backlight: Add pcf50633 backlight driver (2ddfd12f) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/video/backlight/Kconfig

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		@@ -300,6 +300,13 @@ config BACKLIGHT_88PM860X
		help
		Say Y to enable the backlight driver for Marvell 88PM8606.

		config BACKLIGHT_PCF50633
		tristate "Backlight driver for NXP PCF50633 MFD"
		depends on BACKLIGHT_CLASS_DEVICE && MFD_PCF50633
		help
		If you have a backlight driven by a NXP PCF50633 MFD, say Y here to
		enable its driver.

		endif # BACKLIGHT_CLASS_DEVICE

		endif # BACKLIGHT_LCD_SUPPORT

drivers/video/backlight/Makefile

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		@@ -34,4 +34,5 @@ obj-$(CONFIG_BACKLIGHT_ADX) += adx_bl.o
		obj-$(CONFIG_BACKLIGHT_ADP5520) += adp5520_bl.o
		obj-$(CONFIG_BACKLIGHT_ADP8860) += adp8860_bl.o
		obj-$(CONFIG_BACKLIGHT_88PM860X) += 88pm860x_bl.o
		obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o

drivers/video/backlight/pcf50633-backlight.c

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		/*
		* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
		* PCF50633 backlight device driver
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the
		* Free Software Foundation; either version 2 of the License, or (at your
		* option) any later version.
		*
		* You should have received a copy of the GNU General Public License along
		* with this program; if not, write to the Free Software Foundation, Inc.,
		* 675 Mass Ave, Cambridge, MA 02139, USA.
		*
		*/

		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/slab.h>
		#include <linux/platform_device.h>

		#include <linux/backlight.h>
		#include <linux/fb.h>

		#include <linux/mfd/pcf50633/core.h>
		#include <linux/mfd/pcf50633/backlight.h>

		struct pcf50633_bl {
		struct pcf50633 *pcf;
		struct backlight_device *bl;

		unsigned int brightness;
		unsigned int brightness_limit;
		};

		/*
		* pcf50633_bl_set_brightness_limit
		*
		* Update the brightness limit for the pc50633 backlight. The actual brightness
		* will not go above the limit. This is useful to limit power drain for example
		* on low battery.
		*
		* @dev: Pointer to a pcf50633 device
		* @limit: The brightness limit. Valid values are 0-63
		*/
		int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
		{
		struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);

		if (!pcf_bl)
		return -ENODEV;

		pcf_bl->brightness_limit = limit & 0x3f;
		backlight_update_status(pcf_bl->bl);

		return 0;
		}

		static int pcf50633_bl_update_status(struct backlight_device *bl)
		{
		struct pcf50633_bl *pcf_bl = bl_get_data(bl);
		unsigned int new_brightness;


		if (bl->props.state & (BL_CORE_SUSPENDED \| BL_CORE_FBBLANK) \|\|
		bl->props.power != FB_BLANK_UNBLANK)
		new_brightness = 0;
		else if (bl->props.brightness < pcf_bl->brightness_limit)
		new_brightness = bl->props.brightness;
		else
		new_brightness = pcf_bl->brightness_limit;


		if (pcf_bl->brightness == new_brightness)
		return 0;

		if (new_brightness) {
		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
		new_brightness);
		if (!pcf_bl->brightness)
		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
		} else {
		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
		}

		pcf_bl->brightness = new_brightness;

		return 0;
		}

		static int pcf50633_bl_get_brightness(struct backlight_device *bl)
		{
		struct pcf50633_bl *pcf_bl = bl_get_data(bl);
		return pcf_bl->brightness;
		}

		static const struct backlight_ops pcf50633_bl_ops = {
		.get_brightness = pcf50633_bl_get_brightness,
		.update_status = pcf50633_bl_update_status,
		.options = BL_CORE_SUSPENDRESUME,
		};

