This is a simple bit-banging GPIO IR TX driver.
Signed-off-by: Sean Young <sean@xxxxxxxx>
---
.../devicetree/bindings/leds/irled/gpio-ir-tx.txt | 11 ++
drivers/media/rc/Kconfig | 11 ++
drivers/media/rc/Makefile | 1 +
drivers/media/rc/gpio-ir-tx.c | 189 +++++++++++++++++++++
4 files changed, 212 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt
create mode 100644 drivers/media/rc/gpio-ir-tx.c
diff --git a/Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt b/Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt
new file mode 100644
index 0000000..bf4d4fb
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/irled/gpio-ir-tx.txt
@@ -0,0 +1,11 @@
+Device tree bindings for IR LED connected through gpio pin which is used as
+IR transmitter.
+
+Required properties:
+ - compatible: should be "gpio-ir-tx".
+
+Example:
+ irled@0 {
+ compatible = "gpio-ir-tx";
+ gpios = <&gpio1 2 GPIO_ACTIVE_HIGH>;
+ };
diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 5e83b76..ad54011 100644
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -388,6 +388,17 @@ 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
diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 245e2c2..3e64a4e 100644
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -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
diff --git a/drivers/media/rc/gpio-ir-tx.c b/drivers/media/rc/gpio-ir-tx.c
new file mode 100644
index 0000000..c2ea002
--- /dev/null
+++ b/drivers/media/rc/gpio-ir-tx.c
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2017 Sean Young <sean@xxxxxxxx>
+ *
+ * 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.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>
+
+#define DRIVER_NAME "gpio-ir-tx"
+#define DEVICE_NAME "GPIO IR Bit Banging Transmitter"
+
+struct gpio_rc_dev {
+ int gpio_nr;
+ unsigned int carrier;
+ unsigned int duty_cycle;
+ bool active_low;
+ /* 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_rc_dev *gpio_dev = dev->priv;
+
+ gpio_dev->duty_cycle = duty_cycle;
+
+ return 0;
+}
+
+static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier)
+{
+ struct gpio_rc_dev *gpio_dev = dev->priv;
+
+ if (!carrier)
+ return -EINVAL;
+
+ gpio_dev->carrier = carrier;
+
+ return 0;
+}
+
+static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
+ unsigned int count)
+{
+ struct gpio_rc_dev *gpio_dev = dev->priv;
+ unsigned long flags;
+ ktime_t edge;
+ s64 delta;
+ int i;
+ unsigned int pulse, space;
+
+ /* Ensure the dividend fits into 32 bit */
+ pulse = DIV_ROUND_CLOSEST(gpio_dev->duty_cycle * (NSEC_PER_SEC / 100),
+ gpio_dev->carrier);
+ space = DIV_ROUND_CLOSEST((100l - gpio_dev->duty_cycle) *
+ (NSEC_PER_SEC / 100), gpio_dev->carrier);
+
+ spin_lock_irqsave(&gpio_dev->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_dev->lock, flags);
+ usleep_range(delta - 10, delta + 10);
+ spin_lock_irqsave(&gpio_dev->lock, flags);
+ } 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_dev->gpio_nr,
+ gpio_dev->active_low);
+ edge += pulse;
+ delta = ktime_sub(edge, ktime_get());
+ if (delta > 0)
+ ndelay(delta);
+ gpio_set_value(gpio_dev->gpio_nr,
+ !gpio_dev->active_low);
+ edge += space;
+ delta = ktime_sub(edge, ktime_get());
+ if (delta > 0)
+ ndelay(delta);
+ }
+
+ edge = last;
+ }
+ }
+
+ spin_unlock_irqrestore(&gpio_dev->lock, flags);
+
+ return count;
+}
+
+static int gpio_ir_tx_probe(struct platform_device *pdev)
+{
+ struct gpio_rc_dev *gpio_dev;
+ 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;
+ }
+
+ gpio_dev = devm_kzalloc(&pdev->dev, sizeof(*gpio_dev), GFP_KERNEL);
+ if (!gpio_dev)
+ return -ENOMEM;
+
+ rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX);
+ if (!rcdev)
+ return -ENOMEM;
+
+ rcdev->priv = gpio_dev;
+ 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_dev->gpio_nr = gpio;
+ gpio_dev->active_low = (flags & OF_GPIO_ACTIVE_LOW) != 0;
+ spin_lock_init(&gpio_dev->lock);
+ gpio_dev->carrier = 38000;
+ gpio_dev->duty_cycle = 50;
+
+ rc = devm_gpio_request(&pdev->dev, gpio, "gpio-ir-tx");
+ if (rc < 0)
+ return rc;
+
+ rc = gpio_direction_output(gpio, !gpio_dev->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");
+ return rc;
+ }
+
+ platform_set_drvdata(pdev, gpio_dev);
+
+ return 0;
+}
+
+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@xxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.9.4
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