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0fd1958050
The ep93xx backlight driver uses a single register within the framebuffer's register space. Currently the backlight driver uses a static IO mapping for the register since the memory cannot be requested by both drivers. Convert the static mapping to use ioremap so that we can remove the dependency on mach/hardware.h. To do so, we need remove the request_mem_region from both the backlight and framebuffer drivers, since whichever driver is loaded second will fail with -EBUSY otherwise. A proper fix is still required, and a FIXME comment has been added to both drivers. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Suggested-by: Arnd Bergmann <arnd@arndb.de> Cc: Mika Westerberg <mika.westerberg@iki.fi> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
/*
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* Driver for the Cirrus EP93xx lcd backlight
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*
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* Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This driver controls the pulse width modulated brightness control output,
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* BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/fb.h>
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#include <linux/backlight.h>
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#define EP93XX_MAX_COUNT 255
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#define EP93XX_MAX_BRIGHT 255
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#define EP93XX_DEF_BRIGHT 128
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struct ep93xxbl {
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void __iomem *mmio;
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int brightness;
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};
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static int ep93xxbl_set(struct backlight_device *bl, int brightness)
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{
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struct ep93xxbl *ep93xxbl = bl_get_data(bl);
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writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
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ep93xxbl->brightness = brightness;
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return 0;
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}
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static int ep93xxbl_update_status(struct backlight_device *bl)
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{
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int brightness = bl->props.brightness;
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if (bl->props.power != FB_BLANK_UNBLANK ||
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bl->props.fb_blank != FB_BLANK_UNBLANK)
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brightness = 0;
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return ep93xxbl_set(bl, brightness);
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}
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static int ep93xxbl_get_brightness(struct backlight_device *bl)
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{
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struct ep93xxbl *ep93xxbl = bl_get_data(bl);
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return ep93xxbl->brightness;
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}
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static const struct backlight_ops ep93xxbl_ops = {
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.update_status = ep93xxbl_update_status,
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.get_brightness = ep93xxbl_get_brightness,
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};
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static int __init ep93xxbl_probe(struct platform_device *dev)
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{
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struct ep93xxbl *ep93xxbl;
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struct backlight_device *bl;
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struct backlight_properties props;
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struct resource *res;
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ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
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if (!ep93xxbl)
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return -ENOMEM;
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res = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (!res)
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return -ENXIO;
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/*
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* FIXME - We don't do a request_mem_region here because we are
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* sharing the register space with the framebuffer driver (see
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* drivers/video/ep93xx-fb.c) and doing so will cause the second
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* loaded driver to return -EBUSY.
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*
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* NOTE: No locking is required; the framebuffer does not touch
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* this register.
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*/
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ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start,
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resource_size(res));
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if (!ep93xxbl->mmio)
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return -ENXIO;
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memset(&props, 0, sizeof(struct backlight_properties));
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props.type = BACKLIGHT_RAW;
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props.max_brightness = EP93XX_MAX_BRIGHT;
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bl = backlight_device_register(dev->name, &dev->dev, ep93xxbl,
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&ep93xxbl_ops, &props);
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if (IS_ERR(bl))
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return PTR_ERR(bl);
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bl->props.brightness = EP93XX_DEF_BRIGHT;
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platform_set_drvdata(dev, bl);
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ep93xxbl_update_status(bl);
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return 0;
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}
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static int ep93xxbl_remove(struct platform_device *dev)
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{
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struct backlight_device *bl = platform_get_drvdata(dev);
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backlight_device_unregister(bl);
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platform_set_drvdata(dev, NULL);
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return 0;
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}
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#ifdef CONFIG_PM
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static int ep93xxbl_suspend(struct platform_device *dev, pm_message_t state)
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{
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struct backlight_device *bl = platform_get_drvdata(dev);
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return ep93xxbl_set(bl, 0);
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}
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static int ep93xxbl_resume(struct platform_device *dev)
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{
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struct backlight_device *bl = platform_get_drvdata(dev);
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backlight_update_status(bl);
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return 0;
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}
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#else
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#define ep93xxbl_suspend NULL
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#define ep93xxbl_resume NULL
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#endif
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static struct platform_driver ep93xxbl_driver = {
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.driver = {
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.name = "ep93xx-bl",
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.owner = THIS_MODULE,
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},
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.probe = ep93xxbl_probe,
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.remove = __devexit_p(ep93xxbl_remove),
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.suspend = ep93xxbl_suspend,
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.resume = ep93xxbl_resume,
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};
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module_platform_driver(ep93xxbl_driver);
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MODULE_DESCRIPTION("EP93xx Backlight Driver");
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MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ep93xx-bl");
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