Patch "regulator: axp20x: Fix axp809 ldo_io registration error on cold boot" has been added to the 4.9-stable tree

Patch "regulator: axp20x: Fix axp809 ldo_io registration error on cold boot" has been added to the 4.9-stable tree

[gregkh]

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

    regulator: axp20x: Fix axp809 ldo_io registration error on cold boot

to the 4.9-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:
     regulator-axp20x-fix-axp809-ldo_io-registration-error-on-cold-boot.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 618c808968852609d2d9f0e5cfc351a4807ef8d0 Mon Sep 17 00:00:00 2001
From: Chen-Yu Tsai <wens@csie.org>
Date: Fri, 11 Nov 2016 11:12:43 +0800
Subject: regulator: axp20x: Fix axp809 ldo_io registration error on cold boot

From: Chen-Yu Tsai <wens@csie.org>

commit 618c808968852609d2d9f0e5cfc351a4807ef8d0 upstream.

The maximum supported voltage for ldo_io# is 3.3V, but on cold boot
the selector comes up at 0x1f, which maps to 3.8V. This was previously
corrected by Allwinner's U-boot, which set all regulators on the PMICs
to some pre-configured voltage. With recent progress in U-boot SPL
support, this is no longer the case. In any case we should handle
this quirk in the kernel driver as well.

This invalid setting causes _regulator_get_voltage() to fail with -EINVAL
which causes regulator registration to fail when constrains are used:

[    1.054181] vcc-pg: failed to get the current voltage(-22)
[    1.059670] axp20x-regulator axp20x-regulator.0: Failed to register ldo_io0
[    1.069749] axp20x-regulator: probe of axp20x-regulator.0 failed with error -22

This commits makes the axp20x regulator driver accept the 0x1f register
value, fixing this.

The datasheet does not guarantee reliable operation above 3.3V, so on
boards where this regulator is used the regulator-max-microvolt setting
must be 3.3V or less.

This is essentially the same as the commit f40d4896bf32 ("regulator:
axp20x: Fix axp22x ldo_io registration error on cold boot") for AXP22x
PMICs.

Fixes: a51f9f4622a3 ("regulator: axp20x: support AXP809 variant")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/regulator/axp20x-regulator.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/regulator/axp20x-regulator.c
+++ b/drivers/regulator/axp20x-regulator.c
@@ -337,10 +337,18 @@ static const struct regulator_desc axp80
 		 AXP22X_ELDO2_V_OUT, 0x1f, AXP22X_PWR_OUT_CTRL2, BIT(1)),
 	AXP_DESC(AXP809, ELDO3, "eldo3", "eldoin", 700, 3300, 100,
 		 AXP22X_ELDO3_V_OUT, 0x1f, AXP22X_PWR_OUT_CTRL2, BIT(2)),
-	AXP_DESC_IO(AXP809, LDO_IO0, "ldo_io0", "ips", 700, 3300, 100,
+	/*
+	 * Note the datasheet only guarantees reliable operation up to
+	 * 3.3V, this needs to be enforced via dts provided constraints
+	 */
+	AXP_DESC_IO(AXP809, LDO_IO0, "ldo_io0", "ips", 700, 3800, 100,
 		    AXP22X_LDO_IO0_V_OUT, 0x1f, AXP20X_GPIO0_CTRL, 0x07,
 		    AXP22X_IO_ENABLED, AXP22X_IO_DISABLED),
-	AXP_DESC_IO(AXP809, LDO_IO1, "ldo_io1", "ips", 700, 3300, 100,
+	/*
+	 * Note the datasheet only guarantees reliable operation up to
+	 * 3.3V, this needs to be enforced via dts provided constraints
+	 */
+	AXP_DESC_IO(AXP809, LDO_IO1, "ldo_io1", "ips", 700, 3800, 100,
 		    AXP22X_LDO_IO1_V_OUT, 0x1f, AXP20X_GPIO1_CTRL, 0x07,
 		    AXP22X_IO_ENABLED, AXP22X_IO_DISABLED),
 	AXP_DESC_FIXED(AXP809, RTC_LDO, "rtc_ldo", "ips", 1800),


Patches currently in stable-queue which might be from wens@csie.org are

queue-4.9/regulator-axp20x-fix-axp809-ldo_io-registration-error-on-cold-boot.patch