_cnt++;
                if (delta > 100 && pin->state != CEC_ST_IDLE) {
                        /* Keep track of timer overruns */
                        pin->timer_sum_overrun += delta;
                        pin->timer_100us_overruns++;
                        if (delta > 300)
                                pin->timer_300us_overruns++;
                        if (delta > pin->timer_max_overrun)
                                pin->timer_max_overrun = delta;
                }
        }
        if (adap->monitor_pin_cnt)
                cec_pin_read(pin);

        if (pin->wait_usecs) {
                /*
                 * If we are monitoring the pin, then we have to
                 * sample at regular intervals.
                 */
                if (pin->wait_usecs > 150) {
                        pin->wait_usecs -= 100;
                        pin->timer_ts = ktime_add_us(ts, 100);
                        hrtimer_forward_now(timer, us_to_ktime(100));
                        return HRTIMER_RESTART;
                }
                if (pin->wait_usecs > 100) {
                        pin->wait_usecs /= 2;
                        pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
                        hrtimer_forward_now(timer,
                                        us_to_ktime(pin->wait_usecs));
                        return HRTIMER_RESTART;
                }
                pin->timer_ts = ktime_add_us(ts, pin->wait_usecs);
                hrtimer_forward_now(timer,
                                    us_to_ktime(pin->wait_usecs));
                pin->wait_usecs = 0;
                return HRTIMER_RESTART;
        }

        switch (pin->state) {
        /* Transmit states */
        case CEC_ST_TX_WAIT_FOR_HIGH:
        case CEC_ST_TX_START_BIT_LOW:
        case CEC_ST_TX_START_BIT_HIGH:
        case CEC_ST_TX_START_BIT_HIGH_SHORT:
        case CEC_ST_TX_START_BIT_HIGH_LONG:
        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
        case CEC_ST_TX_DATA_BIT_0_LOW:
        case CEC_ST_TX_DATA_BIT_0_HIGH:
        case CEC_ST_TX_DATA_BIT_0_HIGH_SHORT:
        case CEC_ST_TX_DATA_BIT_0_HIGH_LONG:
        case CEC_ST_TX_DATA_BIT_1_LOW:
        case CEC_ST_TX_DATA_BIT_1_HIGH:
        case CEC_ST_TX_DATA_BIT_1_HIGH_SHORT:
        case CEC_ST_TX_DATA_BIT_1_HIGH_LONG:
        case CEC_ST_TX_DATA_BIT_1_HIGH_PRE_SAMPLE:
        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE:
        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_SHORT:
        case CEC_ST_TX_DATA_BIT_1_HIGH_POST_SAMPLE_LONG:
        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
        case CEC_ST_TX_PULSE_LOW_CUSTOM:
        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
                cec_pin_tx_states(pin, ts);
                break;

        /* Receive states */
        case CEC_ST_RX_START_BIT_LOW:
        case CEC_ST_RX_START_BIT_HIGH:
        case CEC_ST_RX_DATA_SAMPLE:
        case CEC_ST_RX_DATA_POST_SAMPLE:
        case CEC_ST_RX_DATA_WAIT_FOR_LOW:
        case CEC_ST_RX_ACK_LOW:
        case CEC_ST_RX_ACK_LOW_POST:
        case CEC_ST_RX_ACK_HIGH_POST:
        case CEC_ST_RX_ACK_FINISH:
                cec_pin_rx_states(pin, ts);
                break;

