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authorChris Packham <chris.packham@alliedtelesis.co.nz>2021-06-16 15:42:18 +1200
committerGuenter Roeck <linux@roeck-us.net>2021-06-17 04:21:25 -0700
commit6e9ef8ca687e69e9d4cc89033d98e06350b0f3e0 (patch)
tree36606f32712c1b7371cf94b362d15e07814201e3 /drivers/hwmon
parent009c9aa5be652675a06d5211e1640e02bbb1c33d (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')
-rw-r--r--drivers/hwmon/pmbus/bpa-rs600.c29
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;