// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (C) 2008 Nokia Corporation
 *
 *  Based on lirc_serial.c
 */
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/wait.h>
#include <linux/pwm.h>
#include <linux/of.h>
#include <linux/hrtimer.h>

#include <media/rc-core.h>

#define WBUF_LEN 256

struct ir_rx51 {
        struct rc_dev *rcdev;
        struct pwm_device *pwm;
        struct hrtimer timer;
        struct device        *dev;
        wait_queue_head_t     wqueue;

        unsigned int    freq;           /* carrier frequency */
        unsigned int    duty_cycle;     /* carrier duty cycle */
        int             wbuf[WBUF_LEN];
        int             wbuf_index;
        unsigned long   device_is_open;
};

static inline void ir_rx51_on(struct ir_rx51 *ir_rx51)
{
        pwm_enable(ir_rx51->pwm);
}

static inline void ir_rx51_off(struct ir_rx51 *ir_rx51)
{
        pwm_disable(ir_rx51->pwm);
}

static int init_timing_params(struct ir_rx51 *ir_rx51)
{
        struct pwm_device *pwm = ir_rx51->pwm;
        int duty, period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq);

        duty = DIV_ROUND_CLOSEST(ir_rx51->duty_cycle * period, 100);

        pwm_config(pwm, duty, period);

        return 0;
}

static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer)
{
        struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer);
        ktime_t now;

        if (ir_rx51->wbuf_index < 0) {
                dev_err_ratelimited(ir_rx51->dev,
                                    "BUG wbuf_index has value of %i\n",
                                    ir_rx51->wbuf_index);
                goto end;
        }

        /*
         * If we happen to hit an odd latency spike, loop through the
         * pulses until we catch up.
         */
        do {
                u64 ns;

                if (ir_rx51->wbuf_index >= WBUF_LEN)
                        goto end;
                if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1)
                        goto end;

                if (ir_rx51->wbuf_index % 2)
                        ir_rx51_off(ir_rx51);
                else
                        ir_rx51_on(ir_rx51);

                ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]);
                hrtimer_add_expires_ns(timer, ns);

                ir_rx51->wbuf_index++;

                now = timer->base->get_time();

        } while (hrtimer_get_expires_tv64(timer) < now);

        return HRTIMER_RESTART;
end:
        /* Stop TX here */
        ir_rx51_off(ir_rx51);
        ir_rx51->wbuf_index = -1;

        wake_up_interruptible(&ir_rx51->wqueue);

        return HRTIMER_NORESTART;
}

static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer,
                      unsigned int count)
{
        struct ir_rx51 *ir_rx51 = dev->priv;

        if (count > WBUF_LEN)
                return -EINVAL;

        memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int));

        /* Wait any pending transfers to finish */
        wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);

        init_timing_params(ir_rx51);
        if (count < WBUF_LEN)
                ir_rx51->wbuf[count] = -1; /* Insert termination mark */

        /*
         * REVISIT: Adjust latency requirements so the device doesn't go in too
         * deep sleep states with pm_qos_add_request().
         */

        ir_rx51_on(ir_rx51);
        ir_rx51->wbuf_index = 1;
        hrtimer_start(&ir_rx51->timer,
                      ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])),
                      HRTIMER_MODE_REL);
        /*
         * Don't return back to the userspace until the transfer has
         * finished
         */
        wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0);

        /* REVISIT: Remove pm_qos constraint, we can sleep again */

        return count;
}

static int ir_rx51_open(struct rc_dev *dev)
{
        struct ir_rx51 *ir_rx51 = dev->priv;

        if (test_and_set_bit(1, &ir_rx51->device_is_open))
                return -EBUSY;

        ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL);
        if (IS_ERR(ir_rx51->pwm)) {
                int res = PTR_ERR(ir_rx51->pwm);

                dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res);
                return res;
        }

        return 0;
}

static void ir_rx51_release(struct rc_dev *dev)
{
        struct ir_rx51 *ir_rx51 = dev->priv;

        hrtimer_cancel(&ir_rx51->timer);
        ir_rx51_off(ir_rx51);
        pwm_put(ir_rx51->pwm);

        clear_bit(1, &ir_rx51->device_is_open);
}

static struct ir_rx51 ir_rx51 = {
        .duty_cycle     = 50,
        .wbuf_index     = -1,
};

static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty)
{
        struct ir_rx51 *ir_rx51 = dev->priv;

        ir_rx51->duty_cycle = duty;

        return 0;
}

static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier)
{
        struct ir_rx51 *ir_rx51 = dev->priv;

        if (carrier > 500000 || carrier < 20000)
                return -EINVAL;

        ir_rx51->freq = carrier;

        return 0;
}

#ifdef CONFIG_PM

static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state)
{
        /*
         * In case the device is still open, do not suspend. Normally
         * this should not be a problem as lircd only keeps the device
         * open only for short periods of time. We also don't want to
         * get involved with race conditions that might happen if we
         * were in a middle of a transmit. Thus, we defer any suspend
         * actions until transmit has completed.
         */
        if (test_and_set_bit(1, &ir_rx51.device_is_open))
                return -EAGAIN;

        clear_bit(1, &ir_rx51.device_is_open);

        return 0;
}

static int ir_rx51_resume(struct platform_device *dev)
{
        return 0;
}

#else

#define ir_rx51_suspend NULL
#define ir_rx51_resume  NULL

#endif /* CONFIG_PM */

static int ir_rx51_probe(struct platform_device *dev)
{
        struct pwm_device *pwm;
        struct rc_dev *rcdev;

        pwm = pwm_get(&dev->dev, NULL);
        if (IS_ERR(pwm)) {
                int err = PTR_ERR(pwm);

                if (err != -EPROBE_DEFER)
                        dev_err(&dev->dev, "pwm_get failed: %d\n", err);
                return err;
        }

        /* Use default, in case userspace does not set the carrier */
        ir_rx51.freq = DIV_ROUND_CLOSEST(pwm_get_period(pwm), NSEC_PER_SEC);
        pwm_put(pwm);

        hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        ir_rx51.timer.function = ir_rx51_timer_cb;

        ir_rx51.dev = &dev->dev;

        rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX);
        if (!rcdev)
                return -ENOMEM;

        rcdev->priv = &ir_rx51;
        rcdev->open = ir_rx51_open;
        rcdev->close = ir_rx51_release;
        rcdev->tx_ir = ir_rx51_tx;
        rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle;
        rcdev->s_tx_carrier = ir_rx51_set_tx_carrier;
        rcdev->driver_name = KBUILD_MODNAME;

        ir_rx51.rcdev = rcdev;

        return devm_rc_register_device(&dev->dev, ir_rx51.rcdev);
}

static int ir_rx51_remove(struct platform_device *dev)
{
        return 0;
}

static const struct of_device_id ir_rx51_match[] = {
        {
                .compatible = "nokia,n900-ir",
        },
        {},
};
MODULE_DEVICE_TABLE(of, ir_rx51_match);

static struct platform_driver ir_rx51_platform_driver = {
        .probe          = ir_rx51_probe,
        .remove         = ir_rx51_remove,
        .suspend        = ir_rx51_suspend,
        .resume         = ir_rx51_resume,
        .driver         = {
                .name   = KBUILD_MODNAME,
                .of_match_table = of_match_ptr(ir_rx51_match),
        },
};
module_platform_driver(ir_rx51_platform_driver);

MODULE_DESCRIPTION("IR TX driver for Nokia RX51");
MODULE_AUTHOR("Nokia Corporation");
MODULE_LICENSE("GPL");