// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Feature Integration Technology Inc. (aka Fintek) LPC CIR
 *
 * Copyright (C) 2011 Jarod Wilson <jarod@redhat.com>
 *
 * Special thanks to Fintek for providing hardware and spec sheets.
 * This driver is based upon the nuvoton, ite and ene drivers for
 * similar hardware.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pnp.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <media/rc-core.h>

#include "fintek-cir.h"

/* write val to config reg */
static inline void fintek_cr_write(struct fintek_dev *fintek, u8 val, u8 reg)
{
        fit_dbg("%s: reg 0x%02x, val 0x%02x  (ip/dp: %02x/%02x)",
                __func__, reg, val, fintek->cr_ip, fintek->cr_dp);
        outb(reg, fintek->cr_ip);
        outb(val, fintek->cr_dp);
}

/* read val from config reg */
static inline u8 fintek_cr_read(struct fintek_dev *fintek, u8 reg)
{
        u8 val;

        outb(reg, fintek->cr_ip);
        val = inb(fintek->cr_dp);

        fit_dbg("%s: reg 0x%02x, val 0x%02x  (ip/dp: %02x/%02x)",
                __func__, reg, val, fintek->cr_ip, fintek->cr_dp);
        return val;
}

/* update config register bit without changing other bits */
static inline void fintek_set_reg_bit(struct fintek_dev *fintek, u8 val, u8 reg)
{
        u8 tmp = fintek_cr_read(fintek, reg) | val;
        fintek_cr_write(fintek, tmp, reg);
}

/* enter config mode */
static inline void fintek_config_mode_enable(struct fintek_dev *fintek)
{
        /* Enabling Config Mode explicitly requires writing 2x */
        outb(CONFIG_REG_ENABLE, fintek->cr_ip);
        outb(CONFIG_REG_ENABLE, fintek->cr_ip);
}

/* exit config mode */
static inline void fintek_config_mode_disable(struct fintek_dev *fintek)
{
        outb(CONFIG_REG_DISABLE, fintek->cr_ip);
}

/*
 * When you want to address a specific logical device, write its logical
 * device number to GCR_LOGICAL_DEV_NO
 */
static inline void fintek_select_logical_dev(struct fintek_dev *fintek, u8 ldev)
{
        fintek_cr_write(fintek, ldev, GCR_LOGICAL_DEV_NO);
}

/* write val to cir config register */
static inline void fintek_cir_reg_write(struct fintek_dev *fintek, u8 val, u8 offset)
{
        outb(val, fintek->cir_addr + offset);
}

/* read val from cir config register */
static u8 fintek_cir_reg_read(struct fintek_dev *fintek, u8 offset)
{
        return inb(fintek->cir_addr + offset);
}

/* dump current cir register contents */
static void cir_dump_regs(struct fintek_dev *fintek)
{
        fintek_config_mode_enable(fintek);
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);

        pr_info("%s: Dump CIR logical device registers:\n", FINTEK_DRIVER_NAME);
        pr_info(" * CR CIR BASE ADDR: 0x%x\n",
                (fintek_cr_read(fintek, CIR_CR_BASE_ADDR_HI) << 8) |
                fintek_cr_read(fintek, CIR_CR_BASE_ADDR_LO));
        pr_info(" * CR CIR IRQ NUM:   0x%x\n",
                fintek_cr_read(fintek, CIR_CR_IRQ_SEL));

        fintek_config_mode_disable(fintek);

        pr_info("%s: Dump CIR registers:\n", FINTEK_DRIVER_NAME);
        pr_info(" * STATUS:     0x%x\n",
                fintek_cir_reg_read(fintek, CIR_STATUS));
        pr_info(" * CONTROL:    0x%x\n",
                fintek_cir_reg_read(fintek, CIR_CONTROL));
        pr_info(" * RX_DATA:    0x%x\n",
                fintek_cir_reg_read(fintek, CIR_RX_DATA));
        pr_info(" * TX_CONTROL: 0x%x\n",
                fintek_cir_reg_read(fintek, CIR_TX_CONTROL));
        pr_info(" * TX_DATA:    0x%x\n",
                fintek_cir_reg_read(fintek, CIR_TX_DATA));
}

