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// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Backlight driver for HP Jornada 700 series (710/720/728)
* Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
*/
#include <linux/backlight.h>
#include <linux/device.h>
#include <linux/fb.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <mach/jornada720.h>
#include <mach/hardware.h>
#include <video/s1d13xxxfb.h>
#define BL_MAX_BRIGHT 255
#define BL_DEF_BRIGHT 25
static int jornada_bl_get_brightness(struct backlight_device *bd)
{
int ret;
/* check if backlight is on */
if (!(PPSR & PPC_LDD1))
return 0;
jornada_ssp_start();
/* cmd should return txdummy */
ret = jornada_ssp_byte(GETBRIGHTNESS);
if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
dev_err(&bd->dev, "get brightness timeout\n");
jornada_ssp_end();
return -ETIMEDOUT;
}
/* exchange txdummy for value */
ret = jornada_ssp_byte(TXDUMMY);
jornada_ssp_end();
return BL_MAX_BRIGHT - ret;
}
static int jornada_bl_update_status(struct backlight_device *bd)
{
int ret = 0;
jornada_ssp_start();
/* If backlight is off then really turn it off */
if (backlight_is_blank(bd)) {
ret = jornada_ssp_byte(BRIGHTNESSOFF);
if (ret != TXDUMMY) {
dev_info(&bd->dev, "brightness off timeout\n");
/* turn off backlight */
PPSR &= ~PPC_LDD1;
PPDR |= PPC_LDD1;
ret = -ETIMEDOUT;
}
} else /* turn on backlight */
PPSR |= PPC_LDD1;
/* send command to our mcu */
if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
dev_info(&bd->dev, "failed to set brightness\n");
ret = -ETIMEDOUT;
goto out;
}
/*
* at this point we expect that the mcu has accepted
* our command and is waiting for our new value
* please note that maximum brightness is 255,
* but due to physical layout it is equal to 0, so we simply
* invert the value (MAX VALUE - NEW VALUE).
*/
if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness)
!= TXDUMMY) {
dev_err(&bd->dev, "set brightness failed\n");
ret = -ETIMEDOUT;
}
/*
* If infact we get an TXDUMMY as output we are happy and dont
* make any further comments about it
*/
out:
jornada_ssp_end();
return ret;
}
static const struct backlight_ops jornada_bl_ops = {
.get_brightness = jornada_bl_get_brightness,
.update_status = jornada_bl_update_status,
.options = BL_CORE_SUSPENDRESUME,
};
static int jornada_bl_probe(struct platform_device *pdev)
{
struct backlight_properties props;
int ret;
struct backlight_device *bd;
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
props.max_brightness = BL_MAX_BRIGHT;
bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME,
&pdev->dev, NULL, &jornada_bl_ops,
&props);
if (IS_ERR(bd)) {
ret = PTR_ERR(bd);
dev_err(&pdev->dev, "failed to register device, err=%x\n", ret);
return ret;
}
bd->props.power = FB_BLANK_UNBLANK;
bd->props.brightness = BL_DEF_BRIGHT;
/*
* note. make sure max brightness is set otherwise
* you will get seemingly non-related errors when
* trying to change brightness
*/
jornada_bl_update_status(bd);
platform_set_drvdata(pdev, bd);
dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n");
return 0;
}
static struct platform_driver jornada_bl_driver = {
.probe = jornada_bl_probe,
.driver = {
.name = "jornada_bl",
},
};
module_platform_driver(jornada_bl_driver);
MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
MODULE_LICENSE("GPL");
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