cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

pwm-ir-tx.c (2806B)

      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	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_state(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_state(pwm, &state);
     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");