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alistair23-linux/include/linux/pwm_backlight.h

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[ARM] pxa: add generic PWM backlight driver Patch mostly from Eric Miao, with minor edits by rmk to convert Eric's driver to a generic PWM-based backlight driver. Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-04-14 02:35:08 -06:00
/*
* Generic PWM backlight driver data - see drivers/video/backlight/pwm_bl.c
*/
#ifndef __LINUX_PWM_BACKLIGHT_H
#define __LINUX_PWM_BACKLIGHT_H
pwm_backlight: add check_fb() hook In systems with multiple framebuffer devices, one of the devices might be blanked while another is unblanked. In order for the backlight blanking logic to know whether to turn off the backlight for a particular framebuffer's blanking notification, it needs to be able to check if a given framebuffer device corresponds to the backlight. This plumbs the check_fb hook from core backlight through the pwm_backlight helper to allow platform code to plug in a check_fb hook. Signed-off-by: Robert Morell <rmorell@nvidia.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Arun Murthy <arun.murthy@stericsson.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:30:31 -06:00
#include <linux/backlight.h>
[ARM] pxa: add generic PWM backlight driver Patch mostly from Eric Miao, with minor edits by rmk to convert Eric's driver to a generic PWM-based backlight driver. Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-04-14 02:35:08 -06:00
struct platform_pwm_backlight_data {
int pwm_id;
unsigned int max_brightness;
unsigned int dft_brightness;
backlight: add low threshold to pwm backlight The intensity of the backlight can be varied from a range of max_brightness to zero. Though most, if not all the pwm based backlight devices start flickering at lower brightness value. And also for each device there exists a brightness value below which the backlight appears to be turned off though the value is not equal to zero. If the range of brightness for a device is from zero to max_brightness. A graph is plotted for brightness Vs intensity for the pwm based backlight device has to be a linear graph. intensity | / | / | / |/ --------- 0 max_brightness But pratically on measuring the above we note that the intensity of backlight goes to zero(OFF) when the value in not zero almost nearing to zero(some x%). so the graph looks like intensity | / | / | / | | ------------ 0 x max_brightness In order to overcome this drawback knowing this x% i.e nothing but the low threshold beyond which the backlight is off and will have no effect, the brightness value is being offset by the low threshold value(retaining the linearity of the graph). Now the graph becomes intensity | / | / | / | / ------------- 0 max_brightness With this for each and every digit increment in the brightness from zero there is a change in the intensity of backlight. Devices having this behaviour can set the low threshold brightness(lth_brightness) and pass the same as platform data else can have it as zero. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Arun Murthy <arun.murthy@stericsson.com> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Acked-by: Richard Purdie <rpurdie@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-11 15:05:28 -07:00
unsigned int lth_brightness;
[ARM] pxa: add generic PWM backlight driver Patch mostly from Eric Miao, with minor edits by rmk to convert Eric's driver to a generic PWM-based backlight driver. Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-04-14 02:35:08 -06:00
unsigned int pwm_period_ns;
pwm-backlight: Add rudimentary device tree support This commit adds very basic support for device tree probing. Currently, only a PWM and a list of distinct brightness levels can be specified. Enabling or disabling backlight power via GPIOs is not yet supported. Reviewed-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-12-16 13:25:29 -07:00
unsigned int *levels;
pwm-backlight: switch to gpiod interface Switch to the new gpiod interface, which allows to handle GPIO properties such as active low transparently and removes a whole bunch of code. There are still a couple of users of this driver that rely on passing the enable GPIO number through platform data, so a fallback mechanism using a GPIO number is still available to avoid breaking them. It will be removed once current users have switched to the GPIO lookup tables provided by the gpiod interface. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-02-26 22:53:34 -07:00
/* TODO remove once all users are switched to gpiod_* API */
pwm-backlight: Add optional enable GPIO To support a wider variety of backlight setups, introduce an optional enable GPIO. Legacy users of the platform data already have a means of supporting GPIOs by using the .init(), .exit() and .notify() hooks. DT users however cannot use those, so an alternative method is required. In order to ease the introduction of the optional enable GPIO, make it available in the platform data first, so that existing users can be converted. Once that has happened a second patch will add code to make use of it in the driver. Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-08-30 03:51:22 -06:00
int enable_gpio;
[ARM] 5044/1: pwm_bl: add init/notify/exit callbacks This allows platform code to manipulate GPIOs and brightness level as needed. Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-05-22 07:18:40 -06:00
int (*init)(struct device *dev);
backlight: Pass device through notify callback in the pwm driver Add the device to the notify callback's arguments in the PWM backlight driver. This brings the notify callback into line with the other callbacks defined by this driver. Signed-off-by: Ben Dooks <ben@simtec.co.uk> Signed-off-by: Simtec Linux Team <linux@simtec.co.uk> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-11-10 10:20:40 -07:00
int (*notify)(struct device *dev, int brightness);
backlight: add a callback 'notify_after' for backlight control We need a callback to do some things after pwm_enable, pwm_disable and pwm_config. Signed-off-by: Dilan Lee <dilee@nvidia.com> Reviewed-by: Robert Morell <rmorell@nvidia.com> Reviewed-by: Arun Murthy <arun.murthy@stericsson.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-25 16:59:17 -06:00
void (*notify_after)(struct device *dev, int brightness);
[ARM] 5044/1: pwm_bl: add init/notify/exit callbacks This allows platform code to manipulate GPIOs and brightness level as needed. Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-05-22 07:18:40 -06:00
void (*exit)(struct device *dev);
pwm_backlight: add check_fb() hook In systems with multiple framebuffer devices, one of the devices might be blanked while another is unblanked. In order for the backlight blanking logic to know whether to turn off the backlight for a particular framebuffer's blanking notification, it needs to be able to check if a given framebuffer device corresponds to the backlight. This plumbs the check_fb hook from core backlight through the pwm_backlight helper to allow platform code to plug in a check_fb hook. Signed-off-by: Robert Morell <rmorell@nvidia.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Arun Murthy <arun.murthy@stericsson.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:30:31 -06:00
int (*check_fb)(struct device *dev, struct fb_info *info);
[ARM] pxa: add generic PWM backlight driver Patch mostly from Eric Miao, with minor edits by rmk to convert Eric's driver to a generic PWM-based backlight driver. Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-04-14 02:35:08 -06:00
};
#endif