@@ -67,6 +67,8 @@
#define AD4170_FILTER_FS_REG(x) (0xC7 + 14 * (x))
#define AD4170_OFFSET_REG(x) (0xCA + 14 * (x))
#define AD4170_GAIN_REG(x) (0xCD + 14 * (x))
+#define AD4170_V_BIAS_REG 0x135
+#define AD4170_CURRENT_SRC_REG(x) (0x139 + 2 * (x))
#define AD4170_GPIO_MODE_REG 0x191
#define AD4170_GPIO_OUTPUT_REG 0x193
#define AD4170_GPIO_INPUT_REG 0x195
@@ -98,6 +100,10 @@
#define AD4170_CHAN_MAP_AINP_MSK GENMASK(12, 8)
#define AD4170_CHAN_MAP_AINM_MSK GENMASK(4, 0)
+/* AD4170_MISC_REG */
+#define AD4170_MISC_CHOP_IEXC_MSK GENMASK(15, 14)
+#define AD4170_MISC_CHOP_ADC_MSK GENMASK(9, 8)
+
/* AD4170_AFE_REG */
#define AD4170_AFE_REF_BUF_M_MSK GENMASK(11, 10)
#define AD4170_AFE_REF_BUF_P_MSK GENMASK(9, 8)
@@ -108,12 +114,19 @@
/* AD4170_FILTER_REG */
#define AD4170_FILTER_FILTER_TYPE_MSK GENMASK(3, 0)
+/* AD4170_CURRENT_SRC_REG */
+#define AD4170_CURRENT_SRC_I_OUT_PIN_MSK GENMASK(12, 8)
+#define AD4170_CURRENT_SRC_I_OUT_VAL_MSK GENMASK(2, 0)
+
/* AD4170_GPIO_MODE_REG */
#define AD4170_GPIO_MODE_GPIO0_MSK GENMASK(1, 0)
#define AD4170_GPIO_MODE_GPIO1_MSK GENMASK(3, 2)
#define AD4170_GPIO_MODE_GPIO2_MSK GENMASK(5, 4)
#define AD4170_GPIO_MODE_GPIO3_MSK GENMASK(7, 6)
+/* AD4170_GPIO_OUTPUT_REG */
+#define AD4170_GPIO_OUTPUT_GPIO_MSK(x) BIT(x)
+
/* AD4170 register constants */
/* AD4170_CLOCK_CTRL_REG constants */
@@ -137,6 +150,11 @@
#define AD4170_CHAN_MAP_REFIN2_N 28
#define AD4170_CHAN_MAP_REFOUT 29
+/* AD4170_MISC_REG constants */
+#define AD4170_MISC_CHOP_IEXC_PAIR1 0x1
+#define AD4170_MISC_CHOP_IEXC_PAIR2 0x2
+#define AD4170_MISC_CHOP_IEXC_BOTH 0x3
+
/* AD4170_PIN_MUXING_REG constants */
#define AD4170_PIN_MUXING_DIG_AUX1_DISABLED 0x0
#define AD4170_PIN_MUXING_DIG_AUX1_RDY 0x1
@@ -154,6 +172,10 @@
#define AD4170_FILTER_FILTER_TYPE_SINC5 0x4
#define AD4170_FILTER_FILTER_TYPE_SINC3 0x6
+/* AD4170_CURRENT_SRC_REG constants */
+#define AD4170_CURRENT_SRC_I_OUT_PIN_AIN(x) (x)
+#define AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(x) ((x) + 17)
+
/* AD4170_GPIO_MODE_REG constants */
#define AD4170_GPIO_MODE_GPIO_INPUT 1
#define AD4170_GPIO_MODE_GPIO_OUTPUT 2
@@ -167,6 +189,7 @@
#define AD4170_MAX_SETUPS 8
#define AD4170_INVALID_SETUP 9
#define AD4170_SPI_MAX_XFER_LEN 6
+#define AD4170_NUM_CURRENT_SRC 4
#define AD4170_DEFAULT_SAMP_RATE (125 * HZ_PER_KHZ)
#define AD4170_INT_REF_2_5V 2500000
@@ -188,8 +211,19 @@
#define AD4170_ADC_CTRL_CONT_READ_EXIT 0xA5
+/* Analog pin functions */
+#define AD4170_PIN_UNASSIGNED 0x00
+#define AD4170_PIN_ANALOG_IN 0x01
+#define AD4170_PIN_CURRENT_OUT 0x02
+#define AD4170_PIN_VBIAS 0x04
+
/* GPIO pin functions */
#define AD4170_GPIO_UNASSIGNED 0x00
+#define AD4170_GPIO_AC_EXCITATION 0x02
+#define AD4170_GPIO_OUTPUT 0x04
