1 files changed, 279 insertions, 69 deletions

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 21866ec6965..38ca88bc5c3 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -10,6 +10,8 @@
  * 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>
@@ -19,6 +21,7 @@
 #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 {
@@ -26,34 +29,89 @@ struct pwm_bl_data {
 	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;
 	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(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(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 = dev_get_drvdata(&bl->dev);
+	struct pwm_bl_data *pb = bl_get_data(bl);
 	int brightness = bl->props.brightness;
-	int max = bl->props.max_brightness;
-
-	if (bl->props.power != FB_BLANK_UNBLANK)
-		brightness = 0;
+	int duty_cycle;
 
-	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+	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) {
-		pwm_config(pb->pwm, 0, pb->period);
-		pwm_disable(pb->pwm);
-	} else {
-		brightness = pb->lth_brightness +
-			(brightness * (pb->period - pb->lth_brightness) / max);
-		pwm_config(pb->pwm, brightness, pb->period);
-		pwm_enable(pb->pwm);
-	}
+	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;
 }
 
@@ -62,22 +120,99 @@ static int pwm_backlight_get_brightness(struct backlight_device *bl)
 	return bl->props.brightness;
 }
 
+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,
 	.get_brightness	= pwm_backlight_get_brightness,
+	.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--;
+	}
+
+	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 platform_pwm_backlight_data *data = pdev->dev.platform_data;
 	struct backlight_device *bl;
 	struct pwm_bl_data *pb;
 	int ret;
 
 	if (!data) {
-		dev_err(&pdev->dev, "failed to find platform data\n");
-		return -EINVAL;
+		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) {
@@ -86,35 +221,108 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 			return ret;
 	}
 
-	pb = kzalloc(sizeof(*pb), GFP_KERNEL);
+	pb = devm_kzalloc(&pdev->dev, sizeof(*pb), GFP_KERNEL);
 	if (!pb) {
-		dev_err(&pdev->dev, "no memory for state\n");
 		ret = -ENOMEM;
 		goto err_alloc;
 	}
 
-	pb->period = data->pwm_period_ns;
+	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->lth_brightness = data->lth_brightness *
-		(data->pwm_period_ns / data->max_brightness);
+	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(&pdev->dev, "enable");
+	if (IS_ERR(pb->enable_gpio)) {
+		ret = PTR_ERR(pb->enable_gpio);
+		if (ret == -ENOENT)
+			pb->enable_gpio = NULL;
+		else
+			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);
+	}
 
-	pb->pwm = pwm_request(data->pwm_id, "backlight");
+	if (pb->enable_gpio)
+		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;
+	}
+
+	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
 	if (IS_ERR(pb->pwm)) {
-		dev_err(&pdev->dev, "unable to request PWM for backlight\n");
-		ret = PTR_ERR(pb->pwm);
-		goto err_pwm;
-	} else
-		dev_dbg(&pdev->dev, "got pwm for backlight\n");
+		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
+
+		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
+		if (IS_ERR(pb->pwm)) {
+			dev_err(&pdev->dev, "unable to request legacy PWM\n");
+			ret = PTR_ERR(pb->pwm);
+			goto err_alloc;
+		}
+	}
+
+	dev_dbg(&pdev->dev, "got pwm for backlight\n");
+
+	/*
+	 * 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.
+	 */
+	pb->period = pwm_get_period(pb->pwm);
+	if (!pb->period && (data->pwm_period_ns > 0)) {
+		pb->period = data->pwm_period_ns;
+		pwm_set_period(pb->pwm, 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);
-		goto err_bl;
+		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;
@@ -123,10 +331,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, bl);
 	return 0;
 
-err_bl:
-	pwm_free(pb->pwm);
-err_pwm:
-	kfree(pb);
 err_alloc:
 	if (data->exit)
 		data->exit(&pdev->dev);
@@ -135,70 +339,76 @@ err_alloc:
 
 static int pwm_backlight_remove(struct platform_device *pdev)
 {
-	struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
 	struct backlight_device *bl = platform_get_drvdata(pdev);
-	struct pwm_bl_data *pb = dev_get_drvdata(&bl->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_free(pb->pwm);
-	kfree(pb);
-	if (data->exit)
-		data->exit(&pdev->dev);
+	pwm_backlight_power_off(pb);
+
+	if (pb->exit)
+		pb->exit(&pdev->dev);
+
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int pwm_backlight_suspend(struct platform_device *pdev,
-				 pm_message_t state)
+static void pwm_backlight_shutdown(struct platform_device *pdev)
 {
 	struct backlight_device *bl = platform_get_drvdata(pdev);
-	struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
+	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_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;
 }
 
-static int pwm_backlight_resume(struct platform_device *pdev)
+static int pwm_backlight_resume(struct device *dev)
 {
-	struct backlight_device *bl = platform_get_drvdata(pdev);
+	struct backlight_device *bl = dev_get_drvdata(dev);
 
 	backlight_update_status(bl);
+
 	return 0;
 }
-#else
-#define pwm_backlight_suspend	NULL
-#define pwm_backlight_resume	NULL
 #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",
-		.owner	= THIS_MODULE,
+		.name		= "pwm-backlight",
+		.owner		= THIS_MODULE,
+		.pm		= &pwm_backlight_pm_ops,
+		.of_match_table	= of_match_ptr(pwm_backlight_of_match),
 	},
 	.probe		= pwm_backlight_probe,
 	.remove		= pwm_backlight_remove,
-	.suspend	= pwm_backlight_suspend,
-	.resume		= pwm_backlight_resume,
+	.shutdown	= pwm_backlight_shutdown,
 };
 
-static int __init pwm_backlight_init(void)
-{
-	return platform_driver_register(&pwm_backlight_driver);
-}
-module_init(pwm_backlight_init);
-
-static void __exit pwm_backlight_exit(void)
-{
-	platform_driver_unregister(&pwm_backlight_driver);
-}
-module_exit(pwm_backlight_exit);
+module_platform_driver(pwm_backlight_driver);
 
 MODULE_DESCRIPTION("PWM based Backlight Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:pwm-backlight");
-