| Message ID | 20210508205658.91105-1-dev@lynxeye.de |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | [1/2] dt-bindings: mmc: add no-mmc-hs400 flag | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success | |
| robh/dt-meta-schema | success | |
| robh/dtbs-check | success |
> -----Original Message----- > From: Lucas Stach [mailto:dev@lynxeye.de] > Sent: 2021年5月9日 4:57 > To: Rob Herring <robh+dt@kernel.org>; Ulf Hansson <ulf.hansson@linaro.org>; > Adrian Hunter <adrian.hunter@intel.com> > Cc: Pengutronix Kernel Team <kernel@pengutronix.de>; Fabio Estevam > <festevam@gmail.com>; linux-mmc@vger.kernel.org; > devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org > Subject: [PATCH 2/2] mmc: sdhci-esdhc-imx: add support for disabling HS400 > mode via DT > > On some boards the data strobe line isn't wired up, rendering HS400 support > broken, even if both the controller and the eMMC claim to support it. Allow to > disable HS400 mode via DT. > > Signed-off-by: Lucas Stach <dev@lynxeye.de> > --- > drivers/mmc/host/sdhci-esdhc-imx.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c > b/drivers/mmc/host/sdhci-esdhc-imx.c > index a20459744d21..1d6068507fb6 100644 > --- a/drivers/mmc/host/sdhci-esdhc-imx.c > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c > @@ -1483,6 +1483,9 @@ sdhci_esdhc_imx_probe_dt(struct platform_device > *pdev, > if (of_find_property(np, "no-1-8-v", NULL)) > host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V; > > + if (of_find_property(np, "no-mmc-hs400", NULL)) > + host->quirks2 &= ~SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400; > + Hi Lucas I suggest you move the change to mmc_of_parse() in drivers/mmc/core/host.c You also need to take care of the HS400ES mode. Regards Haibo Chen > if (of_property_read_u32(np, "fsl,delay-line", &boarddata->delay_line)) > boarddata->delay_line = 0; > > -- > 2.31.1
On Sat, 08 May 2021 22:56:57 +0200, Lucas Stach wrote: > HS400 requires a data strobe line in addition to the other MMC signal > lines, so if a board design neglects to wire up this signal, HS400 mode > is no available, even if both the controller and the eMMC are claiming > to support this mode. Add a DT flag to allow boards to disable the > HS400 support in this case. > > Signed-off-by: Lucas Stach <dev@lynxeye.de> > --- > Documentation/devicetree/bindings/mmc/mmc-controller.yaml | 5 +++++ > 1 file changed, 5 insertions(+) > Acked-by: Rob Herring <robh@kernel.org>
diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml index e141330c1114..ac80d09df3a9 100644 --- a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml +++ b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml @@ -220,6 +220,11 @@ properties: description: eMMC HS400 enhanced strobe mode is supported + no-mmc-hs400: + $ref: /schemas/types.yaml#/definitions/flag + description: + All eMMC HS400 modes are not supported. + dsr: description: Value the card Driver Stage Register (DSR) should be programmed
HS400 requires a data strobe line in addition to the other MMC signal lines, so if a board design neglects to wire up this signal, HS400 mode is no available, even if both the controller and the eMMC are claiming to support this mode. Add a DT flag to allow boards to disable the HS400 support in this case. Signed-off-by: Lucas Stach <dev@lynxeye.de> --- Documentation/devicetree/bindings/mmc/mmc-controller.yaml | 5 +++++ 1 file changed, 5 insertions(+)