[PATCH v3] hwmon: (pmbus/lm25066) Fix PMBus coefficients for LM5064/5066/5066i

From: Potin Lai

Date: Thu Jun 11 2026 - 01:50:20 EST


Swap the high setting and low setting coefficients in the lm25066_coeff
table for LM5064, LM5066, and LM5066i. The coefficients were previously
mapped incorrectly, resulting in inverted current and power scaling.

Additionally, dynamically assign the exponent (R) registers inside the
probe's LM25066_DEV_SETUP_CL check. This ensures that the proper
exponent is applied (e.g., for LM25056, high setting power exponent
is -4, but low setting power exponent is -3).

Signed-off-by: Potin Lai <potin.lai.pt@xxxxxxxxx>
---
Changes in v3:
- change signed-off consistent with email sender
- Link to v2: https://patch.msgid.link/20260611-lm25066-driver-fix-v2-1-5d28861b0d8e@xxxxxxxxxxxx

Changes in v2:
- based on comment in v1, only swap the coefficients setting for LM5064/5066/5066i
- Link to v1: https://patch.msgid.link/20260610-lm25066-driver-fix-v1-1-ff9b39961a2a@xxxxxxxxxxxx
---
drivers/hwmon/pmbus/lm25066.c | 54 ++++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 26 deletions(-)

diff --git a/drivers/hwmon/pmbus/lm25066.c b/drivers/hwmon/pmbus/lm25066.c
index dd7275a67a0a..6e23ada64e2f 100644
--- a/drivers/hwmon/pmbus/lm25066.c
+++ b/drivers/hwmon/pmbus/lm25066.c
@@ -132,23 +132,23 @@ static const struct __coeff lm25066_coeff[][PSC_NUM_CLASSES + 2] = {
.R = -2,
},
[PSC_CURRENT_IN] = {
- .m = 10742,
- .b = 1552,
+ .m = 5456,
+ .b = 2118,
.R = -2,
},
[PSC_CURRENT_IN_L] = {
- .m = 5456,
- .b = 2118,
+ .m = 10742,
+ .b = 1552,
.R = -2,
},
[PSC_POWER] = {
- .m = 1204,
- .b = 8524,
+ .m = 612,
+ .b = 11202,
.R = -3,
},
[PSC_POWER_L] = {
- .m = 612,
- .b = 11202,
+ .m = 1204,
+ .b = 8524,
.R = -3,
},
[PSC_TEMPERATURE] = {
@@ -167,23 +167,23 @@ static const struct __coeff lm25066_coeff[][PSC_NUM_CLASSES + 2] = {
.R = -2,
},
[PSC_CURRENT_IN] = {
- .m = 10753,
- .b = -1200,
+ .m = 5405,
+ .b = -600,
.R = -2,
},
[PSC_CURRENT_IN_L] = {
- .m = 5405,
- .b = -600,
+ .m = 10753,
+ .b = -1200,
.R = -2,
},
[PSC_POWER] = {
- .m = 1204,
- .b = -6000,
+ .m = 605,
+ .b = -8000,
.R = -3,
},
[PSC_POWER_L] = {
- .m = 605,
- .b = -8000,
+ .m = 1204,
+ .b = -6000,
.R = -3,
},
[PSC_TEMPERATURE] = {
@@ -202,23 +202,23 @@ static const struct __coeff lm25066_coeff[][PSC_NUM_CLASSES + 2] = {
.R = -2,
},
[PSC_CURRENT_IN] = {
- .m = 15076,
- .b = -504,
+ .m = 7645,
+ .b = 100,
.R = -2,
},
[PSC_CURRENT_IN_L] = {
- .m = 7645,
- .b = 100,
+ .m = 15076,
+ .b = -504,
.R = -2,
},
[PSC_POWER] = {
- .m = 1701,
- .b = -4000,
+ .m = 861,
+ .b = -965,
.R = -3,
},
[PSC_POWER_L] = {
- .m = 861,
- .b = -965,
+ .m = 1701,
+ .b = -4000,
.R = -3,
},
[PSC_TEMPERATURE] = {
@@ -519,18 +519,20 @@ static int lm25066_probe(struct i2c_client *client)
info->m[PSC_VOLTAGE_OUT] = coeff[PSC_VOLTAGE_OUT].m;
info->b[PSC_VOLTAGE_OUT] = coeff[PSC_VOLTAGE_OUT].b;
info->R[PSC_VOLTAGE_OUT] = coeff[PSC_VOLTAGE_OUT].R;
- info->R[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN].R;
- info->R[PSC_POWER] = coeff[PSC_POWER].R;
if (config & LM25066_DEV_SETUP_CL) {
info->m[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN_L].m;
info->b[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN_L].b;
+ info->R[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN_L].R;
info->m[PSC_POWER] = coeff[PSC_POWER_L].m;
info->b[PSC_POWER] = coeff[PSC_POWER_L].b;
+ info->R[PSC_POWER] = coeff[PSC_POWER_L].R;
} else {
info->m[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN].m;
info->b[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN].b;
+ info->R[PSC_CURRENT_IN] = coeff[PSC_CURRENT_IN].R;
info->m[PSC_POWER] = coeff[PSC_POWER].m;
info->b[PSC_POWER] = coeff[PSC_POWER].b;
+ info->R[PSC_POWER] = coeff[PSC_POWER].R;
}

/*

---
base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b
change-id: 20260610-lm25066-driver-fix-ae435577fce1

Best regards,
--
Potin Lai <potin.lai.pt@xxxxxxxxx>