On 12/05, Jonathan Cameron wrote:
> 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 b186dda03432..90241560f5cf 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';
> @@ -814,6 +827,26 @@ 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,
> @@ -847,19 +880,46 @@ 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,
> };
>
> @@ -868,8 +928,6 @@ 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));
> @@ -892,7 +950,7 @@ 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)
> @@ -902,27 +960,13 @@ 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;
> };
> --
> 2.34.1
>
