On Tue, Oct 8, 2024 at 4:53 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > > On 08/10/2024 12:23, Joy Chakraborty wrote: > > On Mon, Oct 7, 2024 at 8:26 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: > >> > >> On 07/10/2024 15:55, Joy Chakraborty wrote: > >>> PIPE4 spec defines an 18bit de-emphasis setting to be passed from > >>> controller to the PHY. > >>> TxDeemph[17:0] is split as [5:0] C-1, [11:6] C0, [17:12] C+1 for 3 tap > >>> filter used for USB Gen2(10GT/s). > >>> > >>> Signed-off-by: Joy Chakraborty <joychakr@xxxxxxxxxx> > >>> --- > >>> Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 12 ++++++++++++ > >>> 1 file changed, 12 insertions(+) > >>> > >>> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml > >>> index 1cd0ca90127d..a1f1bbcf1467 100644 > >>> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml > >>> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml > >>> @@ -190,6 +190,18 @@ properties: > >>> - 1 # -3.5dB de-emphasis > >>> - 2 # No de-emphasis > >>> > >>> + snps,tx_gen2_de_emphasis_quirk: > >> > >> No underscores. > > > > Ack, will fix it with a follow up patch. > > > >> > >>> + description: When set core will set Tx de-emphasis for USB Gen2 > >> > >> And why it cannot be implied by compatible? > > > > As per my understanding these are tuning coefficients for de-emphasis > > particular to a platform and not the dwc3 controller, hence should not > > be a controller compatible. > > Platforms must have specific compatible, so this should be implied by > compatible. Maybe I am using the word "platform" incorrectly here, what I understand is that the same controller(in a chip) when used on 2 different physical form factors might need different deemphasis coefficient values to be passed to its Phy. Someone could correct me from the USB link stand point if I am mistaken here. Thanks Joy > > > Similar to the property defined right above this definition which is > > from PIPE3 spec for USB Gen1. > > > Best regards, > Krzysztof >
