LXR linux/drivers/media/rc/pwm-ir-tx.c

   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
  18struct pwm_ir {
  19        struct pwm_device *pwm;
  20        unsigned int carrier;
  21        unsigned int duty_cycle;
  22};
  23
  24static const struct of_device_id pwm_ir_of_match[] = {
  25        { .compatible = "pwm-ir-tx", },
  26        { },
  27};
  28MODULE_DEVICE_TABLE(of, pwm_ir_of_match);
  29
  30static 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
  39static 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
  51static 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
  84static 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
 119static 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};
 126module_platform_driver(pwm_ir_driver);
 127
 128MODULE_DESCRIPTION("PWM IR Transmitter");
 129MODULE_AUTHOR("Sean Young <sean@mess.org>");
 130MODULE_LICENSE("GPL");
 131