Re: [PATCH 6/6] iio: adc: ad7173: Add support for AD411x devices

From: David Lechner
Date: Mon Apr 01 2024 - 15:45:54 EST

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In reply to: Dumitru Ceclan via B4 Relay: "[PATCH 6/6] iio: adc: ad7173: Add support for AD411x devices"
Next in thread: David Lechner: "Re: [PATCH 6/6] iio: adc: ad7173: Add support for AD411x devices"
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On Mon, Apr 1, 2024 at 10:10 AM Dumitru Ceclan via B4 Relay
<devnull+dumitru.ceclan.analog.com@xxxxxxxxxx> wrote:
>
> From: Dumitru Ceclan <dumitru.ceclan@xxxxxxxxxx>
>
> Add support for AD4111/AD4112/AD4114/AD4115/AD4116.
>
> The AD411X family encompasses a series of low power, low noise, 24-bit,
> sigma-delta analog-to-digital converters that offer a versatile range of
> specifications.
>
> This family of ADCs integrates an analog front end suitable for processing
> both fully differential and single-ended, bipolar voltage inputs
> addressing a wide array of industrial and instrumentation requirements.
>
> - All ADCs have inputs with a precision voltage divider with a division
> ratio of 10.
> - AD4116 has 5 low level inputs without a voltage divider.
> - AD4111 and AD4112 support current inputs (0 mA to 20 mA) using a 50ohm
> shunt resistor.
>
> Signed-off-by: Dumitru Ceclan <dumitru.ceclan@xxxxxxxxxx>
> ---
> drivers/iio/adc/ad7173.c | 224 ++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 210 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
> index 9526585e6929..ac32bd7dbd1e 100644
> --- a/drivers/iio/adc/ad7173.c
> +++ b/drivers/iio/adc/ad7173.c
> @@ -1,8 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0+
> /*
> - * AD717x family SPI ADC driver
> + * AD717x and AD411x family SPI ADC driver
> *
> * Supported devices:
> + * AD4111/AD4112/AD4114/AD4115/AD4116
> * AD7172-2/AD7172-4/AD7173-8/AD7175-2
> * AD7175-8/AD7176-2/AD7177-2
> *
> @@ -72,6 +73,11 @@
> #define AD7175_2_ID 0x0cd0
> #define AD7172_4_ID 0x2050
> #define AD7173_ID 0x30d0
> +#define AD4111_ID 0x30d0
> +#define AD4112_ID 0x30d0
> +#define AD4114_ID 0x30d0

It might make it a bit more obvious that not all chips have a unique
ID if we rename AD7173_ID to AD7173_AD4111_AD4112_AD4114_ID rather
than introducing multiple macros with the same value.

Or leave it as AD7173_ID to keep it short and add a comment where it
is used with 411x chips in ad7173_device_info[].

> +#define AD4116_ID 0x34d0
> +#define AD4115_ID 0x38d0
> #define AD7175_8_ID 0x3cd0
> #define AD7177_ID 0x4fd0
> #define AD7173_ID_MASK GENMASK(15, 4)
> @@ -120,11 +126,20 @@
> #define AD7173_VOLTAGE_INT_REF_uV 2500000
> #define AD7173_TEMP_SENSIIVITY_uV_per_C 477
> #define AD7177_ODR_START_VALUE 0x07
> +#define AD4111_SHUNT_RESISTOR_OHM 50
> +#define AD4111_DIVIDER_RATIO 10
> +#define AD411X_VCOM_INPUT 0X10
> +#define AD4111_CURRENT_CHAN_CUTOFF 16
>
> #define AD7173_FILTER_ODR0_MASK GENMASK(5, 0)
> #define AD7173_MAX_CONFIGS 8
>
> enum ad7173_ids {
> + ID_AD4111,
> + ID_AD4112,
> + ID_AD4114,
> + ID_AD4115,
> + ID_AD4116,
> ID_AD7172_2,
> ID_AD7172_4,
> ID_AD7173_8,
> @@ -134,16 +149,26 @@ enum ad7173_ids {
> ID_AD7177_2,
> };
>
> +enum ad4111_current_channels {
> + AD4111_CURRENT_IN0P_IN0N,
> + AD4111_CURRENT_IN1P_IN1N,
> + AD4111_CURRENT_IN2P_IN2N,
> + AD4111_CURRENT_IN3P_IN3N,
> +};
> +
> struct ad7173_device_info {
> const unsigned int *sinc5_data_rates;
> unsigned int num_sinc5_data_rates;
> unsigned int odr_start_value;
> + unsigned int num_inputs_with_divider;
> unsigned int num_channels;
> unsigned int num_configs;
> unsigned int num_inputs;

Probably a good idea to change num_inputs to num_voltage_inputs so it
isn't confused with the total number of inputs.

