Subject: Re: [PATCH 5/5] usb: gadget: composite: parse dt overrides

From: Rob Herring <[email-masked]>
Date: Tue, 26 Jun 2012 13:43:03 -0500

On 06/26/2012 09:27 AM, Alexandre Pereira da Silva wrote:
> Grab the devicetree node properties to override VendorId, ProductId,
> bcdDevice, Manucacturer, Product and SerialNumber

I'm still confused about what is the order of priority for the 2
possible sources of these values. The way it is written, the DT value is
a default, not an override.

Rob

> 
> Signed-off-by: Alexandre Pereira da Silva <[email-masked]>
> ---
>  Documentation/devicetree/bindings/usb/gadget.txt |   20 +++++++++++
>  drivers/usb/gadget/composite.c                   |   39 ++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/usb/gadget.txt
> 
> diff --git a/Documentation/devicetree/bindings/usb/gadget.txt b/Documentation/devicetree/bindings/usb/gadget.txt
> new file mode 100644
> index 0000000..93388d3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/gadget.txt
> @@ -0,0 +1,20 @@
> +Usb Gadget DeviceTree bindings
> +
> +These optional properties inside the usb device controller node are used to
> +change some of the gadget drivers configuration:
> +- vendor-id: Usb vendor id
> +- product-id: Usb product id
> +- release: Version of this device
> +- vendor: Textual description of the vendor
> +- device: Textual description of this device
> +- serial: Textual representation of the device's serial number
> +
> +Binding Example:
> +	usbd@31020000 {
> +		vendor-id = <0x0525>;
> +		product-id = <0xa4a6>;
> +		release = <1>;
> +		vendor = "Some Corp";
> +		device = "Test Device";
> +		serial = "12345";
> +	};
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 390749b..b39aef4 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -17,6 +17,7 @@
>  #include <linux/module.h>
>  #include <linux/device.h>
>  #include <linux/utsname.h>
> +#include <linux/of.h>
>  
>  #include <linux/usb/composite.h>
>  #include <asm/unaligned.h>
> @@ -1419,10 +1420,44 @@ static u8 override_id(struct usb_composite_dev *cdev, u8 *desc)
>  	return *desc;
>  }
>  
> +static void composite_parse_dt(struct usb_composite_dev *cdev,
> +	struct device_node *np)
> +{
> +	u32 reg;
> +
> +	if (!idVendor && of_property_read_u32(np, "vendor-id", &reg) == 0)
> +		idVendor = reg;
> +
> +	if (!idProduct && of_property_read_u32(np, "product-id", &reg) == 0)
> +		idProduct = reg;
> +
> +	if (!bcdDevice && of_property_read_u32(np, "release", &reg) == 0)
> +		bcdDevice = reg;
> +
> +	if (!iManufacturer)
> +		if (of_property_read_string(np, "vendor",
> +			&composite->iManufacturer) == 0)
> +			cdev->manufacturer_override = override_id(cdev,
> +				&cdev->desc.iManufacturer);
> +
> +	if (!iProduct)
> +		if (of_property_read_string(np, "device",
> +			&composite->iProduct) == 0)
> +			cdev->product_override = override_id(cdev,
> +				&cdev->desc.iProduct);
> +
> +	if (!iSerialNumber)
> +		if (of_property_read_string(np, "serial",
> +			&composite->iSerialNumber) == 0)
> +			cdev->serial_override = override_id(cdev,
> +				&cdev->desc.iSerialNumber);
> +}
> +
>  static int composite_bind(struct usb_gadget *gadget)
>  {
>  	struct usb_composite_dev	*cdev;
>  	int				status = -ENOMEM;
> +	struct device_node		*np = gadget->dev.of_node;
>  
>  	cdev = kzalloc(sizeof *cdev, GFP_KERNEL);
>  	if (!cdev)
> @@ -1470,6 +1505,10 @@ static int composite_bind(struct usb_gadget *gadget)
>  
>  	cdev->desc = *composite->dev;
>  
> +	/* grab overrides from devicetree */
> +	if (np)
> +		composite_parse_dt(cdev, np);
> +
>  	/* standardized runtime overrides for device ID data */
>  	if (idVendor)
>  		cdev->desc.idVendor = cpu_to_le16(idVendor);