		static int __devinit pcf50633_bl_probe(struct platform_device *pdev)
		{
		int ret;
		struct pcf50633_bl *pcf_bl;
		struct device *parent = pdev->dev.parent;
		struct pcf50633_platform_data *pcf50633_data = parent->platform_data;
		struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
		struct backlight_properties bl_props;

		pcf_bl = kzalloc(sizeof(*pcf_bl), GFP_KERNEL);
		if (!pcf_bl)
		return -ENOMEM;

		bl_props.max_brightness = 0x3f;
		bl_props.power = FB_BLANK_UNBLANK;

		if (pdata) {
		bl_props.brightness = pdata->default_brightness;
		pcf_bl->brightness_limit = pdata->default_brightness_limit;
		} else {
		bl_props.brightness = 0x3f;
		pcf_bl->brightness_limit = 0x3f;
		}

		pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);

		pcf_bl->bl = backlight_device_register(pdev->name, &pdev->dev, pcf_bl,
		&pcf50633_bl_ops, &bl_props);

		if (IS_ERR(pcf_bl->bl)) {
		ret = PTR_ERR(pcf_bl->bl);
		goto err_free;
		}

		platform_set_drvdata(pdev, pcf_bl);

		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);

		/* Should be different from bl_props.brightness, so we do not exit
		* update_status early the first time it's called */
		pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;

		backlight_update_status(pcf_bl->bl);

		return 0;

		err_free:
		kfree(pcf_bl);

		return ret;
		}

		static int __devexit pcf50633_bl_remove(struct platform_device *pdev)
		{
		struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev);

		backlight_device_unregister(pcf_bl->bl);

		platform_set_drvdata(pdev, NULL);

		kfree(pcf_bl);

		return 0;
		}

		static struct platform_driver pcf50633_bl_driver = {
		.probe = pcf50633_bl_probe,
		.remove = __devexit_p(pcf50633_bl_remove),
		.driver = {
		.name = "pcf50633-backlight",
		},
		};

		static int __init pcf50633_bl_init(void)
		{
		return platform_driver_register(&pcf50633_bl_driver);
		}
		module_init(pcf50633_bl_init);

		static void __exit pcf50633_bl_exit(void)
		{
		platform_driver_unregister(&pcf50633_bl_driver);
		}
		module_exit(pcf50633_bl_exit);

		MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
		MODULE_DESCRIPTION("PCF50633 backlight driver");
		MODULE_LICENSE("GPL");
		MODULE_ALIAS("platform:pcf50633-backlight");

include/linux/mfd/pcf50633/backlight.h

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		/*
		* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
		* PCF50633 backlight device driver
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the
		* Free Software Foundation; either version 2 of the License, or (at your
		* option) any later version.
		*
		* You should have received a copy of the GNU General Public License along
		* with this program; if not, write to the Free Software Foundation, Inc.,
		* 675 Mass Ave, Cambridge, MA 02139, USA.
		*
		*/

		#ifndef __LINUX_MFD_PCF50633_BACKLIGHT
		#define __LINUX_MFD_PCF50633_BACKLIGHT

		/*
		* @default_brightness: Backlight brightness is initialized to this value
		*
		* Brightness to be used after the driver has been probed.
		* Valid range 0-63.
		*
		* @default_brightness_limit: The actual brightness is limited by this value
		*
		* Brightness limit to be used after the driver has been probed. This is useful
		* when it is not known how much power is available for the backlight during
		* probe.
		* Valid range 0-63. Can be changed later with pcf50633_bl_set_brightness_limit.
		*
		* @ramp_time: Display ramp time when changing brightness
		*
		* When changing the backlights brightness the change is not instant, instead
		* it fades smooth from one state to another. This value specifies how long
		* the fade should take. The lower the value the higher the fade time.
		* Valid range 0-255
		*/
		struct pcf50633_bl_platform_data {
		unsigned int default_brightness;
		unsigned int default_brightness_limit;
		uint8_t ramp_time;
		};


		struct pcf50633;

		int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit);

		#endif