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 int i, duty, period;
57 ktime_t edge;
58 long delta;
59
60 period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
61 duty = DIV_ROUND_CLOSEST(pwm_ir->duty_cycle * period, 100);
62
63 pwm_config(pwm, duty, period);
64
65 edge = ktime_get();
66
67 for (i = 0; i < count; i++) {
68 if (i % 2) // space
69 pwm_disable(pwm);
70 else
71 pwm_enable(pwm);
72
73 edge = ktime_add_us(edge, txbuf[i]);
74 delta = ktime_us_delta(edge, ktime_get());
75 if (delta > 0)
76 usleep_range(delta, delta + 10);
77 }
78
79 pwm_disable(pwm);
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 = of_match_ptr(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
