Commit c5fe2f53 authored by Jonathan Cameron's avatar Jonathan Cameron
Browse files

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: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarMarcelo Schmitt <marcelo.schmitt1@gmail.com>
Link: https://lore.kernel.org/r/20220206190328.333093-11-jic23@kernel.org
parent e0a3ae8e

drivers/staging/iio/adc/ad7280a.c

+72 −28
Original line number Original line Diff line number Diff line
@@ -129,6 +129,10 @@ 




#define AD7280A_DEVADDR_MASTER		0

#define AD7280A_DEVADDR_MASTER		0

#define AD7280A_DEVADDR_ALL		0x1F

#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 */

/* 5-bit device address is sent LSB first */

static unsigned int ad7280a_devaddr(unsigned int addr)

static unsigned int ad7280a_devaddr(unsigned int addr)

{

{
@@ -161,7 +165,8 @@ struct ad7280_state { 
	int				scan_cnt;

	int				scan_cnt;

	int				readback_delay_us;

	int				readback_delay_us;

	unsigned char			crc_tab[CRC8_TABLE_SIZE];

	unsigned char			crc_tab[CRC8_TABLE_SIZE];

	unsigned char			ctrl_hb;

	u8				oversampling_ratio;

	u8				acquisition_time;

	unsigned char			ctrl_lb;

	unsigned char			ctrl_lb;

	unsigned char			cell_threshhigh;

	unsigned char			cell_threshhigh;

	unsigned char			cell_threshlow;

	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) |

				      AD7280A_CTRL_HB_CONV_INPUT_ALL) |

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

				      AD7280A_CTRL_HB_CONV_RREAD_NO) |

				      AD7280A_CTRL_HB_CONV_RREAD_NO) |

			   st->ctrl_hb);

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,

				      st->oversampling_ratio));

	if (ret)

	if (ret)

		return 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) |

				      AD7280A_CTRL_HB_CONV_INPUT_ALL) |

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

				      AD7280A_CTRL_HB_CONV_RREAD_ALL) |

				      AD7280A_CTRL_HB_CONV_RREAD_ALL) |

			   st->ctrl_hb);

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,

				      st->oversampling_ratio));

	if (ret)

	if (ret)

		return 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) |

				      AD7280A_CTRL_HB_CONV_INPUT_ALL) |

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_RREAD_MSK,

				      AD7280A_CTRL_HB_CONV_RREAD_NO) |

				      AD7280A_CTRL_HB_CONV_RREAD_NO) |

			   st->ctrl_hb);

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,

				      st->oversampling_ratio));

	if (ret)

	if (ret)

		return 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) |

				      AD7280A_CTRL_HB_CONV_RREAD_ALL) |

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,

				      AD7280A_CTRL_HB_CONV_START_CS) |

				      AD7280A_CTRL_HB_CONV_START_CS) |

			   st->ctrl_hb);

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,

				      st->oversampling_ratio));

	if (ret)

	if (ret)

		return 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) |

				      AD7280A_CTRL_HB_CONV_RREAD_ALL) |

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_START_MSK,

				      AD7280A_CTRL_HB_CONV_START_CS) |

				      AD7280A_CTRL_HB_CONV_START_CS) |

			   st->ctrl_hb);

			   FIELD_PREP(AD7280A_CTRL_HB_CONV_AVG_MSK,

				      st->oversampling_ratio));

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -389,7 +399,8 @@ static void ad7280_sw_power_down(void *data) 
	struct ad7280_state *st = data;

	struct ad7280_state *st = data;





	ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CTRL_HB_REG, 1,

	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)

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:

error_power_down:

	ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CTRL_HB_REG, 1,

	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;

	return ret;

}

}
@@ -590,6 +602,7 @@ static void ad7280_common_fields_init(struct iio_chan_spec *chan, int addr, 
	chan->indexed = 1;

	chan->indexed = 1;

	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);

