Cc: Richard Purdie <rpurdie@xxxxxxxxx> Cc: Jingoo Han <jg1.han@xxxxxxxxxxx> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Cc: Rob Herring <rob.herring@xxxxxxxxxxx> Cc: Pawel Moll <pawel.moll@xxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Stephen Warren <swarren@xxxxxxxxxxxxx> Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx> Cc: devicetree@xxxxxxxxxxxxxxx Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: Lothar Waßmann <LW@xxxxxxxxxxxxxxxxxxx> Cc: Jean-Christophe Plagniol-Villard <plagnioj@xxxxxxxxxxxx> Cc: Thierry Reding <thierry.reding@xxxxxxxxx> Cc: Eric Bénard <eric@xxxxxxxxxx> Signed-off-by: Denis Carikli <denis@xxxxxxxxxx> --- ChangeLog v5->v6: - The default state handling was reworked: - it's now called default-state, and looks like the gpio-leds default-state. - it now has a "keep" option, like for the gpio-leds. - that "keep" option is the default when the default-state property is not set. - The documentation was updated accordingly. ChangeLog v4->v5: - The default-brightness property now defaults to 0 in the driver. - def_value int becomes a bool. - The check for the gpio validity has been reworked. --- .../bindings/video/backlight/gpio-backlight.txt | 23 +++++++ drivers/video/backlight/gpio_backlight.c | 72 +++++++++++++++++--- 2 files changed, 87 insertions(+), 8 deletions(-) create mode 100644 Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt diff --git a/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt new file mode 100644 index 0000000..f36f6e3 --- /dev/null +++ b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt @@ -0,0 +1,23 @@ +gpio-backlight bindings + +Required properties: + - compatible: "gpio-backlight" + - gpios: describes the gpio that is used for enabling/disabling the backlight + (see GPIO binding[0] for more details). + +Optional properties: + - default-state: The initial state of the backlight. + Valid values are "on", "off", and "keep". + The "keep" setting will keep the backlight at whatever its current + state is, without producing a glitch. The default is keep if this + property is not present. + +[0]: Documentation/devicetree/bindings/gpio/gpio.txt + +Example: + + backlight { + compatible = "gpio-backlight"; + gpios = <&gpio3 4 0>; + default-state = "on"; + }; diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c index 6ddeba9..66e3aa2 100644 --- a/drivers/video/backlight/gpio_backlight.c +++ b/drivers/video/backlight/gpio_backlight.c @@ -13,6 +13,8 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> +#include <linux/of.h> +#include <linux/of_gpio.h> #include <linux/platform_data/gpio_backlight.h> #include <linux/platform_device.h> #include <linux/slab.h> @@ -61,6 +63,43 @@ static const struct backlight_ops gpio_backlight_ops = { .check_fb = gpio_backlight_check_fb, }; +static int gpio_backlight_probe_dt(struct platform_device *pdev, + struct gpio_backlight *gbl) +{ + struct device_node *np = pdev->dev.of_node; + enum of_gpio_flags gpio_flags; + const char *state; + int ret; + + gbl->fbdev = NULL; + gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags); + + if (!gpio_is_valid(gbl->gpio)) { + if (gbl->gpio != -EPROBE_DEFER) { + dev_err(&pdev->dev, + "Error: The gpios parameter is missing or invalid.\n"); + } + return gbl->gpio; + } + + gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1; + + state = of_get_property(np, "default-state", NULL); + if (state) { + if (!strcmp(state, "keep")) + gbl->def_value = BACKLIGHT_GPIO_DEFSTATE_KEEP; + else if (!strcmp(state, "on")) + gbl->def_value = BACKLIGHT_GPIO_DEFSTATE_ON; + else + gbl->def_value = BACKLIGHT_GPIO_DEFSTATE_OFF; + } else { + /* we don't want to touch the hardware if we're not told to */ + gbl->def_value = BACKLIGHT_GPIO_DEFSTATE_KEEP; + } + + return 0; +} + static int gpio_backlight_probe(struct platform_device *pdev) { struct gpio_backlight_platform_data *pdata = @@ -68,10 +107,12 @@ static int gpio_backlight_probe(struct platform_device *pdev) struct backlight_properties props; struct backlight_device *bl; struct gpio_backlight *gbl; + struct device_node *np = pdev->dev.of_node; int ret; - if (!pdata) { - dev_err(&pdev->dev, "failed to find platform data\n"); + if (!pdata && !np) { + dev_err(&pdev->dev, + "failed to find platform data or device tree node.\n"); return -ENODEV; } @@ -80,14 +121,23 @@ static int gpio_backlight_probe(struct platform_device *pdev) return -ENOMEM; gbl->dev = &pdev->dev; - gbl->fbdev = pdata->fbdev; - gbl->gpio = pdata->gpio; - gbl->active = pdata->active_low ? 0 : 1; + + if (np) { + ret = gpio_backlight_probe_dt(pdev, gbl); + if (ret) + return ret; + } else { + gbl->fbdev = pdata->fbdev; + gbl->gpio = pdata->gpio; + gbl->active = pdata->active_low ? 0 : 1; + if (pdata->def_value != BACKLIGHT_GPIO_DEFSTATE_KEEP) + gbl->def_value = pdata->def_value; + } ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT | (gbl->active ? GPIOF_INIT_LOW : GPIOF_INIT_HIGH), - pdata->name); + pdata ? pdata->name : "backlight"); if (ret < 0) { dev_err(&pdev->dev, "unable to request GPIO\n"); return ret; @@ -104,8 +154,8 @@ static int gpio_backlight_probe(struct platform_device *pdev) return PTR_ERR(bl); } - if (pdata->def_value != BACKLIGHT_GPIO_DEFSTATE_KEEP) { - bl->props.brightness = pdata->def_value; + if (gbl->def_value != BACKLIGHT_GPIO_DEFSTATE_KEEP) { + bl->props.brightness = gbl->def_value; backlight_update_status(bl); } @@ -113,10 +163,16 @@ static int gpio_backlight_probe(struct platform_device *pdev) return 0; } +static struct of_device_id gpio_backlight_of_match[] = { + { .compatible = "gpio-backlight" }, + { /* sentinel */ } +}; + static struct platform_driver gpio_backlight_driver = { .driver = { .name = "gpio-backlight", .owner = THIS_MODULE, + .of_match_table = of_match_ptr(gpio_backlight_of_match), }, .probe = gpio_backlight_probe, }; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html