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yaml
---
r: 295170
b: refs/heads/master
c: 35c1682
h: refs/heads/master
v: v3
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Grazvydas Ignotas authored and Linus Torvalds committed Mar 23, 2012
1 parent 20350bb commit 4ea7dbd
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Showing 4 changed files with 180 additions and 1 deletion.
2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: c8df7428635c02ca3051e39179c83297d8b76fba
refs/heads/master: 35c1682cc069fc1f677012d3170757135e246b39
7 changes: 7 additions & 0 deletions trunk/drivers/video/backlight/Kconfig
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Expand Up @@ -348,6 +348,13 @@ config BACKLIGHT_OT200
To compile this driver as a module, choose M here: the module will be
called ot200_bl.

config BACKLIGHT_PANDORA
tristate "Backlight driver for Pandora console"
depends on TWL4030_CORE
help
If you have a Pandora console, say Y to enable the
backlight driver.

endif # BACKLIGHT_CLASS_DEVICE

endif # BACKLIGHT_LCD_SUPPORT
1 change: 1 addition & 0 deletions trunk/drivers/video/backlight/Makefile
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Expand Up @@ -24,6 +24,7 @@ obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomolcd.o
obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o
obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o
obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o
obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
Expand Down
171 changes: 171 additions & 0 deletions trunk/drivers/video/backlight/pandora_bl.c
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/*
* Backlight driver for Pandora handheld.
* Pandora uses TWL4030 PWM0 -> TPS61161 combo for control backlight.
* Based on pwm_bl.c
*
* Copyright 2009,2012 Gražvydas Ignotas <notasas@gmail.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.
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/i2c/twl.h>
#include <linux/err.h>

#define TWL_PWM0_ON 0x00
#define TWL_PWM0_OFF 0x01

#define TWL_INTBR_GPBR1 0x0c
#define TWL_INTBR_PMBR1 0x0d

#define TWL_PMBR1_PWM0_MUXMASK 0x0c
#define TWL_PMBR1_PWM0 0x04
#define PWM0_CLK_ENABLE BIT(0)
#define PWM0_ENABLE BIT(2)

/* range accepted by hardware */
#define MIN_VALUE 9
#define MAX_VALUE 63
#define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE)

#define PANDORABL_WAS_OFF BL_CORE_DRIVER1

static int pandora_backlight_update_status(struct backlight_device *bl)
{
int brightness = bl->props.brightness;
u8 r;

if (bl->props.power != FB_BLANK_UNBLANK)
brightness = 0;
if (bl->props.state & BL_CORE_FBBLANK)
brightness = 0;
if (bl->props.state & BL_CORE_SUSPENDED)
brightness = 0;

if ((unsigned int)brightness > MAX_USER_VALUE)
brightness = MAX_USER_VALUE;

if (brightness == 0) {
if (bl->props.state & PANDORABL_WAS_OFF)
goto done;

/* first disable PWM0 output, then clock */
twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
r &= ~PWM0_ENABLE;
twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
r &= ~PWM0_CLK_ENABLE;
twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);

goto done;
}

if (bl->props.state & PANDORABL_WAS_OFF) {
/*
* set PWM duty cycle to max. TPS61161 seems to use this
* to calibrate it's PWM sensitivity when it starts.
*/
twl_i2c_write_u8(TWL4030_MODULE_PWM0, MAX_VALUE,
TWL_PWM0_OFF);

/* first enable clock, then PWM0 out */
twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
r &= ~PWM0_ENABLE;
r |= PWM0_CLK_ENABLE;
twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
r |= PWM0_ENABLE;
twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);

/*
* TI made it very easy to enable digital control, so easy that
* it often triggers unintentionally and disabes PWM control,
* so wait until 1 wire mode detection window ends.
*/
usleep_range(2000, 10000);
}

twl_i2c_write_u8(TWL4030_MODULE_PWM0, MIN_VALUE + brightness,
TWL_PWM0_OFF);

done:
if (brightness != 0)
bl->props.state &= ~PANDORABL_WAS_OFF;
else
bl->props.state |= PANDORABL_WAS_OFF;

return 0;
}

static int pandora_backlight_get_brightness(struct backlight_device *bl)
{
return bl->props.brightness;
}

static const struct backlight_ops pandora_backlight_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = pandora_backlight_update_status,
.get_brightness = pandora_backlight_get_brightness,
};

static int pandora_backlight_probe(struct platform_device *pdev)
{
struct backlight_properties props;
struct backlight_device *bl;
u8 r;

memset(&props, 0, sizeof(props));
props.max_brightness = MAX_USER_VALUE;
props.type = BACKLIGHT_RAW;
bl = backlight_device_register(pdev->name, &pdev->dev,
NULL, &pandora_backlight_ops, &props);
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
return PTR_ERR(bl);
}

platform_set_drvdata(pdev, bl);

/* 64 cycle period, ON position 0 */
twl_i2c_write_u8(TWL4030_MODULE_PWM0, 0x80, TWL_PWM0_ON);

bl->props.state |= PANDORABL_WAS_OFF;
bl->props.brightness = MAX_USER_VALUE;
backlight_update_status(bl);

/* enable PWM function in pin mux */
twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1);
r &= ~TWL_PMBR1_PWM0_MUXMASK;
r |= TWL_PMBR1_PWM0;
twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1);

return 0;
}

static int pandora_backlight_remove(struct platform_device *pdev)
{
struct backlight_device *bl = platform_get_drvdata(pdev);
backlight_device_unregister(bl);
return 0;
}

static struct platform_driver pandora_backlight_driver = {
.driver = {
.name = "pandora-backlight",
.owner = THIS_MODULE,
},
.probe = pandora_backlight_probe,
.remove = pandora_backlight_remove,
};

module_platform_driver(pandora_backlight_driver);

MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
MODULE_DESCRIPTION("Pandora Backlight Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pandora-backlight");

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