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Date: Thu, 27 Feb 2014 15:28:33 +0100
From: Denis Carikli <denis@...rea.com>
To: Lee Jones <lee.jones@...aro.org>
Cc: Bryan Wu <cooloney@...il.com>, Jingoo Han <jg1.han@...sung.com>,
Eric Bénard <eric@...rea.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Denis Carikli <denis@...rea.com>
Subject: [PATCHv12] video: backlight: gpio-backlight: Add DT support.
Signed-off-by: Denis Carikli <denis@...rea.com>
---
ChangeLog v11-resend->v12:
- Moved the Cc from the commit message to the "email patch".
- The documentation is now more clear.
- The unnecessary default_on variable was removed.
- gbl->fbdev was already NULL and didn't need to be re-assigned,
so the re-assignement was removed.
- The of_device_id struct and .of_match_table are now guarded
against the driver beeing compiled without CONFIG_OF.
ChangeLog v11->v11-resend:
- Removed the Cc list because it's only one patch.
ChangeLog v10->v11:
- Shrinked the Cc list.
- Fixed the of_match_table warning.
ChangeLog v9->v10:
- Only the respective maintainers, or people who responded to the patch
were kept in the Cc.
- The unnecessary of_match_ptr in of_match_table was removed.
ChangeLog v8->v9:
- Added Shawn Guo in the Cc list.
- The default-brightness-level is now a boolean default-on property,
the gpio is only touched if the gpio-backlight driver instance probes.
- The code and documentation was updated accordingly.
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 | 16 ++++++
drivers/video/backlight/gpio_backlight.c | 58 +++++++++++++++++---
2 files changed, 67 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..321be66
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/gpio-backlight.txt
@@ -0,0 +1,16 @@
+gpio-backlight bindings
+
+Required properties:
+ - compatible: "gpio-backlight"
+ - gpios: describes the gpio that is used for enabling/disabling the backlight.
+ refer to bindings/gpio/gpio.txt for more details.
+
+Optional properties:
+ - default-on: enable the backlight at boot.
+
+Example:
+ backlight {
+ compatible = "gpio-backlight";
+ gpios = <&gpio3 4 GPIO_ACTIVE_HIGH>;
+ default-on;
+ };
diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 81fb127..a2eba12 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 +63,29 @@ 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;
+
+ 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;
+
+ gbl->def_value = of_property_read_bool(np, "default-on");
+
+ return 0;
+}
+
static int gpio_backlight_probe(struct platform_device *pdev)
{
struct gpio_backlight_platform_data *pdata =
@@ -67,10 +93,12 @@ 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 +107,22 @@ 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 +139,25 @@ 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;
}
+#ifdef CONFIG_OF
+static struct of_device_id gpio_backlight_of_match[] = {
+ { .compatible = "gpio-backlight" },
+ { /* sentinel */ }
+};
+#endif
+
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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