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iio: adc: Add MAX1241 driver
Add driver for the Maxim MAX1241 12-bit, single-channel ADC. Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com> Signed-off-by: Alexandru Lazar <alazar@startmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Alexandru Lazar
Jonathan Cameron
parent
fc20a26a21
commit
8a80a71d90
3 changed files with 238 additions and 0 deletions
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@ -630,6 +630,16 @@ config MAX1118
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To compile this driver as a module, choose M here: the module will be
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called max1118.
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config MAX1241
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tristate "Maxim max1241 ADC driver"
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depends on SPI_MASTER
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help
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Say yes here to build support for Maxim max1241 12-bit, single-channel
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ADC.
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To compile this driver as a module, choose M here: the module will be
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called max1241.
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config MAX1363
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tristate "Maxim max1363 ADC driver"
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depends on I2C
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@ -59,6 +59,7 @@ obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.o
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obj-$(CONFIG_MAX1027) += max1027.o
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obj-$(CONFIG_MAX11100) += max11100.o
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obj-$(CONFIG_MAX1118) += max1118.o
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obj-$(CONFIG_MAX1241) += max1241.o
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obj-$(CONFIG_MAX1363) += max1363.o
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obj-$(CONFIG_MAX9611) += max9611.o
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obj-$(CONFIG_MCP320X) += mcp320x.o
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227
drivers/iio/adc/max1241.c
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227
drivers/iio/adc/max1241.c
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@ -0,0 +1,227 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* MAX1241 low-power, 12-bit serial ADC
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*
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* Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf
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*/
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/iio/iio.h>
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#include <linux/module.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#define MAX1241_VAL_MASK GENMASK(11, 0)
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#define MAX1241_SHUTDOWN_DELAY_USEC 4
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enum max1241_id {
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max1241,
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};
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struct max1241 {
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struct spi_device *spi;
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struct mutex lock;
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struct regulator *vdd;
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struct regulator *vref;
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struct gpio_desc *shutdown;
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__be16 data ____cacheline_aligned;
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};
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static const struct iio_chan_spec max1241_channels[] = {
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{
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.type = IIO_VOLTAGE,
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.indexed = 1,
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.channel = 0,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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},
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};
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static int max1241_read(struct max1241 *adc)
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{
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struct spi_transfer xfers[] = {
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/*
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* Begin conversion by bringing /CS low for at least
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* tconv us.
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*/
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{
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.len = 0,
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.delay.value = 8,
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.delay.unit = SPI_DELAY_UNIT_USECS,
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},
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/*
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* Then read two bytes of data in our RX buffer.
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*/
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{
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.rx_buf = &adc->data,
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.len = 2,
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},
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};
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return spi_sync_transfer(adc->spi, xfers, ARRAY_SIZE(xfers));
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}
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static int max1241_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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int ret, vref_uV;
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struct max1241 *adc = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(&adc->lock);
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if (adc->shutdown) {
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gpiod_set_value(adc->shutdown, 0);
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udelay(MAX1241_SHUTDOWN_DELAY_USEC);
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ret = max1241_read(adc);
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gpiod_set_value(adc->shutdown, 1);
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} else
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ret = max1241_read(adc);
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if (ret) {
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mutex_unlock(&adc->lock);
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return ret;
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}
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*val = (be16_to_cpu(adc->data) >> 3) & MAX1241_VAL_MASK;
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mutex_unlock(&adc->lock);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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vref_uV = regulator_get_voltage(adc->vref);
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if (vref_uV < 0)
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return vref_uV;
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*val = vref_uV / 1000;
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*val2 = 12;
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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 max1241_info = {
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.read_raw = max1241_read_raw,
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};
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static void max1241_disable_vdd_action(void *data)
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{
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struct max1241 *adc = data;
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struct device *dev = &adc->spi->dev;
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int err;
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err = regulator_disable(adc->vdd);
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if (err)
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dev_err(dev, "could not disable vdd regulator.\n");
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}
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static void max1241_disable_vref_action(void *data)
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{
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struct max1241 *adc = data;
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struct device *dev = &adc->spi->dev;
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int err;
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err = regulator_disable(adc->vref);
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if (err)
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dev_err(dev, "could not disable vref regulator.\n");
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}
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static int max1241_probe(struct spi_device *spi)
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{
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struct device *dev = &spi->dev;
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struct iio_dev *indio_dev;
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struct max1241 *adc;
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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
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if (!indio_dev)
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return -ENOMEM;
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adc = iio_priv(indio_dev);
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adc->spi = spi;
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mutex_init(&adc->lock);
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spi_set_drvdata(spi, indio_dev);
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adc->vdd = devm_regulator_get(dev, "vdd");
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if (IS_ERR(adc->vdd)) {
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dev_err(dev, "failed to get vdd regulator\n");
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return PTR_ERR(adc->vdd);
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}
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ret = regulator_enable(adc->vdd);
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if (ret)
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return ret;
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ret = devm_add_action_or_reset(dev, max1241_disable_vdd_action, adc);
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if (ret) {
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dev_err(dev, "could not set up vdd regulator cleanup action\n");
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return ret;
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}
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adc->vref = devm_regulator_get(dev, "vref");
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if (IS_ERR(adc->vref)) {
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dev_err(dev, "failed to get vref regulator\n");
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return PTR_ERR(adc->vref);
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}
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ret = regulator_enable(adc->vref);
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if (ret)
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return ret;
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ret = devm_add_action_or_reset(dev, max1241_disable_vref_action, adc);
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if (ret) {
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dev_err(dev, "could not set up vref regulator cleanup action\n");
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return ret;
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}
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adc->shutdown = devm_gpiod_get_optional(dev, "shutdown",
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GPIOD_OUT_HIGH);
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if (IS_ERR(adc->shutdown))
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return PTR_ERR(adc->shutdown);
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if (adc->shutdown)
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dev_dbg(dev, "shutdown pin passed, low-power mode enabled");
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else
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dev_dbg(dev, "no shutdown pin passed, low-power mode disabled");
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->dev.parent = dev;
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indio_dev->info = &max1241_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = max1241_channels;
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indio_dev->num_channels = ARRAY_SIZE(max1241_channels);
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return devm_iio_device_register(dev, indio_dev);
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}
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static const struct spi_device_id max1241_id[] = {
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{ "max1241", max1241 },
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{}
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};
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static const struct of_device_id max1241_dt_ids[] = {
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{ .compatible = "maxim,max1241" },
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{}
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};
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MODULE_DEVICE_TABLE(of, max1241_dt_ids);
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static struct spi_driver max1241_spi_driver = {
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.driver = {
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.name = "max1241",
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.of_match_table = max1241_dt_ids,
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},
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.probe = max1241_probe,
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.id_table = max1241_id,
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};
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module_spi_driver(max1241_spi_driver);
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MODULE_AUTHOR("Alexandru Lazar <alazar@startmail.com>");
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MODULE_DESCRIPTION("MAX1241 ADC driver");
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MODULE_LICENSE("GPL v2");
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