diff mbox series

[v3,05/15] ARM: dts: dra76x-mmc-iodelay: Add a new pinctrl group for clk line without pullup

Message ID 20180425125449.19755-6-kishon@ti.com
State New
Headers show
Series dra7: mmc: Update mmc dt node to use sdhci-omap | expand

Commit Message

Kishon Vijay Abraham I April 25, 2018, 12:54 p.m. UTC 
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 line 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: Kishon Vijay Abraham I <kishon@ti.com>

---
 arch/arm/boot/dts/dra76x-mmc-iodelay.dtsi | 11 +++++++++++
 1 file changed, 11 insertions(+)

-- 
2.17.0

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diff mbox series

Patch

diff --git a/arch/arm/boot/dts/dra76x-mmc-iodelay.dtsi b/arch/arm/boot/dts/dra76x-mmc-iodelay.dtsi
index baba7b00eca7..b6327220a88e 100644
--- a/arch/arm/boot/dts/dra76x-mmc-iodelay.dtsi
+++ b/arch/arm/boot/dts/dra76x-mmc-iodelay.dtsi
@@ -38,6 +38,17 @@ 
 		>;
 	};
 
+	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 */
+		>;
+	};
+
 	mmc1_pins_hs: mmc1_pins_hs {
 		pinctrl-single,pins = <
 			DRA7XX_CORE_IOPAD(0x3754, PIN_INPUT_PULLUP | MUX_VIRTUAL_MODE11 | MUX_MODE0) /* mmc1_clk.clk */