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SubjectRe: [RFC 2/2] usb: gadget: composite: parse dt overrides
On 6/25/2012 1:49 PM, Rob Herring wrote:
> On 06/25/2012 03:23 PM, Alexandre Pereira da Silva wrote:
>> Grab the devicetree node properties to override VendorId, ProductId,
>> bcdDevice, Manucacturer, Product and SerialNumber
>>
>> Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
>> ---
>> drivers/usb/gadget/composite.c | 31 +++++++++++++++++++++++++++++++
>> 1 file changed, 31 insertions(+)
>
> Are these bindings documented? I think they should be less generic.
> Perhaps prefixed with 'usb-'.

There is precedent for the following properties in the USB node, namely
the device tree that has been used on OLPC systems for the past several
years. Also, I think that Sun machines from the same timeframe use the
same property names, based on the fact that Sun is using my USB 2.0 OFW
driver code.

Here's a listing of the properties of a representative USB child device,
in this case a USB FLASH drive.

configuration# 00000001
bulk-out-size 00000200
bulk-out-pipe 00000001
bulk-in-size 00000200
bulk-in-pipe 00000001
serial$ 200435137016ae938861
device$ Cruzer Mini
vendor$ SanDisk Corporation
compatible usb781,5150.20
usb781,5150
usbif781,class8.6.50
usbif781,class8.6
usbif781,class8
usbif,class8.6.50
usbif,class8.6
usbif,class8
usb,device
vendor-id 00000781
device-id 00005150
release 00000020
name scsi
class 00000008
subclass 00000006
protocol 00000050
high-speed
assigned-address 00000002
reg 00000003 00000000
#size-cells 00000000
#address-cells 00000001
Note that:

a) The separator in "vendor-id" is hyphen, not underscore, in keeping
with the established property naming convention (except for the
unfortunate "device_type").

b) There is no "usb," prefix, since the presence of this in a device
node that is a child of a USB bus implicitly identifies the kind of ID.
"vendor-id" and "device-id" in PCI bus child devices is similarly
un-prefixed.

c) Some of these property names are defined in
http://www.openfirmware.org/ofwg/bindings/usb/usb-1_0.ps




>
>>
>> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
>> index 390749b..f3b480e 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>
>> @@ -1423,6 +1424,7 @@ 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 +1472,35 @@ static int composite_bind(struct usb_gadget *gadget)
>>
>> cdev->desc = *composite->dev;
>>
>> + /* grab overrides from devicetree */
>
> Reading the code, it looks more like the DT entries are defaults rather
> than overrides.
>
>> + if (np) {
>> + u32 reg;
>> +
>> + if (!idVendor &&
>> + of_property_read_u32(np, "vendor_id", &reg) == 0)
>> + idVendor = reg;
>
> if (!idVendor)
> of_property_read_u32(np, "vendor_id", &idVendor);
>
> Rob
>
>> +
>> + if (!idProduct &&
>> + of_property_read_u32(np, "product_id", &reg) == 0)
>> + idProduct = reg;
>> +
>> + if (!bcdDevice &&
>> + of_property_read_u32(np, "bcd_device", &reg) == 0)
>> + bcdDevice = reg;
>> +
>> + if (!iManufacturer)
>> + of_property_read_string(np, "manufacturer",
>> + &iManufacturer);
>> +
>> + if (!iProduct)
>> + of_property_read_string(np, "product",
>> + &iProduct);
>> +
>> + if (!iSerialNumber)
>> + of_property_read_string(np, "serial_number",
>> + &iSerialNumber);
>> + }
>> +
>> /* standardized runtime overrides for device ID data */
>> if (idVendor)
>> cdev->desc.idVendor = cpu_to_le16(idVendor);
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss
>



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