Re: [PATCH v2] media: rc: gpio-ir-recv: add support for device tree parsing

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On 02/08/2013 09:38 PM, Sebastian Hesselbarth wrote:
This patch adds device tree parsing for gpio_ir_recv platform_data and
the mandatory binding documentation. It basically follows what we already
have for e.g. gpio_keys. All required device tree properties are OS
independent but an optional property allow linux specific support for rc
maps.

There was a similar patch sent by Matus Ujhelyi but that discussion
died after the first reviews.

Signed-off-by: Sebastian Hesselbarth<sebastian.hesselbarth@xxxxxxxxx>
---
Changelog

v1->v2:
- get rid of ptr returned by _get_devtree_pdata()
- check for of_node instead for NULL pdata
- remove unneccessary double check for gpios property
- remove unneccessary #ifdef CONFIG_OF around match table

Cc: Grant Likely<grant.likely@xxxxxxxxxxxx>
Cc: Rob Herring<rob.herring@xxxxxxxxxxx>
Cc: Rob Landley<rob@xxxxxxxxxxx>
Cc: Mauro Carvalho Chehab<mchehab@xxxxxxxxxx>
Cc: Sebastian Hesselbarth<sebastian.hesselbarth@xxxxxxxxx>
Cc: Benoit Thebaudeau<benoit.thebaudeau@xxxxxxxxxxxx>
Cc: David Hardeman<david@xxxxxxxxxxx>
Cc: Trilok Soni<tsoni@xxxxxxxxxxxxxx>
Cc: Sylwester Nawrocki<s.nawrocki@xxxxxxxxxxx>
Cc: Matus Ujhelyi<ujhelyi.m@xxxxxxxxx>
Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-media@xxxxxxxxxxxxxxx
---
  .../devicetree/bindings/media/gpio-ir-receiver.txt |   16 ++++++
  drivers/media/rc/gpio-ir-recv.c                    |   57 ++++++++++++++++++++
  2 files changed, 73 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/media/gpio-ir-receiver.txt

diff --git a/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt b/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt
new file mode 100644
index 0000000..8589f30
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt
@@ -0,0 +1,16 @@
+Device-Tree bindings for GPIO IR receiver
+
+Required properties:
+	- compatible = "gpio-ir-receiver";
+	- gpios: OF device-tree gpio specification.

Perhaps:
	- compatible: should be "gpio-ir-receiver";
	- gpios: specifies GPIO used for IR signal reception.
?
+
+Optional properties:
+	- linux,rc-map-name: Linux specific remote control map name.
+
+Example node:
+
+	ir: ir-receiver {
+		compatible = "gpio-ir-receiver";
+		gpios =<&gpio0 19 1>;
+		linux,rc-map-name = "rc-rc6-mce";
+	};
diff --git a/drivers/media/rc/gpio-ir-recv.c b/drivers/media/rc/gpio-ir-recv.c
index 4f71a7d..3c62006 100644
--- a/drivers/media/rc/gpio-ir-recv.c
+++ b/drivers/media/rc/gpio-ir-recv.c
@@ -16,6 +16,7 @@
  #include<linux/interrupt.h>
  #include<linux/gpio.h>
  #include<linux/slab.h>
+#include<linux/of_gpio.h>
  #include<linux/platform_device.h>
  #include<linux/irq.h>
  #include<media/rc-core.h>
@@ -30,6 +31,50 @@ struct gpio_rc_dev {
  	bool active_low;
  };

+#ifdef CONFIG_OF
+/*
+ * Translate OpenFirmware node properties into platform_data
+ */
+static int gpio_ir_recv_get_devtree_pdata(struct device *dev,
+				  struct gpio_ir_recv_platform_data *pdata)
+{
+	struct device_node *np = dev->of_node;
+	enum of_gpio_flags flags;
+	int gpio;
+
+	gpio = of_get_gpio_flags(np, 0,&flags);
+	if (gpio<  0) {
+		if (gpio != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get gpio flags, error: %d\n",
+				gpio);

			dev_err(dev, "Failed to get gpio flags (%d)\n",	gpio);
?
+		return gpio;
+	}
+
+	pdata->gpio_nr = gpio;
+	pdata->active_low = (flags&  OF_GPIO_ACTIVE_LOW) ? true : false;

This could be simplified to:

	pdata->active_low = (flags & OF_GPIO_ACTIVE_LOW);

+	/* probe() takes care of map_name == NULL or allowed_protos == 0 */
+	pdata->map_name = of_get_property(np, "linux,rc-map-name", NULL);
+	pdata->allowed_protos = 0;
+
+	return 0;
+}
+
+static struct of_device_id gpio_ir_recv_of_match[] = {
+	{ .compatible = "gpio-ir-receiver", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, gpio_ir_recv_of_match);
+
+#else /* !CONFIG_OF */
+
+static inline struct gpio_ir_recv_platform_data *
+gpio_ir_recv_get_devtree_pdata(struct device *dev)

Please check how it compiles with CONFIG_OF disabled ;)

You could also make it:

#define gpio_ir_recv_get_devtree_pdata  (-ENOSYS)

+{
+	return ERR_PTR(-ENODEV);
+}
+
+#endif
+
  static irqreturn_t gpio_ir_recv_irq(int irq, void *dev_id)
  {
  	struct gpio_rc_dev *gpio_dev = dev_id;
@@ -66,6 +111,17 @@ static int gpio_ir_recv_probe(struct platform_device *pdev)
  					pdev->dev.platform_data;
  	int rc;

+	if (pdev->dev.of_node) {
+		struct gpio_ir_recv_platform_data *dtpdata =

I think you could use pdata here instead, as previously. But I'm fine with
as it is now as well.

+			devm_kzalloc(&pdev->dev, sizeof(*dtpdata), GFP_KERNEL);
+		if (!dtpdata)
+			return -ENOMEM;
+		rc = gpio_ir_recv_get_devtree_pdata(&pdev->dev, dtpdata);
+		if (rc)
+			return rc;
+		pdata = dtpdata;
+	}
+
  	if (!pdata)
  		return -EINVAL;

@@ -192,6 +248,7 @@ static struct platform_driver gpio_ir_recv_driver = {
  	.driver = {
  		.name   = GPIO_IR_DRIVER_NAME,
  		.owner  = THIS_MODULE,
+		.of_match_table = of_match_ptr(gpio_ir_recv_of_match),
  #ifdef CONFIG_PM
  		.pm	=&gpio_ir_recv_pm_ops,
  #endif

The patch looks good to me in general, after fixing the empty function
declaration please feel free to add:

Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>

--

Thanks,
Sylwester


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