[PATCH 1/7] backlight: Add GPIO-based backlight driver
Simon Horman
horms+renesas at verge.net.au
Fri Jul 19 00:35:26 EDT 2013
From: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
The GPIO backlight driver controls the backlight in on/off mode through
a single GPIO.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
Acked-by: Jingoo Han <jg1.han at samsung.com>
Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
---
drivers/video/backlight/Kconfig | 7 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/gpio_backlight.c | 133 ++++++++++++++++++++++++++
include/linux/platform_data/gpio_backlight.h | 21 ++++
4 files changed, 162 insertions(+)
create mode 100644 drivers/video/backlight/gpio_backlight.c
create mode 100644 include/linux/platform_data/gpio_backlight.h
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index d5ab658..5ab6423 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -425,6 +425,13 @@ config BACKLIGHT_AS3711
If you have an Austrian Microsystems AS3711 say Y to enable the
backlight driver.
+config BACKLIGHT_GPIO
+ tristate "Generic GPIO based Backlight Driver"
+ depends on GPIOLIB
+ help
+ If you have a LCD backlight adjustable by GPIO, say Y to enable
+ this driver.
+
endif # BACKLIGHT_CLASS_DEVICE
endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 92711fe..65698a8 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_BACKLIGHT_DA903X) += da903x_bl.o
obj-$(CONFIG_BACKLIGHT_DA9052) += da9052_bl.o
obj-$(CONFIG_BACKLIGHT_EP93XX) += ep93xx_bl.o
obj-$(CONFIG_BACKLIGHT_GENERIC) += generic_bl.o
+obj-$(CONFIG_BACKLIGHT_GPIO) += gpio_backlight.o
obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_LM3533) += lm3533_bl.o
diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
new file mode 100644
index 0000000..5fa217f
--- /dev/null
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -0,0 +1,133 @@
+/*
+ * gpio_backlight.c - Simple GPIO-controlled backlight
+ *
+ * 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/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_data/gpio_backlight.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct gpio_backlight {
+ struct device *dev;
+ struct device *fbdev;
+
+ int gpio;
+ int active;
+};
+
+static int gpio_backlight_update_status(struct backlight_device *bl)
+{
+ struct gpio_backlight *gbl = bl_get_data(bl);
+ int brightness = bl->props.brightness;
+
+ if (bl->props.power != FB_BLANK_UNBLANK ||
+ bl->props.fb_blank != FB_BLANK_UNBLANK ||
+ bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+ brightness = 0;
+
+ gpio_set_value(gbl->gpio, brightness ? gbl->active : !gbl->active);
+
+ return 0;
+}
+
+static int gpio_backlight_get_brightness(struct backlight_device *bl)
+{
+ return bl->props.brightness;
+}
+
+static int gpio_backlight_check_fb(struct backlight_device *bl,
+ struct fb_info *info)
+{
+ struct gpio_backlight *gbl = bl_get_data(bl);
+
+ return gbl->fbdev == NULL || gbl->fbdev == info->dev;
+}
+
+static const struct backlight_ops gpio_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = gpio_backlight_update_status,
+ .get_brightness = gpio_backlight_get_brightness,
+ .check_fb = gpio_backlight_check_fb,
+};
+
+static int gpio_backlight_probe(struct platform_device *pdev)
+{
+ struct gpio_backlight_platform_data *pdata = pdev->dev.platform_data;
+ struct backlight_properties props;
+ struct backlight_device *bl;
+ struct gpio_backlight *gbl;
+ int ret;
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "failed to find platform data\n");
+ return -ENODEV;
+ }
+
+ gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
+ if (gbl == NULL)
+ return -ENOMEM;
+
+ gbl->dev = &pdev->dev;
+ gbl->fbdev = pdata->fbdev;
+ gbl->gpio = pdata->gpio;
+ gbl->active = pdata->active_low ? 0 : 1;
+
+ ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT |
+ (gbl->active ? GPIOF_INIT_LOW
+ : GPIOF_INIT_HIGH),
+ pdata->name);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "unable to request GPIO\n");
+ return ret;
+ }
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 1;
+ bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, gbl,
+ &gpio_backlight_ops, &props);
+ if (IS_ERR(bl)) {
+ dev_err(&pdev->dev, "failed to register backlight\n");
+ return PTR_ERR(bl);
+ }
+
+ bl->props.brightness = pdata->def_value;
+ backlight_update_status(bl);
+
+ platform_set_drvdata(pdev, bl);
+ return 0;
+}
+
+static int gpio_backlight_remove(struct platform_device *pdev)
+{
+ struct backlight_device *bl = platform_get_drvdata(pdev);
+
+ backlight_device_unregister(bl);
+ return 0;
+}
+
+static struct platform_driver gpio_backlight_driver = {
+ .driver = {
+ .name = "gpio-backlight",
+ .owner = THIS_MODULE,
+ },
+ .probe = gpio_backlight_probe,
+ .remove = gpio_backlight_remove,
+};
+
+module_platform_driver(gpio_backlight_driver);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart at ideasonboard.com>");
+MODULE_DESCRIPTION("GPIO-based Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-backlight");
diff --git a/include/linux/platform_data/gpio_backlight.h b/include/linux/platform_data/gpio_backlight.h
new file mode 100644
index 0000000..5ae0d9c
--- /dev/null
+++ b/include/linux/platform_data/gpio_backlight.h
@@ -0,0 +1,21 @@
+/*
+ * gpio_backlight.h - Simple GPIO-controlled backlight
+ *
+ * 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 __GPIO_BACKLIGHT_H__
+#define __GPIO_BACKLIGHT_H__
+
+struct device;
+
+struct gpio_backlight_platform_data {
+ struct device *fbdev;
+ int gpio;
+ int def_value;
+ bool active_low;
+ const char *name;
+};
+
+#endif
--
1.7.10.4
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