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backlight: Add pcf50633 backlight driver 

This patch adds a backlight driver for controlling the pcf50633 LED module.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
This commit is contained in:
Lars-Peter Clausen 2010-05-12 02:44:32 +02:00 committed by Richard Purdie
parent 1f976996c7
commit 2ddfd12f35
4 changed files with 249 additions and 0 deletions
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7
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

1
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

190
drivers/video/backlight/pcf50633-backlight.c Normal file
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@ -0,0 +1,190 @@
/*
* 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");

51
include/linux/mfd/pcf50633/backlight.h Normal file
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@ -0,0 +1,51 @@
/*
* 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