diff options
| author | Chris Packham <chris.packham@alliedtelesis.co.nz> | 2021-06-16 15:42:18 +1200 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2021-06-17 04:21:25 -0700 |
| commit | 6e9ef8ca687e69e9d4cc89033d98e06350b0f3e0 (patch) | |
| tree | 36606f32712c1b7371cf94b362d15e07814201e3 /drivers/hwmon/pmbus | |
| parent | 009c9aa5be652675a06d5211e1640e02bbb1c33d (diff) | |
hwmon: (pmbus/bpa-rs600) Handle Vin readings >= 256V
The BPA-RS600 doesn't follow the PMBus spec for linear data.
Specifically it treats the mantissa as an unsigned 11-bit value instead
of a two's complement 11-bit value. At this point it's unclear whether
this only affects Vin or if Pin/Pout1 are affected as well. Erring on
the side of caution only Vin is dealt with here.
Fixes: 15b2703e5e02 ("hwmon: (pmbus) Add driver for BluTek BPA-RS600")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20210616034218.25821-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/pmbus')
| -rw-r--r-- | drivers/hwmon/pmbus/bpa-rs600.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/bpa-rs600.c b/drivers/hwmon/pmbus/bpa-rs600.c index f6558ee9dec3..2be69fedfa36 100644 --- a/drivers/hwmon/pmbus/bpa-rs600.c +++ b/drivers/hwmon/pmbus/bpa-rs600.c @@ -46,6 +46,32 @@ static int bpa_rs600_read_byte_data(struct i2c_client *client, int page, int reg return ret; } +/* + * The BPA-RS600 violates the PMBus spec. Specifically it treats the + * mantissa as unsigned. Deal with this here to allow the PMBus core + * to work with correctly encoded data. + */ +static int bpa_rs600_read_vin(struct i2c_client *client) +{ + int ret, exponent, mantissa; + + ret = pmbus_read_word_data(client, 0, 0xff, PMBUS_READ_VIN); + if (ret < 0) + return ret; + + if (ret & BIT(10)) { + exponent = ret >> 11; + mantissa = ret & 0x7ff; + + exponent++; + mantissa >>= 1; + + ret = (exponent << 11) | mantissa; + } + + return ret; +} + static int bpa_rs600_read_word_data(struct i2c_client *client, int page, int phase, int reg) { int ret; @@ -85,6 +111,9 @@ static int bpa_rs600_read_word_data(struct i2c_client *client, int page, int pha /* These commands return data but it is invalid/un-documented */ ret = -ENXIO; break; + case PMBUS_READ_VIN: + ret = bpa_rs600_read_vin(client); + break; default: if (reg >= PMBUS_VIRT_BASE) ret = -ENXIO; |