/* detect hardware features */
static int fintek_hw_detect(struct fintek_dev *fintek)
{
        unsigned long flags;
        u8 chip_major, chip_minor;
        u8 vendor_major, vendor_minor;
        u8 portsel, ir_class;
        u16 vendor, chip;

        fintek_config_mode_enable(fintek);

        /* Check if we're using config port 0x4e or 0x2e */
        portsel = fintek_cr_read(fintek, GCR_CONFIG_PORT_SEL);
        if (portsel == 0xff) {
                fit_pr(KERN_INFO, "first portsel read was bunk, trying alt");
                fintek_config_mode_disable(fintek);
                fintek->cr_ip = CR_INDEX_PORT2;
                fintek->cr_dp = CR_DATA_PORT2;
                fintek_config_mode_enable(fintek);
                portsel = fintek_cr_read(fintek, GCR_CONFIG_PORT_SEL);
        }
        fit_dbg("portsel reg: 0x%02x", portsel);

        ir_class = fintek_cir_reg_read(fintek, CIR_CR_CLASS);
        fit_dbg("ir_class reg: 0x%02x", ir_class);

        switch (ir_class) {
        case CLASS_RX_2TX:
        case CLASS_RX_1TX:
                fintek->hw_tx_capable = true;
                break;
        case CLASS_RX_ONLY:
        default:
                fintek->hw_tx_capable = false;
                break;
        }

        chip_major = fintek_cr_read(fintek, GCR_CHIP_ID_HI);
        chip_minor = fintek_cr_read(fintek, GCR_CHIP_ID_LO);
        chip  = chip_major << 8 | chip_minor;

        vendor_major = fintek_cr_read(fintek, GCR_VENDOR_ID_HI);
        vendor_minor = fintek_cr_read(fintek, GCR_VENDOR_ID_LO);
        vendor = vendor_major << 8 | vendor_minor;

        if (vendor != VENDOR_ID_FINTEK)
                fit_pr(KERN_WARNING, "Unknown vendor ID: 0x%04x", vendor);
        else
                fit_dbg("Read Fintek vendor ID from chip");

        fintek_config_mode_disable(fintek);

        spin_lock_irqsave(&fintek->fintek_lock, flags);
        fintek->chip_major  = chip_major;
        fintek->chip_minor  = chip_minor;
        fintek->chip_vendor = vendor;

        /*
         * Newer reviews of this chipset uses port 8 instead of 5
         */
        if ((chip != 0x0408) && (chip != 0x0804))
                fintek->logical_dev_cir = LOGICAL_DEV_CIR_REV2;
        else
                fintek->logical_dev_cir = LOGICAL_DEV_CIR_REV1;

        spin_unlock_irqrestore(&fintek->fintek_lock, flags);

        return 0;
}

static void fintek_cir_ldev_init(struct fintek_dev *fintek)
{
        /* Select CIR logical device and enable */
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_cr_write(fintek, LOGICAL_DEV_ENABLE, CIR_CR_DEV_EN);

        /* Write allocated CIR address and IRQ information to hardware */
        fintek_cr_write(fintek, fintek->cir_addr >> 8, CIR_CR_BASE_ADDR_HI);
        fintek_cr_write(fintek, fintek->cir_addr & 0xff, CIR_CR_BASE_ADDR_LO);

        fintek_cr_write(fintek, fintek->cir_irq, CIR_CR_IRQ_SEL);

        fit_dbg("CIR initialized, base io address: 0x%lx, irq: %d (len: %d)",
                fintek->cir_addr, fintek->cir_irq, fintek->cir_port_len);
}