+
+/* Current source */
+#define AD4170_CURRENT_SRC_DISABLED 0xFF
static const unsigned int ad4170_reg_size[] = {
[AD4170_CONFIG_A_REG] = 1,
@@ -228,6 +262,8 @@ static const unsigned int ad4170_reg_size[] = {
[AD4170_OFFSET_REG(5) ... AD4170_GAIN_REG(5)] = 3,
[AD4170_OFFSET_REG(6) ... AD4170_GAIN_REG(6)] = 3,
[AD4170_OFFSET_REG(7) ... AD4170_GAIN_REG(7)] = 3,
+ [AD4170_V_BIAS_REG] = 2,
+ [AD4170_CURRENT_SRC_REG(0) ... AD4170_CURRENT_SRC_REG(3)] = 2,
[AD4170_GPIO_MODE_REG] = 2,
[AD4170_GPIO_OUTPUT_REG] = 2,
[AD4170_GPIO_INPUT_REG] = 2,
@@ -290,6 +326,41 @@ static const unsigned int ad4170_sinc5_filt_fs_tbl[] = {
1, 2, 4, 8, 12, 16, 20, 40, 48, 80, 100, 256,
};
+static const unsigned int ad4170_iout_pin_tbl[] = {
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(0),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(1),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(2),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(3),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(4),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(5),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(6),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(7),
+ AD4170_CURRENT_SRC_I_OUT_PIN_AIN(8),
+ AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(0),
+ AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(1),
+ AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(2),
+ AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(3),
+};
+
+static const unsigned int ad4170_iout_current_ua_tbl[] = {
+ 0, 10, 50, 100, 250, 500, 1000, 1500,
+};
+
+enum ad4170_sensor_enum {
+ AD4170_ADC_SENSOR = 0,
+ AD4170_WEIGH_SCALE_SENSOR = 1,
+ AD4170_RTD_SENSOR = 2,
+ AD4170_THERMOCOUPLE_SENSOR = 3,
+};
+
+/* maps adi,sensor-type property value to enum */
+static const char * const ad4170_sensor_type[] = {
+ [AD4170_ADC_SENSOR] = "adc",
+ [AD4170_WEIGH_SCALE_SENSOR] = "weighscale",
+ [AD4170_RTD_SENSOR] = "rtd",
+ [AD4170_THERMOCOUPLE_SENSOR] = "thermocouple",
+};
+
struct ad4170_chip_info {
const char *name;
};
@@ -374,6 +445,7 @@ struct ad4170_state {
struct gpio_chip gpiochip;
unsigned int clock_ctrl;
int gpio_fn[AD4170_NUM_GPIO_PINS];
+ unsigned int cur_src_pins[AD4170_NUM_CURRENT_SRC];
/*
* DMA (thus cache coherency maintenance) requires the transfer buffers
* to live in their own cache lines.
@@ -918,6 +990,19 @@ static int ad4170_get_ain_voltage_uv(struct ad4170_state *st, int ain_n,
int v_diff;
*ain_voltage = 0;
+ /*
+ * The voltage bias (vbias) sets the common-mode voltage of the channel
+ * to (AVDD + AVSS)/2. If provided, AVSS supply provides the magnitude
+ * (absolute value) of the negative voltage supplied to the AVSS pin.
