Messages in this thread | | | From | Andrey Smirnov <> | Date | Fri, 25 May 2018 09:59:16 -0700 | Subject | Re: [PATCH] ARM: dts: imx51-zii-rdu1: Make sure SD1_WP is low |
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On Fri, May 25, 2018 at 7:16 AM, Lucas Stach <l.stach@pengutronix.de> wrote: > Am Donnerstag, den 24.05.2018, 20:01 -0700 schrieb Andrey Smirnov: >> Make sure that MX51_PAD_GPIO1_1 does not remain configure as >> ALT0/SD1_WP (it is out of reset). This is needed because of external >> pull-up resistor attached to that pad that, when left unchanged, will >> drive SD1_WP high preventing eSDHC1/eMMC from working correctly. >> >> To fix that add a pinmux configuration line configureing the pad to >> function as a GPIO. While we are at it, add a corresponding input GPIO >> hog in an effort to minimize current consumption. > > Enabling the input part of the pad also consumes (a small amount of) > power, if you are after minimizing power consumption, better configure > the pin as output and drive it in the pull direction. >
Sure, sounds good, will do in v2.
>> >> > Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com> >> > Cc: Shawn Guo <shawnguo@kernel.org> >> > Cc: Fabio Estevam <fabio.estevam@nxp.com> >> > Cc: Lucas Stach <l.stach@pengutronix.de> >> > Cc: Chris Healy <cphealy@gmail.com> >> > Cc: Rob Herring <robh+dt@kernel.org> >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: devicetree@vger.kernel.org >> Cc: linux-kernel@vger.kernel.org >> > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> >> --- >> arch/arm/boot/dts/imx51-zii-rdu1.dts | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/arch/arm/boot/dts/imx51-zii-rdu1.dts b/arch/arm/boot/dts/imx51-zii-rdu1.dts >> index df9eca94d812..d484e7e46b27 100644 >> --- a/arch/arm/boot/dts/imx51-zii-rdu1.dts >> +++ b/arch/arm/boot/dts/imx51-zii-rdu1.dts >> @@ -476,6 +476,17 @@ >> > status = "okay"; >> }; >> >> +&gpio1 { >> > + unused-sd3-wp-gpio { >> > + /* >> > + * See pinctrl_esdhc1 below for more details on this >> > + */ >> > + gpio-hog; >> > + gpios = <1 GPIO_ACTIVE_HIGH>; >> > + input; >> > + }; >> +}; >> + >> &i2c2 { >> > pinctrl-names = "default"; >> > pinctrl-0 = <&pinctrl_i2c2>; >> @@ -660,6 +671,23 @@ >> > > MX51_PAD_SD1_DATA1__SD1_DATA1 0x20d5 >> > > MX51_PAD_SD1_DATA2__SD1_DATA2 0x20d5 >> > > MX51_PAD_SD1_DATA3__SD1_DATA3 0x20d5 >> > + /* >> > + * GPIO1_1 is not directly used by eSDHC1 in >> > + * any capacity, but earlier versions of RDU1 >> > + * used that pin as WP GPIO for eSDHC3 and >> > + * because of that that pad has an external >> > + * pull-up resistor. This is problematic >> > + * because out of reset the pad is configured >> > + * as ALT0 which serves as SD1_WP, which, when >> > + * pulled high by and external pull-up, will >> > + * inhibit execution of any write request to >> > + * attached eMMC device. >> > + * >> > + * To avoid this problem we configure the pad >> > + * to ALT1/GPIO and avoid driving SD1_WP >> + * signal high. > > Applying the patch complains about whitespace damage in the above 2 > lines. >
My bad, sorry about that, will fix in v2.
Thanks, Andrey Smirnov
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