[PATCH linux dev-5.4 1/2] hwmon: (pmbus/ibm-cffps) Add another PSU CCIN to version detection

[Eddie James <eajames@linux.ibm.com>]

There is an additional CCIN for the IBM CFFPS that may be classifed as
either version one or version two, based upon the rest of the bits of
the CCIN. Add support for it in the version detection.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/1583948590-17220-1-git-send-email-eajames@linux.ibm.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/pmbus/ibm-cffps.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
index 27593b723d74..7d3720665ad4 100644
--- a/drivers/hwmon/pmbus/ibm-cffps.c
+++ b/drivers/hwmon/pmbus/ibm-cffps.c
@@ -33,9 +33,12 @@
 #define CFFPS_INPUT_HISTORY_CMD			0xD6
 #define CFFPS_INPUT_HISTORY_SIZE		100
 
+#define CFFPS_CCIN_REVISION			GENMASK(7, 0)
+#define  CFFPS_CCIN_REVISION_LEGACY		 0xde
 #define CFFPS_CCIN_VERSION			GENMASK(15, 8)
 #define CFFPS_CCIN_VERSION_1			 0x2b
 #define CFFPS_CCIN_VERSION_2			 0x2e
+#define CFFPS_CCIN_VERSION_3			 0x51
 
 /* STATUS_MFR_SPECIFIC bits */
 #define CFFPS_MFR_FAN_FAULT			BIT(0)
@@ -489,11 +492,14 @@ static int ibm_cffps_probe(struct i2c_client *client,
 		vs = (enum versions)id->driver_data;
 
 	if (vs == cffps_unknown) {
+		u16 ccin_revision = 0;
 		u16 ccin_version = CFFPS_CCIN_VERSION_1;
 		int ccin = i2c_smbus_read_word_swapped(client, CFFPS_CCIN_CMD);
 
-		if (ccin > 0)
+		if (ccin > 0) {
+			ccin_revision = FIELD_GET(CFFPS_CCIN_REVISION, ccin);
 			ccin_version = FIELD_GET(CFFPS_CCIN_VERSION, ccin);
+		}
 
 		switch (ccin_version) {
 		default:
@@ -503,6 +509,12 @@ static int ibm_cffps_probe(struct i2c_client *client,
 		case CFFPS_CCIN_VERSION_2:
 			vs = cffps2;
 			break;
+		case CFFPS_CCIN_VERSION_3:
+			if (ccin_revision == CFFPS_CCIN_REVISION_LEGACY)
+				vs = cffps1;
+			else
+				vs = cffps2;
+			break;
 		}
 
 		/* Set the client name to include the version number. */
-- 
2.24.0