+ * So, we do AVDD - AVSS to compute the DC voltage generated by the bias
+ * voltage generator.
+ */
+ if (st->pins_fn[ain_n] & AD4170_PIN_VBIAS) {
+ int v_diff = st->vrefs_uv[AD4170_AVDD_SUP] - st->vrefs_uv[AD4170_AVSS_SUP];
+ *ain_voltage = v_diff / 2;
+ return 0;
+ }
+
if (ain_n <= AD4170_CHAN_MAP_TEMP_SENSOR)
return 0;
@@ -972,6 +1057,19 @@ static int ad4170_get_ain_voltage_uv(struct ad4170_state *st, int ain_n,
}
}
+static int ad4170_validate_analog_input(struct ad4170_state *st, int pin)
+{
+ if (pin <= AD4170_MAX_ANALOG_PINS) {
+ if (st->pins_fn[pin] & AD4170_PIN_CURRENT_OUT)
+ return dev_err_probe(&st->spi->dev, -EINVAL,
+ "Pin %d already used with fn %u.\n",
+ pin, st->pins_fn[pin]);
+
+ st->pins_fn[pin] |= AD4170_PIN_ANALOG_IN;
+ }
+ return 0;
+}
+
static int ad4170_validate_channel_input(struct ad4170_state *st, int pin, bool com)
{
/* Check common-mode input pin is mapped to a special input. */
@@ -986,7 +1084,7 @@ static int ad4170_validate_channel_input(struct ad4170_state *st, int pin, bool
"Invalid analog input pin number. %d\n",
pin);
- return 0;
+ return ad4170_validate_analog_input(st, pin);
}
/*
@@ -1723,6 +1821,371 @@ static int ad4170_gpio_init(struct iio_dev *indio_dev)
return devm_gpiochip_add_data(&st->spi->dev, &st->gpiochip, indio_dev);
}
+static int ad4170_validate_excitation_pin(struct ad4170_state *st, u32 pin)
+{
+ struct device *dev = &st->spi->dev;
+ unsigned int i;
+
+ /* Check the pin number is valid */
+ for (i = 0; i < ARRAY_SIZE(ad4170_iout_pin_tbl); i++)
+ if (ad4170_iout_pin_tbl[i] == pin)
+ break;
+
+ if (i == ARRAY_SIZE(ad4170_iout_pin_tbl))
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid excitation pin: %u\n",
+ pin);
+
+ /* Check the pin is available */
+ if (pin <= AD4170_MAX_ANALOG_PINS) {
+ if (st->pins_fn[pin] != AD4170_PIN_UNASSIGNED)
+ return dev_err_probe(dev, -EINVAL,
+ "Pin %u already used with fn %u\n",
+ pin, st->pins_fn[pin]);
+
+ st->pins_fn[pin] |= AD4170_PIN_CURRENT_OUT;
+ } else {
+ unsigned int gpio = pin - AD4170_CURRENT_SRC_I_OUT_PIN_GPIO(0);
+
+ if (st->gpio_fn[gpio] != AD4170_GPIO_UNASSIGNED)
+ return dev_err_probe(dev, -EINVAL,
+ "GPIO %u already used with fn %u\n",
+ gpio, st->gpio_fn[gpio]);
+
+ st->gpio_fn[gpio] |= AD4170_GPIO_AC_EXCITATION;
+ }
+
+ return 0;
+}
+
+static int ad4170_validate_excitation_pins(struct ad4170_state *st,
+ u32 *exc_pins, int num_exc_pins)
+{
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < num_exc_pins; i++) {
+ ret = ad4170_validate_excitation_pin(st, exc_pins[i]);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
+static const char *const ad4170_i_out_pin_dt_props[] = {
+ "adi,excitation-pin-0",
+ "adi,excitation-pin-1",
+ "adi,excitation-pin-2",
+ "adi,excitation-pin-3",
+};
+
+static const char *const ad4170_i_out_val_dt_props[] = {
+ "adi,excitation-current-0-microamp",
+ "adi,excitation-current-1-microamp",
+ "adi,excitation-current-2-microamp",
+ "adi,excitation-current-3-microamp",
+};
+
+/*
+ * Parses firmware data describing output current source setup. There are 4
+ * excitation currents (IOUT0 to IOUT3) that can be configured independently.
