media: rc: gpio-ir-tx: add new driver (24d79ebc) · Commits · e / devices / android_kernel_fairphone_FP5

MAINTAINERS

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		@@ -5769,6 +5769,12 @@ S: Maintained
		F: Documentation/acpi/gpio-properties.txt
		F: drivers/gpio/gpiolib-acpi.c

		GPIO IR Transmitter
		M: Sean Young <sean@mess.org>
		L: linux-media@vger.kernel.org
		S: Maintained
		F: drivers/media/rc/gpio-ir-tx.c

		GPIO MOCKUP DRIVER
		M: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
		L: linux-gpio@vger.kernel.org

drivers/media/rc/Kconfig

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		@@ -399,6 +399,17 @@ config IR_GPIO_CIR
		To compile this driver as a module, choose M here: the module will
		be called gpio-ir-recv.

		config IR_GPIO_TX
		tristate "GPIO IR Bit Banging Transmitter"
		depends on RC_CORE
		depends on LIRC
		---help---
		Say Y if you want to a GPIO based IR transmitter. This is a
		bit banging driver.

		To compile this driver as a module, choose M here: the module will
		be called gpio-ir-tx.

		config RC_ST
		tristate "ST remote control receiver"
		depends on RC_CORE

drivers/media/rc/Makefile

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		@@ -32,6 +32,7 @@ obj-$(CONFIG_IR_STREAMZAP) += streamzap.o
		obj-$(CONFIG_IR_WINBOND_CIR) += winbond-cir.o
		obj-$(CONFIG_RC_LOOPBACK) += rc-loopback.o
		obj-$(CONFIG_IR_GPIO_CIR) += gpio-ir-recv.o
		obj-$(CONFIG_IR_GPIO_TX) += gpio-ir-tx.o
		obj-$(CONFIG_IR_IGORPLUGUSB) += igorplugusb.o
		obj-$(CONFIG_IR_IGUANA) += iguanair.o
		obj-$(CONFIG_IR_TTUSBIR) += ttusbir.o

drivers/media/rc/gpio-ir-tx.c

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		/*
		* Copyright (C) 2017 Sean Young <sean@mess.org>
		*
		* 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.
		*/

		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/gpio/consumer.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 "gpio-ir-tx"
		#define DEVICE_NAME "GPIO IR Bit Banging Transmitter"

		struct gpio_ir {
		struct gpio_desc *gpio;
		unsigned int carrier;
		unsigned int duty_cycle;
		/* we need a spinlock to hold the cpu while transmitting */
		spinlock_t lock;
		};

		static const struct of_device_id gpio_ir_tx_of_match[] = {
		{ .compatible = "gpio-ir-tx", },
		{ },
		};
		MODULE_DEVICE_TABLE(of, gpio_ir_tx_of_match);

		static int gpio_ir_tx_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
		{
		struct gpio_ir *gpio_ir = dev->priv;

		gpio_ir->duty_cycle = duty_cycle;

		return 0;
		}

		static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier)
		{
		struct gpio_ir *gpio_ir = dev->priv;

		if (!carrier)
		return -EINVAL;

		gpio_ir->carrier = carrier;

		return 0;
		}

		static int gpio_ir_tx(struct rc_dev dev, unsigned int txbuf,
		unsigned int count)
		{
		struct gpio_ir *gpio_ir = dev->priv;
		unsigned long flags;
		ktime_t edge;
		/*
		* delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on
		* m68k ndelay(s64) does not compile; so use s32 rather than s64.
		*/
		s32 delta;
		int i;
		unsigned int pulse, space;

		/* Ensure the dividend fits into 32 bit */
		pulse = DIV_ROUND_CLOSEST(gpio_ir->duty_cycle * (NSEC_PER_SEC / 100),
		gpio_ir->carrier);
		space = DIV_ROUND_CLOSEST((100 - gpio_ir->duty_cycle) *
		(NSEC_PER_SEC / 100), gpio_ir->carrier);

		spin_lock_irqsave(&gpio_ir->lock, flags);

		edge = ktime_get();

		for (i = 0; i < count; i++) {
		if (i % 2) {
		// space
		edge = ktime_add_us(edge, txbuf[i]);
		delta = ktime_us_delta(edge, ktime_get());
		if (delta > 10) {
		spin_unlock_irqrestore(&gpio_ir->lock, flags);
		usleep_range(delta, delta + 10);
		spin_lock_irqsave(&gpio_ir->lock, flags);
		} else if (delta > 0) {
		udelay(delta);
		}
		} else {
		// pulse
		ktime_t last = ktime_add_us(edge, txbuf[i]);

		while (ktime_get() < last) {
		gpiod_set_value(gpio_ir->gpio, 1);
		edge += pulse;
		delta = edge - ktime_get();
		if (delta > 0)
		ndelay(delta);
		gpiod_set_value(gpio_ir->gpio, 0);
		edge += space;
		delta = edge - ktime_get();
		if (delta > 0)
		ndelay(delta);
		}

		edge = last;
		}
		}

		spin_unlock_irqrestore(&gpio_ir->lock, flags);

		return count;
		}

		static int gpio_ir_tx_probe(struct platform_device *pdev)
		{
		struct gpio_ir *gpio_ir;
		struct rc_dev *rcdev;
		int rc;

		gpio_ir = devm_kmalloc(&pdev->dev, sizeof(*gpio_ir), GFP_KERNEL);
		if (!gpio_ir)
		return -ENOMEM;

		rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);
		if (!rcdev)
		return -ENOMEM;

		gpio_ir->gpio = devm_gpiod_get(&pdev->dev, NULL, GPIOD_OUT_LOW);
		if (IS_ERR(gpio_ir->gpio)) {
		if (PTR_ERR(gpio_ir->gpio) != -EPROBE_DEFER)
		dev_err(&pdev->dev, "Failed to get gpio (%ld)\n",
		PTR_ERR(gpio_ir->gpio));
		return PTR_ERR(gpio_ir->gpio);
		}

		rcdev->priv = gpio_ir;
		rcdev->driver_name = DRIVER_NAME;
		rcdev->device_name = DEVICE_NAME;
		rcdev->tx_ir = gpio_ir_tx;
		rcdev->s_tx_duty_cycle = gpio_ir_tx_set_duty_cycle;
		rcdev->s_tx_carrier = gpio_ir_tx_set_carrier;

		gpio_ir->carrier = 38000;
		gpio_ir->duty_cycle = 50;
		spin_lock_init(&gpio_ir->lock);

		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 gpio_ir_tx_driver = {
		.probe = gpio_ir_tx_probe,
		.driver = {
		.name = DRIVER_NAME,
		.of_match_table = of_match_ptr(gpio_ir_tx_of_match),
		},
		};
		module_platform_driver(gpio_ir_tx_driver);

		MODULE_DESCRIPTION("GPIO IR Bit Banging Transmitter");
		MODULE_AUTHOR("Sean Young <sean@mess.org>");
		MODULE_LICENSE("GPL");