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

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

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index 55d756712baf458245a94968a5b56c6d945e353d..a4736049d1f1493a4f62c9dfae6b362036922d9c 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -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

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index b6433c57a02468fdfe989afbd73430e85921c06e..06179d37a7c7685214cbbc7d31ff379e35e8f7f7 100644 (file)
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -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

diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 245e2c2d0b223b94e93961b33a63fd8bdaacfc79..3e64a4e4b3129108af3fa45370d5855d021fbd43 100644 (file)
--- 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 (file)
index 0000000..0b83408
--- /dev/null
+++ b/drivers/media/rc/gpio-ir-tx.c
@@ -0,0 +1,174 @@
+/*
+ * 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");