FAILED: patch "[PATCH] iio: dac: ad5686: fix ref bit initialization for" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] iio: dac: ad5686: fix ref bit initialization for" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x ecae2ae606d493cf11457946436335bd0e726663
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026060402-peroxide-remold-68a1@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ecae2ae606d493cf11457946436335bd0e726663 Mon Sep 17 00:00:00 2001
From: Rodrigo Alencar <rodrigo.alencar@analog.com>
Date: Fri, 1 May 2026 10:14:54 +0100
Subject: [PATCH] iio: dac: ad5686: fix ref bit initialization for
 single-channel parts

The reference bit position was ignored when writing the register at the
probe() function (!!val was used). When such bit is 1, internal voltage
reference is disabled so that an external one can be used. For
multi-channel devices, bit 0 of the Internal Reference Setup command
behaves the same way, so AD5686_REF_BIT_MSK is created. The issue exists
since support for single-channel devices were first introduced.

Fixes: be1b24d24541 ("iio:dac:ad5686: Add AD5691R/AD5692R/AD5693/AD5693R support")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
index 4b18498aa074..b85d5c5a864b 100644
--- a/drivers/iio/dac/ad5686.c
+++ b/drivers/iio/dac/ad5686.c
@@ -509,7 +509,7 @@ int ad5686_probe(struct device *dev,
 		break;
 	case AD5686_REGMAP:
 		cmd = AD5686_CMD_INTERNAL_REFER_SETUP;
-		ref_bit_msk = 0;
+		ref_bit_msk = AD5686_REF_BIT_MSK;
 		break;
 	case AD5693_REGMAP:
 		cmd = AD5686_CMD_CONTROL_REG;
@@ -520,9 +520,9 @@ int ad5686_probe(struct device *dev,
 		return -EINVAL;
 	}
 
-	val = (has_external_vref | ref_bit_msk);
+	val = has_external_vref ? ref_bit_msk : 0;
 
-	ret = st->write(st, cmd, 0, !!val);
+	ret = st->write(st, cmd, 0, val);
 	if (ret)
 		return ret;
 
diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
index e7d36bae3e59..36e16c5c4581 100644
--- a/drivers/iio/dac/ad5686.h
+++ b/drivers/iio/dac/ad5686.h
@@ -46,6 +46,7 @@
 
 #define AD5310_REF_BIT_MSK			BIT(8)
 #define AD5683_REF_BIT_MSK			BIT(12)
+#define AD5686_REF_BIT_MSK			BIT(0)
 #define AD5693_REF_BIT_MSK			BIT(12)
 
 /**

[PATCH 6.6.y] iio: dac: ad5686: fix ref bit initialization for single-channel parts

[Sasha Levin]

From: Rodrigo Alencar <rodrigo.alencar@analog.com>

[ Upstream commit ecae2ae606d493cf11457946436335bd0e726663 ]

The reference bit position was ignored when writing the register at the
probe() function (!!val was used). When such bit is 1, internal voltage
reference is disabled so that an external one can be used. For
multi-channel devices, bit 0 of the Internal Reference Setup command
behaves the same way, so AD5686_REF_BIT_MSK is created. The issue exists
since support for single-channel devices were first introduced.

Fixes: be1b24d24541 ("iio:dac:ad5686: Add AD5691R/AD5692R/AD5693/AD5693R support")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[ adapted `has_external_vref` to the in-tree equivalent `voltage_uv` variable in the `val =` computation ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/dac/ad5686.c | 6 +++---
 drivers/iio/dac/ad5686.h | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
index 4c9f7ade52b32d..39c76e9dcb498c 100644
--- a/drivers/iio/dac/ad5686.c
+++ b/drivers/iio/dac/ad5686.c
@@ -520,7 +520,7 @@ int ad5686_probe(struct device *dev,
 		break;
 	case AD5686_REGMAP:
 		cmd = AD5686_CMD_INTERNAL_REFER_SETUP;
-		ref_bit_msk = 0;
+		ref_bit_msk = AD5686_REF_BIT_MSK;
 		break;
 	case AD5693_REGMAP:
 		cmd = AD5686_CMD_CONTROL_REG;
@@ -532,9 +532,9 @@ int ad5686_probe(struct device *dev,
 		goto error_disable_reg;
 	}
 
-	val = (voltage_uv | ref_bit_msk);
+	val = voltage_uv ? ref_bit_msk : 0;
 
-	ret = st->write(st, cmd, 0, !!val);
+	ret = st->write(st, cmd, 0, val);
 	if (ret)
 		goto error_disable_reg;
 
diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
index 760f852911df76..182d951912d847 100644
--- a/drivers/iio/dac/ad5686.h
+++ b/drivers/iio/dac/ad5686.h
@@ -46,6 +46,7 @@
 
 #define AD5310_REF_BIT_MSK			BIT(8)
 #define AD5683_REF_BIT_MSK			BIT(12)
+#define AD5686_REF_BIT_MSK			BIT(0)
 #define AD5693_REF_BIT_MSK			BIT(12)
 
 /**
-- 
2.53.0