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 = 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");
131