mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-29 23:53:32 +00:00
0c9501f823
Some backlight GPIOs might be connected to some i2c based expanders whose access might sleep. Since it's not in any critical path, use the cansleep variant of the GPIO API. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
437 lines
10 KiB
C
437 lines
10 KiB
C
/*
|
|
* linux/drivers/video/backlight/pwm_bl.c
|
|
*
|
|
* simple PWM based backlight control, board code has to setup
|
|
* 1) pin configuration so PWM waveforms can output
|
|
* 2) platform_data being correctly configured
|
|
*
|
|
* 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/gpio/consumer.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/backlight.h>
|
|
#include <linux/err.h>
|
|
#include <linux/pwm.h>
|
|
#include <linux/pwm_backlight.h>
|
|
#include <linux/regulator/consumer.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct pwm_bl_data {
|
|
struct pwm_device *pwm;
|
|
struct device *dev;
|
|
unsigned int period;
|
|
unsigned int lth_brightness;
|
|
unsigned int *levels;
|
|
bool enabled;
|
|
struct regulator *power_supply;
|
|
struct gpio_desc *enable_gpio;
|
|
unsigned int scale;
|
|
bool legacy;
|
|
int (*notify)(struct device *,
|
|
int brightness);
|
|
void (*notify_after)(struct device *,
|
|
int brightness);
|
|
int (*check_fb)(struct device *, struct fb_info *);
|
|
void (*exit)(struct device *);
|
|
};
|
|
|
|
static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
|
|
{
|
|
int err;
|
|
|
|
if (pb->enabled)
|
|
return;
|
|
|
|
err = regulator_enable(pb->power_supply);
|
|
if (err < 0)
|
|
dev_err(pb->dev, "failed to enable power supply\n");
|
|
|
|
if (pb->enable_gpio)
|
|
gpiod_set_value_cansleep(pb->enable_gpio, 1);
|
|
|
|
pwm_enable(pb->pwm);
|
|
pb->enabled = true;
|
|
}
|
|
|
|
static void pwm_backlight_power_off(struct pwm_bl_data *pb)
|
|
{
|
|
if (!pb->enabled)
|
|
return;
|
|
|
|
pwm_config(pb->pwm, 0, pb->period);
|
|
pwm_disable(pb->pwm);
|
|
|
|
if (pb->enable_gpio)
|
|
gpiod_set_value_cansleep(pb->enable_gpio, 0);
|
|
|
|
regulator_disable(pb->power_supply);
|
|
pb->enabled = false;
|
|
}
|
|
|
|
static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)
|
|
{
|
|
unsigned int lth = pb->lth_brightness;
|
|
int duty_cycle;
|
|
|
|
if (pb->levels)
|
|
duty_cycle = pb->levels[brightness];
|
|
else
|
|
duty_cycle = brightness;
|
|
|
|
return (duty_cycle * (pb->period - lth) / pb->scale) + lth;
|
|
}
|
|
|
|
static int pwm_backlight_update_status(struct backlight_device *bl)
|
|
{
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
int brightness = bl->props.brightness;
|
|
int duty_cycle;
|
|
|
|
if (bl->props.power != FB_BLANK_UNBLANK ||
|
|
bl->props.fb_blank != FB_BLANK_UNBLANK ||
|
|
bl->props.state & BL_CORE_FBBLANK)
|
|
brightness = 0;
|
|
|
|
if (pb->notify)
|
|
brightness = pb->notify(pb->dev, brightness);
|
|
|
|
if (brightness > 0) {
|
|
duty_cycle = compute_duty_cycle(pb, brightness);
|
|
pwm_config(pb->pwm, duty_cycle, pb->period);
|
|
pwm_backlight_power_on(pb, brightness);
|
|
} else
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->notify_after)
|
|
pb->notify_after(pb->dev, brightness);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_check_fb(struct backlight_device *bl,
|
|
struct fb_info *info)
|
|
{
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
return !pb->check_fb || pb->check_fb(pb->dev, info);
|
|
}
|
|
|
|
static const struct backlight_ops pwm_backlight_ops = {
|
|
.update_status = pwm_backlight_update_status,
|
|
.check_fb = pwm_backlight_check_fb,
|
|
};
|
|
|
|
#ifdef CONFIG_OF
|
|
static int pwm_backlight_parse_dt(struct device *dev,
|
|
struct platform_pwm_backlight_data *data)
