> From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Thursday, October 10, 2013 10:46 AM > > On Thu, Oct 10, 2013 at 12:54:40PM -0400, Matt Porter wrote: > > On 10/10/2013 11:29 AM, Felipe Balbi wrote: > > >On Mon, Oct 07, 2013 at 06:12:29AM -0400, Matt Porter wrote: > > >>Extend dwc2 binding with an optional utmi phy width property. > > >>Enable the s3c-hsotg.c driver to use standard dwc2 binding > > >>and enable configuration of the UTMI phy width based on the > > >>property. > > >> > > >>Signed-off-by: Matt Porter <matt.porter@xxxxxxxxxx> > > >>Reviewed-by: Markus Mayer <markus.mayer@xxxxxxxxxx> > > >>Reviewed-by: Tim Kryger <tim.kryger@xxxxxxxxxx> > > >>--- > > >> Documentation/devicetree/bindings/staging/dwc2.txt | 4 ++++ > > >> drivers/usb/gadget/s3c-hsotg.c | 18 +++++++++++++++++- > > >> drivers/usb/gadget/s3c-hsotg.h | 1 + > > >> 3 files changed, 22 insertions(+), 1 deletion(-) > > >> > > >>diff --git a/Documentation/devicetree/bindings/staging/dwc2.txt > b/Documentation/devicetree/bindings/staging/dwc2.txt > > >>index 1a1b7cf..fb6b8ee 100644 > > >>--- a/Documentation/devicetree/bindings/staging/dwc2.txt > > >>+++ b/Documentation/devicetree/bindings/staging/dwc2.txt > > >>@@ -6,10 +6,14 @@ Required properties: > > >> - reg : Should contain 1 register range (address and length) > > >> - interrupts : Should contain 1 interrupt > > >> > > >>+Optional properties: > > >>+- snps,phy-utmi-width: Must contain the UTMI data width (either 8 or 16) > > > > > >isn't this available in any of the configuration registers ? > > > > Yes and no. HWCFG4 has a UTMI data width field. However, it has 3 > > valid states, "8", "16", or "8 or 16". The BCM281xx implementation is > > set to the latter and the attached phy is 8-bit. > > > > Looking at dwc2 prior to Matthijs Kooijman's patch [1] which starts > > validating the value of phy_utmi_width in that driver, the pci.c > > dwc2_module_params .phy_utmi_width field there even had the comment, > > "/* 16 bits - NOT DETECTABLE */". The autodetect code in > > dwc2_set_param_phy_utmi_width() will fail if HWCFG4 has the "8 or 16" > > option as it just decides to default to a phy width of 16 if nothing > > is configured by the platform glue. This property would also allow > > this issue to be addressed in that driver. > > fair enough, but I'd really like to hear from DT folks if your suggested > binding is acceptable. It seems like we can equally argue that it's a SW > configuration or HW description. It's definitely a HW description - the width of the UTMI data connection. But, which PHY is this? Does it have a register that could tell what the data width is? The dwc2 core has an (optional) PHY Vendor Control Register that allows reading the PHY registers. -- Paul -- 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
