On Tue, Nov 21, 2023 at 4:17 AM Nuno Sa via B4 Relay <devnull+nuno.sa.analog.com@xxxxxxxxxx> wrote: > > From: Nuno Sa <nuno.sa@xxxxxxxxxx> > > When calling ad9467_set_scale(), multiple calls to ad9467_spi_write() > are done which means we need to properly protect the whole operation so > we are sure we will be in a sane state if two concurrent calls occur. > > Fixes: ad6797120238 ("iio: adc: ad9467: add support AD9467 ADC") > Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx> > --- > drivers/iio/adc/ad9467.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c > index 04474dbfa631..91821dee03b7 100644 > --- a/drivers/iio/adc/ad9467.c > +++ b/drivers/iio/adc/ad9467.c > @@ -4,7 +4,7 @@ > * > * Copyright 2012-2020 Analog Devices Inc. > */ > - > +#include <linux/cleanup.h> > #include <linux/module.h> > #include <linux/mutex.h> Ah, the case of the misplaced header from the previous patch is solved. :-) > #include <linux/device.h> > @@ -122,6 +122,8 @@ struct ad9467_state { > unsigned int output_mode; > > struct gpio_desc *pwrdown_gpio; > + /* protect against concurrent accesses to the device */ > + struct mutex lock; > }; > > static int ad9467_spi_read(struct spi_device *spi, unsigned int reg) > @@ -162,6 +164,7 @@ static int ad9467_reg_access(struct adi_axi_adc_conv *conv, unsigned int reg, > int ret; > > if (!readval) { > + guard(mutex)(&st->lock); > ret = ad9467_spi_write(spi, reg, writeval); > if (ret) > return ret; > @@ -310,6 +313,7 @@ static int ad9467_set_scale(struct adi_axi_adc_conv *conv, int val, int val2) > if (scale_val[0] != val || scale_val[1] != val2) > continue; > > + guard(mutex)(&st->lock); > ret = ad9467_spi_write(st->spi, AN877_ADC_REG_VREF, > info->scale_table[i][1]); > if (ret < 0) > > -- > 2.42.1 > > Alternately, this could probably be solved with spi_bus_lock/unlock and spi_sync_locked rather than introducing a new mutex.