On 14/10/2014 21:54, Paul Zimmerman wrote: >> From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of John Crispin >> Sent: Friday, October 10, 2014 10:27 AM >> >> We need this for dwc2 to work on older ralink SoC like the rt3052. >> >> Signed-off-by: John Crispin <blogic@xxxxxxxxxxx> >> --- >> drivers/usb/dwc2/hcd.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c >> index 4d918ed..8b5f966 100644 >> --- a/drivers/usb/dwc2/hcd.c >> +++ b/drivers/usb/dwc2/hcd.c >> @@ -47,6 +47,7 @@ >> #include <linux/io.h> >> #include <linux/slab.h> >> #include <linux/usb.h> >> +#include <linux/reset.h> >> >> #include <linux/usb/hcd.h> >> #include <linux/usb/ch11.h> >> @@ -2764,6 +2765,11 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg, int irq, >> >> dev_dbg(hsotg->dev, "DWC OTG HCD INIT\n"); >> >> + /* reset the device if a reset controller is present */ >> + retval = device_reset_optional(hsotg->dev); >> + if (retval && retval != -ENOSYS) >> + return retval; >> + >> /* Detect config values from hardware */ >> retval = dwc2_get_hwparams(hsotg); >> > Hmm. Can you explain this a bit more? I'm not familiar with the reset > control API. > > But I see that there is currently no user of device_reset_optional() in > the kernel. Looks like drivers typically call devm_reset_control_get() > in their probe functions, then save the returned pointer and call it > later to do the reset. I wonder why dwc2 would be the only driver not > to do it that way? > Hi, we originally used device_reset(), when the reset api was new. this had the problem that there was no stub in the headers for when the api was not enabled. when i rebased the patch last week, i simply checked the header file and saw that there was a new stub and used it. hence the use of device_reset_optional(). i will rework the patch and use devm_reset_control_get instead. John -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
