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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190523091651.414247666@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
168 lines
4 KiB
C
168 lines
4 KiB
C
// 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/gpio/consumer.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 "gpio-ir-tx"
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#define DEVICE_NAME "GPIO IR Bit Banging Transmitter"
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struct gpio_ir {
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struct gpio_desc *gpio;
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unsigned int carrier;
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unsigned int duty_cycle;
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/* we need a spinlock to hold the cpu while transmitting */
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spinlock_t lock;
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};
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static const struct of_device_id gpio_ir_tx_of_match[] = {
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{ .compatible = "gpio-ir-tx", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, gpio_ir_tx_of_match);
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static int gpio_ir_tx_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
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{
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struct gpio_ir *gpio_ir = dev->priv;
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gpio_ir->duty_cycle = duty_cycle;
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return 0;
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}
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static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier)
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{
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struct gpio_ir *gpio_ir = dev->priv;
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if (!carrier)
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return -EINVAL;
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gpio_ir->carrier = carrier;
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return 0;
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}
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static int gpio_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 gpio_ir *gpio_ir = dev->priv;
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unsigned long flags;
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ktime_t edge;
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/*
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* delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on
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* m68k ndelay(s64) does not compile; so use s32 rather than s64.
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*/
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s32 delta;
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int i;
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unsigned int pulse, space;
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/* Ensure the dividend fits into 32 bit */
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pulse = DIV_ROUND_CLOSEST(gpio_ir->duty_cycle * (NSEC_PER_SEC / 100),
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gpio_ir->carrier);
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space = DIV_ROUND_CLOSEST((100 - gpio_ir->duty_cycle) *
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(NSEC_PER_SEC / 100), gpio_ir->carrier);
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spin_lock_irqsave(&gpio_ir->lock, flags);
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edge = ktime_get();
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for (i = 0; i < count; i++) {
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if (i % 2) {
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// space
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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 > 10) {
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spin_unlock_irqrestore(&gpio_ir->lock, flags);
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usleep_range(delta, delta + 10);
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spin_lock_irqsave(&gpio_ir->lock, flags);
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} else if (delta > 0) {
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udelay(delta);
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}
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} else {
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// pulse
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ktime_t last = ktime_add_us(edge, txbuf[i]);
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while (ktime_before(ktime_get(), last)) {
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gpiod_set_value(gpio_ir->gpio, 1);
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edge = ktime_add_ns(edge, pulse);
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delta = ktime_to_ns(ktime_sub(edge,
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ktime_get()));
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if (delta > 0)
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ndelay(delta);
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gpiod_set_value(gpio_ir->gpio, 0);
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edge = ktime_add_ns(edge, space);
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delta = ktime_to_ns(ktime_sub(edge,
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ktime_get()));
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if (delta > 0)
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ndelay(delta);
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}
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edge = last;
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}
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}
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spin_unlock_irqrestore(&gpio_ir->lock, flags);
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return count;
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}
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static int gpio_ir_tx_probe(struct platform_device *pdev)
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{
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struct gpio_ir *gpio_ir;
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struct rc_dev *rcdev;
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int rc;
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gpio_ir = devm_kmalloc(&pdev->dev, sizeof(*gpio_ir), GFP_KERNEL);
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if (!gpio_ir)
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return -ENOMEM;
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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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gpio_ir->gpio = devm_gpiod_get(&pdev->dev, NULL, GPIOD_OUT_LOW);
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if (IS_ERR(gpio_ir->gpio)) {
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if (PTR_ERR(gpio_ir->gpio) != -EPROBE_DEFER)
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dev_err(&pdev->dev, "Failed to get gpio (%ld)\n",
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PTR_ERR(gpio_ir->gpio));
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return PTR_ERR(gpio_ir->gpio);
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}
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rcdev->priv = gpio_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 = gpio_ir_tx;
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rcdev->s_tx_duty_cycle = gpio_ir_tx_set_duty_cycle;
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rcdev->s_tx_carrier = gpio_ir_tx_set_carrier;
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gpio_ir->carrier = 38000;
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gpio_ir->duty_cycle = 50;
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spin_lock_init(&gpio_ir->lock);
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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 gpio_ir_tx_driver = {
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.probe = gpio_ir_tx_probe,
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.driver = {
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.name = DRIVER_NAME,
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.of_match_table = of_match_ptr(gpio_ir_tx_of_match),
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},
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};
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module_platform_driver(gpio_ir_tx_driver);
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MODULE_DESCRIPTION("GPIO IR Bit Banging Transmitter");
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MODULE_AUTHOR("Sean Young <sean@mess.org>");
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MODULE_LICENSE("GPL");
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