/* enable CIR interrupts */
static void fintek_enable_cir_irq(struct fintek_dev *fintek)
{
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_EN, CIR_STATUS);
}

static void fintek_cir_regs_init(struct fintek_dev *fintek)
{
        /* clear any and all stray interrupts */
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_MASK, CIR_STATUS);

        /* and finally, enable interrupts */
        fintek_enable_cir_irq(fintek);
}

static void fintek_enable_wake(struct fintek_dev *fintek)
{
        fintek_config_mode_enable(fintek);
        fintek_select_logical_dev(fintek, LOGICAL_DEV_ACPI);

        /* Allow CIR PME's to wake system */
        fintek_set_reg_bit(fintek, ACPI_WAKE_EN_CIR_BIT, LDEV_ACPI_WAKE_EN_REG);
        /* Enable CIR PME's */
        fintek_set_reg_bit(fintek, ACPI_PME_CIR_BIT, LDEV_ACPI_PME_EN_REG);
        /* Clear CIR PME status register */
        fintek_set_reg_bit(fintek, ACPI_PME_CIR_BIT, LDEV_ACPI_PME_CLR_REG);
        /* Save state */
        fintek_set_reg_bit(fintek, ACPI_STATE_CIR_BIT, LDEV_ACPI_STATE_REG);

        fintek_config_mode_disable(fintek);
}

static int fintek_cmdsize(u8 cmd, u8 subcmd)
{
        int datasize = 0;

        switch (cmd) {
        case BUF_COMMAND_NULL:
                if (subcmd == BUF_HW_CMD_HEADER)
                        datasize = 1;
                break;
        case BUF_HW_CMD_HEADER:
                if (subcmd == BUF_CMD_G_REVISION)
                        datasize = 2;
                break;
        case BUF_COMMAND_HEADER:
                switch (subcmd) {
                case BUF_CMD_S_CARRIER:
                case BUF_CMD_S_TIMEOUT:
                case BUF_RSP_PULSE_COUNT:
                        datasize = 2;
                        break;
                case BUF_CMD_SIG_END:
                case BUF_CMD_S_TXMASK:
                case BUF_CMD_S_RXSENSOR:
                        datasize = 1;
                        break;
                }
        }

        return datasize;
}

/* process ir data stored in driver buffer */
static void fintek_process_rx_ir_data(struct fintek_dev *fintek)
{
        struct ir_raw_event rawir = {};
        u8 sample;
        bool event = false;
        int i;

        for (i = 0; i < fintek->pkts; i++) {
                sample = fintek->buf[i];
                switch (fintek->parser_state) {
                case CMD_HEADER:
                        fintek->cmd = sample;
                        if ((fintek->cmd == BUF_COMMAND_HEADER) ||
                            ((fintek->cmd & BUF_COMMAND_MASK) !=
                             BUF_PULSE_BIT)) {
                                fintek->parser_state = SUBCMD;
                                continue;
                        }
                        fintek->rem = (fintek->cmd & BUF_LEN_MASK);
                        fit_dbg("%s: rem: 0x%02x", __func__, fintek->rem);
                        if (fintek->rem)
                                fintek->parser_state = PARSE_IRDATA;
                        else
                                ir_raw_event_overflow(fintek->rdev);
                        break;
                case SUBCMD:
                        fintek->rem = fintek_cmdsize(fintek->cmd, sample);
                        fintek->parser_state = CMD_DATA;
                        break;
                case CMD_DATA:
                        fintek->rem--;
                        break;
                case PARSE_IRDATA:
                        fintek->rem--;
                        rawir.pulse = ((sample & BUF_PULSE_BIT) != 0);
                        rawir.duration = (sample & BUF_SAMPLE_MASK)
                                          * CIR_SAMPLE_PERIOD;

                        fit_dbg("Storing %s with duration %d",
                                rawir.pulse ? "pulse" : "space",
                                rawir.duration);
                        if (ir_raw_event_store_with_filter(fintek->rdev,
                                                                        &rawir))
                                event = true;
                        break;
                }

                if ((fintek->parser_state != CMD_HEADER) && !fintek->rem)
                        fintek->parser_state = CMD_HEADER;
        }

        fintek->pkts = 0;

        if (event) {
                fit_dbg("Calling ir_raw_event_handle");
                ir_raw_event_handle(fintek->rdev);
        }
}

