[PATCH 04/16] iio: adc: at91-sama5d2_adc: handle different EMR.OSR for different hw versions

Claudiu Beznea
2022-06-09T08:30:36Z

SAMA7G5 introduces 64 and 256 oversampling rates. Due to this EMR.OSR is 3
bits long. Change the code to reflect this. Commit prepares the code
for the addition of 64 and 256 oversampling rates.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 55 ++++++++++++++++++++++--------
1 file changed, 40 insertions(+), 15 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index b76328da0cb2..1ceab097335c 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -138,8 +138,7 @@ struct at91_adc_reg_layout {
/* Extended Mode Register */
u16 EMR;
/* Extended Mode Register - Oversampling rate */
-#define AT91_SAMA5D2_EMR_OSR(V) ((V) << 16)
-#define AT91_SAMA5D2_EMR_OSR_MASK GENMASK(17, 16)
+#define AT91_SAMA5D2_EMR_OSR(V, M) (((V) << 16) & (M))
#define AT91_SAMA5D2_EMR_OSR_1SAMPLES 0
#define AT91_SAMA5D2_EMR_OSR_4SAMPLES 1
#define AT91_SAMA5D2_EMR_OSR_16SAMPLES 2
@@ -403,6 +402,8 @@ static const struct at91_adc_reg_layout sama7g5_layout = {
* @max_index: highest channel index (highest index may be higher
* than the total channel number)
* @hw_trig_cnt: number of possible hardware triggers
+ * @osr_mask: oversampling ratio bitmask on EMR register
+ * @osr_vals: available oversampling rates
*/
struct at91_adc_platform {
const struct at91_adc_reg_layout *layout;
@@ -414,6 +415,8 @@ struct at91_adc_platform {
unsigned int max_channels;
unsigned int max_index;
unsigned int hw_trig_cnt;
+ unsigned int osr_mask;
+ unsigned int osr_vals;
};

/**
@@ -612,6 +615,10 @@ static const struct at91_adc_platform sama5d2_platform = {
.max_index = AT91_SAMA5D2_MAX_CHAN_IDX,
#define AT91_SAMA5D2_HW_TRIG_CNT 3
.hw_trig_cnt = AT91_SAMA5D2_HW_TRIG_CNT,
+ .osr_mask = GENMASK(17, 16),
+ .osr_vals = BIT(AT91_SAMA5D2_EMR_OSR_1SAMPLES) |
+ BIT(AT91_SAMA5D2_EMR_OSR_4SAMPLES) |
+ BIT(AT91_SAMA5D2_EMR_OSR_16SAMPLES),
};

static const struct at91_adc_platform sama7g5_platform = {
@@ -627,6 +634,10 @@ static const struct at91_adc_platform sama7g5_platform = {
.max_index = AT91_SAMA7G5_MAX_CHAN_IDX,
#define AT91_SAMA7G5_HW_TRIG_CNT 3
.hw_trig_cnt = AT91_SAMA7G5_HW_TRIG_CNT,
+ .osr_mask = GENMASK(18, 16),
+ .osr_vals = BIT(AT91_SAMA5D2_EMR_OSR_1SAMPLES) |
+ BIT(AT91_SAMA5D2_EMR_OSR_4SAMPLES) |
+ BIT(AT91_SAMA5D2_EMR_OSR_16SAMPLES),
};

static int at91_adc_chan_xlate(struct iio_dev *indio_dev, int chan)
@@ -725,34 +736,45 @@ static void at91_adc_eoc_ena(struct at91_adc_state *st, unsigned int channel)
at91_adc_writel(st, EOC_IER, BIT(channel));
}

-static void at91_adc_config_emr(struct at91_adc_state *st)
+static int at91_adc_config_emr(struct at91_adc_state *st,
+ u32 oversampling_ratio)
{
/* configure the extended mode register */
unsigned int emr = at91_adc_readl(st, EMR);
+ unsigned int osr_mask = st->soc_info.platform->osr_mask;
+ unsigned int osr_vals = st->soc_info.platform->osr_vals;

/* select oversampling per single trigger event */
emr |= AT91_SAMA5D2_EMR_ASTE(1);

/* delete leftover content if it's the case */
- emr &= ~AT91_SAMA5D2_EMR_OSR_MASK;
+ emr &= ~osr_mask;

/* select oversampling ratio from configuration */
- switch (st->oversampling_ratio) {
+ switch (oversampling_ratio) {
case AT91_OSR_1SAMPLES:
- emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_1SAMPLES) &
- AT91_SAMA5D2_EMR_OSR_MASK;
+ if (!(osr_vals & BIT(AT91_SAMA5D2_EMR_OSR_1SAMPLES)))
+ return -EINVAL;
+ emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_1SAMPLES,
+ osr_mask);
break;
case AT91_OSR_4SAMPLES:
- emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_4SAMPLES) &
- AT91_SAMA5D2_EMR_OSR_MASK;
+ if (!(osr_vals & BIT(AT91_SAMA5D2_EMR_OSR_4SAMPLES)))
+ return -EINVAL;
+ emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_4SAMPLES,
+ osr_mask);
break;
case AT91_OSR_16SAMPLES:
- emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_16SAMPLES) &
- AT91_SAMA5D2_EMR_OSR_MASK;
+ if (!(osr_vals & BIT(AT91_SAMA5D2_EMR_OSR_16SAMPLES)))
+ return -EINVAL;
+ emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_16SAMPLES,
+ osr_mask);
break;
}

at91_adc_writel(st, EMR, emr);
+
+ return 0;
}

static int at91_adc_adjust_val_osr(struct at91_adc_state *st, int *val)
@@ -1643,6 +1665,7 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
+ int ret = 0;

if (iio_buffer_enabled(indio_dev))
return -EBUSY;
@@ -1656,12 +1679,14 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
mutex_lock(&st->lock);
if (val == st->oversampling_ratio)
goto unlock;
- st->oversampling_ratio = val;
/* update ratio */
- at91_adc_config_emr(st);
+ ret = at91_adc_config_emr(st, val);
+ if (ret)
+ goto unlock;
+ st->oversampling_ratio = val;
unlock:
mutex_unlock(&st->lock);
- return 0;
+ return ret;
case IIO_CHAN_INFO_SAMP_FREQ:
if (val < st->soc_info.min_sample_rate ||
val > st->soc_info.max_sample_rate)
@@ -1834,7 +1859,7 @@ 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);
+ at91_adc_config_emr(st, st->oversampling_ratio);
}

static ssize_t at91_adc_get_fifo_state(struct device *dev,
--
2.34.1