+ * Excitation currents are added if they are output on the same pin.
+ */
+static int ad4170_parse_exc_current(struct ad4170_state *st,
+ struct fwnode_handle *child,
+ unsigned int *exc_pins,
+ unsigned int *exc_curs,
+ unsigned int *num_exc_pins)
+{
+ struct device *dev = &st->spi->dev;
+ unsigned int num_pins, i, j;
+ u32 pin, val;
+ int ret;
+
+ num_pins = 0;
+ for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++) {
+ /* Parse excitation current output pin properties. */
+ pin = AD4170_CURRENT_SRC_I_OUT_PIN_AIN(0);
+ ret = fwnode_property_read_u32(child, ad4170_i_out_pin_dt_props[i],
+ &pin);
+ if (ret)
+ continue;
+
+ exc_pins[num_pins] = pin;
+
+ /* Parse excitation current value properties. */
+ val = ad4170_iout_current_ua_tbl[0];
+ fwnode_property_read_u32(child,
+ ad4170_i_out_val_dt_props[i], &val);
+
+ for (j = 0; j < ARRAY_SIZE(ad4170_iout_current_ua_tbl); j++)
+ if (ad4170_iout_current_ua_tbl[j] == val)
+ break;
+
+ if (j == ARRAY_SIZE(ad4170_iout_current_ua_tbl))
+ return dev_err_probe(dev, -EINVAL, "Invalid %s: %uuA\n",
+ ad4170_i_out_val_dt_props[i], val);
+
+ exc_curs[num_pins] = j;
+ num_pins++;
+ }
+ *num_exc_pins = num_pins;
+
+ return 0;
+}
+
+static int ad4170_setup_current_src(struct ad4170_state *st,
+ struct fwnode_handle *child,
+ struct ad4170_setup *setup, u32 *exc_pins,
+ unsigned int *exc_curs, int num_exc_pins,
+ bool ac_excited)
+{
+ unsigned int exc_cur_pair, i, j;
+ int ret;
+
+ for (i = 0; i < num_exc_pins; i++) {
+ unsigned int exc_cur = exc_curs[i];
+ unsigned int pin = exc_pins[i];
+ unsigned int current_src = 0;
+
+ for (j = 0; j < AD4170_NUM_CURRENT_SRC; j++)
+ if (st->cur_src_pins[j] == AD4170_CURRENT_SRC_DISABLED)
+ break;
+
+ if (j == AD4170_NUM_CURRENT_SRC)
+ return dev_err_probe(&st->spi->dev, -EINVAL,
+ "Too many excitation current sources\n");
+
+ current_src |= FIELD_PREP(AD4170_CURRENT_SRC_I_OUT_PIN_MSK, pin);
+ current_src |= FIELD_PREP(AD4170_CURRENT_SRC_I_OUT_VAL_MSK, exc_cur);
+ st->cur_src_pins[j] = pin;
+ ret = regmap_write(st->regmap, AD4170_CURRENT_SRC_REG(j),
+ current_src);
+ if (ret)
+ return ret;
+ }
+
+ if (!ac_excited)
+ return 0;
+
+ if (num_exc_pins < 2)
+ return dev_err_probe(&st->spi->dev, -EINVAL,
+ "Current chopping requested but only one pin provided: %u\n",
+ exc_pins[0]);
+
+ /*
+ * Two use cases to handle here:
+ * - 2 pairs of excitation currents;
+ * - 1 pair of excitation currents.
