Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
iio: adc: add ltc2309 support
The LTC2309 is an 8-Channel, 12-Bit SAR ADC with an I2C Interface.
This implements support for all single-ended and differential channels,
in unipolar mode only.
Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Link: https://lore.kernel.org/r/20230828-ltc2309-v3-2-338b3a8fab8b@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by
Liam Beguin
and committed by
Jonathan Cameron
733e0fed
0679ea0b
+257
+10
drivers/iio/adc/Kconfig
+10
drivers/iio/adc/Kconfig
···
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activate only one via device tree selection. Provides direct access
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via sysfs.
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config LTC2309
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tristate "Linear Technology LTC2309 ADC driver"
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depends on I2C
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help
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Say yes here to build support for Linear Technology LTC2309, a low
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noise, low power, 8-channel, 12-bit SAR ADC
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This driver can also be built as a module. If so, the module will
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be called ltc2309.
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config LTC2471
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tristate "Linear Technology LTC2471 and LTC2473 ADC driver"
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depends on I2C
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drivers/iio/adc/Makefile
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drivers/iio/adc/Makefile
···
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obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
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obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
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obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
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obj-$(CONFIG_LTC2309) += ltc2309.o
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obj-$(CONFIG_LTC2471) += ltc2471.o
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obj-$(CONFIG_LTC2485) += ltc2485.o
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obj-$(CONFIG_LTC2496) += ltc2496.o ltc2497-core.o
+246
drivers/iio/adc/ltc2309.c
+246
drivers/iio/adc/ltc2309.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* The LTC2309 is an 8-Channel, 12-Bit SAR ADC with an I2C Interface.
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*
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* Datasheet:
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* https://www.analog.com/media/en/technical-documentation/data-sheets/2309fd.pdf
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*
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* Copyright (c) 2023, Liam Beguin <liambeguin@gmail.com>
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*/
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#include <linux/bitfield.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/regulator/consumer.h>
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#define LTC2309_ADC_RESOLUTION 12
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#define LTC2309_DIN_CH_MASK GENMASK(7, 4)
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#define LTC2309_DIN_SDN BIT(7)
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#define LTC2309_DIN_OSN BIT(6)
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#define LTC2309_DIN_S1 BIT(5)
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#define LTC2309_DIN_S0 BIT(4)
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#define LTC2309_DIN_UNI BIT(3)
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#define LTC2309_DIN_SLEEP BIT(2)
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/**
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* struct ltc2309 - internal device data structure
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* @dev: Device reference
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* @client: I2C reference
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* @vref: External reference source
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* @lock: Lock to serialize data access
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* @vref_mv: Internal voltage reference
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*/
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struct ltc2309 {
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struct device *dev;
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struct i2c_client *client;
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struct regulator *vref;
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struct mutex lock; /* serialize data access */
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int vref_mv;
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};
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/* Order matches expected channel address, See datasheet Table 1. */
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enum ltc2309_channels {
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LTC2309_CH0_CH1 = 0,
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LTC2309_CH2_CH3,
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LTC2309_CH4_CH5,
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LTC2309_CH6_CH7,
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LTC2309_CH1_CH0,
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LTC2309_CH3_CH2,
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LTC2309_CH5_CH4,
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LTC2309_CH7_CH6,
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LTC2309_CH0,
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LTC2309_CH2,
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LTC2309_CH4,
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LTC2309_CH6,
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LTC2309_CH1,
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LTC2309_CH3,
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LTC2309_CH5,
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LTC2309_CH7,
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};
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#define LTC2309_CHAN(_chan, _addr) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.address = _addr, \
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.channel = _chan, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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#define LTC2309_DIFF_CHAN(_chan, _chan2, _addr) { \
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.type = IIO_VOLTAGE, \
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.differential = 1, \
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.indexed = 1, \
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.address = _addr, \
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.channel = _chan, \
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.channel2 = _chan2, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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}
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static const struct iio_chan_spec ltc2309_channels[] = {
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LTC2309_CHAN(0, LTC2309_CH0),
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LTC2309_CHAN(1, LTC2309_CH1),
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LTC2309_CHAN(2, LTC2309_CH2),
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LTC2309_CHAN(3, LTC2309_CH3),
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LTC2309_CHAN(4, LTC2309_CH4),
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LTC2309_CHAN(5, LTC2309_CH5),
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LTC2309_CHAN(6, LTC2309_CH6),
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LTC2309_CHAN(7, LTC2309_CH7),
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LTC2309_DIFF_CHAN(0, 1, LTC2309_CH0_CH1),
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LTC2309_DIFF_CHAN(2, 3, LTC2309_CH2_CH3),
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LTC2309_DIFF_CHAN(4, 5, LTC2309_CH4_CH5),
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LTC2309_DIFF_CHAN(6, 7, LTC2309_CH6_CH7),