Similarly num_voltage_inputs_with_divider instead of num_inputs_with_divider.

Also could use a comment to make it clear if num_voltage_inputs
includes num_voltage_inputs_with_divider or not. And that it doesn't
include VINCOM.

Probably also need some flag here to differentiate ADCINxx voltage
inputs on AD4116.

> unsigned int clock;
> unsigned int id;
> char *name;
> + bool has_current_inputs;

Maybe more future-proof to have num_current_inputs instead of bool?

> + bool has_vcom;

For consistency: has_vcom_input

> bool has_temp;
> bool has_input_buf;
> bool has_int_ref;
> @@ -189,6 +214,24 @@ struct ad7173_state {
> #endif
> };
>
> +static unsigned int ad4115_sinc5_data_rates[] = {
> + 24845000, 24845000, 20725000, 20725000, /* 0-3 */
> + 15564000, 13841000, 10390000, 10390000, /* 4-7 */
> + 4994000, 2499000, 1000000, 500000, /* 8-11 */
> + 395500, 200000, 100000, 59890, /* 12-15 */
> + 49920, 20000, 16660, 10000, /* 16-19 */
> + 5000, 2500, 2500, /* 20-22 */
> +};
> +
> +static unsigned int ad4116_sinc5_data_rates[] = {
> + 12422360, 12422360, 12422360, 12422360, /* 0-3 */
> + 10362690, 10362690, 7782100, 6290530, /* 4-7 */
> + 5194800, 2496900, 1007600, 499900, /* 8-11 */
> + 390600, 200300, 100000, 59750, /* 12-15 */
> + 49840, 20000, 16650, 10000, /* 16-19 */
> + 5000, 2500, 1250, /* 20-22 */
> +};
> +
> static const unsigned int ad7173_sinc5_data_rates[] = {
> 6211000, 6211000, 6211000, 6211000, 6211000, 6211000, 5181000, 4444000, /* 0-7 */
> 3115000, 2597000, 1007000, 503800, 381000, 200300, 100500, 59520, /* 8-15 */
> @@ -204,7 +247,91 @@ static const unsigned int ad7175_sinc5_data_rates[] = {
> 5000, /* 20 */
> };
>
> +static unsigned int ad4111_current_channel_config[] = {
> + [AD4111_CURRENT_IN0P_IN0N] = 0x1E8,
> + [AD4111_CURRENT_IN1P_IN1N] = 0x1C9,
> + [AD4111_CURRENT_IN2P_IN2N] = 0x1AA,
> + [AD4111_CURRENT_IN3P_IN3N] = 0x18B,
> +};

As mentioned in the DT bindings review, it would make more sense to
just use the datasheet numbers for the current input channels in the
diff-channels DT property, then we don't need this lookup table.

> +
> static const struct ad7173_device_info ad7173_device_info[] = {
> + [ID_AD4111] = {
> + .id = AD4111_ID,
> + .num_inputs_with_divider = 8,
> + .num_channels = 16,
> + .num_configs = 8,
> + .num_inputs = 8,
> + .num_gpios = 2,
> + .has_temp = true,
> + .has_vcom = true,
> + .has_input_buf = true,
> + .has_current_inputs = true,
> + .has_int_ref = true,
> + .clock = 2 * HZ_PER_MHZ,
> + .sinc5_data_rates = ad7173_sinc5_data_rates,
> + .num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
> + },
> + [ID_AD4112] = {
> + .id = AD4112_ID,
> + .num_inputs_with_divider = 8,
> + .num_channels = 16,
> + .num_configs = 8,
> + .num_inputs = 8,
> + .num_gpios = 2,
> + .has_vcom = true,
> + .has_temp = true,
> + .has_input_buf = true,
> + .has_current_inputs = true,
> + .has_int_ref = true,
> + .clock = 2 * HZ_PER_MHZ,
> + .sinc5_data_rates = ad7173_sinc5_data_rates,
> + .num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
> + },
> + [ID_AD4114] = {
> + .id = AD4114_ID,
> + .num_inputs_with_divider = 16,
> + .num_channels = 16,
> + .num_configs = 8,
> + .num_inputs = 16,
> + .num_gpios = 4,
> + .has_vcom = true,
> + .has_temp = true,
> + .has_input_buf = true,
> + .has_int_ref = true,
> + .clock = 2 * HZ_PER_MHZ,
> + .sinc5_data_rates = ad7173_sinc5_data_rates,
> + .num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
> + },
> + [ID_AD4115] = {
> + .id = AD4115_ID,
> + .num_inputs_with_divider = 16,
> + .num_channels = 16,
> + .num_configs = 8,
> + .num_inputs = 16,
> + .num_gpios = 4,
> + .has_vcom = true,
> + .has_temp = true,
> + .has_input_buf = true,
> + .has_int_ref = true,
> + .clock = 8 * HZ_PER_MHZ,
> + .sinc5_data_rates = ad4115_sinc5_data_rates,
> + .num_sinc5_data_rates = ARRAY_SIZE(ad4115_sinc5_data_rates),
> + },
> + [ID_AD4116] = {
> + .id = AD4116_ID,
> + .num_inputs_with_divider = 11,
> + .num_channels = 16,
> + .num_configs = 8,
> + .num_inputs = 16,
> + .num_gpios = 4,
> + .has_vcom = true,
> + .has_temp = true,
> + .has_input_buf = true,
> + .has_int_ref = true,
> + .clock = 4 * HZ_PER_MHZ,
> + .sinc5_data_rates = ad4116_sinc5_data_rates,
> + .num_sinc5_data_rates = ARRAY_SIZE(ad4116_sinc5_data_rates),
> + },
> [ID_AD7172_2] = {
> .name = "ad7172-2",
> .id = AD7172_2_ID,
> @@ -670,18 +797,34 @@ static int ad7173_read_raw(struct iio_dev *indio_dev,
>
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_SCALE:
> - if (chan->type == IIO_TEMP) {
> +
> + switch (chan->type) {
> + case IIO_TEMP:
> temp = AD7173_VOLTAGE_INT_REF_uV * MILLI;
> temp /= AD7173_TEMP_SENSIIVITY_uV_per_C;
> *val = temp;
> *val2 = chan->scan_type.realbits;
> - } else {
> + break;

