From 7c95a3f51a54db694d3eeef60e77e3a8558ef25e Mon Sep 17 00:00:00 2001 From: William Breathitt Gray Date: Thu, 6 Apr 2023 10:40:15 -0400 Subject: [PATCH] iio: addac: stx104: Use regmap_read_poll_timeout() for conversion poll ADC sample captures take a certain amount of time to complete after initiated; this conversion time range can be anywhere from 5 microseconds to 53.68 seconds depending on the configuration of the Analog Input Frame Timer register. When the conversion is in progress, the ADC Status register CNV bit is high. Call regmap_read_poll_timeout() to poll until the ADC conversion is completed (or timeout if more than 53.68 seconds passes). Suggested-by: Jonathan Cameron Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/9ef433f107afd1d4dcd2d97ef0e932d7045c2bbd.1680790580.git.william.gray@linaro.org Signed-off-by: Jonathan Cameron --- drivers/iio/addac/stx104.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c index 798f98a..d1f7ce0 100644 --- a/drivers/iio/addac/stx104.c +++ b/drivers/iio/addac/stx104.c @@ -205,21 +205,25 @@ static int stx104_read_raw(struct iio_dev *indio_dev, return err; } - /* trigger ADC sample capture by writing to the 8-bit - * Software Strobe Register and wait for completion + /* + * Trigger ADC sample capture by writing to the 8-bit Software Strobe Register and + * wait for completion; the conversion time range is 5 microseconds to 53.68 seconds + * in steps of 25 nanoseconds. The actual Analog Input Frame Timer time interval is + * calculated as: + * ai_time_frame_ns = ( AIFT + 1 ) * ( 25 nanoseconds ). + * Where 0 <= AIFT <= 2147483648. */ err = regmap_write(priv->aio_ctl_map, STX104_SOFTWARE_STROBE, 0); if (err) { mutex_unlock(&priv->lock); return err; } - do { - err = regmap_read(priv->aio_ctl_map, STX104_ADC_STATUS, &adc_status); - if (err) { - mutex_unlock(&priv->lock); - return err; - } - } while (u8_get_bits(adc_status, STX104_CNV)); + err = regmap_read_poll_timeout(priv->aio_ctl_map, STX104_ADC_STATUS, adc_status, + !u8_get_bits(adc_status, STX104_CNV), 0, 53687092); + if (err) { + mutex_unlock(&priv->lock); + return err; + } err = regmap_read(priv->aio_data_map, STX104_ADC_DATA, &value); if (err) { -- 2.7.4