xref: /openbmc/linux/drivers/media/rc/pwm-ir-tx.c (revision a10c3d5f)
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 
18 struct pwm_ir {
19 	struct pwm_device *pwm;
20 	unsigned int carrier;
21 	unsigned int duty_cycle;
22 };
23 
24 static const struct of_device_id pwm_ir_of_match[] = {
25 	{ .compatible = "pwm-ir-tx", },
26 	{ },
27 };
28 MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
29 
pwm_ir_set_duty_cycle(struct rc_dev * dev,u32 duty_cycle)30 static 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 
pwm_ir_set_carrier(struct rc_dev * dev,u32 carrier)39 static 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 
pwm_ir_tx(struct rc_dev * dev,unsigned int * txbuf,unsigned int count)51 static 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_might_sleep(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_might_sleep(pwm, &state);
80 
81 	return count;
82 }
83 
pwm_ir_probe(struct platform_device * pdev)84 static 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 
119 static 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 };
126 module_platform_driver(pwm_ir_driver);
127 
128 MODULE_DESCRIPTION("PWM IR Transmitter");
129 MODULE_AUTHOR("Sean Young <sean@mess.org>");
130 MODULE_LICENSE("GPL");
131