On Saturday, November 24, 2012 1:35 AM, Laurent Pinchart wrote
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
CC'ed Andrew Morton
It looks good. Also, I tested this patch with SMDK4210 board.
Acked-by: Jingoo Han <jg1.han@xxxxxxxxxxx>
Best regards,
Jingoo Han
> ---
> drivers/video/backlight/Kconfig | 7 ++
> drivers/video/backlight/Makefile | 1 +
> drivers/video/backlight/gpio_backlight.c | 158 ++++++++++++++++++++++++++++++
> include/video/gpio_backlight.h | 21 ++++
> 4 files changed, 187 insertions(+), 0 deletions(-)
> create mode 100644 drivers/video/backlight/gpio_backlight.c
> create mode 100644 include/video/gpio_backlight.h
>
> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
> index 765a945..259442d 100644
> --- a/drivers/video/backlight/Kconfig
> +++ b/drivers/video/backlight/Kconfig
> @@ -390,6 +390,13 @@ config BACKLIGHT_TPS65217
> If you have a Texas Instruments TPS65217 say Y to enable the
> backlight driver.
>
> +config BACKLIGHT_GPIO
> + tristate "Generic GPIO based Backlight Driver"
> + depends on GENERIC_GPIO
> + 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 e7ce729..ec91c4a 100644
> --- a/drivers/video/backlight/Makefile
> +++ b/drivers/video/backlight/Makefile
> @@ -45,3 +45,4 @@ obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
> obj-$(CONFIG_BACKLIGHT_AAT2870) += aat2870_bl.o
> obj-$(CONFIG_BACKLIGHT_OT200) += ot200_bl.o
> obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o
> +obj-$(CONFIG_BACKLIGHT_GPIO) += gpio_backlight.o
> diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> new file mode 100644
> index 0000000..5a8cd34
> --- /dev/null
> +++ b/drivers/video/backlight/gpio_backlight.c
> @@ -0,0 +1,158 @@
> +/*
> + * 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_device.h>
> +#include <linux/slab.h>
> +#include <video/gpio_backlight.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 == info->dev;
> +}
> +
> +static const struct backlight_ops gpio_backlight_ops = {
> + .update_status = gpio_backlight_update_status,
> + .get_brightness = gpio_backlight_get_brightness,
> + .check_fb = gpio_backlight_check_fb,
> +};
> +
> +#ifdef CONFIG_PM
> +static int gpio_backlight_suspend(struct device *dev)
> +{
> + struct backlight_device *bl = dev_get_drvdata(dev);
> + struct gpio_backlight *gbl = bl_get_data(bl);
> +
> + gpio_set_value(gbl->gpio, !gbl->active);
> +
> + return 0;
> +}
> +
> +static int gpio_backlight_resume(struct device *dev)
> +{
> + struct backlight_device *bl = dev_get_drvdata(dev);
> +
> + backlight_update_status(bl);
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(gpio_backlight_pm_ops, gpio_backlight_suspend,
> + gpio_backlight_resume);
> +
> +#endif
> +
> +static int __devinit 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;
> +
> + gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
> + if (gbl == NULL)
> + return -ENOMEM;
> +
> + gbl->dev = &pdev->dev;
> +
> + if (!pdata) {
> + dev_err(&pdev->dev, "failed to find platform data\n");
> + return -ENODEV;
> + }
> +
> + 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,
> + 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 __devexit 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,
> +#ifdef CONFIG_PM
> + .pm = &gpio_backlight_pm_ops,
> +#endif
> + },
> + .probe = gpio_backlight_probe,
> + .remove = __devexit_p(gpio_backlight_remove),
> +};
> +
> +module_platform_driver(gpio_backlight_driver);
> +
> +MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("GPIO-based Backlight Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:gpio-backlight");
> diff --git a/include/video/gpio_backlight.h b/include/video/gpio_backlight.h
> new file mode 100644
> index 0000000..5ae0d9c
> --- /dev/null
> +++ b/include/video/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
> --
> 1.7.8.6
>
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