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drivers: adc: implement voltage biasing for ADS114s08

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Implement voltage biasing on the inputs of the ADC ADS114s08.

Signed-off-by: Benedikt Schmidt <benedikt.schmidt@embedded-solutions.at>
This commit is contained in:
Benedikt Schmidt 2023-11-29 16:55:21 +01:00 • committed by Anas Nashif
commit b47c66e3f2
6 changed files with 65 additions and 3 deletions
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5
drivers/adc/Kconfig
View file

@ -33,6 +33,11 @@ config ADC_CONFIGURABLE_INPUTS
config ADC_CONFIGURABLE_EXCITATION_CURRENT_SOURCE_PIN
bool
# By selecting or not this option particular ADC drivers indicate if they
# allow a configurable voltage bias pin.
config ADC_CONFIGURABLE_VBIAS_PIN
bool
config ADC_ASYNC
bool "Asynchronous call support"
select POLL

1
drivers/adc/Kconfig.ads114s0x
View file

@ -9,6 +9,7 @@ menuconfig ADC_ADS114S0X
select SPI
select ADC_CONFIGURABLE_INPUTS
select ADC_CONFIGURABLE_EXCITATION_CURRENT_SOURCE_PIN
select ADC_CONFIGURABLE_VBIAS_PIN
help
Enable the driver implementation for the ADS114S0X family

32
drivers/adc/adc_ads114s0x.c
View file

@ -32,6 +32,8 @@ LOG_MODULE_REGISTER(ads114s0x, CONFIG_ADC_LOG_LEVEL);
#define ADS114S0X_REF_INTERNAL 2500
#define ADS114S0X_GPIO_MAX 3
#define ADS114S0X_POWER_ON_RESET_TIME_IN_US 2200
#define ADS114S0X_VBIAS_PIN_MAX 7
#define ADS114S0X_VBIAS_PIN_MIN 0
/* Not mentioned in the datasheet, but instead determined experimentally. */
#define ADS114S0X_RESET_DELAY_TIME_SAFETY_MARGIN_IN_US 1000
@ -317,6 +319,14 @@ enum ads114s0x_register {
#define ADS114S0X_REGISTER_IDACMUX_I1MUX_SET(target, value) \
ADS114S0X_REGISTER_SET_VALUE(target, value, ADS114S0X_REGISTER_IDACMUX_I1MUX_POS, \
ADS114S0X_REGISTER_IDACMUX_I1MUX_LENGTH)
#define ADS114S0X_REGISTER_VBIAS_VB_LEVEL_LENGTH 1
#define ADS114S0X_REGISTER_VBIAS_VB_LEVEL_POS 7
#define ADS114S0X_REGISTER_VBIAS_VB_LEVEL_GET(value) \
ADS114S0X_REGISTER_GET_VALUE(value, ADS114S0X_REGISTER_VBIAS_VB_LEVEL_POS, \
ADS114S0X_REGISTER_VBIAS_VB_LEVEL_LENGTH)
#define ADS114S0X_REGISTER_VBIAS_VB_LEVEL_SET(target, value) \
ADS114S0X_REGISTER_SET_VALUE(target, value, ADS114S0X_REGISTER_VBIAS_VB_LEVEL_POS, \
ADS114S0X_REGISTER_VBIAS_VB_LEVEL_LENGTH)
#define ADS114S0X_REGISTER_GPIODAT_DIR_LENGTH 4
#define ADS114S0X_REGISTER_GPIODAT_DIR_POS 4
#define ADS114S0X_REGISTER_GPIODAT_DIR_GET(value) \
@ -410,6 +420,7 @@ struct ads114s0x_config {
const struct gpio_dt_spec gpio_data_ready;
const struct gpio_dt_spec gpio_start_sync;
int idac_current;
uint8_t vbias_level;
};
struct ads114s0x_data {
@ -597,9 +608,10 @@ static int ads114s0x_channel_setup(const struct device *dev,
uint8_t idac_magnitude = 0;
uint8_t idac_mux = 0;
uint8_t pin_selections[4];
uint8_t vbias = 0;
size_t pin_selections_size;
int result;
enum ads114s0x_register register_addresses[6];
enum ads114s0x_register register_addresses[7];
uint8_t values[ARRAY_SIZE(register_addresses)];
uint16_t acquisition_time_value = ADC_ACQ_TIME_VALUE(channel_cfg->acquisition_time);
uint16_t acquisition_time_unit = ADC_ACQ_TIME_UNIT(channel_cfg->acquisition_time);
@ -820,20 +832,33 @@ static int ads114s0x_channel_setup(const struct device *dev,
}
}
ADS114S0X_REGISTER_VBIAS_VB_LEVEL_SET(vbias, config->vbias_level);
if ((channel_cfg->vbias_pins &
~GENMASK(ADS114S0X_VBIAS_PIN_MAX, ADS114S0X_VBIAS_PIN_MIN)) != 0) {
LOG_ERR("%s: invalid VBIAS pin selection 0x%08X", dev->name,
channel_cfg->vbias_pins);
return -EINVAL;
}
vbias |= channel_cfg->vbias_pins;
register_addresses[0] = ADS114S0X_REGISTER_INPMUX;
register_addresses[1] = ADS114S0X_REGISTER_PGA;
register_addresses[2] = ADS114S0X_REGISTER_DATARATE;
register_addresses[3] = ADS114S0X_REGISTER_REF;
register_addresses[4] = ADS114S0X_REGISTER_IDACMAG;
register_addresses[5] = ADS114S0X_REGISTER_IDACMUX;
BUILD_ASSERT(ARRAY_SIZE(register_addresses) == 6);
register_addresses[6] = ADS114S0X_REGISTER_VBIAS;
BUILD_ASSERT(ARRAY_SIZE(register_addresses) == 7);
values[0] = input_mux;
values[1] = gain;
values[2] = data_rate;
values[3] = reference_control;
values[4] = idac_magnitude;
values[5] = idac_mux;
BUILD_ASSERT(ARRAY_SIZE(values) == 6);
values[6] = vbias;
BUILD_ASSERT(ARRAY_SIZE(values) == 7);
result = ads114s0x_write_multiple_registers(dev, register_addresses, values,
ARRAY_SIZE(values));
@ -1474,6 +1499,7 @@ BUILD_ASSERT(CONFIG_ADC_INIT_PRIORITY > CONFIG_SPI_INIT_PRIORITY,
.gpio_data_ready = GPIO_DT_SPEC_INST_GET(n, drdy_gpios), \
.gpio_start_sync = GPIO_DT_SPEC_INST_GET_OR(n, start_sync_gpios, {0}), \
.idac_current = DT_INST_PROP(n, idac_current), \
.vbias_level = DT_INST_PROP(n, vbias_level), \
}; \
static struct ads114s0x_data data_##n; \
DEVICE_DT_INST_DEFINE(n, ads114s0x_init, NULL, &data_##n, &config_##n, POST_KERNEL, \

