diff options
Diffstat (limited to 'drivers/video/backlight/pwm_bl.c')
| -rw-r--r-- | drivers/video/backlight/pwm_bl.c | 168 |
1 files changed, 131 insertions, 37 deletions
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 1fea627394d7..fb80d68f4d33 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.h> +#include <linux/of_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 { @@ -27,6 +30,11 @@ 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 *, @@ -35,11 +43,65 @@ struct pwm_bl_data { 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 || @@ -49,24 +111,12 @@ static int pwm_backlight_update_status(struct backlight_device *bl) 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); @@ -98,6 +148,7 @@ static int pwm_backlight_parse_dt(struct device *dev, 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; @@ -138,11 +189,13 @@ static int pwm_backlight_parse_dt(struct device *dev, 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; } @@ -163,12 +216,11 @@ static int pwm_backlight_parse_dt(struct device *dev, static int pwm_backlight_probe(struct platform_device *pdev) { - struct platform_pwm_backlight_data *data = pdev->dev.platform_data; + 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 pwm_bl_data *pb; - unsigned int max; int ret; if (!data) { @@ -195,16 +247,46 @@ static int pwm_backlight_probe(struct platform_device *pdev) } 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)) { @@ -214,7 +296,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) 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; } } @@ -229,7 +311,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) 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; @@ -239,7 +321,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) 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) { @@ -255,6 +337,9 @@ static int pwm_backlight_probe(struct platform_device *pdev) 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); @@ -267,10 +352,11 @@ static int pwm_backlight_remove(struct platform_device *pdev) 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; } @@ -282,10 +368,12 @@ static int pwm_backlight_suspend(struct device *dev) 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; } @@ -294,12 +382,19 @@ static int pwm_backlight_resume(struct device *dev) 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 = { @@ -317,4 +412,3 @@ module_platform_driver(pwm_backlight_driver); MODULE_DESCRIPTION("PWM based Backlight Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:pwm-backlight"); - |