599a52d126
Per device data such as brightness belongs to the indivdual device and should therefore be separate from the the backlight operation function pointers. This patch splits the two types of data and allows simplifcation of some code. Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
83 lines
2.6 KiB
C
83 lines
2.6 KiB
C
/*
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* LCD Lowlevel Control Abstraction
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*
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* Copyright (C) 2003,2004 Hewlett-Packard Company
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*
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*/
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#ifndef _LINUX_LCD_H
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#define _LINUX_LCD_H
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/notifier.h>
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/* Notes on locking:
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*
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* lcd_device->ops_lock is an internal backlight lock protecting the ops
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* field and no code outside the core should need to touch it.
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*
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* Access to set_power() is serialised by the update_lock mutex since
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* most drivers seem to need this and historically get it wrong.
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*
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* Most drivers don't need locking on their get_power() method.
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* If yours does, you need to implement it in the driver. You can use the
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* update_lock mutex if appropriate.
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*
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* Any other use of the locks below is probably wrong.
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*/
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struct lcd_device;
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struct fb_info;
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struct lcd_properties {
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/* The maximum value for contrast (read-only) */
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int max_contrast;
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};
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struct lcd_ops {
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/* Get the LCD panel power status (0: full on, 1..3: controller
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power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
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int (*get_power)(struct lcd_device *);
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/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
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int (*set_power)(struct lcd_device *, int power);
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/* Get the current contrast setting (0-max_contrast) */
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int (*get_contrast)(struct lcd_device *);
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/* Set LCD panel contrast */
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int (*set_contrast)(struct lcd_device *, int contrast);
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/* Check if given framebuffer device is the one LCD is bound to;
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return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
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int (*check_fb)(struct fb_info *);
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};
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struct lcd_device {
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struct lcd_properties props;
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/* This protects the 'ops' field. If 'ops' is NULL, the driver that
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registered this device has been unloaded, and if class_get_devdata()
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points to something in the body of that driver, it is also invalid. */
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struct mutex ops_lock;
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/* If this is NULL, the backing module is unloaded */
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struct lcd_ops *ops;
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/* Serialise access to set_power method */
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struct mutex update_lock;
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/* The framebuffer notifier block */
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struct notifier_block fb_notif;
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/* The class device structure */
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struct class_device class_dev;
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};
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static inline void lcd_set_power(struct lcd_device *ld, int power)
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{
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mutex_lock(&ld->update_lock);
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if (ld->ops && ld->ops->set_power)
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ld->ops->set_power(ld, power);
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mutex_unlock(&ld->update_lock);
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}
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extern struct lcd_device *lcd_device_register(const char *name,
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void *devdata, struct lcd_ops *ops);
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extern void lcd_device_unregister(struct lcd_device *ld);
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#define to_lcd_device(obj) container_of(obj, struct lcd_device, class_dev)
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#endif
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