+ */
+ if (num_exc_pins == 4) {
+ for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++)
+ if (st->cur_src_pins[i] != exc_pins[i])
+ return dev_err_probe(&st->spi->dev, -EINVAL,
+ "Unable to use 4 exc pins\n");
+ } else {
+ /*
+ * Excitation current chopping is configured in pairs. Current
+ * sources IOUT0 and IOUT1 form pair 1, IOUT2 and IOUT3 make up
+ * pair 2. So, if current chopping was requested, check if the
+ * first end of the first pair of excitation currents is
+ * available. Try the next pair if IOUT0 has already been
+ * configured for another channel.
+ */
+ i = st->cur_src_pins[0] == exc_pins[0] ? 0 : 2;
+
+ if (st->cur_src_pins[i] != exc_pins[0] ||
+ st->cur_src_pins[i + 1] != exc_pins[1])
+ return dev_err_probe(&st->spi->dev, -EINVAL,
+ "Failed to setup current chopping\n");
+
+ st->cur_src_pins[i] = exc_pins[0];
+ st->cur_src_pins[i + 1] = exc_pins[1];
+
+ if (i == 0)
+ exc_cur_pair = AD4170_MISC_CHOP_IEXC_PAIR1;
+ else
+ exc_cur_pair = AD4170_MISC_CHOP_IEXC_PAIR2;
+ }
+
+ /*
+ * Configure excitation current chopping.
+ * Chop both pairs if using four excitation pins.
+ */
+ setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_IEXC_MSK,
+ num_exc_pins == 2 ?
+ exc_cur_pair :
+ AD4170_MISC_CHOP_IEXC_BOTH);
+
+ return 0;
+}
+
+static int ad4170_setup_bridge(struct ad4170_state *st,
+ struct fwnode_handle *child,
+ struct ad4170_setup *setup, u32 *exc_pins,
+ unsigned int *exc_curs, int num_exc_pins,
+ bool ac_excited)
+{
+ unsigned long gpio_mask;
+ unsigned int i;
+ int ret;
+
+ /*
+ * If a specific current is provided through
+ * adi,excitation-current-n-microamp, set excitation pins provided
+ * through adi,excitation-pin-n to excite the bridge circuit.
+ */
+ for (i = 0; i < num_exc_pins; i++)
+ if (exc_curs[i] > 0)
+ return ad4170_setup_current_src(st, child, setup, exc_pins,
+ exc_curs, num_exc_pins,
+ ac_excited);
+
+ /*
+ * Else, use predefined ACX1, ACX1 negated, ACX2, ACX2 negated signals
+ * to AC excite the bridge. Those signals are output on GPIO2, GPIO0,
+ * GPIO3, and GPIO1, respectively. If only two pins are specified for AC
+ * excitation, use ACX1 and ACX2 (GPIO2 and GPIO3).
+ *
+ * Also, to avoid any short-circuit condition when more than one channel
+ * is enabled, set GPIO2 and GPIO0 high, and set GPIO1 and GPIO3 low to
+ * DC excite the bridge whenever a channel without AC excitation is
+ * selected. That is needed because GPIO pins are controlled by the next
+ * highest priority GPIO function when a channel doesn't enable AC
+ * excitation. See datasheet Figure 113 Weigh Scale (AC Excitation) for
+ * the reference circuit diagram.
+ */
+ if (num_exc_pins == 2) {
+ setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_ADC_MSK, 0x3);
+
+ gpio_mask = AD4170_GPIO_MODE_GPIO3_MSK | AD4170_GPIO_MODE_GPIO2_MSK;
+ ret = regmap_update_bits(st->regmap, AD4170_GPIO_MODE_REG, gpio_mask,
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO3_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT) |
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO2_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT));
+ if (ret)
+ return ret;
+
+ /*
+ * Set GPIO2 high and GPIO3 low to DC excite the bridge when
+ * a different channel is selected.
