From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Oversampling has nothing directly to do with analog circuits or
similar so belongs in the control of userspace as a policy decision.
The only complexity in here was that the acquisition time needs
updating if this setting is changed at runtime (as oversampling
is time consuming).
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@xxxxxxxxx>
---
drivers/staging/iio/adc/ad7280a.c | 100 +++++++++++++++++++++---------
drivers/staging/iio/adc/ad7280a.h | 6 --
2 files changed, 72 insertions(+), 34 deletions(-)
diff --git a/drivers/staging/iio/adc/ad7280a.c b/drivers/staging/iio/adc/ad7280a.c
index e32526fbed5a..2ba9379ce0a7 100644
--- a/drivers/staging/iio/adc/ad7280a.c
+++ b/drivers/staging/iio/adc/ad7280a.c
@@ -129,6 +129,10 @@
#define AD7280A_DEVADDR_MASTER 0
#define AD7280A_DEVADDR_ALL 0x1F
+
+static const unsigned short ad7280a_n_avg[4] = {1, 2, 4, 8};
+static const unsigned short ad7280a_t_acq_ns[4] = {465, 1010, 1460, 1890};
+
/* 5-bit device address is sent LSB first */
static unsigned int ad7280a_devaddr(unsigned int addr)
{
@@ -161,7 +165,8 @@ struct ad7280_state {
int scan_cnt;
int readback_delay_us;
unsigned char crc_tab[CRC8_TABLE_SIZE];
- unsigned char ctrl_hb;
+ u8 oversampling_ratio;
+ u8 acquisition_time;
unsigned char ctrl_lb;
unsigned char cell_threshhigh;
unsigned char cell_threshlow;
@@ -260,7 +265,8 @@ static int ad7280_read_reg(struct ad7280_state *st, unsigned int devaddr,
AD7280A_CTRL_HB_CONV_INPUT_ALL) |
FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,
AD7280A_CTRL_HB_CONV_RREAD_NO) |
- st->ctrl_hb);
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,
+ st->oversampling_ratio));
if (ret)
return ret;
@@ -270,7 +276,8 @@ static int ad7280_read_reg(struct ad7280_state *st, unsigned int devaddr,
AD7280A_CTRL_HB_CONV_INPUT_ALL) |
FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,
AD7280A_CTRL_HB_CONV_RREAD_ALL) |
- st->ctrl_hb);
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,
+ st->oversampling_ratio));
if (ret)
return ret;
@@ -310,7 +317,8 @@ static int ad7280_read_channel(struct ad7280_state *st, unsigned int devaddr,
AD7280A_CTRL_HB_CONV_INPUT_ALL) |
FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,
AD7280A_CTRL_HB_CONV_RREAD_NO) |
- st->ctrl_hb);
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,
+ st->oversampling_ratio));
if (ret)
return ret;
@@ -321,7 +329,8 @@ static int ad7280_read_channel(struct ad7280_state *st, unsigned int devaddr,
AD7280A_CTRL_HB_CONV_RREAD_ALL) |
FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,
AD7280A_CTRL_HB_CONV_START_CS) |
- st->ctrl_hb);
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,
+ st->oversampling_ratio));
if (ret)
return ret;
@@ -359,7 +368,8 @@ static int ad7280_read_all_channels(struct ad7280_state *st, unsigned int cnt,
AD7280A_CTRL_HB_CONV_RREAD_ALL) |
FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,
AD7280A_CTRL_HB_CONV_START_CS) |
- st->ctrl_hb);
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,
+ st->oversampling_ratio));
if (ret)
return ret;
@@ -389,7 +399,8 @@ static void ad7280_sw_power_down(void *data)
struct ad7280_state *st = data;
ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CTRL_HB_REG, 1,
- AD7280A_CTRL_HB_PWRDN_SW | st->ctrl_hb);
+ AD7280A_CTRL_HB_PWRDN_SW |
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK, st->oversampling_ratio));
}
static int ad7280_chain_setup(struct ad7280_state *st)
@@ -442,7 +453,8 @@ static int ad7280_chain_setup(struct ad7280_state *st)
error_power_down:
ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CTRL_HB_REG, 1,
- AD7280A_CTRL_HB_PWRDN_SW | st->ctrl_hb);
+ AD7280A_CTRL_HB_PWRDN_SW |
+ FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK, st->oversampling_ratio));
return ret;
}
@@ -590,6 +602,7 @@ static void ad7280_common_fields_init(struct iio_chan_spec *chan, int addr,
chan->indexed = 1;
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
+ chan->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
chan->address = addr;
chan->scan_index = cnt;
chan->scan_type.sign = 'u';
@@ -829,6 +842,26 @@ static irqreturn_t ad7280_event_handler(int irq, void *private)
return IRQ_HANDLED;
