On Mon, Mar 18, 2019 at 07:51:55AM -0700, Guenter Roeck wrote: > On 3/18/19 7:29 AM, Samu Nuutamo wrote: > > When tsi-as-adc is configured it is possible for in7[0123]_input read to > > in{70,71,72,73}_input ? > Yes, and by that I meant the files inside /sys/class/hwmon/hwmon0. The race can be triggered by reading both tsi and adc values (in70-73, in4-6) concurrently, while verifying that the values are as expected. Using a simple test script that read the values continuously I got incorrect readings once every few minutes. > > return an incorrect value if a concurrent read to in[456]_input is > > performed. This is likely caused by a concurrent manipulation of the mux > > channel without proper locking as hwmon and mfd use different locks for > > synchronization. > > > > Switch hwmon to use the same lock as mfd when accessing the TSI channel. > > > > Fixes: 4f16cab19a3d5 ("hwmon: da9052: Add support for TSI channel") > > Signed-off-by: Samu Nuutamo <samu.nuutamo@xxxxxxxxx> > > --- > > drivers/hwmon/da9052-hwmon.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c > > index 8ec5bf4ce392..af136a638065 100644 > > --- a/drivers/hwmon/da9052-hwmon.c > > +++ b/drivers/hwmon/da9052-hwmon.c > > @@ -249,9 +249,9 @@ static ssize_t da9052_tsi_show(struct device *dev, > > int channel = to_sensor_dev_attr(devattr)->index; > > int ret; > > - mutex_lock(&hwmon->hwmon_lock); > > + mutex_lock(&hwmon->da9052->auxadc_lock); > > This is, at best, a kludge. > > The hwmon driver doesn't own struct da9052 and should not really access any of its > structure members. The problem suggests that __da9052_read_tsi() should have > been implemented in the mfd core, similar to da9052_adc_manual_read(). > Not sure if I have resources to do a proper fix at this point. - Samu