The gpio-backlight driver currently supports only a single GPIO to enable or disable a backlight device. Some panels require multiple enable GPIOs to be asserted together.
Extend the driver to support an array of GPIOs for a single backlight instance. All configured GPIOs are toggled together based on the backlight state. Existing single-GPIO Device Tree users remain unaffected. Signed-off-by: Sudarshan Shetty <[email protected]> --- drivers/video/backlight/gpio_backlight.c | 66 ++++++++++++++++-------- 1 file changed, 45 insertions(+), 21 deletions(-) diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 728a546904b0..11d21de82cf5 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -14,17 +14,29 @@ #include <linux/platform_device.h> #include <linux/property.h> #include <linux/slab.h> +#include <linux/bitmap.h> struct gpio_backlight { struct device *dev; - struct gpio_desc *gpiod; + struct gpio_descs *gpiods; + unsigned long *bitmap; }; static int gpio_backlight_update_status(struct backlight_device *bl) { struct gpio_backlight *gbl = bl_get_data(bl); + unsigned int n = gbl->gpiods->ndescs; + int br = backlight_get_brightness(bl); - gpiod_set_value_cansleep(gbl->gpiod, backlight_get_brightness(bl)); + if (br) + bitmap_fill(gbl->bitmap, n); + else + bitmap_zero(gbl->bitmap, n); + + gpiod_set_array_value_cansleep(n, + gbl->gpiods->desc, + gbl->gpiods->info, + gbl->bitmap); return 0; } @@ -48,26 +60,43 @@ static int gpio_backlight_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct gpio_backlight_platform_data *pdata = dev_get_platdata(dev); struct device_node *of_node = dev->of_node; - struct backlight_properties props; + struct backlight_properties props = { }; struct backlight_device *bl; struct gpio_backlight *gbl; - int ret, init_brightness, def_value; + bool def_value; + enum gpiod_flags flags; + unsigned int n; + int words; - gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL); - if (gbl == NULL) + gbl = devm_kcalloc(dev, 1, sizeof(*gbl), GFP_KERNEL); + if (!gbl) return -ENOMEM; if (pdata) gbl->dev = pdata->dev; def_value = device_property_read_bool(dev, "default-on"); + flags = def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW; + + gbl->gpiods = devm_gpiod_get_array(dev, NULL, flags); + if (IS_ERR(gbl->gpiods)) { + if (PTR_ERR(gbl->gpiods) == -ENODEV) + return dev_err_probe(dev, -EINVAL, + "The gpios parameter is missing or invalid\n"); + return PTR_ERR(gbl->gpiods); + } - gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS); - if (IS_ERR(gbl->gpiod)) - return dev_err_probe(dev, PTR_ERR(gbl->gpiod), - "The gpios parameter is missing or invalid\n"); + n = gbl->gpiods->ndescs; + if (!n) + return dev_err_probe(dev, -EINVAL, + "No GPIOs provided\n"); + + words = BITS_TO_LONGS(n); + gbl->bitmap = devm_kcalloc(dev, words, sizeof(unsigned long), + GFP_KERNEL); + if (!gbl->bitmap) + return -ENOMEM; - memset(&props, 0, sizeof(props)); props.type = BACKLIGHT_RAW; props.max_brightness = 1; bl = devm_backlight_device_register(dev, dev_name(dev), dev, gbl, @@ -81,21 +110,16 @@ static int gpio_backlight_probe(struct platform_device *pdev) if (!of_node || !of_node->phandle) /* Not booted with device tree or no phandle link to the node */ bl->props.power = def_value ? BACKLIGHT_POWER_ON - : BACKLIGHT_POWER_OFF; - else if (gpiod_get_value_cansleep(gbl->gpiod) == 0) + : BACKLIGHT_POWER_OFF; + else if (gpiod_get_value_cansleep(gbl->gpiods->desc[0]) == 0) bl->props.power = BACKLIGHT_POWER_OFF; else bl->props.power = BACKLIGHT_POWER_ON; - bl->props.brightness = 1; - - init_brightness = backlight_get_brightness(bl); - ret = gpiod_direction_output(gbl->gpiod, init_brightness); - if (ret) { - dev_err(dev, "failed to set initial brightness\n"); - return ret; - } + bl->props.brightness = def_value ? 1 : 0; + gpio_backlight_update_status(bl); + platform_set_drvdata(pdev, bl); return 0; } -- 2.34.1
