[PATCHv8] video: backlight: gpio-backlight: Add DT support.
Denis Carikli
denis at eukrea.com
Tue Jan 7 05:02:53 EST 2014
Cc: Richard Purdie <rpurdie at rpsys.net>
Cc: Jingoo Han <jg1.han at samsung.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Rob Herring <rob.herring at calxeda.com>
Cc: Pawel Moll <pawel.moll at arm.com>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Stephen Warren <swarren at wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree at hellion.org.uk>
Cc: devicetree at vger.kernel.org
Cc: Sascha Hauer <kernel at pengutronix.de>
Cc: linux-arm-kernel at lists.infradead.org
Cc: Lothar Waßmann <LW at KARO-electronics.de>
Cc: Jean-Christophe Plagniol-Villard <plagnioj at jcrosoft.com>
Cc: Thierry Reding <thierry.reding at gmail.com>
Cc: Eric Bénard <eric at eukrea.com>
Signed-off-by: Denis Carikli <denis at eukrea.com>
---
ChangeLog v7->v8:
- The default-state was renamed to default-brightness-level.
- default-brightness-level is now mandatory, like for backlight-pwm,
That way we avoid having to handle the case where it's not set,
which means that we would need not to set the gpio, but still
report a brightness value for sysfs, when not all gpio controllers are
able to read the gpio value.
- switched the default-brightness-level to boolean values (0 or 1) instead
of using strings ("on", "off", "keep").
- The documentation was updated accordingly.
- The example in the documentation now uses the dts gpio defines.
- The "backlight: gpio_backlight: Use a default state enum." patch was then
dropped, becuase it is not necessary anymore.
ChangeLog v6->v7:
- removed a compilation warning with the removal of the useless ret declaration.
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 | 19 ++++++
drivers/video/backlight/gpio_backlight.c | 64 +++++++++++++++++---
2 files changed, 76 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..d022add
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt
@@ -0,0 +1,19 @@
+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).
+ - default-brightness-level: the default brightness level. Valid values:
+ - 0: off
+ - 1: on
+
+[0]: Documentation/devicetree/bindings/gpio/gpio.txt
+
+Example:
+
+ backlight {
+ compatible = "gpio-backlight";
+ gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
+ default-brightness-level = <1>;
+ };
diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 81fb127..829a5dd 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;
+ int def_value;
};
static int gpio_backlight_update_status(struct backlight_device *bl)
@@ -60,6 +63,37 @@ 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);
+
+ 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;
+
+ ret = of_property_read_u32(np, "default-brightness-level",
+ &gbl->def_value);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Error: The default-brightness-level parameter is missing or invalid.\n");
+ return ret;
+ }
+
+ return 0;
+}
+
static int gpio_backlight_probe(struct platform_device *pdev)
{
struct gpio_backlight_platform_data *pdata =
@@ -67,10 +101,12 @@ 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 +115,22 @@ 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 +147,23 @@ 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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