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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Sean Young <sean@mess.org>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pwm.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/hrtimer.h>
#include <linux/completion.h>
#include <media/rc-core.h>
#define DRIVER_NAME "pwm-ir-tx"
#define DEVICE_NAME "PWM IR Transmitter"
struct pwm_ir {
struct pwm_device *pwm;
struct hrtimer timer;
struct completion tx_done;
struct pwm_state *state;
u32 carrier;
u32 duty_cycle;
const unsigned int *txbuf;
unsigned int txbuf_len;
unsigned int txbuf_index;
};
static const struct of_device_id pwm_ir_of_match[] = {
{ .compatible = "pwm-ir-tx", },
{ .compatible = "nokia,n900-ir" },
{ },
};
MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
{
struct pwm_ir *pwm_ir = dev->priv;
pwm_ir->duty_cycle = duty_cycle;
return 0;
}
static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
{
struct pwm_ir *pwm_ir = dev->priv;
if (!carrier)
return -EINVAL;
pwm_ir->carrier = carrier;
return 0;
}
static int pwm_ir_tx_sleep(struct rc_dev *dev, unsigned int *txbuf,
unsigned int count)
{
struct pwm_ir *pwm_ir = dev->priv;
struct pwm_device *pwm = pwm_ir->pwm;
struct pwm_state state;
int i;
ktime_t edge;
long delta;
pwm_init_state(pwm, &state);
state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
edge = ktime_get();
for (i = 0; i < count; i++) {
state.enabled = !(i % 2);
pwm_apply_might_sleep(pwm, &state);
edge = ktime_add_us(edge, txbuf[i]);
delta = ktime_us_delta(edge, ktime_get());
if (delta > 0)
usleep_range(delta, delta + 10);
}
state.enabled = false;
pwm_apply_might_sleep(pwm, &state);
return count;
}
static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,
unsigned int count)
{
struct pwm_ir *pwm_ir = dev->priv;
struct pwm_device *pwm = pwm_ir->pwm;
struct pwm_state state;
pwm_init_state(pwm, &state);
state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
pwm_ir->txbuf = txbuf;
pwm_ir->txbuf_len = count;
pwm_ir->txbuf_index = 0;
pwm_ir->state = &state;
hrtimer_start(&pwm_ir->timer, 0, HRTIMER_MODE_REL);
wait_for_completion(&pwm_ir->tx_done);
return count;
}
static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
{
struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);
ktime_t now;
/*
* If we happen to hit an odd latency spike, loop through the
* pulses until we catch up.
*/
do {
u64 ns;
pwm_ir->state->enabled = !(pwm_ir->txbuf_index % 2);
pwm_apply_atomic(pwm_ir->pwm, pwm_ir->state);
if (pwm_ir->txbuf_index >= pwm_ir->txbuf_len) {
complete(&pwm_ir->tx_done);
return HRTIMER_NORESTART;
}
ns = US_TO_NS(pwm_ir->txbuf[pwm_ir->txbuf_index]);
hrtimer_add_expires_ns(timer, ns);
pwm_ir->txbuf_index++;
now = timer->base->get_time();
} while (hrtimer_get_expires_tv64(timer) < now);
return HRTIMER_RESTART;
}
static int pwm_ir_probe(struct platform_device *pdev)
{
struct pwm_ir *pwm_ir;
struct rc_dev *rcdev;
int rc;
pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL);
if (!pwm_ir)
return -ENOMEM;
pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pwm_ir->pwm))
return PTR_ERR(pwm_ir->pwm);
pwm_ir->carrier = 38000;
pwm_ir->duty_cycle = 50;
rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);
if (!rcdev)
return -ENOMEM;
if (pwm_might_sleep(pwm_ir->pwm)) {
dev_info(&pdev->dev, "TX will not be accurate as PWM device might sleep\n");
rcdev->tx_ir = pwm_ir_tx_sleep;
} else {
init_completion(&pwm_ir->tx_done);
hrtimer_init(&pwm_ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
pwm_ir->timer.function = pwm_ir_timer;
rcdev->tx_ir = pwm_ir_tx_atomic;
}
rcdev->priv = pwm_ir;
rcdev->driver_name = DRIVER_NAME;
rcdev->device_name = DEVICE_NAME;
rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
rcdev->s_tx_carrier = pwm_ir_set_carrier;
rc = devm_rc_register_device(&pdev->dev, rcdev);
if (rc < 0)
dev_err(&pdev->dev, "failed to register rc device\n");
return rc;
}
static struct platform_driver pwm_ir_driver = {
.probe = pwm_ir_probe,
.driver = {
.name = DRIVER_NAME,
.of_match_table = pwm_ir_of_match,
},
};
module_platform_driver(pwm_ir_driver);
MODULE_DESCRIPTION("PWM IR Transmitter");
MODULE_AUTHOR("Sean Young <sean@mess.org>");
MODULE_LICENSE("GPL");
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