        case CEC_ST_IDLE:
        case CEC_ST_TX_WAIT:
                if (!cec_pin_high(pin)) {
                        /* Start bit, switch to receive state */
                        pin->ts = ts;
                        pin->state = CEC_ST_RX_START_BIT_LOW;
                        /*
                         * If a transmit is pending, then that transmit should
                         * use a signal free time of no more than
                         * CEC_SIGNAL_FREE_TIME_NEW_INITIATOR since it will
                         * have a new initiator due to the receive that is now
                         * starting.
                         */
                        if (pin->tx_msg.len && pin->tx_signal_free_time >
                            CEC_SIGNAL_FREE_TIME_NEW_INITIATOR)
                                pin->tx_signal_free_time =
                                        CEC_SIGNAL_FREE_TIME_NEW_INITIATOR;
                        break;
                }
                if (ktime_to_ns(pin->ts) == 0)
                        pin->ts = ts;
                if (pin->tx_msg.len) {
                        /*
                         * Check if the bus has been free for long enough
                         * so we can kick off the pending transmit.
                         */
                        delta = ktime_us_delta(ts, pin->ts);
                        if (delta / CEC_TIM_DATA_BIT_TOTAL >=
                            pin->tx_signal_free_time) {
                                pin->tx_nacked = false;
                                if (tx_custom_start(pin))
                                        pin->state = CEC_ST_TX_START_BIT_LOW_CUSTOM;
                                else
                                        pin->state = CEC_ST_TX_START_BIT_LOW;
                                /* Generate start bit */
                                cec_pin_low(pin);
                                break;
                        }
                        if (delta / CEC_TIM_DATA_BIT_TOTAL >=
                            pin->tx_signal_free_time - 1)
                                pin->state = CEC_ST_TX_WAIT;
                        break;
                }
                if (pin->tx_custom_pulse && pin->state == CEC_ST_IDLE) {
                        pin->tx_custom_pulse = false;
                        /* Generate custom pulse */
                        cec_pin_low(pin);
                        pin->state = CEC_ST_TX_PULSE_LOW_CUSTOM;
                        break;
                }
                if (pin->state != CEC_ST_IDLE || pin->ops->enable_irq == NULL ||
                    pin->enable_irq_failed || adap->is_configuring ||
                    adap->is_configured || adap->monitor_all_cnt || !adap->monitor_pin_cnt)
                        break;
                /* Switch to interrupt mode */
                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_ENABLE);
                pin->state = CEC_ST_RX_IRQ;
                wake_up_interruptible(&pin->kthread_waitq);
                return HRTIMER_NORESTART;

        case CEC_ST_TX_LOW_DRIVE:
        case CEC_ST_RX_LOW_DRIVE:
                cec_pin_high(pin);
                cec_pin_to_idle(pin);
                break;

        default:
                break;
        }

        switch (pin->state) {
        case CEC_ST_TX_START_BIT_LOW_CUSTOM:
        case CEC_ST_TX_DATA_BIT_LOW_CUSTOM:
        case CEC_ST_TX_PULSE_LOW_CUSTOM:
                usecs = pin->tx_custom_low_usecs;
                break;
        case CEC_ST_TX_START_BIT_HIGH_CUSTOM:
        case CEC_ST_TX_DATA_BIT_HIGH_CUSTOM:
        case CEC_ST_TX_PULSE_HIGH_CUSTOM:
                usecs = pin->tx_custom_high_usecs;
                break;
        default:
                usecs = states[pin->state].usecs;
                break;
        }

        if (!adap->monitor_pin_cnt || usecs <= 150) {
                pin->wait_usecs = 0;
                pin->timer_ts = ktime_add_us(ts, usecs);
                hrtimer_forward_now(timer, us_to_ktime(usecs));
                return HRTIMER_RESTART;
        }
        pin->wait_usecs = usecs - 100;
        pin->timer_ts = ktime_add_us(ts, 100);
        hrtimer_forward_now(timer, us_to_ktime(100));
        return HRTIMER_RESTART;
}

static int cec_pin_thread_func(void *_adap)
{
        struct cec_adapter *adap = _adap;
        struct cec_pin *pin = adap->pin;

        pin->enabled_irq = false;
        pin->enable_irq_failed = false;
        for (;;) {
                wait_event_interruptible(pin->kthread_waitq,
                                         kthread_should_stop() ||
                                         pin->work_rx_msg.len ||
                                         pin->work_tx_status ||
                                         atomic_read(&pin->work_irq_change) ||
                                         atomic_read(&pin->work_pin_num_events));

                if (kthread_should_stop())
                        break;

                if (pin->work_rx_msg.len) {
                        struct cec_msg *msg = &pin->work_rx_msg;

