1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2017 Sean Young <sean@mess.org>
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/kernel.h>
7*4882a593Smuzhiyun #include <linux/module.h>
8*4882a593Smuzhiyun #include <linux/pwm.h>
9*4882a593Smuzhiyun #include <linux/delay.h>
10*4882a593Smuzhiyun #include <linux/slab.h>
11*4882a593Smuzhiyun #include <linux/of.h>
12*4882a593Smuzhiyun #include <linux/platform_device.h>
13*4882a593Smuzhiyun #include <media/rc-core.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #define DRIVER_NAME "pwm-ir-tx"
16*4882a593Smuzhiyun #define DEVICE_NAME "PWM IR Transmitter"
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun struct pwm_ir {
19*4882a593Smuzhiyun struct pwm_device *pwm;
20*4882a593Smuzhiyun unsigned int carrier;
21*4882a593Smuzhiyun unsigned int duty_cycle;
22*4882a593Smuzhiyun };
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun static const struct of_device_id pwm_ir_of_match[] = {
25*4882a593Smuzhiyun { .compatible = "pwm-ir-tx", },
26*4882a593Smuzhiyun { },
27*4882a593Smuzhiyun };
28*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
29*4882a593Smuzhiyun
pwm_ir_set_duty_cycle(struct rc_dev * dev,u32 duty_cycle)30*4882a593Smuzhiyun static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun struct pwm_ir *pwm_ir = dev->priv;
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun pwm_ir->duty_cycle = duty_cycle;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun return 0;
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun
pwm_ir_set_carrier(struct rc_dev * dev,u32 carrier)39*4882a593Smuzhiyun static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)
40*4882a593Smuzhiyun {
41*4882a593Smuzhiyun struct pwm_ir *pwm_ir = dev->priv;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun if (!carrier)
44*4882a593Smuzhiyun return -EINVAL;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun pwm_ir->carrier = carrier;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun return 0;
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
pwm_ir_tx(struct rc_dev * dev,unsigned int * txbuf,unsigned int count)51*4882a593Smuzhiyun static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
52*4882a593Smuzhiyun unsigned int count)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun struct pwm_ir *pwm_ir = dev->priv;
55*4882a593Smuzhiyun struct pwm_device *pwm = pwm_ir->pwm;
56*4882a593Smuzhiyun int i, duty, period;
57*4882a593Smuzhiyun ktime_t edge;
58*4882a593Smuzhiyun long delta;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
61*4882a593Smuzhiyun duty = DIV_ROUND_CLOSEST(pwm_ir->duty_cycle * period, 100);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun pwm_config(pwm, duty, period);
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun edge = ktime_get();
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun for (i = 0; i < count; i++) {
68*4882a593Smuzhiyun if (i % 2) // space
69*4882a593Smuzhiyun pwm_disable(pwm);
70*4882a593Smuzhiyun else
71*4882a593Smuzhiyun pwm_enable(pwm);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun edge = ktime_add_us(edge, txbuf[i]);
74*4882a593Smuzhiyun delta = ktime_us_delta(edge, ktime_get());
75*4882a593Smuzhiyun if (delta > 0)
76*4882a593Smuzhiyun usleep_range(delta, delta + 10);
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun pwm_disable(pwm);
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun return count;
82*4882a593Smuzhiyun }
83*4882a593Smuzhiyun
pwm_ir_probe(struct platform_device * pdev)84*4882a593Smuzhiyun static int pwm_ir_probe(struct platform_device *pdev)
85*4882a593Smuzhiyun {
86*4882a593Smuzhiyun struct pwm_ir *pwm_ir;
87*4882a593Smuzhiyun struct rc_dev *rcdev;
88*4882a593Smuzhiyun int rc;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL);
91*4882a593Smuzhiyun if (!pwm_ir)
92*4882a593Smuzhiyun return -ENOMEM;
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL);
95*4882a593Smuzhiyun if (IS_ERR(pwm_ir->pwm))
96*4882a593Smuzhiyun return PTR_ERR(pwm_ir->pwm);
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun pwm_ir->carrier = 38000;
99*4882a593Smuzhiyun pwm_ir->duty_cycle = 50;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);
102*4882a593Smuzhiyun if (!rcdev)
103*4882a593Smuzhiyun return -ENOMEM;
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun rcdev->priv = pwm_ir;
106*4882a593Smuzhiyun rcdev->driver_name = DRIVER_NAME;
107*4882a593Smuzhiyun rcdev->device_name = DEVICE_NAME;
108*4882a593Smuzhiyun rcdev->tx_ir = pwm_ir_tx;
109*4882a593Smuzhiyun rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
110*4882a593Smuzhiyun rcdev->s_tx_carrier = pwm_ir_set_carrier;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun rc = devm_rc_register_device(&pdev->dev, rcdev);
113*4882a593Smuzhiyun if (rc < 0)
114*4882a593Smuzhiyun dev_err(&pdev->dev, "failed to register rc device\n");
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun return rc;
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun static struct platform_driver pwm_ir_driver = {
120*4882a593Smuzhiyun .probe = pwm_ir_probe,
121*4882a593Smuzhiyun .driver = {
122*4882a593Smuzhiyun .name = DRIVER_NAME,
123*4882a593Smuzhiyun .of_match_table = of_match_ptr(pwm_ir_of_match),
124*4882a593Smuzhiyun },
125*4882a593Smuzhiyun };
126*4882a593Smuzhiyun module_platform_driver(pwm_ir_driver);
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun MODULE_DESCRIPTION("PWM IR Transmitter");
129*4882a593Smuzhiyun MODULE_AUTHOR("Sean Young <sean@mess.org>");
130*4882a593Smuzhiyun MODULE_LICENSE("GPL");
131