From c5fe2f537b91e17c854135fdc0b46aa0f4f9db78 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Sun, 6 Feb 2022 19:03:18 +0000 Subject: [PATCH] staging:iio:adc:ad7280a: Make oversampling_ratio a runtime control 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 Reviewed-by: Marcelo Schmitt Link: https://lore.kernel.org/r/20220206190328.333093-11-jic23@kernel.org --- 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 e32526f..2ba9379 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 @@ out: 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 23f18bb..9929778 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; }; -- 2.7.4