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1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 <linux/hrtimer.h>14#include <linux/completion.h>15#include <media/rc-core.h>16 17#define DRIVER_NAME "pwm-ir-tx"18#define DEVICE_NAME "PWM IR Transmitter"19 20struct pwm_ir {21 struct pwm_device *pwm;22 struct hrtimer timer;23 struct completion tx_done;24 struct pwm_state *state;25 u32 carrier;26 u32 duty_cycle;27 const unsigned int *txbuf;28 unsigned int txbuf_len;29 unsigned int txbuf_index;30};31 32static const struct of_device_id pwm_ir_of_match[] = {33 { .compatible = "pwm-ir-tx", },34 { .compatible = "nokia,n900-ir" },35 { },36};37MODULE_DEVICE_TABLE(of, pwm_ir_of_match);38 39static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)40{41 struct pwm_ir *pwm_ir = dev->priv;42 43 pwm_ir->duty_cycle = duty_cycle;44 45 return 0;46}47 48static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier)49{50 struct pwm_ir *pwm_ir = dev->priv;51 52 if (!carrier)53 return -EINVAL;54 55 pwm_ir->carrier = carrier;56 57 return 0;58}59 60static int pwm_ir_tx_sleep(struct rc_dev *dev, unsigned int *txbuf,61 unsigned int count)62{63 struct pwm_ir *pwm_ir = dev->priv;64 struct pwm_device *pwm = pwm_ir->pwm;65 struct pwm_state state;66 int i;67 ktime_t edge;68 long delta;69 70 pwm_init_state(pwm, &state);71 72 state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);73 pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);74 75 edge = ktime_get();76 77 for (i = 0; i < count; i++) {78 state.enabled = !(i % 2);79 pwm_apply_might_sleep(pwm, &state);80 81 edge = ktime_add_us(edge, txbuf[i]);82 delta = ktime_us_delta(edge, ktime_get());83 if (delta > 0)84 usleep_range(delta, delta + 10);85 }86 87 state.enabled = false;88 pwm_apply_might_sleep(pwm, &state);89 90 return count;91}92 93static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,94 unsigned int count)95{96 struct pwm_ir *pwm_ir = dev->priv;97 struct pwm_device *pwm = pwm_ir->pwm;98 struct pwm_state state;99 100 pwm_init_state(pwm, &state);101 102 state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);103 pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);104 105 pwm_ir->txbuf = txbuf;106 pwm_ir->txbuf_len = count;107 pwm_ir->txbuf_index = 0;108 pwm_ir->state = &state;109 110 hrtimer_start(&pwm_ir->timer, 0, HRTIMER_MODE_REL);111 112 wait_for_completion(&pwm_ir->tx_done);113 114 return count;115}116 117static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)118{119 struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);120 ktime_t now;121 122 /*123 * If we happen to hit an odd latency spike, loop through the124 * pulses until we catch up.125 */126 do {127 u64 ns;128 129 pwm_ir->state->enabled = !(pwm_ir->txbuf_index % 2);130 pwm_apply_atomic(pwm_ir->pwm, pwm_ir->state);131 132 if (pwm_ir->txbuf_index >= pwm_ir->txbuf_len) {133 complete(&pwm_ir->tx_done);134 135 return HRTIMER_NORESTART;136 }137 138 ns = US_TO_NS(pwm_ir->txbuf[pwm_ir->txbuf_index]);139 hrtimer_add_expires_ns(timer, ns);140 141 pwm_ir->txbuf_index++;142 143 now = timer->base->get_time();144 } while (hrtimer_get_expires_tv64(timer) < now);145 146 return HRTIMER_RESTART;147}148 149static int pwm_ir_probe(struct platform_device *pdev)150{151 struct pwm_ir *pwm_ir;152 struct rc_dev *rcdev;153 int rc;154 155 pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL);156 if (!pwm_ir)157 return -ENOMEM;158 159 pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL);160 if (IS_ERR(pwm_ir->pwm))161 return PTR_ERR(pwm_ir->pwm);162 163 pwm_ir->carrier = 38000;164 pwm_ir->duty_cycle = 50;165 166 rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);167 if (!rcdev)168 return -ENOMEM;169 170 if (pwm_might_sleep(pwm_ir->pwm)) {171 dev_info(&pdev->dev, "TX will not be accurate as PWM device might sleep\n");172 rcdev->tx_ir = pwm_ir_tx_sleep;173 } else {174 init_completion(&pwm_ir->tx_done);175 hrtimer_init(&pwm_ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);176 pwm_ir->timer.function = pwm_ir_timer;177 rcdev->tx_ir = pwm_ir_tx_atomic;178 }179 180 rcdev->priv = pwm_ir;181 rcdev->driver_name = DRIVER_NAME;182 rcdev->device_name = DEVICE_NAME;183 rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;184 rcdev->s_tx_carrier = pwm_ir_set_carrier;185 186 rc = devm_rc_register_device(&pdev->dev, rcdev);187 if (rc < 0)188 dev_err(&pdev->dev, "failed to register rc device\n");189 190 return rc;191}192 193static struct platform_driver pwm_ir_driver = {194 .probe = pwm_ir_probe,195 .driver = {196 .name = DRIVER_NAME,197 .of_match_table = pwm_ir_of_match,198 },199};200module_platform_driver(pwm_ir_driver);201 202MODULE_DESCRIPTION("PWM IR Transmitter");203MODULE_AUTHOR("Sean Young <sean@mess.org>");204MODULE_LICENSE("GPL");205