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@xxxxxxxxxxxxxxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
Changes since [v1]:
- Switched GPIO hog to be output-high
- Removed whitespace damage
[v1] lkml.kernel.org/r/20180525030153.15986-1-andrew.smirnov@xxxxxxxxx
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..1e343f35a9d9 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>;
+ output-high;
+ };
+};
+
&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.
+ */
+ MX51_PAD_GPIO1_1__GPIO1_1 0x0000
>;
};
--
2.17.0
--
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