Messages in this thread Patch in this message | | | From | Guenter Roeck <> | Subject | [PATCH] hwmon: (pmbus) More stringent checking of VOUT_MODE register | Date | Tue, 1 Mar 2011 21:32:20 -0800 |
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Some PMBus chips do not support the VOUT_MODE register. To make matters worse, such chips may not return an error when reading the register either, but instead return 0xff.
Check if the register exists using pmbus_check_byte_register() before reading its value. In addition, validate the returned value and ignore it if it is 0xff (which is invalid).
Reported-by: Greg Schnorr <gschnorr@cisco.com> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com> --- drivers/hwmon/pmbus_core.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/hwmon/pmbus_core.c b/drivers/hwmon/pmbus_core.c index 0edab1c..b7c64ba 100644 --- a/drivers/hwmon/pmbus_core.c +++ b/drivers/hwmon/pmbus_core.c @@ -1426,10 +1426,11 @@ static void pmbus_find_attributes(struct i2c_client *client, static int pmbus_identify_common(struct i2c_client *client, struct pmbus_data *data) { - int vout_mode, exponent; + int vout_mode = -1, exponent; - vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE); - if (vout_mode >= 0) { + if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE)) + vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE); + if (vout_mode >= 0 && vout_mode != 0xff) { /* * Not all chips support the VOUT_MODE command, * so a failure to read it is not an error. -- 1.7.3.1
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