dt-bindings: iio: amplifiers: add ADA4255

The ADA4255 is a precision programmable gain instrumentation amplifier (PGIA) with integrated bipolar charge pumps.

With its integrated charge pumps, the ADA4255 internally produces the high voltage bipolar supplies needed to achieve a wide input voltage range (38V typical with VDDCP = 5V) without lowering input impedance.

The charge pump topology of the ADA4255 allows channels to be isolated with only low voltage components, reducing complexity, size, and implementation time in industrial and process control systems.

Signed-off-by Cosmin Tanislav <[email protected]>

drivers/iio/amplifiers/ada4255.c new file +7 -0

+ * Author: Cosmin Tanislav <[email protected]>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>

drivers/iio/amplifiers/ada4255.c new file +4 -0

+	 */
+	struct mutex			lock;
+	struct gpio_chip		gc;
+	struct notifier_block		ext_clk_nb;

drivers/iio/amplifiers/ada4255.c new file +6 -0

+};
+
+static const unsigned int ada4255_clk_cp_sel_hz_tbl[] = {
+	16000000, 8000000
+};
+

drivers/iio/amplifiers/ada4255.c new file +16 -0

+		if (val == tbl[i]) {
+			*index = i;
+			return 0;
+		}
+
+	return -EINVAL;
+}
 
+static int ada4255_set_gain(struct ada4255_state *st, int val, int val2)
+{
+	ssize_t tbl_len = ARRAY_SIZE(ada4255_gain_tbl);
+	unsigned int i, g5, g4, g3_0;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(ada4255_gain_tbl); i++)
+		if (val == ada4255_gain_tbl[i][0] &&
+		    val2 == ada4255_gain_tbl[i][1])

drivers/iio/amplifiers/ada4255.c new file +24 -0

+
+	ret = regmap_update_bits(st->regmap, ADA4255_TEST_MUX_REG,
+				 ADA4255_GAIN_G5_MASK,
+				 FIELD_PREP(ADA4255_GAIN_G5_MASK, g5));
+	if (ret)
+		goto out;
+
+	ret = regmap_update_bits(st->regmap, ADA4255_GAIN_MUX_REG,
+				 ADA4255_GAIN_G4_MASK | ADA4255_GAIN_G3_0_MASK,
+				 FIELD_PREP(ADA4255_GAIN_G4_MASK, g4) |
+				 FIELD_PREP(ADA4255_GAIN_G3_0_MASK, g3_0));
+
+out:
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
+
+static int ada4255_get_gain(struct ada4255_state *st, int *val, int *val2)
+{
+	ssize_t tbl_len = ARRAY_SIZE(ada4255_gain_reg_tbl);
+	unsigned int i, gain, test_gain, g5, g4, g3_0;
+	int ret;
+

drivers/iio/amplifiers/ada4255.c new file +20 -0

+
+	if (ret)
+		return ret;
+
+	g5 = FIELD_GET(ADA4255_GAIN_G5_MASK, test_gain);
+	g4 = FIELD_GET(ADA4255_GAIN_G4_MASK, gain);
+	g3_0 = FIELD_GET(ADA4255_GAIN_G3_0_MASK, gain);
+
+	for (i = 0; i < ARRAY_SIZE(ada4255_gain_reg_tbl); i++)
+		if (g5 == ada4255_gain_reg_tbl[i][0] &&
+		    g4 == ada4255_gain_reg_tbl[i][1] &&
+		    g3_0 == ada4255_gain_reg_tbl[i][2])
+			break;
+
+	if (i == tbl_len)
+		return -EINVAL;
+
+	*val = ada4255_gain_tbl[i][0];
+	*val2 = ada4255_gain_tbl[i][1];
+

drivers/iio/amplifiers/ada4255.c new file +22 -0

+
+	ret = ada4255_get_ch_en(st, ch, &current_val);
+	if (ret < 0)
+		goto out;
+
+	if (current_val == val) {
+		ret = 0;
+		goto out;
+	}
+
+	ret = regmap_write(st->regmap, ADA4255_INPUT_MUX_REG, ch_val);
+
+out:
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
 
+static unsigned long ada4255_int_clk_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct ada4255_state *st = ada4255_from_clk_hw(hw);
+	struct device *dev = &st->spi->dev;

drivers/iio/amplifiers/ada4255.c new file +5 -0

+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, ada4255_clk_disable_unprepare,
+				       st->mclk);

drivers/iio/amplifiers/ada4255.c new file +28 -0

+	u32 val;
+
+	st->mclk = devm_clk_get_optional(dev, "mclk");
+	if (IS_ERR(st->mclk))
+		return dev_err_probe(dev, PTR_ERR(st->mclk),
+				     "Failed to get mclk\n");
+
+	if (st->mclk)
+		ret = ada4255_setup_ext_clk(st);
+	else
+		ret = ada4255_setup_int_clk(st);
+
+	if (ret)
+		return ret;
+
+	ret = device_property_read_u32(dev, "adi,excitation-current-microamp", &val);
+	if (!ret) {
+		ret = ada4255_find_tbl_index(ada4255_excitation_current_ua_tbl,
+					     val, &i);
+		if (ret)
+			return ret;
+
+		ret = regmap_update_bits(st->regmap, AD4255_EX_CURRENT_CFG_REG,
+					 AD4255_EX_CURRENT_MASK,
+					 FIELD_PREP(AD4255_EX_CURRENT_MASK, i));
+		if (ret)
+			return ret;
+

drivers/iio/amplifiers/ada4255.c new file +8 -0

+	}
+
+	return 0;
+}
 
+static int ada4255_reset(struct ada4255_state *st)
+{
+	int ret;
+

drivers/iio/amplifiers/ada4255.c new file +39 -0

+	};
+	struct device *dev = &spi->dev;
+	struct iio_dev *indio_dev;
+	struct ada4255_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->spi = spi;
+	st->chip_info = spi_get_device_match_data(spi);
+	if (!st->chip_info)
+		return -EINVAL;
+
+	indio_dev->info = &ada4255_info;
+	indio_dev->name = st->chip_info->name;
+	indio_dev->channels = ada4255_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ada4255_channels);
+
+	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulator_names),
+					     regulator_names);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get regulators\n");
+
+	st->regmap = devm_regmap_init_spi(spi, &ada4255_regmap_config);
+	if (IS_ERR(st->regmap))
+		return PTR_ERR(st->regmap);
+
+	ret = ada4255_reset(st);
+	if (ret)
+		return ret;
+
+	ret = ada4255_setup(st);
+	if (ret)
+		return ret;
+
+	ret = ada4255_setup_gpio_chip(st);

+module_spi_driver(ada4255_driver);

The ADA4255 is a precision programmable gain instrumentation amplifier (PGIA) with integrated bipolar charge pumps.

With its integrated charge pumps, the ADA4255 internally produces the high voltage bipolar supplies needed to achieve a wide input voltage range (38V typical with VDDCP = 5V) without lowering input impedance.

The charge pump topology of the ADA4255 allows channels to be isolated with only low voltage components, reducing complexity, size, and implementation time in industrial and process control systems.

Signed-off-by Cosmin Tanislav <[email protected]>