                        if (msg->len > 1 && msg->len < CEC_MAX_MSG_SIZE &&
                            rx_add_byte(pin)) {
                                /* Error injection: add byte to the message */
                                msg->msg[msg->len++] = 0x55;
                        }
                        if (msg->len > 2 && rx_remove_byte(pin)) {
                                /* Error injection: remove byte from message */
                                msg->len--;
                        }
                        if (msg->len > CEC_MAX_MSG_SIZE)
                                msg->len = CEC_MAX_MSG_SIZE;
                        cec_received_msg_ts(adap, msg,
                                ns_to_ktime(pin->work_rx_msg.rx_ts));
                        msg->len = 0;
                }

                if (pin->work_tx_status) {
                        unsigned int tx_status = pin->work_tx_status;

                        pin->work_tx_status = 0;
                        cec_transmit_attempt_done_ts(adap, tx_status,
                                                     pin->work_tx_ts);
                }

                while (atomic_read(&pin->work_pin_num_events)) {
                        unsigned int idx = pin->work_pin_events_rd;
                        u8 v = pin->work_pin_events[idx];

                        cec_queue_pin_cec_event(adap,
                                                v & CEC_PIN_EVENT_FL_IS_HIGH,
                                                v & CEC_PIN_EVENT_FL_DROPPED,
                                                pin->work_pin_ts[idx]);
                        pin->work_pin_events_rd = (idx + 1) % CEC_NUM_PIN_EVENTS;
                        atomic_dec(&pin->work_pin_num_events);
                }

                switch (atomic_xchg(&pin->work_irq_change,
                                    CEC_PIN_IRQ_UNCHANGED)) {
                case CEC_PIN_IRQ_DISABLE:
                        if (pin->enabled_irq) {
                                pin->ops->disable_irq(adap);
                                pin->enabled_irq = false;
                                pin->enable_irq_failed = false;
                        }
                        cec_pin_high(pin);
                        if (pin->state == CEC_ST_OFF)
                                break;
                        cec_pin_to_idle(pin);
                        hrtimer_start(&pin->timer, ns_to_ktime(0),
                                      HRTIMER_MODE_REL);
                        break;
                case CEC_PIN_IRQ_ENABLE:
                        if (pin->enabled_irq || !pin->ops->enable_irq ||
                            pin->adap->devnode.unregistered)
                                break;
                        pin->enable_irq_failed = !pin->ops->enable_irq(adap);
                        if (pin->enable_irq_failed) {
                                cec_pin_to_idle(pin);
                                hrtimer_start(&pin->timer, ns_to_ktime(0),
                                              HRTIMER_MODE_REL);
                        } else {
                                pin->enabled_irq = true;
                        }
                        break;
                default:
                        break;
                }
        }

        if (pin->enabled_irq) {
                pin->ops->disable_irq(pin->adap);
                pin->enabled_irq = false;
                pin->enable_irq_failed = false;
                cec_pin_high(pin);
        }
        return 0;
}

static int cec_pin_adap_enable(struct cec_adapter *adap, bool enable)
{
        struct cec_pin *pin = adap->pin;

        if (enable) {
                cec_pin_read(pin);
                cec_pin_to_idle(pin);
                pin->tx_msg.len = 0;
                pin->timer_ts = ns_to_ktime(0);
                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_UNCHANGED);
                if (!pin->kthread) {
                        pin->kthread = kthread_run(cec_pin_thread_func, adap,
                                                   "cec-pin");
                        if (IS_ERR(pin->kthread)) {
                                int err = PTR_ERR(pin->kthread);

                                pr_err("cec-pin: kernel_thread() failed\n");
                                pin->kthread = NULL;
                                return err;
                        }
                }
                hrtimer_start(&pin->timer, ns_to_ktime(0),
                              HRTIMER_MODE_REL);
        } else if (pin->kthread) {
                hrtimer_cancel(&pin->timer);
                cec_pin_high(pin);
                cec_pin_to_idle(pin);
                pin->state = CEC_ST_OFF;
                pin->work_tx_status = 0;
                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_DISABLE);
                wake_up_interruptible(&pin->kthread_waitq);
        }
        return 0;
}

static int cec_pin_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
{
        struct cec_pin *pin = adap->pin;

        if (log_addr == CEC_LOG_ADDR_INVALID)
                pin->la_mask = 0;
        else
                pin->la_mask |= (1 << log_addr);
        return 0;
}

void cec_pin_start_timer(struct cec_pin *pin)
{
        if (pin->state != CEC_ST_RX_IRQ)
                return;

        atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_DISABLE);
        wake_up_interruptible(&pin->kthread_waitq);
}

static int cec_pin_adap_transmit(struct cec_adapter *adap, u8 attempts,
                                      u32 signal_free_time, struct cec_msg *msg)
{
        struct cec_pin *pin = adap->pin;

