diff --git a/drivers/iio/adc/ti-ads7138.c b/drivers/iio/adc/ti-ads7138.c index af87f5f19a0f..da82a6947b2b 100644 --- a/drivers/iio/adc/ti-ads7138.c +++ b/drivers/iio/adc/ti-ads7138.c @@ -227,6 +227,26 @@ static int ads7138_osr_to_bits(int osr) return -EINVAL; } +static int ads7138_read_statistics(const struct i2c_client *client, u8 reg, + u8 *out_values, u8 length) +{ + int ret; + + /* Disable statistics update so the value is not updated mid read */ + ret = ads7138_i2c_clear_bit(client, ADS7138_REG_GENERAL_CFG, + ADS7138_GENERAL_CFG_STATS_EN); + if (ret) + return ret; + + ret = ads7138_i2c_read_block(client, reg, out_values, length); + if (ret) + return ret; + + /* Enable statistics update after read */ + return ads7138_i2c_set_bit(client, ADS7138_REG_GENERAL_CFG, + ADS7138_GENERAL_CFG_STATS_EN); +} + static int ads7138_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) @@ -236,28 +256,32 @@ static int ads7138_read_raw(struct iio_dev *indio_dev, u8 values[2]; switch (mask) { + /* + * Reading the statistics registers reinitializes them. This is + * unfortunate but necessary to prevent data races. + */ case IIO_CHAN_INFO_RAW: - ret = ads7138_i2c_read_block(data->client, - ADS7138_REG_RECENT_LSB_CH(chan->channel), - values, ARRAY_SIZE(values)); + ret = ads7138_read_statistics(data->client, + ADS7138_REG_RECENT_LSB_CH(chan->channel), + values, ARRAY_SIZE(values)); if (ret) return ret; *val = get_unaligned_le16(values); return IIO_VAL_INT; case IIO_CHAN_INFO_PEAK: - ret = ads7138_i2c_read_block(data->client, - ADS7138_REG_MAX_LSB_CH(chan->channel), - values, ARRAY_SIZE(values)); + ret = ads7138_read_statistics(data->client, + ADS7138_REG_MAX_LSB_CH(chan->channel), + values, ARRAY_SIZE(values)); if (ret) return ret; *val = get_unaligned_le16(values); return IIO_VAL_INT; case IIO_CHAN_INFO_TROUGH: - ret = ads7138_i2c_read_block(data->client, - ADS7138_REG_MIN_LSB_CH(chan->channel), - values, ARRAY_SIZE(values)); + ret = ads7138_read_statistics(data->client, + ADS7138_REG_MIN_LSB_CH(chan->channel), + values, ARRAY_SIZE(values)); if (ret) return ret;