1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2017 Sean Young <sean@mess.org>
  4 */
  5
  6#include <linux/kernel.h>
  7#include <linux/module.h>
  8#include <linux/pwm.h>
  9#include <linux/delay.h>
 10#include <linux/slab.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <media/rc-core.h>
 14
 15#define DRIVER_NAME	"pwm-ir-tx"
 16#define DEVICE_NAME	"PWM IR Transmitter"
 17
 18struct pwm_ir {
 19	struct pwm_device *pwm;
 20	unsigned int carrier;
 21	unsigned int duty_cycle;
 22};
 23
 24static const struct of_device_id pwm_ir_of_match[] = {
 25	{ .compatible = "pwm-ir-tx", },
 26	{ },
 27};
 28MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
 29
 30static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
 31{
 32	struct pwm_ir *pwm_ir = dev->priv;
 33
 34	pwm_ir->duty_cycle = duty_cycle;
 35
 36	return 0;
 37}
 38
 39static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
 40{
 41	struct pwm_ir *pwm_ir = dev->priv;
 42
 43	if (!carrier)
 44		return -EINVAL;
 45
 46	pwm_ir->carrier = carrier;
 47
 48	return 0;
 49}
 50
 51static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 52		     unsigned int count)
 53{
 54	struct pwm_ir *pwm_ir = dev->priv;
 55	struct pwm_device *pwm = pwm_ir->pwm;
 56	struct pwm_state state;
 57	int i;
 58	ktime_t edge;
 59	long delta;
 60
 61	pwm_init_state(pwm, &state);
 62
 63	state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
 64	pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
 65
 66	edge = ktime_get();
 67
 68	for (i = 0; i < count; i++) {
 69		state.enabled = !(i % 2);
 70		pwm_apply_state(pwm, &state);
 71
 72		edge = ktime_add_us(edge, txbuf[i]);
 73		delta = ktime_us_delta(edge, ktime_get());
 74		if (delta > 0)
 75			usleep_range(delta, delta + 10);
 76	}
 77
 78	state.enabled = false;
 79	pwm_apply_state(pwm, &state);
 80
 81	return count;
 82}
 83
 84static int pwm_ir_probe(struct platform_device *pdev)
 85{
 86	struct pwm_ir *pwm_ir;
 87	struct rc_dev *rcdev;
 88	int rc;
 89
 90	pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL);
 91	if (!pwm_ir)
 92		return -ENOMEM;
 93
 94	pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL);
 95	if (IS_ERR(pwm_ir->pwm))
 96		return PTR_ERR(pwm_ir->pwm);
 97
 98	pwm_ir->carrier = 38000;
 99	pwm_ir->duty_cycle = 50;
100
101	rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);
102	if (!rcdev)
103		return -ENOMEM;
104
105	rcdev->priv = pwm_ir;
106	rcdev->driver_name = DRIVER_NAME;
107	rcdev->device_name = DEVICE_NAME;
108	rcdev->tx_ir = pwm_ir_tx;
109	rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
110	rcdev->s_tx_carrier = pwm_ir_set_carrier;
111
112	rc = devm_rc_register_device(&pdev->dev, rcdev);
113	if (rc < 0)
114		dev_err(&pdev->dev, "failed to register rc device\n");
115
116	return rc;
117}
118
119static struct platform_driver pwm_ir_driver = {
120	.probe = pwm_ir_probe,
121	.driver = {
122		.name	= DRIVER_NAME,
123		.of_match_table = of_match_ptr(pwm_ir_of_match),
124	},
125};
126module_platform_driver(pwm_ir_driver);
127
128MODULE_DESCRIPTION("PWM IR Transmitter");
129MODULE_AUTHOR("Sean Young <sean@mess.org>");
130MODULE_LICENSE("GPL");