[PATCH v2 11/19] iio: adc: at91-sama5d2_adc: add 64 and 256 oversampling ratio

Claudiu Beznea
2022-06-28T15:22:38Z

Add 64 and 256 oversampling ratio support. It is necessary for temperature
sensor.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 31 +++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index f12f46708f22..254c084f7198 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -142,6 +142,8 @@ struct at91_adc_reg_layout {
#define AT91_SAMA5D2_EMR_OSR_1SAMPLES 0
#define AT91_SAMA5D2_EMR_OSR_4SAMPLES 1
#define AT91_SAMA5D2_EMR_OSR_16SAMPLES 2
+#define AT91_SAMA5D2_EMR_OSR_64SAMPLES 3
+#define AT91_SAMA5D2_EMR_OSR_256SAMPLES 4

/* Extended Mode Register - Averaging on single trigger event */
#define AT91_SAMA5D2_EMR_ASTE(V) ((V) << 20)
@@ -421,7 +423,7 @@ struct at91_adc_platform {
unsigned int max_index;
unsigned int hw_trig_cnt;
unsigned int osr_mask;
- unsigned int oversampling_avail[3];
+ unsigned int oversampling_avail[5];
unsigned int oversampling_avail_no;
unsigned int chan_realbits;
};
@@ -642,8 +644,8 @@ static const struct at91_adc_platform sama7g5_platform = {
#define AT91_SAMA7G5_HW_TRIG_CNT 3
.hw_trig_cnt = AT91_SAMA7G5_HW_TRIG_CNT,
.osr_mask = GENMASK(18, 16),
- .oversampling_avail = { 1, 4, 16, },
- .oversampling_avail_no = 3,
+ .oversampling_avail = { 1, 4, 16, 64, 256, },
+ .oversampling_avail_no = 5,
.chan_realbits = 16,
};

@@ -749,6 +751,15 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
/* configure the extended mode register */
unsigned int emr = at91_adc_readl(st, EMR);
unsigned int osr_mask = st->soc_info.platform->osr_mask;
+ int i;
+
+ /* Check against supported oversampling values. */
+ for (i = 0; i < st->soc_info.platform->oversampling_avail_no; i++) {
+ if (oversampling_ratio == st->soc_info.platform->oversampling_avail[i])
+ break;
+ }
+ if (i == st->soc_info.platform->oversampling_avail_no)
+ return -EINVAL;

/* select oversampling per single trigger event */
emr |= AT91_SAMA5D2_EMR_ASTE(1);
@@ -770,8 +781,14 @@ static int at91_adc_config_emr(struct at91_adc_state *st,
emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_16SAMPLES,
osr_mask);
break;
- default:
- return -EINVAL;
+ case 64:
+ emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_64SAMPLES,
+ osr_mask);
+ break;
+ case 256:
+ emr |= AT91_SAMA5D2_EMR_OSR(AT91_SAMA5D2_EMR_OSR_256SAMPLES,
+ osr_mask);
+ break;
}

at91_adc_writel(st, EMR, emr);
@@ -789,6 +806,10 @@ static int at91_adc_adjust_val_osr(struct at91_adc_state *st, int *val)
nbits = 13;
else if (st->oversampling_ratio == 16)
nbits = 14;
+ else if (st->oversampling_ratio == 64)
+ nbits = 15;
+ else if (st->oversampling_ratio == 256)
+ nbits = 16;

/*
* We have nbits of real data and channel is registered as