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 | { .compatible = "nokia,n900-ir" }, |
27 | { }, |
28 | }; |
29 | MODULE_DEVICE_TABLE(of, pwm_ir_of_match); |
30 | |
31 | static 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 | |
40 | static 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 | |
52 | static 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 | |
85 | static 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 | |
120 | static 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 | }; |
127 | module_platform_driver(pwm_ir_driver); |
128 | |
129 | MODULE_DESCRIPTION("PWM IR Transmitter" ); |
130 | MODULE_AUTHOR("Sean Young <sean@mess.org>" ); |
131 | MODULE_LICENSE("GPL" ); |
132 | |