5.4-stable review patch. If anyone has any objections, please let me know.
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From: Erik Schumacher erik.schumacher@iris-sensing.com
[ Upstream commit e278d5e8aef4c0a1d9a9fa8b8910d713a89aa800 ]
Leading zero bits are sent on the bus before the temperature value is transmitted. If any of these bits are high, the connection might be unstable or there could be no AD7314 / ADT730x (or compatible) at all. Return -EIO in that case.
Signed-off-by: Erik Schumacher erik.schumacher@iris-sensing.com Fixes: 4f3a659581cab ("hwmon: AD7314 driver (ported from IIO)") Link: https://lore.kernel.org/r/24a50c2981a318580aca8f50d23be7987b69ea00.camel@iri... Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hwmon/ad7314.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/hwmon/ad7314.c b/drivers/hwmon/ad7314.c index 7802bbf5f9587..59424103f6348 100644 --- a/drivers/hwmon/ad7314.c +++ b/drivers/hwmon/ad7314.c @@ -22,11 +22,13 @@ */ #define AD7314_TEMP_MASK 0x7FE0 #define AD7314_TEMP_SHIFT 5 +#define AD7314_LEADING_ZEROS_MASK BIT(15)
/* * ADT7301 and ADT7302 temperature masks */ #define ADT7301_TEMP_MASK 0x3FFF +#define ADT7301_LEADING_ZEROS_MASK (BIT(15) | BIT(14))
enum ad7314_variant { adt7301, @@ -65,12 +67,20 @@ static ssize_t ad7314_temperature_show(struct device *dev, return ret; switch (spi_get_device_id(chip->spi_dev)->driver_data) { case ad7314: + if (ret & AD7314_LEADING_ZEROS_MASK) { + /* Invalid read-out, leading zero part is missing */ + return -EIO; + } data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT; data = sign_extend32(data, 9);
return sprintf(buf, "%d\n", 250 * data); case adt7301: case adt7302: + if (ret & ADT7301_LEADING_ZEROS_MASK) { + /* Invalid read-out, leading zero part is missing */ + return -EIO; + } /* * Documented as a 13 bit twos complement register * with a sign bit - which is a 14 bit 2's complement