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-rw-r--r--drivers/hwmon/pmbus/pmbus.h11
-rw-r--r--drivers/hwmon/pmbus/pmbus_core.c12
2 files changed, 23 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index d198af3a92b6..90d6c9e23d5f 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -22,6 +22,8 @@ enum pmbus_regs {
PMBUS_CLEAR_FAULTS = 0x03,
PMBUS_PHASE = 0x04,
+ PMBUS_WRITE_PROTECT = 0x10,
+
PMBUS_CAPABILITY = 0x19,
PMBUS_QUERY = 0x1A,
@@ -226,6 +228,15 @@ enum pmbus_regs {
#define PB_OPERATION_CONTROL_ON BIT(7)
/*
+ * WRITE_PROTECT
+ */
+#define PB_WP_ALL BIT(7) /* all but WRITE_PROTECT */
+#define PB_WP_OP BIT(6) /* all but WP, OPERATION, PAGE */
+#define PB_WP_VOUT BIT(5) /* all but WP, OPERATION, PAGE, VOUT, ON_OFF */
+
+#define PB_WP_ANY (PB_WP_ALL | PB_WP_OP | PB_WP_VOUT)
+
+/*
* CAPABILITY
*/
#define PB_CAPABILITY_SMBALERT BIT(4)
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 8470097907bc..2c196eddbb8d 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -1088,6 +1088,9 @@ static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data,
snprintf(sensor->name, sizeof(sensor->name), "%s%d",
name, seq);
+ if (data->flags & PMBUS_WRITE_PROTECTED)
+ readonly = true;
+
sensor->page = page;
sensor->reg = reg;
sensor->class = class;
@@ -2141,6 +2144,15 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK))
client->flags |= I2C_CLIENT_PEC;
+ /*
+ * Check if the chip is write protected. If it is, we can not clear
+ * faults, and we should not try it. Also, in that case, writes into
+ * limit registers need to be disabled.
+ */
+ ret = i2c_smbus_read_byte_data(client, PMBUS_WRITE_PROTECT);
+ if (ret > 0 && (ret & PB_WP_ANY))
+ data->flags |= PMBUS_WRITE_PROTECTED | PMBUS_SKIP_STATUS_CHECK;
+
if (data->info->pages)
pmbus_clear_faults(client);
else