        /*
         * If a receive is in progress, then this transmit should use
         * a signal free time of max CEC_SIGNAL_FREE_TIME_NEW_INITIATOR
         * since when it starts transmitting it will have a new initiator.
         */
        if (pin->state != CEC_ST_IDLE &&
            signal_free_time > CEC_SIGNAL_FREE_TIME_NEW_INITIATOR)
                signal_free_time = CEC_SIGNAL_FREE_TIME_NEW_INITIATOR;

        pin->tx_signal_free_time = signal_free_time;
        pin->tx_extra_bytes = 0;
        pin->tx_msg = *msg;
        if (msg->len > 1) {
                /* Error injection: add byte to the message */
                pin->tx_extra_bytes = tx_add_bytes(pin);
        }
        if (msg->len > 2 && tx_remove_byte(pin)) {
                /* Error injection: remove byte from the message */
                pin->tx_msg.len--;
        }
        pin->work_tx_status = 0;
        pin->tx_bit = 0;
        cec_pin_start_timer(pin);
        return 0;
}

static void cec_pin_adap_status(struct cec_adapter *adap,
                                       struct seq_file *file)
{
        struct cec_pin *pin = adap->pin;

        seq_printf(file, "state: %s\n", states[pin->state].name);
        seq_printf(file, "tx_bit: %d\n", pin->tx_bit);
        seq_printf(file, "rx_bit: %d\n", pin->rx_bit);
        seq_printf(file, "cec pin: %d\n", call_pin_op(pin, read));
        seq_printf(file, "cec pin events dropped: %u\n",
                   pin->work_pin_events_dropped_cnt);
        if (pin->ops->enable_irq)
                seq_printf(file, "irq %s\n", pin->enabled_irq ? "enabled" :
                           (pin->enable_irq_failed ? "failed" : "disabled"));
        if (pin->timer_100us_overruns) {
                seq_printf(file, "timer overruns > 100us: %u of %u\n",
                           pin->timer_100us_overruns, pin->timer_cnt);
                seq_printf(file, "timer overruns > 300us: %u of %u\n",
                           pin->timer_300us_overruns, pin->timer_cnt);
                seq_printf(file, "max timer overrun: %u usecs\n",
                           pin->timer_max_overrun);
                seq_printf(file, "avg timer overrun: %u usecs\n",
                           pin->timer_sum_overrun / pin->timer_100us_overruns);
        }
        if (pin->rx_start_bit_low_too_short_cnt)
                seq_printf(file,
                           "rx start bit low too short: %u (delta %u, ts %llu)\n",
                           pin->rx_start_bit_low_too_short_cnt,
                           pin->rx_start_bit_low_too_short_delta,
                           pin->rx_start_bit_low_too_short_ts);
        if (pin->rx_start_bit_too_short_cnt)
                seq_printf(file,
                           "rx start bit too short: %u (delta %u, ts %llu)\n",
                           pin->rx_start_bit_too_short_cnt,
                           pin->rx_start_bit_too_short_delta,
                           pin->rx_start_bit_too_short_ts);
        if (pin->rx_start_bit_too_long_cnt)
                seq_printf(file, "rx start bit too long: %u\n",
                           pin->rx_start_bit_too_long_cnt);
        if (pin->rx_data_bit_too_short_cnt)
                seq_printf(file,
                           "rx data bit too short: %u (delta %u, ts %llu)\n",
                           pin->rx_data_bit_too_short_cnt,
                           pin->rx_data_bit_too_short_delta,
                           pin->rx_data_bit_too_short_ts);
        if (pin->rx_data_bit_too_long_cnt)
                seq_printf(file, "rx data bit too long: %u\n",
                           pin->rx_data_bit_too_long_cnt);
        seq_printf(file, "rx initiated low drive: %u\n", pin->rx_low_drive_cnt);
        seq_printf(file, "tx detected low drive: %u\n", pin->tx_low_drive_cnt);
        pin->work_pin_events_dropped_cnt = 0;
        pin->timer_cnt = 0;
        pin->timer_100us_overruns = 0;
        pin->timer_300us_overruns = 0;
        pin->timer_max_overrun = 0;
        pin->timer_sum_overrun = 0;
        pin->rx_start_bit_low_too_short_cnt = 0;
        pin->rx_start_bit_too_short_cnt = 0;
        pin->rx_start_bit_too_long_cnt = 0;
        pin->rx_data_bit_too_short_cnt = 0;
        pin->rx_data_bit_too_long_cnt = 0;
        pin->rx_low_drive_cnt = 0;
        pin->tx_low_drive_cnt = 0;
        call_void_pin_op(pin, status, file);
}

