133 lines
3.1 KiB
C
133 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Driver for the Cirrus EP93xx lcd backlight
|
|
*
|
|
* Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com>
|
|
*
|
|
* This driver controls the pulse width modulated brightness control output,
|
|
* BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/io.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/backlight.h>
|
|
|
|
#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);
|
|
|
|
writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
|
|
|
|
ep93xxbl->brightness = brightness;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ep93xxbl_update_status(struct backlight_device *bl)
|
|
{
|
|
return ep93xxbl_set(bl, backlight_get_brightness(bl));
|
|
}
|
|
|
|
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 ep93xxbl_probe(struct platform_device *dev)
|
|
{
|
|
struct ep93xxbl *ep93xxbl;
|
|
struct backlight_device *bl;
|
|
struct backlight_properties props;
|
|
struct resource *res;
|
|
|
|
ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
|
|
if (!ep93xxbl)
|
|
return -ENOMEM;
|
|
|
|
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
|
|
if (!res)
|
|
return -ENXIO;
|
|
|
|
/*
|
|
* FIXME - We don't do a request_mem_region here because we are
|
|
* sharing the register space with the framebuffer driver (see
|
|
* drivers/video/ep93xx-fb.c) and doing so will cause the second
|
|
* loaded driver to return -EBUSY.
|
|
*
|
|
* NOTE: No locking is required; the framebuffer does not touch
|
|
* this register.
|
|
*/
|
|
ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start,
|
|
resource_size(res));
|
|
if (!ep93xxbl->mmio)
|
|
return -ENXIO;
|
|
|
|
memset(&props, 0, sizeof(struct backlight_properties));
|
|
props.type = BACKLIGHT_RAW;
|
|
props.max_brightness = EP93XX_MAX_BRIGHT;
|
|
bl = devm_backlight_device_register(&dev->dev, 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;
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int ep93xxbl_suspend(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
|
|
return ep93xxbl_set(bl, 0);
|
|
}
|
|
|
|
static int ep93xxbl_resume(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
|
|
backlight_update_status(bl);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static SIMPLE_DEV_PM_OPS(ep93xxbl_pm_ops, ep93xxbl_suspend, ep93xxbl_resume);
|
|
|
|
static struct platform_driver ep93xxbl_driver = {
|
|
.driver = {
|
|
.name = "ep93xx-bl",
|
|
.pm = &ep93xxbl_pm_ops,
|
|
},
|
|
.probe = ep93xxbl_probe,
|
|
};
|
|
|
|
module_platform_driver(ep93xxbl_driver);
|
|
|
|
MODULE_DESCRIPTION("EP93xx Backlight Driver");
|
|
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:ep93xx-bl");
|