* published by the Free Software Foundation.
*/
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.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 {
unsigned int period;
unsigned int lth_brightness;
unsigned int *levels;
+ bool enabled;
+ struct regulator *power_supply;
+ int enable_gpio;
+ unsigned long enable_gpio_flags;
+ unsigned int scale;
int (*notify)(struct device *,
int brightness);
void (*notify_after)(struct device *,
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 (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 0);
+ else
+ gpio_set_value(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 (gpio_is_valid(pb->enable_gpio)) {
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ gpio_set_value(pb->enable_gpio, 1);
+ else
+ gpio_set_value(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 max = bl->props.max_brightness;
+ int duty_cycle;
if (bl->props.power != FB_BLANK_UNBLANK ||
bl->props.fb_blank != FB_BLANK_UNBLANK ||
if (pb->notify)
brightness = pb->notify(pb->dev, brightness);
- if (brightness == 0) {
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
- } else {
- int duty_cycle;
-
- if (pb->levels) {
- duty_cycle = pb->levels[brightness];
- max = pb->levels[max];
- } else {
- duty_cycle = brightness;
- }
-
- duty_cycle = pb->lth_brightness +
- (duty_cycle * (pb->period - pb->lth_brightness) / max);
+ if (brightness > 0) {
+ duty_cycle = compute_duty_cycle(pb, brightness);
pwm_config(pb->pwm, duty_cycle, pb->period);
- pwm_enable(pb->pwm);
- }
+ pwm_backlight_power_on(pb, brightness);
+ } else
+ pwm_backlight_power_off(pb);
if (pb->notify_after)
pb->notify_after(pb->dev, brightness);
struct platform_pwm_backlight_data *data)
{
struct device_node *node = dev->of_node;
+ enum of_gpio_flags flags;
struct property *prop;
int length;
u32 value;
data->max_brightness--;
}
- /*
- * TODO: Most users of this driver use a number of GPIOs to control
- * backlight power. Support for specifying these needs to be
- * added.
- */
+ data->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0,
+ &flags);
+ if (data->enable_gpio == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+
+ if (gpio_is_valid(data->enable_gpio) && (flags & OF_GPIO_ACTIVE_LOW))
+ data->enable_gpio_flags |= PWM_BACKLIGHT_GPIO_ACTIVE_LOW;
return 0;
}
struct backlight_properties props;
struct backlight_device *bl;
struct pwm_bl_data *pb;
- unsigned int max;
int ret;
if (!data) {
}
if (data->levels) {
- max = data->levels[data->max_brightness];
+ 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
- max = data->max_brightness;
+ pb->scale = data->max_brightness;
+ pb->enable_gpio = data->enable_gpio;
+ pb->enable_gpio_flags = data->enable_gpio_flags;
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;
+
+ if (gpio_is_valid(pb->enable_gpio)) {
+ unsigned long flags;
+
+ if (pb->enable_gpio_flags & PWM_BACKLIGHT_GPIO_ACTIVE_LOW)
+ flags = GPIOF_OUT_INIT_HIGH;
+ else
+ flags = GPIOF_OUT_INIT_LOW;
+
+ ret = gpio_request_one(pb->enable_gpio, flags, "enable");
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request GPIO#%d: %d\n",
+ pb->enable_gpio, ret);
+ goto err_alloc;
+ }
+ }
+
+ pb->power_supply = devm_regulator_get(&pdev->dev, "power");
+ if (IS_ERR(pb->power_supply)) {
+ ret = PTR_ERR(pb->power_supply);
+ goto err_gpio;
+ }
pb->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(pb->pwm)) {
if (IS_ERR(pb->pwm)) {
dev_err(&pdev->dev, "unable to request legacy PWM\n");
ret = PTR_ERR(pb->pwm);
- goto err_alloc;
+ goto err_gpio;
}
}
pwm_set_period(pb->pwm, data->pwm_period_ns);
pb->period = pwm_get_period(pb->pwm);
- pb->lth_brightness = data->lth_brightness * (pb->period / max);
+ pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale);
memset(&props, 0, sizeof(struct backlight_properties));
props.type = BACKLIGHT_RAW;
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
ret = PTR_ERR(bl);
- goto err_alloc;
+ goto err_gpio;
}
if (data->dft_brightness > data->max_brightness) {
platform_set_drvdata(pdev, bl);
return 0;
+err_gpio:
+ if (gpio_is_valid(pb->enable_gpio))
+ gpio_free(pb->enable_gpio);
err_alloc:
if (data->exit)
data->exit(&pdev->dev);
struct pwm_bl_data *pb = bl_get_data(bl);
backlight_device_unregister(bl);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+ pwm_backlight_power_off(pb);
+
if (pb->exit)
pb->exit(&pdev->dev);
+
return 0;
}
if (pb->notify)
pb->notify(pb->dev, 0);
- pwm_config(pb->pwm, 0, pb->period);
- pwm_disable(pb->pwm);
+
+ pwm_backlight_power_off(pb);
+
if (pb->notify_after)
pb->notify_after(pb->dev, 0);
+
return 0;
}
struct backlight_device *bl = dev_get_drvdata(dev);
backlight_update_status(bl);
+
return 0;
}
#endif
-static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
- pwm_backlight_resume);
+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 = {
MODULE_DESCRIPTION("PWM based Backlight Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pwm-backlight");
-
projects / linux-drm-fsl-dcu.git / blobdiff