static int cec_pin_adap_monitor_all_enable(struct cec_adapter *adap,
                                                  bool enable)
{
        struct cec_pin *pin = adap->pin;

        pin->monitor_all = enable;
        return 0;
}

static void cec_pin_adap_free(struct cec_adapter *adap)
{
        struct cec_pin *pin = adap->pin;

        if (pin->kthread)
                kthread_stop(pin->kthread);
        pin->kthread = NULL;
        if (pin->ops->free)
                pin->ops->free(adap);
        adap->pin = NULL;
        kfree(pin);
}

static int cec_pin_received(struct cec_adapter *adap, struct cec_msg *msg)
{
        struct cec_pin *pin = adap->pin;

        if (pin->ops->received && !adap->devnode.unregistered)
                return pin->ops->received(adap, msg);
        return -ENOMSG;
}

void cec_pin_changed(struct cec_adapter *adap, bool value)
{
        struct cec_pin *pin = adap->pin;

        cec_pin_update(pin, value, false);
        if (!value && (adap->is_configuring || adap->is_configured ||
                       adap->monitor_all_cnt || !adap->monitor_pin_cnt))
                atomic_set(&pin->work_irq_change, CEC_PIN_IRQ_DISABLE);
}
EXPORT_SYMBOL_GPL(cec_pin_changed);

static const struct cec_adap_ops cec_pin_adap_ops = {
        .adap_enable = cec_pin_adap_enable,
        .adap_monitor_all_enable = cec_pin_adap_monitor_all_enable,
        .adap_log_addr = cec_pin_adap_log_addr,
        .adap_transmit = cec_pin_adap_transmit,
        .adap_status = cec_pin_adap_status,
        .adap_free = cec_pin_adap_free,
#ifdef CONFIG_CEC_PIN_ERROR_INJ
        .error_inj_parse_line = cec_pin_error_inj_parse_line,
        .error_inj_show = cec_pin_error_inj_show,
#endif
        .received = cec_pin_received,
};

struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
                                        void *priv, const char *name, u32 caps)
{
        struct cec_adapter *adap;
        struct cec_pin *pin = kzalloc_obj(*pin);

        if (pin == NULL)
                return ERR_PTR(-ENOMEM);
        pin->ops = pin_ops;
        atomic_set(&pin->work_pin_num_events, 0);
        hrtimer_setup(&pin->timer, cec_pin_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        init_waitqueue_head(&pin->kthread_waitq);
        pin->tx_custom_low_usecs = CEC_TIM_CUSTOM_DEFAULT;
        pin->tx_custom_high_usecs = CEC_TIM_CUSTOM_DEFAULT;
        pin->tx_glitch_low_usecs = CEC_TIM_GLITCH_DEFAULT;
        pin->tx_glitch_high_usecs = CEC_TIM_GLITCH_DEFAULT;

        adap = cec_allocate_adapter(&cec_pin_adap_ops, priv, name,
                            caps | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN,
                            CEC_MAX_LOG_ADDRS);

        if (IS_ERR(adap)) {
                kfree(pin);
                return adap;
        }

        adap->pin = pin;
        pin->adap = adap;
        cec_pin_update(pin, cec_pin_high(pin), true);
        return adap;
}
EXPORT_SYMBOL_GPL(cec_pin_allocate_adapter);