/* copy data from hardware rx register into driver buffer */
static void fintek_get_rx_ir_data(struct fintek_dev *fintek, u8 rx_irqs)
{
        unsigned long flags;
        u8 sample, status;

        spin_lock_irqsave(&fintek->fintek_lock, flags);

        /*
         * We must read data from CIR_RX_DATA until the hardware IR buffer
         * is empty and clears the RX_TIMEOUT and/or RX_RECEIVE flags in
         * the CIR_STATUS register
         */
        do {
                sample = fintek_cir_reg_read(fintek, CIR_RX_DATA);
                fit_dbg("%s: sample: 0x%02x", __func__, sample);

                fintek->buf[fintek->pkts] = sample;
                fintek->pkts++;

                status = fintek_cir_reg_read(fintek, CIR_STATUS);
                if (!(status & CIR_STATUS_IRQ_EN))
                        break;
        } while (status & rx_irqs);

        fintek_process_rx_ir_data(fintek);

        spin_unlock_irqrestore(&fintek->fintek_lock, flags);
}

static void fintek_cir_log_irqs(u8 status)
{
        fit_pr(KERN_INFO, "IRQ 0x%02x:%s%s%s%s%s", status,
                status & CIR_STATUS_IRQ_EN      ? " IRQEN"      : "",
                status & CIR_STATUS_TX_FINISH   ? " TXF"        : "",
                status & CIR_STATUS_TX_UNDERRUN ? " TXU"        : "",
                status & CIR_STATUS_RX_TIMEOUT  ? " RXTO"       : "",
                status & CIR_STATUS_RX_RECEIVE  ? " RXOK"       : "");
}

/* interrupt service routine for incoming and outgoing CIR data */
static irqreturn_t fintek_cir_isr(int irq, void *data)
{
        struct fintek_dev *fintek = data;
        u8 status, rx_irqs;

        fit_dbg_verbose("%s firing", __func__);

        fintek_config_mode_enable(fintek);
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_config_mode_disable(fintek);

        /*
         * Get IR Status register contents. Write 1 to ack/clear
         *
         * bit: reg name    - description
         *   3: TX_FINISH   - TX is finished
         *   2: TX_UNDERRUN - TX underrun
         *   1: RX_TIMEOUT  - RX data timeout
         *   0: RX_RECEIVE  - RX data received
         */
        status = fintek_cir_reg_read(fintek, CIR_STATUS);
        if (!(status & CIR_STATUS_IRQ_MASK) || status == 0xff) {
                fit_dbg_verbose("%s exiting, IRSTS 0x%02x", __func__, status);
                fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_MASK, CIR_STATUS);
                return IRQ_RETVAL(IRQ_NONE);
        }

        if (debug)
                fintek_cir_log_irqs(status);

        rx_irqs = status & (CIR_STATUS_RX_RECEIVE | CIR_STATUS_RX_TIMEOUT);
        if (rx_irqs)
                fintek_get_rx_ir_data(fintek, rx_irqs);

        /* ack/clear all irq flags we've got */
        fintek_cir_reg_write(fintek, status, CIR_STATUS);

        fit_dbg_verbose("%s done", __func__);
        return IRQ_RETVAL(IRQ_HANDLED);
}

static void fintek_enable_cir(struct fintek_dev *fintek)
{
        /* set IRQ enabled */
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_EN, CIR_STATUS);

        fintek_config_mode_enable(fintek);

        /* enable the CIR logical device */
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_cr_write(fintek, LOGICAL_DEV_ENABLE, CIR_CR_DEV_EN);

        fintek_config_mode_disable(fintek);

        /* clear all pending interrupts */
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_MASK, CIR_STATUS);