	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_type = BIT(IIO_CHAN_INFO_SCALE);

	chan->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);

	chan->address = addr;

	chan->address = addr;

	chan->scan_index = cnt;

	chan->scan_index = cnt;

	chan->scan_type.sign = 'u';

	chan->scan_type.sign = 'u';
@@ -829,6 +842,26 @@ static irqreturn_t ad7280_event_handler(int irq, void *private) 
	return IRQ_HANDLED;

	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,

static int ad7280_read_raw(struct iio_dev *indio_dev,

			   struct iio_chan_spec const *chan,

			   struct iio_chan_spec const *chan,

			   int *val,

			   int *val,
@@ -862,19 +895,46 @@ static int ad7280_read_raw(struct iio_dev *indio_dev, 




		*val2 = AD7280A_BITS;

		*val2 = AD7280A_BITS;

		return IIO_VAL_FRACTIONAL_LOG2;

		return IIO_VAL_FRACTIONAL_LOG2;

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		*val = ad7280a_n_avg[st->oversampling_ratio];

		return IIO_VAL_INT;

	}

	}

	return -EINVAL;

	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 = {

static const struct iio_info ad7280_info = {

	.read_raw = ad7280_read_raw,

	.read_raw = ad7280_read_raw,

	.write_raw = ad7280_write_raw,

	.read_event_value = &ad7280a_read_thresh,

	.read_event_value = &ad7280a_read_thresh,

	.write_event_value = &ad7280a_write_thresh,

	.write_event_value = &ad7280a_write_thresh,

};

};





static const struct ad7280_platform_data ad7793_default_pdata = {

static const struct ad7280_platform_data ad7793_default_pdata = {

	.acquisition_time = AD7280A_ACQ_TIME_400ns,

	.acquisition_time = AD7280A_ACQ_TIME_400ns,

	.conversion_averaging = AD7280A_CONV_AVG_DIS,

	.thermistor_term_en = true,

	.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);

	const struct ad7280_platform_data *pdata = dev_get_platdata(&spi->dev);

	struct ad7280_state *st;

	struct ad7280_state *st;

	int ret;

	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;

	struct iio_dev *indio_dev;





	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));

	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) |

	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);

		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);

	ret = ad7280_chain_setup(st);

	if (ret < 0)

	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->scan_cnt = (st->slave_num + 1) * AD7280A_NUM_CH;

	st->cell_threshhigh = 0xFF;

	st->cell_threshhigh = 0xFF;

	st->aux_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);

	ret = devm_add_action_or_reset(&spi->dev, ad7280_sw_power_down, st);

	if (ret)

	if (ret)

		return ret;

		return ret;





	/*

	ad7280_update_delay(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 =

		((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 */





	indio_dev->name = spi_get_device_id(spi)->name;

	indio_dev->name = spi_get_device_id(spi)->name;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->modes = INDIO_DIRECT_MODE;

drivers/staging/iio/adc/ad7280a.h

+0 −6
Original line number Original line Diff line number Diff line
@@ -17,11 +17,6 @@ 
#define AD7280A_ACQ_TIME_1200ns			2

#define AD7280A_ACQ_TIME_1200ns			2

#define AD7280A_ACQ_TIME_1600ns			3

#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_VIN5		BIT(2)

#define AD7280A_ALERT_REMOVE_VIN4_VIN5		BIT(3)

#define AD7280A_ALERT_REMOVE_VIN4_VIN5		BIT(3)

#define AD7280A_ALERT_REMOVE_AUX5		BIT(0)

#define AD7280A_ALERT_REMOVE_AUX5		BIT(0)
@@ -29,7 +24,6 @@ 




struct ad7280_platform_data {

struct ad7280_platform_data {

	unsigned int		acquisition_time;

	unsigned int		acquisition_time;

	unsigned int		conversion_averaging;

	unsigned int		chain_last_alert_ignore;

	unsigned int		chain_last_alert_ignore;

	bool			thermistor_term_en;

	bool			thermistor_term_en;

};

};