can we just return here instead of break?

> + case IIO_VOLTAGE:
> *val = ad7173_get_ref_voltage_milli(st, ch->cfgref_sel);
> *val2 = chan->scan_type.realbits - !!(ch->cfg.bipolar);
> +
> + if (chan->channel < st->info->num_inputs_with_divider)
> + *val *= AD4111_DIVIDER_RATIO;
> + break;

same: return here

> + case IIO_CURRENT:
> + *val = ad7173_get_ref_voltage_milli(st, ch->cfgref_sel);
> + *val /= AD4111_SHUNT_RESISTOR_OHM;
> + *val2 = chan->scan_type.realbits - !!(ch->cfg.bipolar);

Static analysis tools like to complain about using bool as int.
Probably more clear to write it as (ch->cfg.bipolar ? 1 : 0) anyway.

> + break;

return here

> + default:
> + return -EINVAL;
> }
> return IIO_VAL_FRACTIONAL_LOG2;
> case IIO_CHAN_INFO_OFFSET:
> - if (chan->type == IIO_TEMP) {
> +
> + switch (chan->type) {
> + case IIO_TEMP:
> /* 0 Kelvin -> raw sample */
> temp = -ABSOLUTE_ZERO_MILLICELSIUS;
> temp *= AD7173_TEMP_SENSIIVITY_uV_per_C;
> @@ -690,8 +833,13 @@ static int ad7173_read_raw(struct iio_dev *indio_dev,
> AD7173_VOLTAGE_INT_REF_uV *
> MILLI);
> *val = -temp;
> - } else {
> + break;

return ...

> + case IIO_VOLTAGE:
> + case IIO_CURRENT:
> *val = -BIT(chan->scan_type.realbits - 1);

Expecting a special case here, at least when ADCIN15 is configured for
pseudo-differential inputs.

> + break;

return ...

> + default:
> + return -EINVAL;
> }
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_SAMP_FREQ:
> @@ -909,6 +1057,24 @@ static int ad7173_register_clk_provider(struct iio_dev *indio_dev)
> &st->int_clk_hw);
> }
>
> +static int ad4111_validate_current_ain(struct ad7173_state *st,
> + unsigned int ain[2])
> +{
> + struct device *dev = &st->sd.spi->dev;
> +
> + if (!st->info->has_current_inputs)
> + return dev_err_probe(dev, -EINVAL,
> + "Reg values equal to or higher than %d are restricted to models with current channels.\n",
> + AD4111_CURRENT_CHAN_CUTOFF);
> +
> + if (ain[1] != 0 && ain[0] >= ARRAY_SIZE(ad4111_current_channel_config))
> + return dev_err_probe(dev, -EINVAL,
> + "For current channel diff-channels must be <[0-%d],0>\n",
> + ARRAY_SIZE(ad4111_current_channel_config) - 1);
> +
> + return 0;
> +}
> +
> static int ad7173_validate_voltage_ain_inputs(struct ad7173_state *st,
> unsigned int ain[2])
> {
> @@ -951,7 +1117,7 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
> struct device *dev = indio_dev->dev.parent;
> struct iio_chan_spec *chan_arr, *chan;
> unsigned int ain[2], chan_index = 0;
> - int ref_sel, ret, num_channels;
> + int ref_sel, ret, reg, num_channels;
>
> num_channels = device_get_child_node_count(dev);
>
> @@ -1004,10 +1170,20 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
> if (ret)
> return ret;
>
> - ret = ad7173_validate_voltage_ain_inputs(st, ain);
> + ret = fwnode_property_read_u32(child, "reg", &reg);
> if (ret)
> return ret;
>
> + if (reg >= AD4111_CURRENT_CHAN_CUTOFF) {

As mentioned in the DT bindings review, using reg to determine if an a
channel is a current input or voltage input seems wrong/fragile. We
should be able to use the has_current_inputs flag and the input
numbers instead to determine the type of input.

