hwmon: (pmbus/core) honor vrm_version in pmbus_data2reg_vid()

pmbus_data2reg_vid() hardcoded the VR11 encoding regardless of the
vrm_version configured by the driver, while pmbus_reg2data_vid()
already switched on it. Any driver that selects a non-VR11 VID mode
and exposes a regulator (or hwmon vout setter) sent dangerously
wrong codes to PMBUS_VOUT_COMMAND -- e.g. an nvidia195mv part asked
for 200 mV got the VR11 clamp to 500 mV encoded as 0xB2, which the
chip interprets as 1080 mV.

Mirror pmbus_reg2data_vid() so writes round-trip with reads.

Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Assisted-by: Claude:claude-opus-4-7 [Claude Code]
Link: https://lore.kernel.org/r/20260620-pmbus-data2reg-vid-v1-1-5518030432c4@nexthop.ai
Fixes: 068c227056b92 ("hwmon: (pmbus) Add support for VR12")
Fixes: d4977c083aeb2 ("hwmon: (pmbus) Add support for Intel VID protocol VR13")
Fixes: 9d72340b6ade9 ("hwmon: (pmbus/core) Add support for Intel IMVP9 and AMD 6.25mV modes")
Fixes: 969a4ec86ca5f ("hwmon: (pmbus/core) Add support for NVIDIA nvidia195mv mode")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index e8fdd799c71c0db0c4affc8a4bbff25cc50ea393..8123a568af40d5845fc2382601f55a5618c748d3 100644 (file)
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -1095,9 +1095,27 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data,
 static u16 pmbus_data2reg_vid(struct pmbus_data *data,
                              struct pmbus_sensor *sensor, s64 val)
 {
-       val = clamp_val(val, 500, 1600);
-
-       return 2 + DIV_ROUND_CLOSEST_ULL((1600LL - val) * 100LL, 625);
+       switch (data->info->vrm_version[sensor->page]) {
+       case vr12:
+               val = clamp_val(val, 250, 1520);
+               return 1 + DIV_ROUND_CLOSEST_ULL(val - 250, 5);
+       case vr13:
+               val = clamp_val(val, 500, 3040);
+               return 1 + DIV_ROUND_CLOSEST_ULL(val - 500, 10);
+       case imvp9:
+               val = clamp_val(val, 200, 2740);
+               return 1 + DIV_ROUND_CLOSEST_ULL(val - 200, 10);
+       case amd625mv:
+               val = clamp_val(val, 200, 1550);
+               return DIV_ROUND_CLOSEST_ULL((1550LL - val) * 100LL, 625);
+       case nvidia195mv:
+               val = clamp_val(val, 195, 1465);
+               return 1 + DIV_ROUND_CLOSEST_ULL(val - 195, 5);
+       case vr11:
+       default:
+               val = clamp_val(val, 500, 1600);
+               return 2 + DIV_ROUND_CLOSEST_ULL((1600LL - val) * 100LL, 625);
+       }
 }
 
 static u16 pmbus_data2reg(struct pmbus_data *data,