ARM: SAMSUNG: Create a common infrastructure for PWM backlight support

This patch creates a common structure for LCD backlight
using PWM timer to be used by various Samsung boards.

Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

4 files changed, 182 insertions, 0 deletions

diff --git a/arch/arm/plat-samsung/Kconfig b/arch/arm/plat-samsung/Kconfig
index 4d79519..b3e1065 100644
--- a/arch/arm/plat-samsung/Kconfig
+++ b/arch/arm/plat-samsung/Kconfig
@@ -280,6 +280,12 @@ config SAMSUNG_DEV_PWM
 	help
 	  Compile in platform device definition for PWM Timer
 
+config SAMSUNG_DEV_BACKLIGHT
+	bool
+	depends on SAMSUNG_DEV_PWM
+	help
+	  Compile in platform device definition LCD backlight with PWM Timer
+
 config S3C24XX_PWM
 	bool "PWM device support"
 	select HAVE_PWM
diff --git a/arch/arm/plat-samsung/Makefile b/arch/arm/plat-samsung/Makefile
index 53eb15b..853764b 100644
--- a/arch/arm/plat-samsung/Makefile
+++ b/arch/arm/plat-samsung/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_SAMSUNG_DEV_IDE)	+= dev-ide.o
 obj-$(CONFIG_SAMSUNG_DEV_TS)	+= dev-ts.o
 obj-$(CONFIG_SAMSUNG_DEV_KEYPAD)	+= dev-keypad.o
 obj-$(CONFIG_SAMSUNG_DEV_PWM)	+= dev-pwm.o
+obj-$(CONFIG_SAMSUNG_DEV_BACKLIGHT)	+= dev-backlight.o
 
