Generic Raspberry Pi IR transmitters

This is a simple bit-banging GPIO IR TX driver.

drivers/media/rc/gpio-ir-tx.c new file +6 -0

new file mode 100644
index 0000000..7a5371d
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2017 Sean Young <[email protected]>
+ *
+ * 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.

drivers/media/rc/gpio-ir-tx.c new file +66 -0

+	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);

drivers/media/rc/gpio-ir-tx.c new file +11 -0

+				edge += space;
+				delta = edge - ktime_get();
+				if (delta > 0)
+					ndelay(delta);
+			}
+
+			edge = last;
+		}
+	}
+
+	spin_unlock_irqrestore(&gpio_ir->lock, flags);

drivers/media/rc/gpio-ir-tx.c new file +20 -0

+
+	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 Bit Banging IR Transmitter");
+MODULE_AUTHOR("Sean Young <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.9.4

Hi Sean,

Quoted 1 line · Sean Young

This is a simple bit-banging GPIO IR TX driver.

thanks a lot for the driver, this is highly appreciated!

I tested the patch series on a RPi2, against RPi downstream kernel 4.13-rc1, and noticed an issue: the polarity of the gpio seems to be reversed.

Other than the polarity issue the driver seems to work fine - at least on the scope screen. Didn't have an IR transmitter to do some real tests yet.

I've configured the gpio as active high:

gpio_ir_tx: gpio-ir-transmitter {
	compatible = "gpio-ir-tx";
	gpios = <&gpio 18 0>;
};

However, when loading the gpio-ir-tx driver the gpio pin changed to 3.3V. I did some tests with ir-ctl -S, idle state of the signal was 3.3V, active state 0V.

I think it's better to use the descriptor based gpio functions instead of the legacy number based ones. That'll simplify the driver and it can delegate polarity handling to gpiod.

Proposed changes and comments are inline. I've also included the patch against your patch that I've been testing with at the end of the message.

Quoted 12 lines

drivers/media/rc/gpio-ir-tx.c new file +6 -0

new file mode 100644
index 0000000..7a5371d
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2017 Sean Young <[email protected]>
+ *
+ * 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.

drivers/media/rc/gpio-ir-tx.c line 16

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+ *
+ * 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.h>

use linux/gpio/consumer.h instead of linux/gpio.h

drivers/media/rc/gpio-ir-tx.c line 20

Quoted 4 lines

drivers/media/rc/gpio-ir-tx.c new file +4 -0

+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>

of_gpio.h can be dropped

drivers/media/rc/gpio-ir-tx.c line 29

Quoted 9 lines

drivers/media/rc/gpio-ir-tx.c new file +9 -0

+#include <linux/platform_device.h>
+#include <media/rc-core.h>
+
+#define DRIVER_NAME	"gpio-ir-tx"
+#define DEVICE_NAME	"GPIO Bit Banging IR Transmitter"
+
+struct gpio_ir {
+	int gpio_nr;
+	bool active_low;

Replace these 2 fields with

	struct gpio_desc *gpio;

Quoted 66 lines

drivers/media/rc/gpio-ir-tx.c new file +66 -0

+	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);

drivers/media/rc/gpio-ir-tx.c line 105

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+			} else if (delta > 0) {
+				udelay(delta);
+			}
+		} else {
+			// pulse
+			ktime_t last = ktime_add_us(edge, txbuf[i]);
+
+			while (ktime_get() < last) {
+				gpio_set_value(gpio_ir->gpio_nr,
+					       gpio_ir->active_low);

				gpiod_set_value(gpio_ir->gpio, 1);

drivers/media/rc/gpio-ir-tx.c line 111

Quoted 6 lines

drivers/media/rc/gpio-ir-tx.c new file +6 -0

+				edge += pulse;
+				delta = edge - ktime_get();
+				if (delta > 0)
+					ndelay(delta);
+				gpio_set_value(gpio_ir->gpio_nr,
+					       !gpio_ir->active_low);

				gpiod_set_value(gpio_ir->gpio, 0);