|
|
{
|
|
struct device_node *node = dev->of_node;
|
|
struct property *prop;
|
|
int length;
|
|
u32 value;
|
|
int ret;
|
|
|
|
if (!node)
|
|
return -ENODEV;
|
|
|
|
memset(data, 0, sizeof(*data));
|
|
|
|
/* determine the number of brightness levels */
|
|
prop = of_find_property(node, "brightness-levels", &length);
|
|
if (!prop)
|
|
return -EINVAL;
|
|
|
|
data->max_brightness = length / sizeof(u32);
|
|
|
|
/* read brightness levels from DT property */
|
|
if (data->max_brightness > 0) {
|
|
size_t size = sizeof(*data->levels) * data->max_brightness;
|
|
|
|
data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
|
|
if (!data->levels)
|
|
return -ENOMEM;
|
|
|
|
ret = of_property_read_u32_array(node, "brightness-levels",
|
|
data->levels,
|
|
data->max_brightness);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ret = of_property_read_u32(node, "default-brightness-level",
|
|
&value);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
data->dft_brightness = value;
|
|
data->max_brightness--;
|
|
}
|
|
|
|
data->enable_gpio = -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static struct of_device_id pwm_backlight_of_match[] = {
|
|
{ .compatible = "pwm-backlight" },
|
|
{ }
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
|
|
#else
|
|
static int pwm_backlight_parse_dt(struct device *dev,
|
|
struct platform_pwm_backlight_data *data)
|
|
{
|
|
return -ENODEV;
|
|
}
|
|
#endif
|
|
|
|
static int pwm_backlight_probe(struct platform_device *pdev)
|
|
{
|
|
struct platform_pwm_backlight_data *data = dev_get_platdata(&pdev->dev);
|
|
struct platform_pwm_backlight_data defdata;
|
|
struct backlight_properties props;
|
|
struct backlight_device *bl;
|
|
struct device_node *node = pdev->dev.of_node;
|
|
struct pwm_bl_data *pb;
|
|
int initial_blank = FB_BLANK_UNBLANK;
|
|
struct pwm_args pargs;
|
|
int ret;
|
|
|
|
if (!data) {
|
|
ret = pwm_backlight_parse_dt(&pdev->dev, &defdata);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "failed to find platform data\n");
|
|
return ret;
|
|
}
|
|
|
|
data = &defdata;
|
|
}
|
|
|
|
if (data->init) {
|
|
ret = data->init(&pdev->dev);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
|
|
if (!pb) {
|
|
ret = -ENOMEM;
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (data->levels) {
|
|
unsigned int i;
|
|
|
|
for (i = 0; i <= data->max_brightness; i++)
|
|
if (data->levels[i] > pb->scale)
|
|
pb->scale = data->levels[i];
|
|
|
|
pb->levels = data->levels;
|
|
} else
|
|
pb->scale = data->max_brightness;
|
|
|
|
pb->notify = data->notify;
|
|
pb->notify_after = data->notify_after;
|
|
pb->check_fb = data->check_fb;
|
|
pb->exit = data->exit;
|
|
pb->dev = &pdev->dev;
|
|
pb->enabled = false;
|
|
|
|
pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
|
|
GPIOD_ASIS);
|
|
if (IS_ERR(pb->enable_gpio)) {
|
|
ret = PTR_ERR(pb->enable_gpio);
|
|
goto err_alloc;
|
|
}
|
|
|
|
/*
|
|
* Compatibility fallback for drivers still using the integer GPIO
|
|
* platform data. Must go away soon.
|
|
*/
|
|
if (!pb->enable_gpio && gpio_is_valid(data->enable_gpio)) {
|
|
ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio,
|
|
GPIOF_OUT_INIT_HIGH, "enable");
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
|
|
data->enable_gpio, ret);
|
|
goto err_alloc;
|
|
}
|
|
|
|
pb->enable_gpio = gpio_to_desc(data->enable_gpio);
|
|
}
|
|
|
|
if (pb->enable_gpio) {
|
|
/*
|
|
* If the driver is probed from the device tree and there is a
|
|
* phandle link pointing to the backlight node, it is safe to
|
|
* assume that another driver will enable the backlight at the
|
|
* appropriate time. Therefore, if it is disabled, keep it so.