> + ret = ad4111_validate_current_ain(st, ain);
> + if (ret)
> + return ret;
> + } else {
> + ret = ad7173_validate_voltage_ain_inputs(st, ain);
> + if (ret)
> + return ret;
> + }
> +
> ret = fwnode_property_match_property_string(child,
> "adi,reference-select",
> ad7173_ref_sel_str,
> @@ -1028,15 +1204,22 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
> *chan = ad7173_channel_template;
> chan->address = chan_index;
> chan->scan_index = chan_index;
> - chan->channel = ain[0];
> - chan->channel2 = ain[1];
> - chan->differential = true;
>
> - chan_st_priv->ain = AD7173_CH_ADDRESS(ain[0], ain[1]);
> + if (reg >= AD4111_CURRENT_CHAN_CUTOFF) {
> + chan->type = IIO_CURRENT;
> + chan->channel = ain[0];
> + chan_st_priv->ain = ad4111_current_channel_config[ain[0]];
> + } else {
> + chan->channel = ain[0];
> + chan->channel2 = ain[1];
> + chan->differential = true;

Expecting chan->differential = false when ADCIN15 is configured for
pseudo-differential inputs.

Also, perhaps missed in previous reviews, I would expect
chan->differential = false when channels are used as single-ended.

> +
> + chan_st_priv->ain = AD7173_CH_ADDRESS(ain[0], ain[1]);
> + chan_st_priv->cfg.input_buf = st->info->has_input_buf;
> + }
> +
> chan_st_priv->chan_reg = chan_index;
> - chan_st_priv->cfg.input_buf = st->info->has_input_buf;
> chan_st_priv->cfg.odr = 0;
> -
> chan_st_priv->cfg.bipolar = fwnode_property_read_bool(child, "bipolar");
> if (chan_st_priv->cfg.bipolar)
> chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET);
> @@ -1167,6 +1350,14 @@ static int ad7173_probe(struct spi_device *spi)
> }
>
> static const struct of_device_id ad7173_of_match[] = {
> + { .compatible = "ad4111",
> + .data = &ad7173_device_info[ID_AD4111]},
> + { .compatible = "ad4112",
> + .data = &ad7173_device_info[ID_AD4112]},
> + { .compatible = "ad4114",
> + .data = &ad7173_device_info[ID_AD4114]},
> + { .compatible = "ad4115",
> + .data = &ad7173_device_info[ID_AD4115]},
> { .compatible = "adi,ad7172-2",
> .data = &ad7173_device_info[ID_AD7172_2]},
> { .compatible = "adi,ad7172-4",
> @@ -1186,6 +1377,11 @@ static const struct of_device_id ad7173_of_match[] = {
> MODULE_DEVICE_TABLE(of, ad7173_of_match);
>
> static const struct spi_device_id ad7173_id_table[] = {
> + { "ad4111", (kernel_ulong_t)&ad7173_device_info[ID_AD4111]},
> + { "ad4112", (kernel_ulong_t)&ad7173_device_info[ID_AD4112]},
> + { "ad4114", (kernel_ulong_t)&ad7173_device_info[ID_AD4114]},
> + { "ad4115", (kernel_ulong_t)&ad7173_device_info[ID_AD4115]},
> + { "ad4116", (kernel_ulong_t)&ad7173_device_info[ID_AD4116]},
> { "ad7172-2", (kernel_ulong_t)&ad7173_device_info[ID_AD7172_2]},
> { "ad7172-4", (kernel_ulong_t)&ad7173_device_info[ID_AD7172_4]},
> { "ad7173-8", (kernel_ulong_t)&ad7173_device_info[ID_AD7173_8]},
> @@ -1210,5 +1406,5 @@ module_spi_driver(ad7173_driver);
> MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);
> MODULE_AUTHOR("Lars-Peter Clausen <lars@xxxxxxxxx>");
> MODULE_AUTHOR("Dumitru Ceclan <dumitru.ceclan@xxxxxxxxxx>");
> -MODULE_DESCRIPTION("Analog Devices AD7172/AD7173/AD7175/AD7176 ADC driver");
> +MODULE_DESCRIPTION("Analog Devices AD717x and AD411x ADC driver");
> MODULE_LICENSE("GPL");
>
> --
> 2.43.0
>
>

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