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 { .compatible = "nokia,n900-ir" },
27 { },
28};
29MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
30
31static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
32{
33 struct pwm_ir *pwm_ir = dev->priv;
34
35 pwm_ir->duty_cycle = duty_cycle;
36
37 return 0;
38}
39
40static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
41{
42 struct pwm_ir *pwm_ir = dev->priv;
43
44 if (!carrier)
45 return -EINVAL;
46
47 pwm_ir->carrier = carrier;
48
49 return 0;
50}
51
52static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
53 unsigned int count)
54{
55 struct pwm_ir *pwm_ir = dev->priv;
56 struct pwm_device *pwm = pwm_ir->pwm;
57 struct pwm_state state;
58 int i;
59 ktime_t edge;
60 long delta;
61
62 pwm_init_state(pwm, state: &state);
63
64 state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
65 pwm_set_relative_duty_cycle(state: &state, duty_cycle: pwm_ir->duty_cycle, scale: 100);
66
67 edge = ktime_get();
68
69 for (i = 0; i < count; i++) {
70 state.enabled = !(i % 2);
71 pwm_apply_state(pwm, state: &state);
72
73 edge = ktime_add_us(kt: edge, usec: txbuf[i]);
74 delta = ktime_us_delta(later: edge, earlier: ktime_get());
75 if (delta > 0)
76 usleep_range(min: delta, max: delta + 10);
77 }
78
79 state.enabled = false;
80 pwm_apply_state(pwm, state: &state);
81
82 return count;
83}
84
85static int pwm_ir_probe(struct platform_device *pdev)
86{
87 struct pwm_ir *pwm_ir;
88 struct rc_dev *rcdev;
89 int rc;
90
91 pwm_ir = devm_kmalloc(dev: &pdev->dev, size: sizeof(*pwm_ir), GFP_KERNEL);
92 if (!pwm_ir)
93 return -ENOMEM;
94
95 pwm_ir->pwm = devm_pwm_get(dev: &pdev->dev, NULL);
96 if (IS_ERR(ptr: pwm_ir->pwm))
97 return PTR_ERR(ptr: pwm_ir->pwm);
98
99 pwm_ir->carrier = 38000;
100 pwm_ir->duty_cycle = 50;
101
102 rcdev = devm_rc_allocate_device(dev: &pdev->dev, RC_DRIVER_IR_RAW_TX);
103 if (!rcdev)
104 return -ENOMEM;
105
106 rcdev->priv = pwm_ir;
107 rcdev->driver_name = DRIVER_NAME;
108 rcdev->device_name = DEVICE_NAME;
109 rcdev->tx_ir = pwm_ir_tx;
110 rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
111 rcdev->s_tx_carrier = pwm_ir_set_carrier;
112
113 rc = devm_rc_register_device(parent: &pdev->dev, dev: rcdev);
114 if (rc < 0)
115 dev_err(&pdev->dev, "failed to register rc device\n");
116
117 return rc;
118}
119
120static struct platform_driver pwm_ir_driver = {
121 .probe = pwm_ir_probe,
122 .driver = {
123 .name = DRIVER_NAME,
124 .of_match_table = pwm_ir_of_match,
125 },
126};
127module_platform_driver(pwm_ir_driver);
128
129MODULE_DESCRIPTION("PWM IR Transmitter");
130MODULE_AUTHOR("Sean Young <sean@mess.org>");
131MODULE_LICENSE("GPL");
132

source code of linux/drivers/media/rc/pwm-ir-tx.c