mirror of https://gitee.com/openkylin/linux.git
155 lines
4.1 KiB
C
155 lines
4.1 KiB
C
/*
|
|
* 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(TWL_MODULE_PWM, 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(TWL_MODULE_PWM, 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 const struct backlight_ops pandora_backlight_ops = {
|
|
.options = BL_CORE_SUSPENDRESUME,
|
|
.update_status = pandora_backlight_update_status,
|
|
};
|
|
|
|
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 = devm_backlight_device_register(&pdev->dev, 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(TWL_MODULE_PWM, 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 struct platform_driver pandora_backlight_driver = {
|
|
.driver = {
|
|
.name = "pandora-backlight",
|
|
},
|
|
.probe = pandora_backlight_probe,
|
|
};
|
|
|
|
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");
|