Quoted 11 lines

drivers/media/rc/gpio-ir-tx.c new file +11 -0

+				edge += space;
+				delta = edge - ktime_get();
+				if (delta > 0)
+					ndelay(delta);
+			}
+
+			edge = last;
+		}
+	}
+
+	spin_unlock_irqrestore(&gpio_ir->lock, flags);

drivers/media/rc/gpio-ir-tx.c line 132

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+
+	return count;
+}
+
+static int gpio_ir_tx_probe(struct platform_device *pdev)
+{
+	struct gpio_ir *gpio_ir;
+	struct rc_dev *rcdev;
+	enum of_gpio_flags flags;
+	int rc, gpio;

Flags can be dropped, gpio as well.

drivers/media/rc/gpio-ir-tx.c line 140

Quoted 8 lines

drivers/media/rc/gpio-ir-tx.c new file +8 -0

+
+	gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
+	if (gpio < 0) {
+		if (gpio != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Failed to get gpio flags (%d)\n",
+				gpio);
+		return -EINVAL;
+	}

Drop this and move getting the gpio a bit down so we don't need a temp variable.

drivers/media/rc/gpio-ir-tx.c line 148

Quoted 8 lines

drivers/media/rc/gpio-ir-tx.c new file +8 -0

+
+	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;

get the gpio here, configure it to output with logical low (idle) level and store it in gpio_ir:

	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);
	}

drivers/media/rc/gpio-ir-tx.c line 158

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+
+	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->gpio_nr = gpio;
+	gpio_ir->active_low = (flags & OF_GPIO_ACTIVE_LOW) != 0;

drop gpio_nr and active_low

drivers/media/rc/gpio-ir-tx.c line 169

Quoted 11 lines

drivers/media/rc/gpio-ir-tx.c new file +11 -0

+	gpio_ir->carrier = 38000;
+	gpio_ir->duty_cycle = 50;
+	spin_lock_init(&gpio_ir->lock);
+
+	rc = devm_gpio_request(&pdev->dev, gpio, "gpio-ir-tx");
+	if (rc < 0)
+		return rc;
+
+	rc = gpio_direction_output(gpio, !gpio_ir->active_low);
+	if (rc < 0)
+		return rc;

drop devm_gpio_request and gpio_direction_output, that is already handled by devm_gpiod_get.

Quoted 22 lines

drivers/media/rc/gpio-ir-tx.c new file +20 -0

+
+	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 Bit Banging IR Transmitter");
+MODULE_AUTHOR("Sean Young <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.9.4

so long,

Hias
---

drivers/media/rc/gpio-ir-tx.c +13 -28

index 7a5371dbb360..ca6834d09467 100644
@@ -13,11 +13,10 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/of.h>
-#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <media/rc-core.h>
 

@@ -25,8 +24,7 @@
 #define DEVICE_NAME	"GPIO Bit Banging IR Transmitter"
 
 struct gpio_ir {
-	int gpio_nr;
-	bool active_low;
+	struct gpio_desc *gpio;
 	unsigned int carrier;
 	unsigned int duty_cycle;
 	/* we need a spinlock to hold the cpu while transmitting */

@@ -101,14 +99,12 @@ static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 			ktime_t last = ktime_add_us(edge, txbuf[i]);
 
 			while (ktime_get() < last) {
-				gpio_set_value(gpio_ir->gpio_nr,
-					       gpio_ir->active_low);
+				gpiod_set_value(gpio_ir->gpio, 1);
 				edge += pulse;
 				delta = edge - ktime_get();
 				if (delta > 0)
 					ndelay(delta);
-				gpio_set_value(gpio_ir->gpio_nr,
-					       !gpio_ir->active_low);
+				gpiod_set_value(gpio_ir->gpio, 0);
 				edge += space;
 				delta = edge - ktime_get();
 				if (delta > 0)

@@ -128,16 +124,7 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 {
 	struct gpio_ir *gpio_ir;
 	struct rc_dev *rcdev;
-	enum of_gpio_flags flags;
-	int rc, gpio;
-
-	gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
-	if (gpio < 0) {
-		if (gpio != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "Failed to get gpio flags (%d)\n",
-				gpio);
-		return -EINVAL;
-	}
+	int rc;
 
 	gpio_ir = devm_kmalloc(&pdev->dev, sizeof(*gpio_ir), GFP_KERNEL);
 	if (!gpio_ir)

@@ -147,6 +134,14 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 	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;

