Re: [RFC 2/2] usb: gadget: composite: parse dt overrides
From: Alexandre Pereira da Silva
Date: Mon Jun 25 2012 - 21:13:27 EST
On Mon, Jun 25, 2012 at 8:49 PM, Rob Herring <robherring2@xxxxxxxxx> 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@xxxxxxxxx>
>> ---
>> 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-'.
Not yet, I will in the final series. This was just to see it had big
issues because the final one needs to change lots of files.
I will add some prefix to them.
About the documentation, should I include it in all of the controllers
bindings or should I add a common file to describe the gadget drivers
binding?
>>
>> 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.
Actually, it's mixed. The DT overrides the hard coded defaults. And
module parameters can override both. I think the safest path is to
keep them like this, so a DT would not break existing code.
>> + if (np) {
>> + u32 reg;
>> +
>> + if (!idVendor &&
>> + of_property_read_u32(np, "vendor_id", ®) == 0)
>> + idVendor = reg;
>
> if (!idVendor)
> of_property_read_u32(np, "vendor_id", &idVendor);
>
> Rob
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