[U-Boot] [PATCH 1/4] ARM: dts: dra7-mmc-iodelay: Add a new pinctrl group for clk line without pullup

[Faiz Abbas]

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: Faiz Abbas <faiz_abbas at ti.com>
---
 arch/arm/dts/am571x-idk.dts        |  3 ++-
 arch/arm/dts/am572x-idk.dts        |  3 ++-
 arch/arm/dts/dra7-mmc-iodelay.dtsi | 19 +++++++++++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/dts/dra7-mmc-iodelay.dtsi

diff --git a/arch/arm/dts/am571x-idk.dts b/arch/arm/dts/am571x-idk.dts
index debf946440..eb5fda81f5 100644
--- a/arch/arm/dts/am571x-idk.dts
+++ b/arch/arm/dts/am571x-idk.dts
@@ -11,6 +11,7 @@
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include "am57xx-idk-common.dtsi"
+#include "dra7-mmc-iodelay.dtsi"
 #include "dra72x-mmc-iodelay.dtsi"
 
 / {
@@ -102,7 +103,7 @@
 
 &mmc1 {
 	pinctrl-names = "default", "hs", "sdr12", "sdr25", "sdr50", "ddr50", "sdr104";
-	pinctrl-0 = <&mmc1_pins_default>;
+	pinctrl-0 = <&mmc1_pins_default_no_clk_pu>;
 	pinctrl-1 = <&mmc1_pins_hs>;
 	pinctrl-2 = <&mmc1_pins_sdr12>;
 	pinctrl-3 = <&mmc1_pins_sdr25>;
diff --git a/arch/arm/dts/am572x-idk.dts b/arch/arm/dts/am572x-idk.dts
index 9212931f25..2247948553 100644
--- a/arch/arm/dts/am572x-idk.dts
+++ b/arch/arm/dts/am572x-idk.dts
@@ -11,6 +11,7 @@
 #include "dra74x.dtsi"
 #include "am572x-idk-common.dtsi"
 #include "am57xx-idk-common.dtsi"
+#include "dra7-mmc-iodelay.dtsi"
 #include "dra74x-mmc-iodelay.dtsi"
 
 / {
@@ -21,7 +22,7 @@
 
 &mmc1 {
 	pinctrl-names = "default", "hs", "sdr12", "sdr25", "sdr50", "ddr50", "sdr104";
-	pinctrl-0 = <&mmc1_pins_default>;
+	pinctrl-0 = <&mmc1_pins_default_no_clk_pu>;
 	pinctrl-1 = <&mmc1_pins_hs>;
 	pinctrl-2 = <&mmc1_pins_sdr12>;
 	pinctrl-3 = <&mmc1_pins_sdr25>;
diff --git a/arch/arm/dts/dra7-mmc-iodelay.dtsi b/arch/arm/dts/dra7-mmc-iodelay.dtsi
new file mode 100644
index 0000000000..4acc215ba3
--- /dev/null
+++ b/arch/arm/dts/dra7-mmc-iodelay.dtsi
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MMC IOdelay values for TI's DRA7xx SoCs.
+ * Copyright (C) 2019 Texas Instruments
+ * Author: Faiz Abbas <faiz_abbas at ti.com>
+ */
+
+&dra7_pmx_core {
+	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 */
+		>;
+	};
+};
-- 
2.19.2