// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (C) 2017 Sean Young <sean@mess.org> */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/pwm.h> #include <linux/delay.h> #include <linux/slab.h> #include <linux/of.h> #include <linux/platform_device.h> #include <media/rc-core.h> #define DRIVER_NAME "pwm-ir-tx" #define DEVICE_NAME "PWM IR Transmitter" struct pwm_ir { struct pwm_device *pwm; unsigned int carrier; unsigned int duty_cycle; }; static const struct of_device_id pwm_ir_of_match[] = { { .compatible = "pwm-ir-tx", }, { }, }; MODULE_DEVICE_TABLE(of, pwm_ir_of_match); static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle) { struct pwm_ir *pwm_ir = dev->priv; pwm_ir->duty_cycle = duty_cycle; return 0; } static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier) { struct pwm_ir *pwm_ir = dev->priv; if (!carrier) return -EINVAL; pwm_ir->carrier = carrier; return 0; } static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf, unsigned int count) { struct pwm_ir *pwm_ir = dev->priv; struct pwm_device *pwm = pwm_ir->pwm; struct pwm_state state; int i; ktime_t edge; long delta; pwm_init_state(pwm, &state); state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier); pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100); edge = ktime_get(); for (i = 0; i < count; i++) { state.enabled = !(i % 2); pwm_apply_state(pwm, &state); edge = ktime_add_us(edge, txbuf[i]); delta = ktime_us_delta(edge, ktime_get()); if (delta > 0) usleep_range(delta, delta + 10); } state.enabled = false; pwm_apply_state(pwm, &state); return count; } static int pwm_ir_probe(struct platform_device *pdev) { struct pwm_ir *pwm_ir; struct rc_dev *rcdev; int rc; pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL); if (!pwm_ir) return -ENOMEM; pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL); if (IS_ERR(pwm_ir->pwm)) return PTR_ERR(pwm_ir->pwm); pwm_ir->carrier = 38000; pwm_ir->duty_cycle = 50; rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX); if (!rcdev) return -ENOMEM; rcdev->priv = pwm_ir; rcdev->driver_name = DRIVER_NAME; rcdev->device_name = DEVICE_NAME; rcdev->tx_ir = pwm_ir_tx; rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle; rcdev->s_tx_carrier = pwm_ir_set_carrier; rc = devm_rc_register_device(&pdev->dev, rcdev); if (rc < 0) dev_err(&pdev->dev, "failed to register rc device\n"); return rc; } static struct platform_driver pwm_ir_driver = { .probe = pwm_ir_probe, .driver = { .name = DRIVER_NAME, .of_match_table = of_match_ptr(pwm_ir_of_match), }, }; module_platform_driver(pwm_ir_driver); MODULE_DESCRIPTION("PWM IR Transmitter"); MODULE_AUTHOR("Sean Young <sean@mess.org>"); MODULE_LICENSE("GPL");