// SPDX-License-Identifier: GPL-2.0+
// handle au0828 IR remotes via linux kernel input layer.
//
// Copyright (c) 2014 Mauro Carvalho Chehab <mchehab@samsung.com>
// Copyright (c) 2014 Samsung Electronics Co., Ltd.
//
// Based on em28xx-input.c.

#include "au0828.h"

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/slab.h>
#include <media/rc-core.h>

static int disable_ir;
module_param(disable_ir,        int, 0444);
MODULE_PARM_DESC(disable_ir, "disable infrared remote support");

struct au0828_rc {
        struct au0828_dev *dev;
        struct rc_dev *rc;
        char name[32];
        char phys[32];

        /* poll decoder */
        int polling;
        struct delayed_work work;

        /* i2c slave address of external device (if used) */
        u16 i2c_dev_addr;

        int  (*get_key_i2c)(struct au0828_rc *ir);
};

/*
 * AU8522 has a builtin IR receiver. Add functions to get IR from it
 */

static int au8522_rc_write(struct au0828_rc *ir, u16 reg, u8 data)
{
        int rc;
        char buf[] = { (reg >> 8) | 0x80, reg & 0xff, data };
        struct i2c_msg msg = { .addr = ir->i2c_dev_addr, .flags = 0,
                               .buf = buf, .len = sizeof(buf) };

        rc = i2c_transfer(ir->dev->i2c_client.adapter, &msg, 1);

        if (rc < 0)
                return rc;

        return (rc == 1) ? 0 : -EIO;
}

static int au8522_rc_read(struct au0828_rc *ir, u16 reg, int val,
                                 char *buf, int size)
{
        int rc;
        char obuf[3];
        struct i2c_msg msg[2] = { { .addr = ir->i2c_dev_addr, .flags = 0,
                                    .buf = obuf, .len = 2 },
                                  { .addr = ir->i2c_dev_addr, .flags = I2C_M_RD,
                                    .buf = buf, .len = size } };

        obuf[0] = 0x40 | reg >> 8;
        obuf[1] = reg & 0xff;
        if (val >= 0) {
                obuf[2] = val;
                msg[0].len++;
        }

        rc = i2c_transfer(ir->dev->i2c_client.adapter, msg, 2);

        if (rc < 0)
                return rc;

        return (rc == 2) ? 0 : -EIO;
}

static int au8522_rc_andor(struct au0828_rc *ir, u16 reg, u8 mask, u8 value)
{
        int rc;
        char buf, oldbuf;

        rc = au8522_rc_read(ir, reg, -1, &buf, 1);
        if (rc < 0)
                return rc;

        oldbuf = buf;
        buf = (buf & ~mask) | (value & mask);

        /* Nothing to do, just return */
        if (buf == oldbuf)
                return 0;

        return au8522_rc_write(ir, reg, buf);
}

#define au8522_rc_set(ir, reg, bit) au8522_rc_andor(ir, (reg), (bit), (bit))
#define au8522_rc_clear(ir, reg, bit) au8522_rc_andor(ir, (reg), (bit), 0)

/* Remote Controller time units */

#define AU8522_UNIT             200 /* us */
#define NEC_START_SPACE         (4500 / AU8522_UNIT)
#define NEC_START_PULSE         (563 * 16)
#define RC5_START_SPACE         (4 * AU8522_UNIT)
#define RC5_START_PULSE         889

static int au0828_get_key_au8522(struct au0828_rc *ir)
{
        unsigned char buf[40];
        struct ir_raw_event rawir = {};
        int i, j, rc;
        int prv_bit, bit, width;
        bool first = true;

        /* do nothing if device is disconnected */
        if (test_bit(DEV_DISCONNECTED, &ir->dev->dev_state))
                return 0;

