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: Sean Young <sean@mess.org>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index a473604..3847165 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -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

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 06179d3..d27be25 100644 (file)
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -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

diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 3e64a4e..466c402 100644 (file)
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -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

diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
new file mode 100644 (file)
index 0000000..27d0f58
--- /dev/null
+++ b/drivers/media/rc/pwm-ir-tx.c
@@ -0,0 +1,138 @@
+/*
+ * 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");