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/*++
linux/drivers/video/backlight/wmt_bl.c
Copyright (c) 2013 WonderMedia Technologies, Inc.
This program is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software Foundation,
either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
WonderMedia Technologies, Inc.
10F, 529, Chung-Cheng Road, Hsin-Tien, Taipei 231, R.O.C.
--*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/pwm_backlight.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/leds.h>
#include <mach/wmt_env.h>
#include "wmt_bl.h"
#define LTH_BRIGHTNESS 0
#define DFT_BRIGHTNESS 180
#define DFT_PWM0_FREQ 4 /* kHz */
static struct {
int gpio;
int active;
} power = { -1, 0, };
static int backlight_delay = 0;
static struct led_trigger *genesis_led;
static BLOCKING_NOTIFIER_HEAD(bl_chain_head);
int register_bl_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&bl_chain_head, nb);
}
EXPORT_SYMBOL_GPL(register_bl_notifier);
int unregister_bl_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&bl_chain_head, nb);
}
EXPORT_SYMBOL_GPL(unregister_bl_notifier);
static inline int bl_notifier_call_chain(unsigned long val)
{
int ret = blocking_notifier_call_chain(&bl_chain_head, val, NULL);
return notifier_to_errno(ret);
}
static void backlight_on(bool on)
{
static int old_state = -1;
if (!gpio_is_valid(power.gpio))
return;
if (old_state != on) {
if (old_state == false) {
/* delay 100 ms between 'lcd power on' and 'backlight
* power on' at resume sequence. */
msleep(100);
/* wmt.backlight.delay */
msleep(backlight_delay);
}
gpio_direction_output(power.gpio, on ? power.active : !power.active);
led_trigger_event(genesis_led, on ? LED_FULL : LED_OFF);
old_state = on;
bl_notifier_call_chain(on ? BL_OPEN : BL_CLOSE);
}
}
static int wmt_bl_notify(struct device *dev, int brightness)
{
return brightness;
}
static void wmt_bl_notify_after(struct device *dev, int brightness)
{
backlight_on(brightness != 0);
}
#define KHZ2PICOS(hz) (1000000000/(hz))
static struct platform_pwm_backlight_data wm8880_pwmbl_data = {
.pwm_id = 0,
.invert = 1,
.lth_brightness = LTH_BRIGHTNESS, /* low threshold */
.hth_brightness = 256, /* high threshold */
.max_brightness = 256,
.dft_brightness = DFT_BRIGHTNESS,
.pwm_period_ns = KHZ2PICOS(DFT_PWM0_FREQ*1000), /* revisit when clocks are implemented */
.notify = wmt_bl_notify,
.notify_after = wmt_bl_notify_after,
};
struct platform_device wm8880_device_pwmbl = {
.name = "pwm-backlight",
.id = 0,
.dev = {
.platform_data = &wm8880_pwmbl_data,
},
};
static int parse_backlight_param(void)
{
static char env[] = "wmt.backlight.param";
struct platform_pwm_backlight_data *pdata = &wm8880_pwmbl_data;
uint8_t buf[64];
size_t l = sizeof(buf);
int pwm_freq = DFT_PWM0_FREQ;
int rc;
if (wmt_getsyspara(env, buf, &l)) {
pr_err("please set %s\n", env);
return -EINVAL;
}
/* wmt.backlight.param
* <pwmid>:<invert>:<gpio>:<active>:
* <lth_brightness>:<hth_brightness>:<pwm0freq>:<dft_brightness>
*/
rc = sscanf(buf, "%d:%d:%d:%d:%d:%d:%d:%d",
&pdata->pwm_id,
&pdata->invert,
&power.gpio, &power.active,
&pdata->lth_brightness,
&pdata->hth_brightness,
&pwm_freq,
&pdata->dft_brightness);
if ((rc < 4)) {
pr_err("bad env %s %s\n", env, buf);
return -EINVAL;
}
if ((pdata->hth_brightness > pdata->max_brightness) ||
(pdata->lth_brightness > pdata->hth_brightness))
pdata->hth_brightness = pdata->max_brightness;
pdata->pwm_period_ns = KHZ2PICOS(pwm_freq * 1000);
pr_info("backlight param: pwm%d(%dkHz), invert %d, brightness %d(%d~%d) ",
pdata->pwm_id, pwm_freq, pdata->invert, pdata->dft_brightness,
pdata->lth_brightness, pdata->hth_brightness);
if (gpio_is_valid(power.gpio)) {
if (gpio_request(power.gpio, "pwm_bl switch")) {
pr_warning("gpio request %d failed\n", power.gpio);
power.gpio = -1;
}
pr_info("gpio%d (active %d)\n", power.gpio, power.active);
} else
pr_info("no gpio control\n");
/* parse wmt.backlight.delay */
l = sizeof(buf);
if (wmt_getsyspara("wmt.backlight.delay", buf, &l) == 0) {
sscanf(buf, "%d", &backlight_delay);
}
pr_info("backlight delay: %dms\n", backlight_delay);
return 0;
}
static int __init wmt_bl_init(void)
{
int rc;
rc = parse_backlight_param();
if (rc)
return rc;
led_trigger_register_simple("genesis", &genesis_led);
return platform_device_register(&wm8880_device_pwmbl);
}
static void __exit wmt_bl_exit(void)
{
led_trigger_unregister_simple(genesis_led);
platform_device_unregister(&wm8880_device_pwmbl);
}
module_init(wmt_bl_init);
module_exit(wmt_bl_exit);
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