        /* enable interrupts */
        fintek_enable_cir_irq(fintek);
}

static void fintek_disable_cir(struct fintek_dev *fintek)
{
        fintek_config_mode_enable(fintek);

        /* disable the CIR logical device */
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_cr_write(fintek, LOGICAL_DEV_DISABLE, CIR_CR_DEV_EN);

        fintek_config_mode_disable(fintek);
}

static int fintek_open(struct rc_dev *dev)
{
        struct fintek_dev *fintek = dev->priv;
        unsigned long flags;

        spin_lock_irqsave(&fintek->fintek_lock, flags);
        fintek_enable_cir(fintek);
        spin_unlock_irqrestore(&fintek->fintek_lock, flags);

        return 0;
}

static void fintek_close(struct rc_dev *dev)
{
        struct fintek_dev *fintek = dev->priv;
        unsigned long flags;

        spin_lock_irqsave(&fintek->fintek_lock, flags);
        fintek_disable_cir(fintek);
        spin_unlock_irqrestore(&fintek->fintek_lock, flags);
}

/* Allocate memory, probe hardware, and initialize everything */
static int fintek_probe(struct pnp_dev *pdev, const struct pnp_device_id *dev_id)
{
        struct fintek_dev *fintek;
        struct rc_dev *rdev;
        int ret = -ENOMEM;

        fintek = kzalloc_obj(struct fintek_dev);
        if (!fintek)
                return ret;

        /* input device for IR remote (and tx) */
        rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
        if (!rdev)
                goto exit_free_dev_rdev;

        ret = -ENODEV;
        /* validate pnp resources */
        if (!pnp_port_valid(pdev, 0)) {
                dev_err(&pdev->dev, "IR PNP Port not valid!\n");
                goto exit_free_dev_rdev;
        }

        if (!pnp_irq_valid(pdev, 0)) {
                dev_err(&pdev->dev, "IR PNP IRQ not valid!\n");
                goto exit_free_dev_rdev;
        }

        fintek->cir_addr = pnp_port_start(pdev, 0);
        fintek->cir_irq  = pnp_irq(pdev, 0);
        fintek->cir_port_len = pnp_port_len(pdev, 0);

        fintek->cr_ip = CR_INDEX_PORT;
        fintek->cr_dp = CR_DATA_PORT;

        spin_lock_init(&fintek->fintek_lock);

        pnp_set_drvdata(pdev, fintek);
        fintek->pdev = pdev;

        ret = fintek_hw_detect(fintek);
        if (ret)
                goto exit_free_dev_rdev;

        /* Initialize CIR & CIR Wake Logical Devices */
        fintek_config_mode_enable(fintek);
        fintek_cir_ldev_init(fintek);
        fintek_config_mode_disable(fintek);

        /* Initialize CIR & CIR Wake Config Registers */
        fintek_cir_regs_init(fintek);

        /* Set up the rc device */
        rdev->priv = fintek;
        rdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
        rdev->open = fintek_open;
        rdev->close = fintek_close;
        rdev->device_name = FINTEK_DESCRIPTION;
        rdev->input_phys = "fintek/cir0";
        rdev->input_id.bustype = BUS_HOST;
        rdev->input_id.vendor = VENDOR_ID_FINTEK;
        rdev->input_id.product = fintek->chip_major;
        rdev->input_id.version = fintek->chip_minor;
        rdev->dev.parent = &pdev->dev;
        rdev->driver_name = FINTEK_DRIVER_NAME;
        rdev->map_name = RC_MAP_RC6_MCE;
        rdev->timeout = 1000;
        /* rx resolution is hardwired to 50us atm, 1, 25, 100 also possible */
        rdev->rx_resolution = CIR_SAMPLE_PERIOD;

        fintek->rdev = rdev;

        ret = -EBUSY;
        /* now claim resources */
        if (!request_region(fintek->cir_addr,
                            fintek->cir_port_len, FINTEK_DRIVER_NAME))
                goto exit_free_dev_rdev;