+ */
+ gpio_mask = AD4170_GPIO_OUTPUT_GPIO_MSK(3) |
+ AD4170_GPIO_OUTPUT_GPIO_MSK(2);
+ ret = regmap_update_bits(st->regmap, AD4170_GPIO_OUTPUT_REG, gpio_mask,
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(3), 0) |
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(2), 1));
+ if (ret)
+ return ret;
+
+ st->gpio_fn[3] |= AD4170_GPIO_OUTPUT;
+ st->gpio_fn[2] |= AD4170_GPIO_OUTPUT;
+ } else {
+ setup->misc |= FIELD_PREP(AD4170_MISC_CHOP_ADC_MSK, 0x2);
+
+ gpio_mask = AD4170_GPIO_MODE_GPIO3_MSK | AD4170_GPIO_MODE_GPIO2_MSK |
+ AD4170_GPIO_MODE_GPIO1_MSK | AD4170_GPIO_MODE_GPIO0_MSK;
+ ret = regmap_update_bits(st->regmap, AD4170_GPIO_MODE_REG, gpio_mask,
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO3_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT) |
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO2_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT) |
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO1_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT) |
+ FIELD_PREP(AD4170_GPIO_MODE_GPIO0_MSK,
+ AD4170_GPIO_MODE_GPIO_OUTPUT));
+ if (ret)
+ return ret;
+
+ /*
+ * Set GPIO2 and GPIO0 high, and set GPIO1 and GPIO3 low to DC
+ * excite the bridge when a different channel is selected.
+ */
+ gpio_mask = AD4170_GPIO_OUTPUT_GPIO_MSK(3) |
+ AD4170_GPIO_OUTPUT_GPIO_MSK(2) |
+ AD4170_GPIO_OUTPUT_GPIO_MSK(1) |
+ AD4170_GPIO_OUTPUT_GPIO_MSK(0);
+ ret = regmap_update_bits(st->regmap, AD4170_GPIO_OUTPUT_REG, gpio_mask,
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(3), 0) |
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(2), 1) |
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(1), 0) |
+ FIELD_PREP(AD4170_GPIO_OUTPUT_GPIO_MSK(0), 1));
+ if (ret)
+ return ret;
+
+ st->gpio_fn[3] |= AD4170_GPIO_OUTPUT;
+ st->gpio_fn[2] |= AD4170_GPIO_OUTPUT;
+ st->gpio_fn[1] |= AD4170_GPIO_OUTPUT;
+ st->gpio_fn[0] |= AD4170_GPIO_OUTPUT;
+ }
+
+ return 0;
+}
+
+static int ad4170_setup_rtd(struct ad4170_state *st,
+ struct fwnode_handle *child,
+ struct ad4170_setup *setup, u32 *exc_pins,
+ unsigned int *exc_curs, int num_exc_pins, bool ac_excited)
+{
+ return ad4170_setup_current_src(st, child, setup, exc_pins,
+ exc_curs, num_exc_pins, ac_excited);
+}
+
+static int ad4170_parse_external_sensor(struct ad4170_state *st,
+ struct fwnode_handle *child,
+ struct ad4170_setup *setup,
+ struct iio_chan_spec *chan, u8 s_type)
+{
+ unsigned int num_exc_pins, reg_val;
+ struct device *dev = &st->spi->dev;
+ u32 pins[2], exc_pins[4], exc_curs[4];
+ bool ac_excited, vbias;
+ int ret;
+
+ ret = fwnode_property_read_u32_array(child, "diff-channels", pins,
+ ARRAY_SIZE(pins));
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to read sensor diff-channels\n");
+
+ chan->differential = true;
+ chan->channel = pins[0];
+ chan->channel2 = pins[1];
+
+ ret = ad4170_parse_exc_current(st, child, exc_pins, exc_curs, &num_exc_pins);
+ if (ret)
+ return ret;
+
+ /* The external sensor may not need excitation from the ADC chip. */
+ if (num_exc_pins == 0)
+ return 0;
+
+ ret = ad4170_validate_excitation_pins(st, exc_pins, num_exc_pins);
+ if (ret)
+ return ret;
+
+ ac_excited = fwnode_property_read_bool(child, "adi,excitation-ac");
+
+ if (s_type == AD4170_THERMOCOUPLE_SENSOR) {
+ vbias = fwnode_property_read_bool(child, "adi,vbias");
+ if (vbias) {
+ st->pins_fn[chan->channel2] |= AD4170_PIN_VBIAS;
+ reg_val = BIT(chan->channel2);
+ return regmap_write(st->regmap, AD4170_V_BIAS_REG,
+ reg_val);
+ }
+ }
+ if (s_type == AD4170_WEIGH_SCALE_SENSOR)
+ ret = ad4170_setup_bridge(st, child, setup, exc_pins, exc_curs,
+ num_exc_pins, ac_excited);
+ else
+ ret = ad4170_setup_rtd(st, child, setup, exc_pins, exc_curs,
+ num_exc_pins, ac_excited);
+
+ return ret;
+}
+
static int ad4170_parse_reference(struct ad4170_state *st,
struct fwnode_handle *child,
struct ad4170_setup *setup)
@@ -1808,6 +2271,7 @@ static int ad4170_parse_channel_node(struct iio_dev *indio_dev,
struct ad4170_setup *setup;
struct iio_chan_spec *chan;
unsigned int ref_select;
+ unsigned int s_type;
unsigned int ch_reg;
bool bipolar;
int ret;
@@ -1836,10 +2300,28 @@ static int ad4170_parse_channel_node(struct iio_dev *indio_dev,
if (ret)
return ret;
- ret = ad4170_parse_adc_channel_type(dev, child, chan);
- if (ret < 0)
- return ret;
+ ret = fwnode_property_match_property_string(child, "adi,sensor-type",
+ ad4170_sensor_type,
+ ARRAY_SIZE(ad4170_sensor_type));
+ /* Default to conventional ADC channel if sensor type not present */
+ s_type = ret < 0 ? AD4170_ADC_SENSOR : ret;
+ switch (s_type) {
+ case AD4170_ADC_SENSOR:
+ ret = ad4170_parse_adc_channel_type(dev, child, chan);
+ if (ret)
+ return ret;
+
+ break;
+ case AD4170_WEIGH_SCALE_SENSOR:
+ case AD4170_THERMOCOUPLE_SENSOR:
+ case AD4170_RTD_SENSOR:
+ ret = ad4170_parse_external_sensor(st, child, setup, chan, s_type);
+ if (ret)
+ return ret;
+
+ break;
+ }
bipolar = fwnode_property_read_bool(child, "bipolar");
setup->afe |= FIELD_PREP(AD4170_AFE_BIPOLAR_MSK, bipolar);
if (bipolar)
@@ -2035,6 +2517,7 @@ static int ad4170_parse_firmware(struct iio_dev *indio_dev)
struct ad4170_state *st = iio_priv(indio_dev);
struct device *dev = &st->spi->dev;
int reg_data, ret;
+ unsigned int i;
ret = ad4170_clock_select(indio_dev);
if (ret)
@@ -2044,6 +2527,9 @@ static int ad4170_parse_firmware(struct iio_dev *indio_dev)
if (ret)
return ret;
+ for (i = 0; i < AD4170_NUM_CURRENT_SRC; i++)
+ st->cur_src_pins[i] = AD4170_CURRENT_SRC_DISABLED;
+
/* On power on, device defaults to using SDO pin for data ready signal */
st->int_pin_sel = AD4170_INT_PIN_SDO;
ret = device_property_match_property_string(dev, "interrupt-names",
The AD4170 design has features to aid interfacing with weigh scale and RTD sensors that are expected to be setup with external circuitry for proper sensor operation. A key characteristic of those sensors is that the circuit they are in must be excited with a pair of signals. The external circuit can be excited either by voltage supply or by AD4170 excitation signals. The sensor can then be read through a different pair of lines that are connected to AD4170 ADC. Configure AD4170 to handle external circuit sensors. Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com> --- Change log v4 -> v5 - Tweaked commits/patches to reduce diff. - Dropped unneeded local variable. drivers/iio/adc/ad4170.c | 494 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 490 insertions(+), 4 deletions(-)