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Serialize the data read operation so to avoid single-sample read requests disrupting each other. Reviewed-by: Andy Shevchenko Signed-off-by: Marcelo Schmitt --- Change log v3 -> v4: - Fixed typo in code comment. drivers/iio/adc/ad4134.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/ad4134.c b/drivers/iio/adc/ad4134.c index 4c8adb8efe4e..a0113fff4b71 100644 --- a/drivers/iio/adc/ad4134.c +++ b/drivers/iio/adc/ad4134.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -15,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -98,6 +100,11 @@ struct ad4134_state { struct regmap *regmap; unsigned long sys_clk_hz; struct gpio_desc *odr_gpio; + /* + * Synchronize access to device state fields and ensure atomicity of + * consecutive register access operations. + */ + struct mutex sync_lock; int refin_mv; /* * DMA (thus cache coherency maintenance) requires the transfer buffers @@ -257,7 +264,9 @@ static int ad4134_read_raw(struct iio_dev *indio_dev, int ret; switch (info) { - case IIO_CHAN_INFO_RAW: + case IIO_CHAN_INFO_RAW: { + guard(mutex)(&st->sync_lock); + gpiod_set_value_cansleep(st->odr_gpio, 1); /* * For slave mode gated DCLK (data sheet page 11), the minimum @@ -276,6 +285,7 @@ static int ad4134_read_raw(struct iio_dev *indio_dev, return ret; return IIO_VAL_INT; + } case IIO_CHAN_INFO_SCALE: *val = st->refin_mv; *val2 = AD4134_CHAN_PRECISION_BITS - 1; @@ -444,6 +454,10 @@ static int ad4134_probe(struct spi_device *spi) crc8_populate_msb(ad4134_spi_crc_table, AD4134_SPI_CRC_POLYNOM); + ret = devm_mutex_init(dev, &st->sync_lock); + if (ret) + return ret; + st->regmap = devm_regmap_init(dev, NULL, st, &ad4134_regmap_config); if (IS_ERR(st->regmap)) return dev_err_probe(dev, PTR_ERR(st->regmap), -- 2.53.0