[PATCH v2 13/19] iio: adc: at91-sama5d2_adc: update trackx on emr

Claudiu Beznea
2022-06-28T15:22:53Z

Add support for updating trackx bits of EMR register. Having different
values of EMR.TRACKX when measuring temperature give a better accuracy.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 57c78cd23634..ee67f944b58c 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -145,6 +145,10 @@ struct at91_adc_reg_layout {
#define AT91_SAMA5D2_EMR_OSR_64SAMPLES 3
#define AT91_SAMA5D2_EMR_OSR_256SAMPLES 4

+/* Extended Mode Register - TRACKX */
+#define AT91_SAMA5D2_TRACKX_MASK GENMASK(23, 22)
+#define AT91_SAMA5D2_TRACKX(x) (((x) << 22) & \
+ AT91_SAMA5D2_TRACKX_MASK)
/* Extended Mode Register - Averaging on single trigger event */
#define AT91_SAMA5D2_EMR_ASTE(V) ((V) << 20)

@@ -746,7 +750,7 @@ static void at91_adc_eoc_ena(struct at91_adc_state *st, unsigned int channel)
}

static int at91_adc_config_emr(struct at91_adc_state *st,
- u32 oversampling_ratio)
+ u32 oversampling_ratio, u32 trackx)
{
/* configure the extended mode register */
unsigned int emr = at91_adc_readl(st, EMR);
@@ -765,7 +769,7 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
emr |= AT91_SAMA5D2_EMR_ASTE(1);

/* delete leftover content if it's the case */
- emr &= ~osr_mask;
+ emr &= ~(osr_mask | AT91_SAMA5D2_TRACKX_MASK);

/* select oversampling ratio from configuration */
switch (oversampling_ratio) {
@@ -791,6 +795,8 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
break;
}

+ /* Update trackx. */
+ emr |= AT91_SAMA5D2_TRACKX(trackx);
at91_adc_writel(st, EMR, emr);

st->oversampling_ratio = oversampling_ratio;
@@ -1703,7 +1709,7 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
return ret;
mutex_lock(&st->lock);
/* update ratio */
- ret = at91_adc_config_emr(st, val);
+ ret = at91_adc_config_emr(st, val, 0);
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return ret;
@@ -1901,7 +1907,7 @@ static void at91_adc_hw_init(struct iio_dev *indio_dev)
at91_adc_setup_samp_freq(indio_dev, st->soc_info.min_sample_rate);

/* configure extended mode register */
- at91_adc_config_emr(st, st->oversampling_ratio);
+ at91_adc_config_emr(st, st->oversampling_ratio, 0);
}

static ssize_t at91_adc_get_fifo_state(struct device *dev,