summaryrefslogtreecommitdiffstats
path: root/drivers/media/rc/pwm-ir-tx.c
blob: 27d0f5837a76b426202415e79e02a5f06ede29f5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/*
 * Copyright (C) 2017 Sean Young <sean@mess.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#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 <media/rc-core.h>

#define DRIVER_NAME	"pwm-ir-tx"
#define DEVICE_NAME	"PWM IR Transmitter"

struct pwm_ir {
	struct pwm_device *pwm;
	unsigned int carrier;
	unsigned int duty_cycle;
};

static const struct of_device_id pwm_ir_of_match[] = {
	{ .compatible = "pwm-ir-tx", },
	{ },
};
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(struct rc_dev *dev, unsigned int *txbuf,
		     unsigned int count)
{
	struct pwm_ir *pwm_ir = dev->priv;
	struct pwm_device *pwm = pwm_ir->pwm;
	int i, duty, period;
	ktime_t edge;
	long delta;

	period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
	duty = DIV_ROUND_CLOSEST(pwm_ir->duty_cycle * period, 100);

	pwm_config(pwm, duty, period);

	edge = ktime_get();

	for (i = 0; i < count; i++) {
		if (i % 2) // space
			pwm_disable(pwm);
		else
			pwm_enable(pwm);

		edge = ktime_add_us(edge, txbuf[i]);
		delta = ktime_us_delta(edge, ktime_get());
		if (delta > 0)
			usleep_range(delta, delta + 10);
	}

	pwm_disable(pwm);

	return count;
}

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;

	rcdev->priv = pwm_ir;
	rcdev->driver_name = DRIVER_NAME;
	rcdev->device_name = DEVICE_NAME;
	rcdev->tx_ir = pwm_ir_tx;
	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 = of_match_ptr(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");