Patch "ARM: dts: am57xx-beagle-x15: set VDD_SD to always-on" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

ARM: dts: am57xx-beagle-x15: set VDD_SD to always-on

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     arm-dts-am57xx-beagle-x15-set-vdd_sd-to-always-on.patch

and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Tomi Valkeinen <[email protected]>
Date: Fri, 25 Sep 2015 16:02:03 +0300
Subject: ARM: dts: am57xx-beagle-x15: set VDD_SD to always-on

From: Tomi Valkeinen <[email protected]>

commit 7e381ec6a36aa44f15fc1a76e6efb9e2cd942e61 upstream.

LDO1 regulator (VDD_SD) is connected to SoC's vddshv8. vddshv8 needs to be kept always powered (see commit 5a0f93c6576a ("ARM: dts: Add am57xx-beagle-x15"), but at the moment VDD_SD is enabled/disabled depending on whether an SD card is inserted or not.

This patch sets LDO1 regulator to always-on.

This patch has a side effect of fixing another issue, HDMI DDC not working when SD card is not inserted:

Why this happens is that the tpd12s015 (HDMI level shifter/ESD protection chip) has LS_OE GPIO input, which needs to be enabled for the HDMI DDC to work. LS_OE comes from gpio6_28. The pin that provides gpio6_28 is powered by vddshv8, and vddshv8 comes from VDD_SD.

So when SD card is not inserted, VDD_SD is disabled, and LS_OE stays off.

The proper fix for the HDMI DDC issue would be to maybe have the pinctrl framework manage the pin specific power.

Apparently this fixes also a third issue (copy paste from Kishon's patch):

ldo1_reg in addition to being connected to the io lines is also connected to the card detect line. On card removal, omap_hsmmc driver does a regulator_disable causing card detect line to be pulled down. This raises a card insertion interrupt and once the MMC core detects there is no card inserted, it does a regulator disable which again raises a card insertion interrupt. This happens in a loop causing infinite MMC interrupts.

---
 arch/arm/boot/dts/am57xx-beagle-x15.dts |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -354,11 +354,12 @@
 				/* SMPS9 unused */
 
 				ldo1_reg: ldo1 {
-					/* VDD_SD  */
+					/* VDD_SD / VDDSHV8  */
 					regulator-name = "ldo1";
 					regulator-min-microvolt = <1800000>;
 					regulator-max-microvolt = <3300000>;
 					regulator-boot-on;
+					regulator-always-on;
 				};
 
 				ldo2_reg: ldo2 {

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/arm-dts-am57xx-beagle-x15-set-vdd_sd-to-always-on.patch