|
|
*/
|
|
if (node && node->phandle &&
|
|
gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT &&
|
|
gpiod_get_value(pb->enable_gpio) == 0)
|
|
initial_blank = FB_BLANK_POWERDOWN;
|
|
else
|
|
gpiod_direction_output(pb->enable_gpio, 1);
|
|
}
|
|
|
|
pb->power_supply = devm_regulator_get(&pdev->dev, "power");
|
|
if (IS_ERR(pb->power_supply)) {
|
|
ret = PTR_ERR(pb->power_supply);
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (node && node->phandle && !regulator_is_enabled(pb->power_supply))
|
|
initial_blank = FB_BLANK_POWERDOWN;
|
|
|
|
pb->pwm = devm_pwm_get(&pdev->dev, NULL);
|
|
if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {
|
|
dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
|
|
pb->legacy = true;
|
|
pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
|
|
}
|
|
|
|
if (IS_ERR(pb->pwm)) {
|
|
ret = PTR_ERR(pb->pwm);
|
|
if (ret != -EPROBE_DEFER)
|
|
dev_err(&pdev->dev, "unable to request PWM\n");
|
|
goto err_alloc;
|
|
}
|
|
|
|
dev_dbg(&pdev->dev, "got pwm for backlight\n");
|
|
|
|
/*
|
|
* FIXME: pwm_apply_args() should be removed when switching to
|
|
* the atomic PWM API.
|
|
*/
|
|
pwm_apply_args(pb->pwm);
|
|
|
|
/*
|
|
* The DT case will set the pwm_period_ns field to 0 and store the
|
|
* period, parsed from the DT, in the PWM device. For the non-DT case,
|
|
* set the period from platform data if it has not already been set
|
|
* via the PWM lookup table.
|
|
*/
|
|
pwm_get_args(pb->pwm, &pargs);
|
|
pb->period = pargs.period;
|
|
if (!pb->period && (data->pwm_period_ns > 0))
|
|
pb->period = data->pwm_period_ns;
|
|
|
|
pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale);
|
|
|
|
memset(&props, 0, sizeof(struct backlight_properties));
|
|
props.type = BACKLIGHT_RAW;
|
|
props.max_brightness = data->max_brightness;
|
|
bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
|
|
&pwm_backlight_ops, &props);
|
|
if (IS_ERR(bl)) {
|
|
dev_err(&pdev->dev, "failed to register backlight\n");
|
|
ret = PTR_ERR(bl);
|
|
if (pb->legacy)
|
|
pwm_free(pb->pwm);
|
|
goto err_alloc;
|
|
}
|
|
|
|
if (data->dft_brightness > data->max_brightness) {
|
|
dev_warn(&pdev->dev,
|
|
"invalid default brightness level: %u, using %u\n",
|
|
data->dft_brightness, data->max_brightness);
|
|
data->dft_brightness = data->max_brightness;
|
|
}
|
|
|
|
bl->props.brightness = data->dft_brightness;
|
|
bl->props.power = initial_blank;
|
|
backlight_update_status(bl);
|
|
|
|
platform_set_drvdata(pdev, bl);
|
|
return 0;
|
|
|
|
err_alloc:
|
|
if (data->exit)
|
|
data->exit(&pdev->dev);
|
|
return ret;
|
|
}
|
|
|
|
static int pwm_backlight_remove(struct platform_device *pdev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(pdev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
backlight_device_unregister(bl);
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->exit)
|
|
pb->exit(&pdev->dev);
|
|
if (pb->legacy)
|
|
pwm_free(pb->pwm);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void pwm_backlight_shutdown(struct platform_device *pdev)
|
|
{
|
|
struct backlight_device *bl = platform_get_drvdata(pdev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
pwm_backlight_power_off(pb);
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int pwm_backlight_suspend(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
struct pwm_bl_data *pb = bl_get_data(bl);
|
|
|
|
if (pb->notify)
|
|
pb->notify(pb->dev, 0);
|
|
|
|
pwm_backlight_power_off(pb);
|
|
|
|
if (pb->notify_after)
|
|
pb->notify_after(pb->dev, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pwm_backlight_resume(struct device *dev)
|
|
{
|
|
struct backlight_device *bl = dev_get_drvdata(dev);
|
|
|
|
backlight_update_status(bl);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static const struct dev_pm_ops pwm_backlight_pm_ops = {
|
|
#ifdef CONFIG_PM_SLEEP
|
|
.suspend = pwm_backlight_suspend,
|
|
.resume = pwm_backlight_resume,
|
|
.poweroff = pwm_backlight_suspend,
|
|
.restore = pwm_backlight_resume,
|
|
#endif
|
|
};
|
|
|
|
static struct platform_driver pwm_backlight_driver = {
|
|
.driver = {
|
|
.name = "pwm-backlight",
|
|
.pm = &pwm_backlight_pm_ops,
|
|
.of_match_table = of_match_ptr(pwm_backlight_of_match),
|
|
},
|
|
.probe = pwm_backlight_probe,
|
|
.remove = pwm_backlight_remove,
|
|
.shutdown = pwm_backlight_shutdown,
|
|
};
|
|
|
|
module_platform_driver(pwm_backlight_driver);
|
|
|
|
MODULE_DESCRIPTION("PWM based Backlight Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:pwm-backlight");
|