}
+static void ad7280_update_delay(struct ad7280_state *st)
+{
+ /*
+ * Total Conversion Time = ((tACQ + tCONV) *
+ * (Number of Conversions per Part)) −
+ * tACQ + ((N - 1) * tDELAY)
+ *
+ * Readback Delay = Total Conversion Time + tWAIT
+ */
+
+ st->readback_delay_us =
+ ((ad7280a_t_acq_ns[st->acquisition_time & 0x3] + 695) *
+ (AD7280A_NUM_CH * ad7280a_n_avg[st->oversampling_ratio & 0x3])) -
+ ad7280a_t_acq_ns[st->acquisition_time & 0x3] + st->slave_num * 250;
+
+ /* Convert to usecs */
+ st->readback_delay_us = DIV_ROUND_UP(st->readback_delay_us, 1000);
+ st->readback_delay_us += 5; /* Add tWAIT */
+}
+
static int ad7280_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
@@ -862,19 +895,46 @@ static int ad7280_read_raw(struct iio_dev *indio_dev,
*val2 = AD7280A_BITS;
return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ *val = ad7280a_n_avg[st->oversampling_ratio];
+ return IIO_VAL_INT;
}
return -EINVAL;
}
+static int ad7280_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ad7280_state *st = iio_priv(indio_dev);
+ int i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ if (val2 != 0)
+ return -EINVAL;
+ for (i = 0; i < ARRAY_SIZE(ad7280a_n_avg); i++) {
+ if (val == ad7280a_n_avg[i]) {
+ st->oversampling_ratio = i;
+ ad7280_update_delay(st);
+ return 0;
+ }
+ }
+ return -EINVAL;
+ default:
+ return -EINVAL;
+ }
+}
+
static const struct iio_info ad7280_info = {
.read_raw = ad7280_read_raw,
+ .write_raw = ad7280_write_raw,
.read_event_value = &ad7280a_read_thresh,
.write_event_value = &ad7280a_write_thresh,
};
static const struct ad7280_platform_data ad7793_default_pdata = {
.acquisition_time = AD7280A_ACQ_TIME_400ns,
- .conversion_averaging = AD7280A_CONV_AVG_DIS,
.thermistor_term_en = true,
};
@@ -883,8 +943,6 @@ static int ad7280_probe(struct spi_device *spi)
const struct ad7280_platform_data *pdata = dev_get_platdata(&spi->dev);
struct ad7280_state *st;
int ret;
- const unsigned short t_acq_ns[4] = {465, 1010, 1460, 1890};
- const unsigned short n_avg[4] = {1, 2, 4, 8};
struct iio_dev *indio_dev;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
@@ -907,7 +965,7 @@ static int ad7280_probe(struct spi_device *spi)
st->ctrl_lb = FIELD_PREP(AD7280A_CTRL_LB_ACQ_TIME_MSK, pdata->acquisition_time) |
FIELD_PREP(AD7280A_CTRL_LB_THERMISTOR_MSK, pdata->thermistor_term_en);
- st->ctrl_hb = FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK, pdata->conversion_averaging);
+ st->oversampling_ratio = 0; /* No oversampling */
ret = ad7280_chain_setup(st);
if (ret < 0)
@@ -917,27 +975,13 @@ static int ad7280_probe(struct spi_device *spi)
st->scan_cnt = (st->slave_num + 1) * AD7280A_NUM_CH;
st->cell_threshhigh = 0xFF;
st->aux_threshhigh = 0xFF;
+ st->acquisition_time = pdata->acquisition_time;
ret = devm_add_action_or_reset(&spi->dev, ad7280_sw_power_down, st);
if (ret)
return ret;
- /*
- * Total Conversion Time = ((tACQ + tCONV) *
- * (Number of Conversions per Part)) −
- * tACQ + ((N - 1) * tDELAY)
- *
- * Readback Delay = Total Conversion Time + tWAIT
- */
-
- st->readback_delay_us =
- ((t_acq_ns[pdata->acquisition_time & 0x3] + 695) *
- (AD7280A_NUM_CH * n_avg[pdata->conversion_averaging & 0x3])) -
- t_acq_ns[pdata->acquisition_time & 0x3] + st->slave_num * 250;
-
- /* Convert to usecs */
- st->readback_delay_us = DIV_ROUND_UP(st->readback_delay_us, 1000);
- st->readback_delay_us += 5; /* Add tWAIT */
+ ad7280_update_delay(st);
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
diff --git a/drivers/staging/iio/adc/ad7280a.h b/drivers/staging/iio/adc/ad7280a.h
index 23f18bb9e279..99297789a46d 100644
--- a/drivers/staging/iio/adc/ad7280a.h
+++ b/drivers/staging/iio/adc/ad7280a.h
@@ -17,11 +17,6 @@
#define AD7280A_ACQ_TIME_1200ns 2
#define AD7280A_ACQ_TIME_1600ns 3
-#define AD7280A_CONV_AVG_DIS 0
-#define AD7280A_CONV_AVG_2 1
-#define AD7280A_CONV_AVG_4 2
-#define AD7280A_CONV_AVG_8 3
-
#define AD7280A_ALERT_REMOVE_VIN5 BIT(2)
#define AD7280A_ALERT_REMOVE_VIN4_VIN5 BIT(3)
#define AD7280A_ALERT_REMOVE_AUX5 BIT(0)
@@ -29,7 +24,6 @@
struct ad7280_platform_data {
unsigned int acquisition_time;
- unsigned int conversion_averaging;
unsigned int chain_last_alert_ignore;
bool thermistor_term_en;
};
--
2.35.1