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LTC2309_DIFF_CHAN(1, 0, LTC2309_CH1_CH0),
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LTC2309_DIFF_CHAN(3, 2, LTC2309_CH3_CH2),
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LTC2309_DIFF_CHAN(5, 4, LTC2309_CH5_CH4),
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LTC2309_DIFF_CHAN(7, 6, LTC2309_CH7_CH6),
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};
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static int ltc2309_read_raw_channel(struct ltc2309 *ltc2309,
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unsigned long address, int *val)
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{
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int ret;
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u16 buf;
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u8 din;
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din = FIELD_PREP(LTC2309_DIN_CH_MASK, address & 0x0f) |
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FIELD_PREP(LTC2309_DIN_UNI, 1) |
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FIELD_PREP(LTC2309_DIN_SLEEP, 0);
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ret = i2c_smbus_write_byte(ltc2309->client, din);
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if (ret < 0) {
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dev_err(ltc2309->dev, "i2c command failed: %pe\n",
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ERR_PTR(ret));
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return ret;
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}
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ret = i2c_master_recv(ltc2309->client, (char *)&buf, 2);
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if (ret < 0) {
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dev_err(ltc2309->dev, "i2c read failed: %pe\n", ERR_PTR(ret));
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return ret;
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}
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*val = be16_to_cpu(buf) >> 4;
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return ret;
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}
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static int ltc2309_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val,
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int *val2, long mask)
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{
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struct ltc2309 *ltc2309 = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(<c2309->lock);
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ret = ltc2309_read_raw_channel(ltc2309, chan->address, val);
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mutex_unlock(<c2309->lock);
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if (ret < 0)
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return -EINVAL;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = ltc2309->vref_mv;
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*val2 = LTC2309_ADC_RESOLUTION;
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return IIO_VAL_FRACTIONAL_LOG2;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info ltc2309_info = {
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.read_raw = ltc2309_read_raw,
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};
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static void ltc2309_regulator_disable(void *regulator)
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{
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regulator_disable(regulator);
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}
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static int ltc2309_probe(struct i2c_client *client)
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{
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struct iio_dev *indio_dev;
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struct ltc2309 *ltc2309;
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int ret;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*ltc2309));
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if (!indio_dev)
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return -ENOMEM;
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ltc2309 = iio_priv(indio_dev);
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ltc2309->dev = &indio_dev->dev;
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ltc2309->client = client;
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ltc2309->vref_mv = 4096; /* Default to the internal ref */
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indio_dev->name = "ltc2309";
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ltc2309_channels;
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indio_dev->num_channels = ARRAY_SIZE(ltc2309_channels);
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indio_dev->info = <c2309_info;
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ltc2309->vref = devm_regulator_get_optional(&client->dev, "vref");
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if (IS_ERR(ltc2309->vref)) {
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ret = PTR_ERR(ltc2309->vref);
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if (ret == -ENODEV)
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ltc2309->vref = NULL;
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else
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return ret;
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}
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if (ltc2309->vref) {
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ret = regulator_enable(ltc2309->vref);
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if (ret)
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return dev_err_probe(ltc2309->dev, ret,
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"failed to enable vref\n");
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ret = devm_add_action_or_reset(ltc2309->dev,
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ltc2309_regulator_disable,
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ltc2309->vref);
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if (ret) {
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return dev_err_probe(ltc2309->dev, ret,
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"failed to add regulator_disable action: %d\n",
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ret);
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}
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ret = regulator_get_voltage(ltc2309->vref);
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if (ret < 0)
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return ret;
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ltc2309->vref_mv = ret / 1000;
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}
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mutex_init(<c2309->lock);
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return devm_iio_device_register(&client->dev, indio_dev);
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}
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static const struct of_device_id ltc2309_of_match[] = {
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{ .compatible = "lltc,ltc2309" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, ltc2309_of_match);
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static const struct i2c_device_id ltc2309_id[] = {
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{ "ltc2309" },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc2309_id);
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static struct i2c_driver ltc2309_driver = {
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.driver = {
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.name = "ltc2309",
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.of_match_table = ltc2309_of_match,
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},
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.probe = ltc2309_probe,
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.id_table = ltc2309_id,
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};
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module_i2c_driver(ltc2309_driver);
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MODULE_AUTHOR("Liam Beguin <liambeguin@gmail.com>");
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MODULE_DESCRIPTION("Linear Technology LTC2309 ADC");
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MODULE_LICENSE("GPL v2");