7
dts/bindings/adc/adc-controller.yaml
View file

@ -160,3 +160,10 @@ child-binding:
interpretation depends on the driver. This is used only for drivers
which select the ADC_CONFIGURABLE_EXCITATION_CURRENT_SOURCE_PIN
Kconfig option.
zephyr,vbias-pins:
type: int
description: |
Output pin selection for the bias voltage. The actual interpretation
depends on the driver. This is used only for drivers which select
the ADC_CONFIGURABLE_VBIAS_PIN Kconfig option.

9
dts/bindings/adc/ti,ads114s08.yaml
View file

@ -45,5 +45,14 @@ properties:
description: |
IDAC current in microampere, the default value turns the current source off
vbias-level:
type: int
enum:
- 0
- 1
default: 0
description: |
bias voltage level: 0 - (AVDD+AVSS)/2, 1 - (AVDD+AVSS)/12
io-channel-cells:
- input

14
include/zephyr/drivers/adc.h
View file

@ -156,6 +156,18 @@ struct adc_channel_cfg {
*/
uint8_t current_source_pin[2];
#endif /* CONFIG_ADC_CONFIGURABLE_EXCITATION_CURRENT_SOURCE_PIN */
#ifdef CONFIG_ADC_CONFIGURABLE_VBIAS_PIN
/**
* Output pins for the bias voltage.
* This is only available if the driver enables this feature
* via the hidden configuration option ADC_CONFIGURABLE_VBIAS_PIN.
* The field is interpreted as a bitmask, where each bit represents
* one of the input pins. The actual mapping to the physical pins
* depends on the driver itself.
*/
uint32_t vbias_pins;
#endif /* CONFIG_ADC_CONFIGURABLE_VBIAS_PIN */
};
/**
@ -236,6 +248,8 @@ IF_ENABLED(DT_PROP(node_id, zephyr_differential), \
IF_ENABLED(CONFIG_ADC_CONFIGURABLE_EXCITATION_CURRENT_SOURCE_PIN, \
(.current_source_pin_set = DT_NODE_HAS_PROP(node_id, zephyr_current_source_pin), \
.current_source_pin = DT_PROP_OR(node_id, zephyr_current_source_pin, {0}),)) \
IF_ENABLED(CONFIG_ADC_CONFIGURABLE_VBIAS_PIN, \
(.vbias_pins = DT_PROP_OR(node_id, zephyr_vbias_pins, 0),)) \
}
/**