@@ -154,20 +149,10 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 	rcdev->s_tx_duty_cycle = gpio_ir_tx_set_duty_cycle;
 	rcdev->s_tx_carrier = gpio_ir_tx_set_carrier;
 
-	gpio_ir->gpio_nr = gpio;
-	gpio_ir->active_low = (flags & OF_GPIO_ACTIVE_LOW) != 0;
 	gpio_ir->carrier = 38000;
 	gpio_ir->duty_cycle = 50;
 	spin_lock_init(&gpio_ir->lock);
 
-	rc = devm_gpio_request(&pdev->dev, gpio, "gpio-ir-tx");
-	if (rc < 0)
-		return rc;
-
-	rc = gpio_direction_output(gpio, !gpio_ir->active_low);
-	if (rc < 0)
-		return rc;
-
 	rc = devm_rc_register_device(&pdev->dev, rcdev);
 	if (rc < 0)
 		dev_err(&pdev->dev, "failed to register rc device\n");

Hi Sean,

Quoted 1 line · Sean Young

This is a simple bit-banging GPIO IR TX driver.

thanks a lot for the driver, this is highly appreciated!

I tested the patch series on a RPi2, against RPi downstream kernel 4.13-rc1, and noticed an issue: the polarity of the gpio seems to be reversed.

Other than the polarity issue the driver seems to work fine - at least on the scope screen. Didn't have an IR transmitter to do some real tests yet.

I've configured the gpio as active high:

gpio_ir_tx: gpio-ir-transmitter {
	compatible = "gpio-ir-tx";
	gpios = <&gpio 18 0>;
};

However, when loading the gpio-ir-tx driver the gpio pin changed to 3.3V. I did some tests with ir-ctl -S, idle state of the signal was 3.3V, active state 0V.

I think it's better to use the descriptor based gpio functions instead of the legacy number based ones. That'll simplify the driver and it can delegate polarity handling to gpiod.

Proposed changes and comments are inline. I've also included the patch against your patch that I've been testing with at the end of the message.

Quoted 13 lines

drivers/media/rc/gpio-ir-tx.c new file +6 -0

new file mode 100644
index 0000000..7a5371d
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2017 Sean Young <[email protected]>
+ *
+ * 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.

drivers/media/rc/gpio-ir-tx.c line 16

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+ *
+ * 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.h>

use linux/gpio/consumer.h instead of linux/gpio.h

drivers/media/rc/gpio-ir-tx.c line 20

Quoted 4 lines

drivers/media/rc/gpio-ir-tx.c new file +4 -0

+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>

of_gpio.h can be dropped

drivers/media/rc/gpio-ir-tx.c line 29

Quoted 9 lines

drivers/media/rc/gpio-ir-tx.c new file +9 -0

+#include <linux/platform_device.h>
+#include <media/rc-core.h>
+
+#define DRIVER_NAME	"gpio-ir-tx"
+#define DEVICE_NAME	"GPIO Bit Banging IR Transmitter"
+
+struct gpio_ir {
+	int gpio_nr;
+	bool active_low;

Replace these 2 fields with

	struct gpio_desc *gpio;

Quoted 66 lines

drivers/media/rc/gpio-ir-tx.c new file +66 -0

+	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);

drivers/media/rc/gpio-ir-tx.c line 105

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+			} else if (delta > 0) {
+				udelay(delta);
+			}
+		} else {
+			// pulse
+			ktime_t last = ktime_add_us(edge, txbuf[i]);
+
+			while (ktime_get() < last) {
+				gpio_set_value(gpio_ir->gpio_nr,
+					       gpio_ir->active_low);

				gpiod_set_value(gpio_ir->gpio, 1);

drivers/media/rc/gpio-ir-tx.c line 111

Quoted 6 lines

drivers/media/rc/gpio-ir-tx.c new file +6 -0

+				edge += pulse;
+				delta = edge - ktime_get();
+				if (delta > 0)
+					ndelay(delta);
+				gpio_set_value(gpio_ir->gpio_nr,
+					       !gpio_ir->active_low);

				gpiod_set_value(gpio_ir->gpio, 0);

