The conversion result registers differs between devices. Make sure the
mapping is correct by using a device dependent .get_raw() callback function.

Fixes: 732ad34260d3 ("iio: adc: mcp3911: add support for the whole MCP39xx family")
Co-developed-by: Lukas Rauber <lukas.rauber@janitza.de>
Signed-off-by: Lukas Rauber <lukas.rauber@janitza.de>
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---
 drivers/iio/adc/mcp3911.c | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 6748b44d568db68120172a950bbfffb6adc7cfa3..60a19c35807ab783505e817898a2405bd8beae34 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -6,7 +6,7 @@
  * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se>
  */
 #include <linux/bitfield.h>
-#include <linux/bits.h>
+#include <linux/bitops.h>
 #include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
@@ -79,6 +79,8 @@
 #define MCP3910_CONFIG1_CLKEXT		BIT(6)
 #define MCP3910_CONFIG1_VREFEXT		BIT(7)
 
+#define MCP3910_CHANNEL(ch)		(MCP3911_REG_CHANNEL0 + (ch))
+
 #define MCP3910_REG_OFFCAL_CH0		0x0f
 #define MCP3910_OFFCAL(ch)		(MCP3910_REG_OFFCAL_CH0 + (ch) * 6)
 
@@ -110,6 +112,7 @@ struct mcp3911_chip_info {
 	int (*get_offset)(struct mcp3911 *adc, int channel, int *val);
 	int (*set_offset)(struct mcp3911 *adc, int channel, int val);
 	int (*set_scale)(struct mcp3911 *adc, int channel, u32 val);
+	int (*get_raw)(struct mcp3911 *adc, int channel, int *val);
 };
 
 struct mcp3911 {
@@ -170,6 +173,18 @@ static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask, u32 val, u8 len
 	return mcp3911_write(adc, reg, val, len);
 }
 
+static int mcp3911_read_s24(struct mcp3911 *const adc, u8 const reg, s32 *const val)
+{
+	u32 uval;
+	int const ret = mcp3911_read(adc, reg, &uval, 3);
+
+	if (ret)
+		return ret;
+
+	*val = sign_extend32(uval, 23);
+	return ret;
+}
+
 static int mcp3910_enable_offset(struct mcp3911 *adc, bool enable)
 {
 	unsigned int mask = MCP3910_CONFIG0_EN_OFFCAL;
@@ -194,6 +209,11 @@ static int mcp3910_set_offset(struct mcp3911 *adc, int channel, int val)
 	return adc->chip->enable_offset(adc, 1);
 }
 
+static int mcp3910_get_raw(struct mcp3911 *adc, int channel, s32 *val)
+{
+	return mcp3911_read_s24(adc, MCP3910_CHANNEL(channel), val);
+}
+
 static int mcp3911_enable_offset(struct mcp3911 *adc, bool enable)
 {
 	unsigned int mask = MCP3911_STATUSCOM_EN_OFFCAL;
@@ -218,6 +238,11 @@ static int mcp3911_set_offset(struct mcp3911 *adc, int channel, int val)
 	return adc->chip->enable_offset(adc, 1);
 }
 
+static int mcp3911_get_raw(struct mcp3911 *adc, int channel, s32 *val)
+{
+	return mcp3911_read_s24(adc, MCP3911_CHANNEL(channel), val);
+}
+
 static int mcp3910_get_osr(struct mcp3911 *adc, u32 *val)
 {
 	int ret;
@@ -321,12 +346,9 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
 	guard(mutex)(&adc->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		ret = mcp3911_read(adc,
-				   MCP3911_CHANNEL(channel->channel), val, 3);
+		ret = adc->chip->get_raw(adc, channel->channel, val);
 		if (ret)
 			return ret;
-
-		*val = sign_extend32(*val, 23);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
 		ret = adc->chip->get_offset(adc, channel->channel, val);
@@ -799,6 +821,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 	[MCP3911] = {
 		.channels = mcp3911_channels,
@@ -810,6 +833,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3911_get_offset,
 		.set_offset = mcp3911_set_offset,
 		.set_scale = mcp3911_set_scale,
+		.get_raw = mcp3911_get_raw,
 	},
 	[MCP3912] = {
 		.channels = mcp3912_channels,
@@ -821,6 +845,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 	[MCP3913] = {
 		.channels = mcp3913_channels,
@@ -832,6 +857,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 	[MCP3914] = {
 		.channels = mcp3914_channels,
@@ -843,6 +869,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 	[MCP3918] = {
 		.channels = mcp3918_channels,
@@ -854,6 +881,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 	[MCP3919] = {
 		.channels = mcp3919_channels,
@@ -865,6 +893,7 @@ static const struct mcp3911_chip_info mcp3911_chip_info[] = {
 		.get_offset = mcp3910_get_offset,
 		.set_offset = mcp3910_set_offset,
 		.set_scale = mcp3910_set_scale,
+		.get_raw = mcp3910_get_raw,
 	},
 };
 static const struct of_device_id mcp3911_dt_ids[] = {

-- 
2.49.0

On Mon, Apr 28, 2025 at 08:54:11AM +0200, Marcus Folkesson wrote:
> The conversion result registers differs between devices. Make sure the
> mapping is correct by using a device dependent .get_raw() callback function.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko