[PATCH 5.4 53/66] hwmon: (pmbus/ltc2978) Fix PMBus polling of MFR_COMMON definitions.

From: Greg Kroah-Hartman
Date: Tue Feb 18 2020 - 15:00:21 EST

From: Mike Jones <michael-a1.jones@xxxxxxxxxx>

commit cf2b012c90e74e85d8aea7d67e48868069cfee0c upstream.

Change 21537dc driver PMBus polling of MFR_COMMON from bits 5/4 to
bits 6/5. This fixs a LTC297X family bug where polling always returns
not busy even when the part is busy. This fixes a LTC388X and
LTM467X bug where polling used PEND and NOT_IN_TRANS, and BUSY was
not polled, which can lead to NACKing of commands. LTC388X and
LTM467X modules now poll BUSY and PEND, increasing reliability by
eliminating NACKing of commands.

Signed-off-by: Mike Jones <michael-a1.jones@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1580234400-2829-2-git-send-email-michael-a1.jones@xxxxxxxxxx
Fixes: e04d1ce9bbb49 ("hwmon: (ltc2978) Add polling for chips requiring it")
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/hwmon/pmbus/ltc2978.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -82,8 +82,8 @@ enum chips { ltc2974, ltc2975, ltc2977,

#define LTC_POLL_TIMEOUT 100 /* in milli-seconds */

-#define LTC_NOT_BUSY BIT(5)
+#define LTC_NOT_BUSY BIT(6)

* LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which