iio: addac: ad74413: don't set DIN_SINK for functions other than digital input

Apparently, despite the name Digital Input Configuration Register, the
settings in the DIN_CONFIGx registers also affect other channel
functions. In particular, setting a non-zero value in the DIN_SINK
field breaks the resistance measurement function.

Now, one can of course argue that specifying a drive-strength-microamp
property along with a adi,ch-func which is not one of the digital
input functions is a bug in the device tree. However, we have a rather
complicated setup with instances of ad74412r on external hardware
modules, and have set a default drive-strength-microamp in our DT
fragments describing those, merely modifying the adi,ch-func settings
to reflect however the modules have been wired up. And restricting
this setting to just being done for digital input doesn't make the
driver any more complex.

Fixes: 504eb485589d1 (iio: ad74413r: wire up support for drive-strength-microamp property)
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20230503105042.453755-1-linux@rasmusvillemoes.dk
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/addac/ad74413r.c b/drivers/iio/addac/ad74413r.c
index e3366cf..6b0e821 100644 (file)
--- a/drivers/iio/addac/ad74413r.c
+++ b/drivers/iio/addac/ad74413r.c
@@ -1317,13 +1317,14 @@ static int ad74413r_setup_gpios(struct ad74413r_state *st)
                }
 
                if (config->func == CH_FUNC_DIGITAL_INPUT_LOGIC ||
-                   config->func == CH_FUNC_DIGITAL_INPUT_LOOP_POWER)
+                   config->func == CH_FUNC_DIGITAL_INPUT_LOOP_POWER) {
                        st->comp_gpio_offsets[comp_gpio_i++] = i;
 
-               strength = config->drive_strength;
-               ret = ad74413r_set_comp_drive_strength(st, i, strength);
-               if (ret)
-                       return ret;
+                       strength = config->drive_strength;
+                       ret = ad74413r_set_comp_drive_strength(st, i, strength);
+                       if (ret)
+                               return ret;
+               }
 
                ret = ad74413r_set_gpo_config(st, i, gpo_config);
                if (ret)