Hi, On Thu, Oct 10, 2013 at 06:14:19PM +0000, Paul Zimmerman wrote: > > From: Felipe Balbi [mailto:balbi@xxxxxx] > > Sent: Thursday, October 10, 2013 11:07 AM > > > > On Thu, Oct 10, 2013 at 05:57:54PM +0000, Paul Zimmerman wrote: > > > > 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. > > > > right, but that description should be passed to the PHY, right ? DWC2 > > works with both widths (8 or 16). > > I don't know what you mean by "passed to the PHY". The data width is the > number of physical wires connecting the PHY to the DWC2 controller. If right, that's well understood. > that value can be read from the PHY, fine. Otherwise, I think a DT > binding is the way to go. Let's see what the DT folks have to say. -- balbi
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