This commit adds very basic support for device-tree probing. Currently, only a PWM and maximum and default brightness values can be specified. Enabling or disabling backlight power via GPIOs is not yet supported.
Signed-off-by: Thierry Reding <[email protected]> --- .../bindings/video/backlight/pwm-backlight | 16 +++++ drivers/video/backlight/Kconfig | 2 +- drivers/video/backlight/pwm_bl.c | 70 ++++++++++++++++++- 3 files changed, 83 insertions(+), 5 deletions(-) create mode 100644 Documentation/devicetree/bindings/video/backlight/pwm-backlight diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight b/Documentation/devicetree/bindings/video/backlight/pwm-backlight new file mode 100644 index 0000000..ce65280 --- /dev/null +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight @@ -0,0 +1,16 @@ +pwm-backlight bindings + +Required properties: + - compatible: "pwm-backlight" + - default-brightness: the default brightness setting + - max-brightness: the maximum brightness setting + - pwm: OF device-tree PWM specification + +Example: + + backlight { + compatible = "pwm-backlight"; + default-brightness = <224>; + max-brightness = <255>; + pwm = <&pwm 0 5000000>; + }; diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 278aeaa..51c3642 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -233,7 +233,7 @@ config BACKLIGHT_CARILLO_RANCH config BACKLIGHT_PWM tristate "Generic PWM based Backlight Driver" - depends on HAVE_PWM + depends on HAVE_PWM || PWM help If you have a LCD backlight adjustable by PWM, say Y to enable this driver. diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 8b5b2a4..742934c 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -17,6 +17,7 @@ #include <linux/fb.h> #include <linux/backlight.h> #include <linux/err.h> +#include <linux/of_pwm.h> #include <linux/pwm.h> #include <linux/pwm_backlight.h> #include <linux/slab.h> @@ -83,17 +84,77 @@ static const struct backlight_ops pwm_backlight_ops = { .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; + u32 value; + int ret; + + if (!node) + return -ENODEV; + + memset(data, 0, sizeof(*data)); + + ret = of_get_named_pwm(node, "pwm", 0, &data->pwm_period_ns); + if (ret < 0) + return ret; + + data->pwm_id = ret; + + ret = of_property_read_u32(node, "default-brightness", &value); + if (ret < 0) + return ret; + + data->dft_brightness = value; + + ret = of_property_read_u32(node, "max-brightness", &value); + if (ret < 0) + return ret; + + data->max_brightness = value; + + /* + * TODO: Most users of this driver use a number of GPIOs to control + * backlight power. Support for specifying these needs to be + * added. + */ + + 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 backlight_properties props; struct platform_pwm_backlight_data *data = pdev->dev.platform_data; + struct platform_pwm_backlight_data defdata; 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) { @@ -198,8 +259,9 @@ static int pwm_backlight_resume(struct platform_device *pdev) static struct platform_driver pwm_backlight_driver = { .driver = { - .name = "pwm-backlight", - .owner = THIS_MODULE, + .name = "pwm-backlight", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(pwm_backlight_of_match), }, .probe = pwm_backlight_probe, .remove = pwm_backlight_remove, -- 1.7.8 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
