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    Subject[PATCH v3 03/15] ARM: dts: dra72x-mmc-iodelay: Add a new pinctrl group for clk line without pullup
    Date
    During a short period when the bus voltage is switched from 3.3v to 1.8v,
    (to enumerate UHS mode), the mmc module is disabled and the mmc IO lines
    are kept in a state according to the programmed pad mux pull type.

    According to 4.2.4.2 Timing to Switch Signal Voltage in "SD Specifications
    Part 1 Physical Layer Specification Version 5.00 February 22, 2016", the
    host should hold CLK low for at least 5ms.

    In order to keep the card line low during voltage switch, the pad mux of
    mmc1_clk line should be configured to pull down.

    Add a new pinctrl group for clock line without pullup to be used in boards
    where mmc1_clk line is not connected to an external pullup.

    Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
    ---
    arch/arm/boot/dts/dra72x-mmc-iodelay.dtsi | 11 +++++++++++
    1 file changed, 11 insertions(+)

    diff --git a/arch/arm/boot/dts/dra72x-mmc-iodelay.dtsi b/arch/arm/boot/dts/dra72x-mmc-iodelay.dtsi
    index 088013c6dc6e..c9351eaf97f0 100644
    --- a/arch/arm/boot/dts/dra72x-mmc-iodelay.dtsi
    +++ b/arch/arm/boot/dts/dra72x-mmc-iodelay.dtsi
    @@ -51,6 +51,17 @@
    >;
    };

    + mmc1_pins_default_no_clk_pu: mmc1_pins_default_no_clk_pu {
    + pinctrl-single,pins = <
    + DRA7XX_CORE_IOPAD(0x3754, PIN_INPUT_PULLDOWN | MUX_MODE0) /* mmc1_clk.clk */
    + DRA7XX_CORE_IOPAD(0x3758, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_cmd.cmd */
    + DRA7XX_CORE_IOPAD(0x375c, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat0.dat0 */
    + DRA7XX_CORE_IOPAD(0x3760, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat1.dat1 */
    + DRA7XX_CORE_IOPAD(0x3764, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat2.dat2 */
    + DRA7XX_CORE_IOPAD(0x3768, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_dat3.dat3 */
    + >;
    + };
    +
    mmc1_pins_sdr12: mmc1_pins_sdr12 {
    pinctrl-single,pins = <
    DRA7XX_CORE_IOPAD(0x3754, PIN_INPUT_PULLUP | MUX_MODE0) /* mmc1_clk.clk */
    --
    2.17.0
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