Quoted 11 lines

drivers/media/rc/gpio-ir-tx.c new file +11 -0

+				edge += space;
+				delta = edge - ktime_get();
+				if (delta > 0)
+					ndelay(delta);
+			}
+
+			edge = last;
+		}
+	}
+
+	spin_unlock_irqrestore(&gpio_ir->lock, flags);

drivers/media/rc/gpio-ir-tx.c line 132

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+
+	return count;
+}
+
+static int gpio_ir_tx_probe(struct platform_device *pdev)
+{
+	struct gpio_ir *gpio_ir;
+	struct rc_dev *rcdev;
+	enum of_gpio_flags flags;
+	int rc, gpio;

Flags can be dropped, gpio as well.

drivers/media/rc/gpio-ir-tx.c line 140

Quoted 8 lines

drivers/media/rc/gpio-ir-tx.c new file +8 -0

+
+	gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
+	if (gpio < 0) {
+		if (gpio != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Failed to get gpio flags (%d)\n",
+				gpio);
+		return -EINVAL;
+	}

Drop this and move getting the gpio a bit down so we don't need a temp variable.

drivers/media/rc/gpio-ir-tx.c line 148

Quoted 8 lines

drivers/media/rc/gpio-ir-tx.c new file +8 -0

+
+	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;

get the gpio here, configure it to output with logical low (idle) level and store it in gpio_ir:

	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);
	}

drivers/media/rc/gpio-ir-tx.c line 158

Quoted 10 lines

drivers/media/rc/gpio-ir-tx.c new file +10 -0

+
+	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->gpio_nr = gpio;
+	gpio_ir->active_low = (flags & OF_GPIO_ACTIVE_LOW) != 0;

drop gpio_nr and active_low

drivers/media/rc/gpio-ir-tx.c line 169

Quoted 11 lines

drivers/media/rc/gpio-ir-tx.c new file +11 -0

+	gpio_ir->carrier = 38000;
+	gpio_ir->duty_cycle = 50;
+	spin_lock_init(&gpio_ir->lock);
+
+	rc = devm_gpio_request(&pdev->dev, gpio, "gpio-ir-tx");
+	if (rc < 0)
+		return rc;
+
+	rc = gpio_direction_output(gpio, !gpio_ir->active_low);
+	if (rc < 0)
+		return rc;

drop devm_gpio_request and gpio_direction_output, that is already handled by devm_gpiod_get.

Quoted 14 lines

drivers/media/rc/gpio-ir-tx.c new file +14 -0

+
+	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),
+	},

Quoted 8 lines

drivers/media/rc/gpio-ir-tx.c new file +6 -0

+};
+module_platform_driver(gpio_ir_tx_driver);
+
+MODULE_DESCRIPTION("GPIO Bit Banging IR Transmitter");
+MODULE_AUTHOR("Sean Young <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.9.4

so long,

Hias
---

drivers/media/rc/gpio-ir-tx.c +13 -28

index 7a5371dbb360..ca6834d09467 100644
@@ -13,11 +13,10 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/of.h>
-#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <media/rc-core.h>
 

@@ -25,8 +24,7 @@
 #define DEVICE_NAME	"GPIO Bit Banging IR Transmitter"
 
 struct gpio_ir {
-	int gpio_nr;
-	bool active_low;
+	struct gpio_desc *gpio;
 	unsigned int carrier;
 	unsigned int duty_cycle;
 	/* we need a spinlock to hold the cpu while transmitting */

@@ -101,14 +99,12 @@ static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 			ktime_t last = ktime_add_us(edge, txbuf[i]);
 
 			while (ktime_get() < last) {
-				gpio_set_value(gpio_ir->gpio_nr,
-					       gpio_ir->active_low);
+				gpiod_set_value(gpio_ir->gpio, 1);
 				edge += pulse;
 				delta = edge - ktime_get();
 				if (delta > 0)
 					ndelay(delta);
-				gpio_set_value(gpio_ir->gpio_nr,
-					       !gpio_ir->active_low);
+				gpiod_set_value(gpio_ir->gpio, 0);
 				edge += space;
 				delta = edge - ktime_get();
 				if (delta > 0)

@@ -128,16 +124,7 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 {
 	struct gpio_ir *gpio_ir;
 	struct rc_dev *rcdev;
-	enum of_gpio_flags flags;
-	int rc, gpio;
-
-	gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
-	if (gpio < 0) {
-		if (gpio != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "Failed to get gpio flags (%d)\n",
-				gpio);
-		return -EINVAL;
-	}
+	int rc;
 
 	gpio_ir = devm_kmalloc(&pdev->dev, sizeof(*gpio_ir), GFP_KERNEL);
 	if (!gpio_ir)

