Re: [RFC 2/2] usb: gadget: composite: parse dt overrides
From: Mitch Bradley
Date: Tue Jun 26 2012 - 01:38:50 EST
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@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-'.
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", ®) == 0)
+ idVendor = reg;
if (!idVendor)
of_property_read_u32(np, "vendor_id", &idVendor);
Rob
+
+ if (!idProduct &&
+ of_property_read_u32(np, "product_id", ®) == 0)
+ idProduct = reg;
+
+ if (!bcdDevice &&
+ of_property_read_u32(np, "bcd_device", ®) == 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);
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