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