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Commit db3df876 authored by Sean Young's avatar Sean Young Committed by Mauro Carvalho Chehab
Browse files

media: rc: pwm-ir-tx: add new driver 



This is new driver which uses pwm, so it is more power-efficient
than the bit banging gpio-ir-tx driver.

Signed-off-by: default avatarSean Young <sean@mess.org>
Reviewed-by: default avatarPavel Machek <pavel@ucw.cz>
Tested-by: default avatarMatthias Reichl <hias@horus.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 24d79ebc

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -10794,6 +10794,12 @@ F: Documentation/devicetree/bindings/hwmon/pwm-fan.txt 
F:	Documentation/hwmon/pwm-fan

F:	drivers/hwmon/pwm-fan.c



PWM IR Transmitter

M:	Sean Young <sean@mess.org>

L:	linux-media@vger.kernel.org

S:	Maintained

F:	drivers/media/rc/pwm-ir-tx.c



PWM SUBSYSTEM

M:	Thierry Reding <thierry.reding@gmail.com>

L:	linux-pwm@vger.kernel.org

drivers/media/rc/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -410,6 +410,18 @@ config IR_GPIO_TX 
	   To compile this driver as a module, choose M here: the module will

	   be called gpio-ir-tx.



config IR_PWM_TX

	tristate "PWM IR transmitter"

	depends on RC_CORE

	depends on LIRC

	depends on PWM

	---help---

	   Say Y if you want to use a PWM based IR transmitter. This is

	   more power efficient than the bit banging gpio driver.



	   To compile this driver as a module, choose M here: the module will

	   be called pwm-ir-tx.



config RC_ST

	tristate "ST remote control receiver"

	depends on RC_CORE

drivers/media/rc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 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_PWM_TX) += pwm-ir-tx.o

obj-$(CONFIG_IR_IGORPLUGUSB) += igorplugusb.o

obj-$(CONFIG_IR_IGUANA) += iguanair.o

obj-$(CONFIG_IR_TTUSBIR) += ttusbir.o

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

0 → 100644
+138 −0
Original line number Diff line number Diff line 
/*

 * 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/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;

	int i, duty, period;

	ktime_t edge;

	long delta;



	period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);

	duty = DIV_ROUND_CLOSEST(pwm_ir->duty_cycle * period, 100);



	pwm_config(pwm, duty, period);



	edge = ktime_get();



	for (i = 0; i < count; i++) {

		if (i % 2) // space

			pwm_disable(pwm);

		else

			pwm_enable(pwm);



		edge = ktime_add_us(edge, txbuf[i]);

		delta = ktime_us_delta(edge, ktime_get());

		if (delta > 0)

			usleep_range(delta, delta + 10);

	}



	pwm_disable(pwm);



	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");