        /* Check IR int */
        rc = au8522_rc_read(ir, 0xe1, -1, buf, 1);
        if (rc < 0 || !(buf[0] & (1 << 4))) {
                /* Be sure that IR is enabled */
                au8522_rc_set(ir, 0xe0, 1 << 4);
                return 0;
        }

        /* Something arrived. Get the data */
        rc = au8522_rc_read(ir, 0xe3, 0x11, buf, sizeof(buf));


        if (rc < 0)
                return rc;

        /* Disable IR */
        au8522_rc_clear(ir, 0xe0, 1 << 4);

        /* Enable IR */
        au8522_rc_set(ir, 0xe0, 1 << 4);

        dprintk(16, "RC data received: %*ph\n", 40, buf);

        prv_bit = (buf[0] >> 7) & 0x01;
        width = 0;
        for (i = 0; i < sizeof(buf); i++) {
                for (j = 7; j >= 0; j--) {
                        bit = (buf[i] >> j) & 0x01;
                        if (bit == prv_bit) {
                                width++;
                                continue;
                        }

                        /*
                         * Fix an au8522 bug: the first pulse event
                         * is lost. So, we need to fake it, based on the
                         * protocol. That means that not all raw decoders
                         * will work, as we need to add a hack for each
                         * protocol, based on the first space.
                         * So, we only support RC5 and NEC.
                         */

                        if (first) {
                                first = false;

                                rawir.pulse = true;
                                if (width > NEC_START_SPACE - 2 &&
                                    width < NEC_START_SPACE + 2) {
                                        /* NEC protocol */
                                        rawir.duration = NEC_START_PULSE;
                                        dprintk(16, "Storing NEC start %s with duration %d",
                                                rawir.pulse ? "pulse" : "space",
                                                rawir.duration);
                                } else {
                                        /* RC5 protocol */
                                        rawir.duration = RC5_START_PULSE;
                                        dprintk(16, "Storing RC5 start %s with duration %d",
                                                rawir.pulse ? "pulse" : "space",
                                                rawir.duration);
                                }
                                ir_raw_event_store(ir->rc, &rawir);
                        }

                        rawir.pulse = prv_bit ? false : true;
                        rawir.duration = AU8522_UNIT * width;
                        dprintk(16, "Storing %s with duration %d",
                                rawir.pulse ? "pulse" : "space",
                                rawir.duration);
                        ir_raw_event_store(ir->rc, &rawir);

                        width = 1;
                        prv_bit = bit;
                }
        }

        rawir.pulse = prv_bit ? false : true;
        rawir.duration = AU8522_UNIT * width;
        dprintk(16, "Storing end %s with duration %d",
                rawir.pulse ? "pulse" : "space",
                rawir.duration);
        ir_raw_event_store(ir->rc, &rawir);

        ir_raw_event_handle(ir->rc);

        return 1;
}

/*
 * Generic IR code
 */

static void au0828_rc_work(struct work_struct *work)
{
        struct au0828_rc *ir = container_of(work, struct au0828_rc, work.work);
        int rc;

        rc = ir->get_key_i2c(ir);
        if (rc < 0)
                pr_info("Error while getting RC scancode\n");

        schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
}

static int au0828_rc_start(struct rc_dev *rc)
{
        struct au0828_rc *ir = rc->priv;

        INIT_DELAYED_WORK(&ir->work, au0828_rc_work);

        /* Enable IR */
        au8522_rc_set(ir, 0xe0, 1 << 4);

        schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));

        return 0;
}

static void au0828_rc_stop(struct rc_dev *rc)
{
        struct au0828_rc *ir = rc->priv;

        cancel_delayed_work_sync(&ir->work);