 # DMA support
 
diff --git a/arch/arm/plat-samsung/dev-backlight.c b/arch/arm/plat-samsung/dev-backlight.c
new file mode 100644
index 0000000..3cedd4c
--- /dev/null
+++ b/arch/arm/plat-samsung/dev-backlight.c
@@ -0,0 +1,149 @@
+/* linux/arch/arm/plat-samsung/dev-backlight.c
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ *
+ * Common infrastructure for PWM Backlight for Samsung boards
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/pwm_backlight.h>
+
+#include <plat/devs.h>
+#include <plat/gpio-cfg.h>
+#include <plat/backlight.h>
+
+static int samsung_bl_init(struct device *dev)
+{
+	int ret = 0;
+	struct platform_device *timer_dev =
+			container_of(dev->parent, struct platform_device, dev);
+	struct samsung_bl_gpio_info *bl_gpio_info =
+			timer_dev->dev.platform_data;
+
+	ret = gpio_request(bl_gpio_info->no, "Backlight");
+	if (ret) {
+		printk(KERN_ERR "failed to request GPIO for LCD Backlight\n");
+		return ret;
+	}
+
+	/* Configure GPIO pin with specific GPIO function for PWM timer */
+	s3c_gpio_cfgpin(bl_gpio_info->no, bl_gpio_info->func);
+
+	return 0;
+}
+
+static void samsung_bl_exit(struct device *dev)
+{
+	struct platform_device *timer_dev =
+			container_of(dev->parent, struct platform_device, dev);
+	struct samsung_bl_gpio_info *bl_gpio_info =
+			timer_dev->dev.platform_data;
+
+	s3c_gpio_cfgpin(bl_gpio_info->no, S3C_GPIO_OUTPUT);
+	gpio_free(bl_gpio_info->no);
+}
+
+/* Initialize few important fields of platform_pwm_backlight_data
+ * structure with default values. These fields can be overridden by
+ * board-specific values sent from machine file.
+ * For ease of operation, these fields are initialized with values
+ * used by most samsung boards.
+ * Users has the option of sending info about other parameters
+ * for their specific boards
+ */
+
+static struct platform_pwm_backlight_data samsung_dfl_bl_data __initdata = {
+	.max_brightness = 255,
+	.dft_brightness = 255,
+	.pwm_period_ns  = 78770,
+	.init           = samsung_bl_init,
+	.exit           = samsung_bl_exit,
+};
+
+static struct platform_device samsung_dfl_bl_device __initdata = {
+	.name		= "pwm-backlight",
+};
+
+/* samsung_bl_set - Set board specific data (if any) provided by user for
+ * PWM Backlight control and register specific PWM and backlight device.
+ * @gpio_info:	structure containing GPIO info for PWM timer
+ * @bl_data:	structure containing Backlight control data
+ */
+void samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,
+	struct platform_pwm_backlight_data *bl_data)
+{
+	int ret = 0;
+	struct platform_device *samsung_bl_device;
+	struct platform_pwm_backlight_data *samsung_bl_data;
+
+	samsung_bl_device = kmemdup(&samsung_dfl_bl_device,
+			sizeof(struct platform_device), GFP_KERNEL);
+	if (!samsung_bl_device) {
+		printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
+		return;
+	}
+
+	samsung_bl_data = s3c_set_platdata(&samsung_dfl_bl_data,
+		sizeof(struct platform_pwm_backlight_data), samsung_bl_device);
+	if (!samsung_bl_data) {
+		printk(KERN_ERR "%s: no memory for platform dev\n", __func__);
+		goto err_data;
+	}
+
+	/* Copy board specific data provided by user */
+	samsung_bl_data->pwm_id = bl_data->pwm_id;
+	samsung_bl_device->dev.parent =
+			&s3c_device_timer[samsung_bl_data->pwm_id].dev;
+
+	if (bl_data->max_brightness)
+		samsung_bl_data->max_brightness = bl_data->max_brightness;
+	if (bl_data->dft_brightness)
+		samsung_bl_data->dft_brightness = bl_data->dft_brightness;
+	if (bl_data->lth_brightness)
+		samsung_bl_data->lth_brightness = bl_data->lth_brightness;
+	if (bl_data->pwm_period_ns)
+		samsung_bl_data->pwm_period_ns = bl_data->pwm_period_ns;
+	if (bl_data->init)
+		samsung_bl_data->init = bl_data->init;
+	if (bl_data->notify)
+		samsung_bl_data->notify = bl_data->notify;
+	if (bl_data->exit)
+		samsung_bl_data->exit = bl_data->exit;
+	if (bl_data->check_fb)
+		samsung_bl_data->check_fb = bl_data->check_fb;
+
+	/* Keep the GPIO info for future use */
+	s3c_device_timer[samsung_bl_data->pwm_id].dev.platform_data = gpio_info;
+
+	/* Register the specific PWM timer dev for Backlight control */
+	ret = platform_device_register(
+			&s3c_device_timer[samsung_bl_data->pwm_id]);
+	if (ret) {
+		printk(KERN_ERR "failed to register pwm timer for backlight: %d\n", ret);
+		goto err_plat_reg1;
+	}
+
+	/* Register the Backlight dev */
+	ret = platform_device_register(samsung_bl_device);
+	if (ret) {
+		printk(KERN_ERR "failed to register backlight device: %d\n", ret);
+		goto err_plat_reg2;
+	}
+
+	return;
+
+err_plat_reg2:
+	platform_device_unregister(&s3c_device_timer[samsung_bl_data->pwm_id]);
+err_plat_reg1:
+	kfree(samsung_bl_data);
+err_data:
+	kfree(samsung_bl_device);
+	return;
+}
diff --git a/arch/arm/plat-samsung/include/plat/backlight.h b/arch/arm/plat-samsung/include/plat/backlight.h
new file mode 100644
index 0000000..51d8da8
--- /dev/null
+++ b/arch/arm/plat-samsung/include/plat/backlight.h
@@ -0,0 +1,26 @@
+/* linux/arch/arm/plat-samsung/include/plat/backlight.h
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ASM_PLAT_BACKLIGHT_H
+#define __ASM_PLAT_BACKLIGHT_H __FILE__
+
+/* samsung_bl_gpio_info - GPIO info for PWM Backlight control
+ * @no:		GPIO number for PWM timer out
+ * @func:	Special function of GPIO line for PWM timer
+ */
+struct samsung_bl_gpio_info {
+	int no;
+	int func;
+};
+
+extern void samsung_bl_set(struct samsung_bl_gpio_info *gpio_info,
+	struct platform_pwm_backlight_data *bl_data);
+
+#endif /* __ASM_PLAT_BACKLIGHT_H */