hwmon: (pmbus) Add new pmbus flag NO_WRITE_PROTECT

Some PMBus chips respond with invalid data when reading the WRITE_PROTECT
register. For such chips, this flag should be set so that the PMBus core
driver doesn't use the WRITE_PROTECT command to determine its behavior.

Signed-off-by: Erik Rosen <erik.rosen@metormote.com>
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 01a1ffc74bb6d9e132ea8ca5df17eaa08ef5f0b8..a5367df1cee833b24f4f3efd9dcbffceeebaf116 100644 (file)
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2231,9 +2231,11 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
         * 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->flags & PMBUS_NO_WRITE_PROTECT)) {
+               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);

diff --git a/include/linux/pmbus.h b/include/linux/pmbus.h
index edd7c84fef658a6fe0fa3e944c4568efb2abfdca..12c515a27d3a0fb48802cd6aedbed7de34c08587 100644 (file)
--- a/include/linux/pmbus.h
+++ b/include/linux/pmbus.h
@@ -56,6 +56,15 @@
  */
 #define PMBUS_READ_STATUS_AFTER_FAILED_CHECK   BIT(3)
 
+/*
+ * PMBUS_NO_WRITE_PROTECT
+ *
+ * Some PMBus chips respond with invalid data when reading the WRITE_PROTECT
+ * register. For such chips, this flag should be set so that the PMBus core
+ * driver doesn't use the WRITE_PROTECT command to determine its behavior.
+ */
+#define PMBUS_NO_WRITE_PROTECT                 BIT(4)
+
 struct pmbus_platform_data {
        u32 flags;              /* Device specific flags */