diff options
Diffstat (limited to 'drivers/video/backlight/ep93xx_bl.c')
| -rw-r--r-- | drivers/video/backlight/ep93xx_bl.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/drivers/video/backlight/ep93xx_bl.c b/drivers/video/backlight/ep93xx_bl.c new file mode 100644 index 00000000000..b0cc4918480 --- /dev/null +++ b/drivers/video/backlight/ep93xx_bl.c @@ -0,0 +1,160 @@ +/* + * 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"); |