[PATCHv4] video: backlight: gpio-backlight: Add DT support.

Grant Likely
2013-10-25T20:10:06Z

On Mon, 21 Oct 2013 11:13:33 +0200, Denis Carikli <denis@eukrea.com> wrote:
> Cc: Richard Purdie <rpurdie@rpsys.net>
> Cc: Jingoo Han <jg1.han@samsung.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Rob Herring <rob.herring@calxeda.com>
> Cc: Pawel Moll <pawel.moll@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Stephen Warren <swarren@wwwdotorg.org>
> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
> Cc: devicetree at vger.kernel.org
> Cc: Sascha Hauer <kernel@pengutronix.de>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: Lothar Wa??mann <LW@KARO-electronics.de>
> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
> Cc: Eric B??nard <eric@eukrea.com>
> Signed-off-by: Denis Carikli <denis@eukrea.com>
> ---
> ChangeLog v3->v4:
> - The default-brightness property is now optional, it defaults to 1 if not set.
> - def_value int becomes an u32.
> - gbl->def_value was set to pdata->def_value in pdata mode to avoid an extra
> check.
> ---
> .../bindings/video/backlight/gpio-backlight.txt | 20 ++++++
> drivers/video/backlight/gpio_backlight.c | 69 ++++++++++++++++++--
> 2 files changed, 82 insertions(+), 7 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..3474d4a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt
> @@ -0,0 +1,20 @@
> +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-brightness-level: the default brightness level (can be 0(off) or
> + 1(on) since GPIOs only support theses levels).

Seems odd to call it brightness since it can only be on or off. Why not
call it "default-state" or and empty bool named "default-on"?

Otherwise looks okay to me.

g.

> +
> +[0]: Documentation/devicetree/bindings/gpio/gpio.txt
> +
> +Example:
> +
> + backlight {
> + compatible = "gpio-backlight";
> + gpios = <&gpio3 4 0>;
> + default-brightness-level = <0>;
> + };
> diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> index 81fb127..248124d 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>
> @@ -23,6 +25,7 @@ struct gpio_backlight {
>
> int gpio;
> int active;
> + u32 def_value;
> };
>
> static int gpio_backlight_update_status(struct backlight_device *bl)
> @@ -60,6 +63,41 @@ 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;
> + int ret;
> +
> + gbl->fbdev = NULL;
> + gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags);
> +
> + gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
> +
> + if (gbl->gpio == -EPROBE_DEFER) {
> + return ERR_PTR(-EPROBE_DEFER);
> + } else if (gbl->gpio < 0) {
> + dev_err(&pdev->dev, "Error: gpios is a required parameter.\n");
> + return gbl->gpio;
> + }
> +
> + ret = of_property_read_u32(np, "default-brightness-level",
> + &gbl->def_value);
> + if (ret < 0) {
> + /* The property is optional. */
> + gbl->def_value = 1;
> + }
> +
> + if (gbl->def_value > 1) {
> + dev_warn(&pdev->dev,
> + "Warning: Invalid default-brightness-level value. Its value can be either 0(off) or 1(on).\n");
> + gbl->def_value = 1;
> + }
> +
> + return 0;
> +}
> +
> static int gpio_backlight_probe(struct platform_device *pdev)
> {
> struct gpio_backlight_platform_data *pdata =
> @@ -67,10 +105,12 @@ 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;
> }
>
> @@ -79,14 +119,22 @@ 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;
> + 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;
> @@ -103,17 +151,24 @@ static int gpio_backlight_probe(struct platform_device *pdev)
> return PTR_ERR(bl);
> }
>
> - bl->props.brightness = pdata->def_value;
> + bl->props.brightness = gbl->def_value;
> +
> backlight_update_status(bl);
>
> platform_set_drvdata(pdev, bl);
> 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
>
>
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