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Add three optional SD6HC >> properties: >> >> - cdns,ddr50-read-dqs-delay: DLL_SLAVE[7:0] read-DQS delay that centres >> the read eye (0-255). >> - cdns,ddr50-use-lpbk-dqs: DQS_TIMING[21] read-DQS source >> (0 = phony, 1 = loopback). >> - cdns,ddr50-phony-dqs-timing: PHY_CTRL[9:4] phony DQS assertion timing >> (0-63) that positions the fabricated strobe relative to the returning >> DDR data; not produced by the Cadence timing calculation. >> >> All three are disallowed for the SD4HC variant. >> >> Signed-off-by: Tze Yee Ng >> --- >> .../devicetree/bindings/mmc/cdns,sd6hc.yaml | 27 +++++++++++++++++++ >> 1 file changed, 27 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml b/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml >> index d5ea2717904b..df86872603d0 100644 >> --- a/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml >> +++ b/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml >> @@ -74,6 +74,33 @@ properties: >> maximum: 1000 >> default: 24 >> >> + cdns,ddr50-read-dqs-delay: >> + description: | >> + SD6HC DDR50 read-DQS delay (DLL_SLAVE[7:0]) used to centre the read >> + eye. DDR50 has no CMD19 tuning, so this is a board/SoC-characterised >> + value. If absent, the driver default is used. >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + minimum: 0 >> + maximum: 0xff > > default: ... > Hi Krysztof, Thanks for your review. No fixed constant. When the property is absent, the driver keeps the value it computes for the mode. I'll reword the descriptions to say that. > Also, look at the existing bindings. How are the delays represented? ps. > Why is this different? > > In the modes this targets (DDR50/DDR52) the PHY runs the DLL bypassed, where this field is a count of delay elements - so it maps to time via cdns,delay-element-ps just like the existing delay. I'll express it in ps: cdns,ddr-read-dqs-delay-ps, convert in the driver (count = ps / delay-element-ps), default 0. >> + >> + cdns,ddr50-use-lpbk-dqs: >> + description: | >> + SD6HC DDR50 read-DQS source (DQS_TIMING[21]): 0 = phony DQS, >> + 1 = loopback DQS. If absent, the driver default is used. > > Then this is just type: boolean > Agreed. I'll make it a boolean. Note: v2 also renames these cdns,ddr50-* -> cdns,ddr-* and applies them in both SD DDR50 and eMMC DDR52 (per Tanmay's review). >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + enum: [0, 1] >> + >> + cdns,ddr50-phony-dqs-timing: >> + description: | >> + SD6HC DDR50 phony DQS assertion timing (PHY_CTRL[9:4]). Positions the >> + fabricated read strobe relative to the returning DDR data; the correct >> + value depends on the board's SD flight time and is not produced by the >> + Cadence timing calculation. If absent, the driver default >> + (REBAR_PULSE_CYCLES-1) is used. >> + $ref: /schemas/types.yaml#/definitions/uint32 >> + minimum: 0 >> + maximum: 0x3f > > Best regards, > Krzysztof