@@ -147,6 +134,14 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 	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;

@@ -154,20 +149,10 @@ static int gpio_ir_tx_probe(struct platform_device *pdev)
 	rcdev->s_tx_duty_cycle = gpio_ir_tx_set_duty_cycle;
 	rcdev->s_tx_carrier = gpio_ir_tx_set_carrier;
 
-	gpio_ir->gpio_nr = gpio;
-	gpio_ir->active_low = (flags & OF_GPIO_ACTIVE_LOW) != 0;
 	gpio_ir->carrier = 38000;
 	gpio_ir->duty_cycle = 50;
 	spin_lock_init(&gpio_ir->lock);
 
-	rc = devm_gpio_request(&pdev->dev, gpio, "gpio-ir-tx");
-	if (rc < 0)
-		return rc;
-
-	rc = gpio_direction_output(gpio, !gpio_ir->active_low);
-	if (rc < 0)
-		return rc;
-
 	rc = devm_rc_register_device(&pdev->dev, rcdev);
 	if (rc < 0)
 		dev_err(&pdev->dev, "failed to register rc device\n");

Document the device tree bindings for the GPIO Bit Banging IR Transmitter.

Signed-off-by Sean Young <[email protected]>

---
 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt

Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt new file +0 -0

new file mode 100644
index 0000000..bc08d89

Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt new file +6 -0

+
+Example:
+	irled@0 {
+		compatible = "gpio-ir-tx";
+		gpios = <&gpio1 2 GPIO_ACTIVE_HIGH>;
+	};

Signature · 6 lines

2.9.4

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Quoted 9 lines · Sean Young

Document the device tree bindings for the GPIO Bit Banging IR Transmitter.

Signed-off-by Sean Young <[email protected]>

---
 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt

Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt line 5

Quoted 11 lines

Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt new file +5 -0

new file mode 100644
index 0000000..bc08d89
@@ -0,0 +1,11 @@
+Device tree bindings for IR LED connected through gpio pin which is used as
+remote controller transmitter.
+
+Required properties:
+	- compatible: should be "gpio-ir-tx".

As I mentioned in the prior version, missing the "gpios" property.

Document the device tree bindings for the GPIO Bit Banging IR Transmitter.

Signed-off-by Sean Young <[email protected]>

---
 .../devicetree/bindings/leds/irled/gpio-ir-tx.txt          | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt

Document the device tree bindings for the PWM IR Transmitter.

Signed-off-by Sean Young <[email protected]>

---
 Documentation/devicetree/bindings/leds/irled/pwm-ir-tx.txt | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/irled/pwm-ir-tx.txt

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

Signed-off-by Sean Young <[email protected]>

---
 MAINTAINERS                  |   6 ++
 drivers/media/rc/Kconfig     |  12 ++++
 drivers/media/rc/Makefile    |   1 +
 drivers/media/rc/pwm-ir-tx.c | 138 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 157 insertions(+)
 create mode 100644 drivers/media/rc/pwm-ir-tx.c

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

Signed-off-by Sean Young <[email protected]>

---
 MAINTAINERS                  |   6 ++
 drivers/media/rc/Kconfig     |  12 ++++
 drivers/media/rc/Makefile    |   1 +
 drivers/media/rc/pwm-ir-tx.c | 138 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 157 insertions(+)
 create mode 100644 drivers/media/rc/pwm-ir-tx.c

MAINTAINERS +6 -0

index 8a37c2f..446a528 100644
@@ -10449,6 +10449,12 @@ 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 <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	drivers/media/rc/pwm-ir-tx.c
+
 PWM SUBSYSTEM
 M:	Thierry Reding <[email protected]>
 L:	[email protected]

drivers/media/rc/Kconfig +12 -0

index ef767d1..bca77f0 100644
@@ -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

index 3e64a4e..466c402 100644
@@ -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 new file +138 -0

new file mode 100644
index 0000000..27d0f58
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2017 Sean Young <[email protected]>
+ *
+ * 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 <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.9.4