        /* do nothing if device is disconnected */
        if (!test_bit(DEV_DISCONNECTED, &ir->dev->dev_state)) {
                /* Disable IR */
                au8522_rc_clear(ir, 0xe0, 1 << 4);
        }
}

static int au0828_probe_i2c_ir(struct au0828_dev *dev)
{
        int i = 0;
        static const unsigned short addr_list[] = {
                 0x47, I2C_CLIENT_END
        };

        while (addr_list[i] != I2C_CLIENT_END) {
                if (i2c_probe_func_quick_read(dev->i2c_client.adapter,
                                              addr_list[i]) == 1)
                        return addr_list[i];
                i++;
        }

        return -ENODEV;
}

int au0828_rc_register(struct au0828_dev *dev)
{
        struct au0828_rc *ir;
        struct rc_dev *rc;
        int err = -ENOMEM;
        u16 i2c_rc_dev_addr = 0;

        if (!dev->board.has_ir_i2c || disable_ir)
                return 0;

        i2c_rc_dev_addr = au0828_probe_i2c_ir(dev);
        if (!i2c_rc_dev_addr)
                return -ENODEV;

        ir = kzalloc_obj(*ir);
        rc = rc_allocate_device(RC_DRIVER_IR_RAW);
        if (!ir || !rc)
                goto error;

        /* record handles to ourself */
        ir->dev = dev;
        dev->ir = ir;
        ir->rc = rc;

        rc->priv = ir;
        rc->open = au0828_rc_start;
        rc->close = au0828_rc_stop;

        if (dev->board.has_ir_i2c) {    /* external i2c device */
                switch (dev->boardnr) {
                case AU0828_BOARD_HAUPPAUGE_HVR950Q:
                        rc->map_name = RC_MAP_HAUPPAUGE;
                        ir->get_key_i2c = au0828_get_key_au8522;
                        break;
                default:
                        err = -ENODEV;
                        goto error;
                }

                ir->i2c_dev_addr = i2c_rc_dev_addr;
        }

        /* This is how often we ask the chip for IR information */
        ir->polling = 100; /* ms */

        /* init input device */
        snprintf(ir->name, sizeof(ir->name), "au0828 IR (%s)",
                 dev->board.name);

        usb_make_path(dev->usbdev, ir->phys, sizeof(ir->phys));
        strlcat(ir->phys, "/input0", sizeof(ir->phys));

        rc->device_name = ir->name;
        rc->input_phys = ir->phys;
        rc->input_id.bustype = BUS_USB;
        rc->input_id.version = 1;
        rc->input_id.vendor = le16_to_cpu(dev->usbdev->descriptor.idVendor);
        rc->input_id.product = le16_to_cpu(dev->usbdev->descriptor.idProduct);
        rc->dev.parent = &dev->usbdev->dev;
        rc->driver_name = "au0828-input";
        rc->allowed_protocols = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX |
                                RC_PROTO_BIT_NEC32 | RC_PROTO_BIT_RC5;

        /* all done */
        err = rc_register_device(rc);
        if (err)
                goto error;

        pr_info("Remote controller %s initialized\n", ir->name);

        return 0;

error:
        dev->ir = NULL;
        rc_free_device(rc);
        kfree(ir);
        return err;
}

void au0828_rc_unregister(struct au0828_dev *dev)
{
        struct au0828_rc *ir = dev->ir;

        /* skip detach on non attached boards */
        if (!ir)
                return;

        rc_unregister_device(ir->rc);

        /* done */
        kfree(ir);
        dev->ir = NULL;
}

int au0828_rc_suspend(struct au0828_dev *dev)
{
        struct au0828_rc *ir = dev->ir;

        if (!ir)
                return 0;

        pr_info("Stopping RC\n");

        cancel_delayed_work_sync(&ir->work);

        /* Disable IR */
        au8522_rc_clear(ir, 0xe0, 1 << 4);

        return 0;
}

int au0828_rc_resume(struct au0828_dev *dev)
{
        struct au0828_rc *ir = dev->ir;

        if (!ir)
                return 0;

        pr_info("Restarting RC\n");

        /* Enable IR */
        au8522_rc_set(ir, 0xe0, 1 << 4);

        schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));

        return 0;
}