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@xxxxxxxxxxxxxxx> know about it. >From 618c808968852609d2d9f0e5cfc351a4807ef8d0 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai <wens@xxxxxxxx> 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@xxxxxxxx> 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@xxxxxxxx> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxx are queue-4.9/regulator-axp20x-fix-axp809-ldo_io-registration-error-on-cold-boot.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html