[PATCH] iio: adc: qcom-spmi-adc5-gen3: Reuse IIO device ID for ADC_TM aux device

[Shawn Guo]

From: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>

adc5_gen3_add_aux_tm_device() never sets the auxiliary device id, so
every ADC5 Gen3 instance with at least one qcom,adc-tm channel tries
to register the same device name. With ADC_TM channels on more than
one PMIC, the second instance to probe fails:

  sysfs: cannot create duplicate filename '/bus/auxiliary/devices/qcom_spmi_adc5_gen3.adc5_tm_gen3.0'
  ...
  auxiliary qcom_spmi_adc5_gen3.adc5_tm_gen3.0: adding auxiliary device failed!: -17
  qcom-spmi-adc5-gen3 c400000.spmi:pmic@8:adc@7200: error -EEXIST: Failed to add auxiliary TM device

The ADC probe then fails as a whole, so that PMIC loses both its IIO
channels and its thermal zones. This shows up on Nord, which has
thermistor channels on two PMAU0102 PMICs.

Each ADC instance already has a unique IIO device ID. Use it as the
auxiliary device id instead of allocating one from a separate driver-wide
IDA, which removes the custom ID allocation and release handling. The
ADC_TM driver matches on the device name only, so the instance number
does not affect binding.

Fixes: baff45179e90 ("iio: adc: Add support for QCOM PMIC5 Gen3 ADC")
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>
Signed-off-by: Shawn Guo <shengchao.guo@xxxxxxxxxxxxxxxx>
---
This is the squashed version as requsted by Jonathan at:
https://lore.kernel.org/all/20261101020047.66034613@jic23-hlaptop/

 drivers/iio/adc/qcom-spmi-adc5-gen3.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/qcom-spmi-adc5-gen3.c b/drivers/iio/adc/qcom-spmi-adc5-gen3.c
index c68c6c5f6aca..a23eb5c9096d 100644
--- a/drivers/iio/adc/qcom-spmi-adc5-gen3.c
+++ b/drivers/iio/adc/qcom-spmi-adc5-gen3.c
@@ -610,7 +610,7 @@ static void adc5_gen3_delete_aux(void *data)
 
 static void adc5_gen3_aux_device_release(struct device *dev) {}
 
-static int adc5_gen3_add_aux_tm_device(struct adc5_chip *adc)
+static int adc5_gen3_add_aux_tm_device(struct adc5_chip *adc, int id)
 {
 	struct tm5_aux_dev_wrapper *aux_device;
 	int i, ret, i_tm = 0;
@@ -620,6 +620,7 @@ static int adc5_gen3_add_aux_tm_device(struct adc5_chip *adc)
 		return -ENOMEM;
 
 	aux_device->aux_dev.name = "adc5_tm_gen3";
+	aux_device->aux_dev.id = id;
 	aux_device->aux_dev.dev.parent = adc->dev;
 	aux_device->aux_dev.dev.release = adc5_gen3_aux_device_release;
 
@@ -799,7 +800,7 @@ static int adc5_gen3_probe(struct platform_device *pdev)
 		return ret;
 
 	if (adc->n_tm_channels > 0) {
-		ret = adc5_gen3_add_aux_tm_device(adc);
+		ret = adc5_gen3_add_aux_tm_device(adc, iio_device_id(indio_dev));
 		if (ret)
 			dev_err_probe(dev, ret,
 				      "Failed to add auxiliary TM device\n");
-- 
2.43.0