Commit bcf14774 authored May 25, 2018 by Andrey Smirnov Committed by Shawn Guo Jun 17, 2018

ARM: dts: imx51-zii-rdu1: Make sure SD1_WP is low



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
output-high GPIO hog in an effort to minimize current consumption.

Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
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>
Tested-By: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

parent 6e21e4c2

arch/arm/boot/dts/imx51-zii-rdu1.dts

+28 −0

Original line number	Diff line number	Diff line
		@@ -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>;
		output-high;
		};
		};

		&i2c2 {
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_i2c2>;
		@@ -668,6 +679,23 @@
		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.
		*/
		MX51_PAD_GPIO1_1__GPIO1_1 0x0000
		>;
		};

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