        if (request_irq(fintek->cir_irq, fintek_cir_isr, IRQF_SHARED,
                        FINTEK_DRIVER_NAME, (void *)fintek))
                goto exit_free_cir_addr;

        ret = rc_register_device(rdev);
        if (ret)
                goto exit_free_irq;

        device_init_wakeup(&pdev->dev, true);

        fit_pr(KERN_NOTICE, "driver has been successfully loaded\n");
        if (debug)
                cir_dump_regs(fintek);

        return 0;

exit_free_irq:
        free_irq(fintek->cir_irq, fintek);
exit_free_cir_addr:
        release_region(fintek->cir_addr, fintek->cir_port_len);
exit_free_dev_rdev:
        rc_free_device(rdev);
        kfree(fintek);

        return ret;
}

static void fintek_remove(struct pnp_dev *pdev)
{
        struct fintek_dev *fintek = pnp_get_drvdata(pdev);
        unsigned long flags;

        spin_lock_irqsave(&fintek->fintek_lock, flags);
        /* disable CIR */
        fintek_disable_cir(fintek);
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_MASK, CIR_STATUS);
        /* enable CIR Wake (for IR power-on) */
        fintek_enable_wake(fintek);
        spin_unlock_irqrestore(&fintek->fintek_lock, flags);

        /* free resources */
        free_irq(fintek->cir_irq, fintek);
        release_region(fintek->cir_addr, fintek->cir_port_len);

        rc_unregister_device(fintek->rdev);

        kfree(fintek);
}

static int fintek_suspend(struct pnp_dev *pdev, pm_message_t state)
{
        struct fintek_dev *fintek = pnp_get_drvdata(pdev);
        unsigned long flags;

        fit_dbg("%s called", __func__);

        spin_lock_irqsave(&fintek->fintek_lock, flags);

        /* disable all CIR interrupts */
        fintek_cir_reg_write(fintek, CIR_STATUS_IRQ_MASK, CIR_STATUS);

        spin_unlock_irqrestore(&fintek->fintek_lock, flags);

        fintek_config_mode_enable(fintek);

        /* disable cir logical dev */
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_cr_write(fintek, LOGICAL_DEV_DISABLE, CIR_CR_DEV_EN);

        fintek_config_mode_disable(fintek);

        /* make sure wake is enabled */
        fintek_enable_wake(fintek);

        return 0;
}

static int fintek_resume(struct pnp_dev *pdev)
{
        struct fintek_dev *fintek = pnp_get_drvdata(pdev);

        fit_dbg("%s called", __func__);

        /* open interrupt */
        fintek_enable_cir_irq(fintek);

        /* Enable CIR logical device */
        fintek_config_mode_enable(fintek);
        fintek_select_logical_dev(fintek, fintek->logical_dev_cir);
        fintek_cr_write(fintek, LOGICAL_DEV_ENABLE, CIR_CR_DEV_EN);

        fintek_config_mode_disable(fintek);

        fintek_cir_regs_init(fintek);

        return 0;
}

static void fintek_shutdown(struct pnp_dev *pdev)
{
        struct fintek_dev *fintek = pnp_get_drvdata(pdev);
        fintek_enable_wake(fintek);
}

static const struct pnp_device_id fintek_ids[] = {
        { "FIT0002", 0 },   /* CIR */
        { "", 0 },
};

static struct pnp_driver fintek_driver = {
        .name           = FINTEK_DRIVER_NAME,
        .id_table       = fintek_ids,
        .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
        .probe          = fintek_probe,
        .remove         = fintek_remove,
        .suspend        = fintek_suspend,
        .resume         = fintek_resume,
        .shutdown       = fintek_shutdown,
};

module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable debugging output");

MODULE_DEVICE_TABLE(pnp, fintek_ids);
MODULE_DESCRIPTION(FINTEK_DESCRIPTION " driver");

MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
MODULE_LICENSE("GPL");

module_pnp_driver(fintek_driver);