| Message ID | 1453354002-28366-9-git-send-email-wens@csie.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Thu, Jan 21, 2016 at 01:26:35PM +0800, Chen-Yu Tsai wrote: > mmc2 and mmc3 are available on the same pins, with different mux values. > However, only mmc3 supports 8 bit DDR transfer modes. > > Since preference for mmc3 over mmc2 is due to DDR transfer modes, just > set the drive strength to 40mA, which is needed for DDR. > > This pinmux setting also includes the hardware reset pin for emmc. > > Signed-off-by: Chen-Yu Tsai <wens@csie.org> > --- > arch/arm/boot/dts/sun6i-a31.dtsi | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arch/arm/boot/dts/sun6i-a31.dtsi b/arch/arm/boot/dts/sun6i-a31.dtsi > index b6ad7850fac6..1867af24ff52 100644 > --- a/arch/arm/boot/dts/sun6i-a31.dtsi > +++ b/arch/arm/boot/dts/sun6i-a31.dtsi > @@ -709,6 +709,16 @@ > allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > }; > > + mmc3_8bit_emmc_pins: mmc3@1 { > + allwinner,pins = "PC6", "PC7", "PC8", "PC9", > + "PC10", "PC11", "PC12", > + "PC13", "PC14", "PC15", > + "PC24"; > + allwinner,function = "mmc3"; > + allwinner,drive = <SUN4I_PINCTRL_40_MA>; > + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > + }; > + Is that reset pin optional? If so, I'd prefer it to be a separate node, like we're doing for the SPI chip selects for example. It allows more reusability between different devices without declaring new nodes. Thanks! Maxime
Hi, On Sat, Jan 23, 2016 at 4:31 AM, Maxime Ripard <maxime.ripard@free-electrons.com> wrote: > Hi, > > On Thu, Jan 21, 2016 at 01:26:35PM +0800, Chen-Yu Tsai wrote: >> mmc2 and mmc3 are available on the same pins, with different mux values. >> However, only mmc3 supports 8 bit DDR transfer modes. >> >> Since preference for mmc3 over mmc2 is due to DDR transfer modes, just >> set the drive strength to 40mA, which is needed for DDR. >> >> This pinmux setting also includes the hardware reset pin for emmc. >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> >> --- >> arch/arm/boot/dts/sun6i-a31.dtsi | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/arch/arm/boot/dts/sun6i-a31.dtsi b/arch/arm/boot/dts/sun6i-a31.dtsi >> index b6ad7850fac6..1867af24ff52 100644 >> --- a/arch/arm/boot/dts/sun6i-a31.dtsi >> +++ b/arch/arm/boot/dts/sun6i-a31.dtsi >> @@ -709,6 +709,16 @@ >> allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; >> }; >> >> + mmc3_8bit_emmc_pins: mmc3@1 { >> + allwinner,pins = "PC6", "PC7", "PC8", "PC9", >> + "PC10", "PC11", "PC12", >> + "PC13", "PC14", "PC15", >> + "PC24"; >> + allwinner,function = "mmc3"; >> + allwinner,drive = <SUN4I_PINCTRL_40_MA>; >> + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; >> + }; >> + > > Is that reset pin optional? > > If so, I'd prefer it to be a separate node, like we're doing for the > SPI chip selects for example. > > It allows more reusability between different devices without declaring > new nodes. All eMMC devices have a reset pin. The MMC standard specifies this as one way to reset the card, others being a special reset command, or powering the card off. It also notes a state when the card will not accept commands, and will require a power cycle or asserting the reset pin. I assume all designs would route this pin. The FEX files also have this pin included by default. Regards ChenYu -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, On Sat, Jan 23, 2016 at 07:04:54PM +0800, Chen-Yu Tsai wrote: > Hi, > > On Sat, Jan 23, 2016 at 4:31 AM, Maxime Ripard > <maxime.ripard@free-electrons.com> wrote: > > Hi, > > > > On Thu, Jan 21, 2016 at 01:26:35PM +0800, Chen-Yu Tsai wrote: > >> mmc2 and mmc3 are available on the same pins, with different mux values. > >> However, only mmc3 supports 8 bit DDR transfer modes. > >> > >> Since preference for mmc3 over mmc2 is due to DDR transfer modes, just > >> set the drive strength to 40mA, which is needed for DDR. > >> > >> This pinmux setting also includes the hardware reset pin for emmc. > >> > >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> > >> --- > >> arch/arm/boot/dts/sun6i-a31.dtsi | 10 ++++++++++ > >> 1 file changed, 10 insertions(+) > >> > >> diff --git a/arch/arm/boot/dts/sun6i-a31.dtsi b/arch/arm/boot/dts/sun6i-a31.dtsi > >> index b6ad7850fac6..1867af24ff52 100644 > >> --- a/arch/arm/boot/dts/sun6i-a31.dtsi > >> +++ b/arch/arm/boot/dts/sun6i-a31.dtsi > >> @@ -709,6 +709,16 @@ > >> allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > >> }; > >> > >> + mmc3_8bit_emmc_pins: mmc3@1 { > >> + allwinner,pins = "PC6", "PC7", "PC8", "PC9", > >> + "PC10", "PC11", "PC12", > >> + "PC13", "PC14", "PC15", > >> + "PC24"; > >> + allwinner,function = "mmc3"; > >> + allwinner,drive = <SUN4I_PINCTRL_40_MA>; > >> + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > >> + }; > >> + > > > > Is that reset pin optional? > > > > If so, I'd prefer it to be a separate node, like we're doing for the > > SPI chip selects for example. > > > > It allows more reusability between different devices without declaring > > new nodes. > > All eMMC devices have a reset pin. The MMC standard specifies this as > one way to reset the card, others being a special reset command, or > powering the card off. It also notes a state when the card will not > accept commands, and will require a power cycle or asserting the reset > pin. > > I assume all designs would route this pin. The FEX files also have this > pin included by default. I was more concerned about the case were you'd have a 8bits bus without an emmc. But I guess that can't happen, since all SD cards are using a 4 bits width anyway. I'll apply this patch. Thanks! Maxime
diff --git a/arch/arm/boot/dts/sun6i-a31.dtsi b/arch/arm/boot/dts/sun6i-a31.dtsi index b6ad7850fac6..1867af24ff52 100644 --- a/arch/arm/boot/dts/sun6i-a31.dtsi +++ b/arch/arm/boot/dts/sun6i-a31.dtsi @@ -709,6 +709,16 @@ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; }; + mmc3_8bit_emmc_pins: mmc3@1 { + allwinner,pins = "PC6", "PC7", "PC8", "PC9", + "PC10", "PC11", "PC12", + "PC13", "PC14", "PC15", + "PC24"; + allwinner,function = "mmc3"; + allwinner,drive = <SUN4I_PINCTRL_40_MA>; + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; + }; + gmac_pins_mii_a: gmac_mii@0 { allwinner,pins = "PA0", "PA1", "PA2", "PA3", "PA8", "PA9", "PA11",
mmc2 and mmc3 are available on the same pins, with different mux values. However, only mmc3 supports 8 bit DDR transfer modes. Since preference for mmc3 over mmc2 is due to DDR transfer modes, just set the drive strength to 40mA, which is needed for DDR. This pinmux setting also includes the hardware reset pin for emmc. Signed-off-by: Chen-Yu Tsai <wens@csie.org> --- arch/arm/boot/dts/sun6i-a31.dtsi | 10 ++++++++++ 1 file changed, 10 insertions(+)