08b3924b24
The EP9307, EP9312, and EP9315 processors include a framebuffer peripheral. This peripheral has a dedicated pwm output called BRIGHT that can be used to control the backlight on an LCD. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
161 lines
3.8 KiB
C
161 lines
3.8 KiB
C
/*
|
|
* Driver for the Cirrus EP93xx lcd backlight
|
|
*
|
|
* Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.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.
|
|
*
|
|
* This driver controls the pulse width modulated brightness control output,
|
|
* BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
|
|
*/
|
|
|
|
|
|
#include <linux/platform_device.h>
|
|
#include <linux/io.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/backlight.h>
|
|
|
|
#include <mach/hardware.h>
|
|
|
|
#define EP93XX_RASTER_REG(x) (EP93XX_RASTER_BASE + (x))
|
|
#define EP93XX_RASTER_BRIGHTNESS EP93XX_RASTER_REG(0x20)
|
|
|
|
#define EP93XX_MAX_COUNT 255
|
|
#define EP93XX_MAX_BRIGHT 255
|
|
#define EP93XX_DEF_BRIGHT 128
|
|
|
|
struct ep93xxbl {
|
|
void __iomem *mmio;
|
|
int brightness;
|
|
};
|
|
|
|
static int ep93xxbl_set(struct backlight_device *bl, int brightness)
|
|
{
|
|
struct ep93xxbl *ep93xxbl = bl_get_data(bl);
|
|
|
|
__raw_writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
|
|
|
|
ep93xxbl->brightness = brightness;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ep93xxbl_update_status(struct backlight_device *bl)
|
|
{
|
|
int brightness = bl->props.brightness;
|
|
|
|
if (bl->props.power != FB_BLANK_UNBLANK ||
|
|
bl->props.fb_blank != FB_BLANK_UNBLANK)
|
|
brightness = 0;
|
|
|
|
return ep93xxbl_set(bl, brightness);
|
|
}
|
|
|
|
static int ep93xxbl_get_brightness(struct backlight_device *bl)
|
|
{
|
|
struct ep93xxbl *ep93xxbl = bl_get_data(bl);
|
|
|
|
return ep93xxbl->brightness;
|
|
}
|
|
|
|
static const struct backlight_ops ep93xxbl_ops = {
|
|
.update_status = ep93xxbl_update_status,
|
|
.get_brightness = ep93xxbl_get_brightness,
|
|
};
|
|
|
|
static int __init ep93xxbl_probe(struct platform_device *dev)
|
|
{
|
|
struct ep93xxbl *ep93xxbl;
|
|
struct backlight_device *bl;
|
|
struct backlight_properties props;
|
|
|
|
ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
|
|
if (!ep93xxbl)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* This register is located in the range already ioremap'ed by
|
|
* the framebuffer driver. A MFD driver seems a bit of overkill
|
|
* to handle this so use the static I/O mapping; this address
|
|
* is already virtual.
|
|
*
|
|
* NOTE: No locking is required; the framebuffer does not touch
|
|
* this register.
|
|
*/
|
|
ep93xxbl->mmio = EP93XX_RASTER_BRIGHTNESS;
|
|
|
|
memset(&props, 0, sizeof(struct backlight_properties));
|
|
props.max_brightness = EP93XX_MAX_BRIGHT;
|
|
bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl,
|
|
&ep93xxbl_ops, &props);
|
|
if (IS_ERR(bl))
|
|
return PTR_ERR(bl);
|
|
|
|
bl->props.brightness = EP93XX_DEF_BRIGHT;
|
|
|
|
platform_set_drvdata(dev, bl);
|
|
|
|
ep93xxbl_update_status(bl);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ep93xxbl_remove(struct platform_device *dev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(dev);
|
|
|
|
backlight_device_unregister(bl);
|
|
platform_set_drvdata(dev, NULL);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
static int ep93xxbl_suspend(struct platform_device *dev, pm_message_t state)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(dev);
|
|
|
|
return ep93xxbl_set(bl, 0);
|
|
}
|
|
|
|
static int ep93xxbl_resume(struct platform_device *dev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(dev);
|
|
|
|
backlight_update_status(bl);
|
|
return 0;
|
|
}
|
|
#else
|
|
#define ep93xxbl_suspend NULL
|
|
#define ep93xxbl_resume NULL
|
|
#endif
|
|
|
|
static struct platform_driver ep93xxbl_driver = {
|
|
.driver = {
|
|
.name = "ep93xx-bl",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.probe = ep93xxbl_probe,
|
|
.remove = __devexit_p(ep93xxbl_remove),
|
|
.suspend = ep93xxbl_suspend,
|
|
.resume = ep93xxbl_resume,
|
|
};
|
|
|
|
static int __init ep93xxbl_init(void)
|
|
{
|
|
return platform_driver_register(&ep93xxbl_driver);
|
|
}
|
|
module_init(ep93xxbl_init);
|
|
|
|
static void __exit ep93xxbl_exit(void)
|
|
{
|
|
platform_driver_unregister(&ep93xxbl_driver);
|
|
}
|
|
module_exit(ep93xxbl_exit);
|
|
|
|
MODULE_DESCRIPTION("EP93xx Backlight Driver");
|
|
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:ep93xx-bl");
|