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309 lines
6.9 KiB
309 lines
6.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver |
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* |
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* Copyright (c) 2017 Akinobu Mita <[email protected]> |
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* |
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* Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf |
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* |
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* SPI interface connections |
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* |
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* SPI MAXIM |
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* Master Direction MAX1117/8/9 |
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* ------ --------- ----------- |
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* nCS --> CNVST |
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* SCK --> SCLK |
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* MISO <-- DOUT |
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* ------ --------- ----------- |
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*/ |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/spi/spi.h> |
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#include <linux/iio/iio.h> |
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#include <linux/iio/buffer.h> |
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#include <linux/iio/triggered_buffer.h> |
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#include <linux/iio/trigger_consumer.h> |
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#include <linux/regulator/consumer.h> |
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enum max1118_id { |
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max1117, |
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max1118, |
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max1119, |
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}; |
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struct max1118 { |
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struct spi_device *spi; |
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struct mutex lock; |
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struct regulator *reg; |
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/* Ensure natural alignment of buffer elements */ |
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struct { |
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u8 channels[2]; |
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s64 ts __aligned(8); |
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} scan; |
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u8 data ____cacheline_aligned; |
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}; |
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#define MAX1118_CHANNEL(ch) \ |
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{ \ |
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.type = IIO_VOLTAGE, \ |
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.indexed = 1, \ |
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.channel = (ch), \ |
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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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.scan_index = ch, \ |
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.scan_type = { \ |
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.sign = 'u', \ |
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.realbits = 8, \ |
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.storagebits = 8, \ |
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}, \ |
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} |
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static const struct iio_chan_spec max1118_channels[] = { |
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MAX1118_CHANNEL(0), |
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MAX1118_CHANNEL(1), |
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IIO_CHAN_SOFT_TIMESTAMP(2), |
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}; |
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static int max1118_read(struct spi_device *spi, int channel) |
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{ |
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struct iio_dev *indio_dev = spi_get_drvdata(spi); |
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struct max1118 *adc = iio_priv(indio_dev); |
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struct spi_transfer xfers[] = { |
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/* |
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* To select CH1 for conversion, CNVST pin must be brought high |
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* and low for a second time. |
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*/ |
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{ |
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.len = 0, |
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.delay = { /* > CNVST Low Time 100 ns */ |
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.value = 1, |
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.unit = SPI_DELAY_UNIT_USECS |
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}, |
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.cs_change = 1, |
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}, |
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/* |
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* The acquisition interval begins with the falling edge of |
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* CNVST. The total acquisition and conversion process takes |
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* <7.5us. |
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*/ |
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{ |
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.len = 0, |
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.delay = { |
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.value = 8, |
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.unit = SPI_DELAY_UNIT_USECS |
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}, |
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}, |
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{ |
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.rx_buf = &adc->data, |
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.len = 1, |
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}, |
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}; |
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int ret; |
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if (channel == 0) |
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ret = spi_sync_transfer(spi, xfers + 1, 2); |
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else |
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ret = spi_sync_transfer(spi, xfers, 3); |
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if (ret) |
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return ret; |
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return adc->data; |
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} |
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static int max1118_get_vref_mV(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev = spi_get_drvdata(spi); |
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struct max1118 *adc = iio_priv(indio_dev); |
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const struct spi_device_id *id = spi_get_device_id(spi); |
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int vref_uV; |
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switch (id->driver_data) { |
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case max1117: |
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return 2048; |
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case max1119: |
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return 4096; |
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case max1118: |
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vref_uV = regulator_get_voltage(adc->reg); |
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if (vref_uV < 0) |
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return vref_uV; |
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return vref_uV / 1000; |
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} |
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return -ENODEV; |
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} |
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static int max1118_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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struct max1118 *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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*val = max1118_read(adc->spi, chan->channel); |
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mutex_unlock(&adc->lock); |
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if (*val < 0) |
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return *val; |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_SCALE: |
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*val = max1118_get_vref_mV(adc->spi); |
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if (*val < 0) |
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return *val; |
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*val2 = 8; |
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return IIO_VAL_FRACTIONAL_LOG2; |
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} |
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return -EINVAL; |
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} |
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static const struct iio_info max1118_info = { |
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.read_raw = max1118_read_raw, |
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}; |
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static irqreturn_t max1118_trigger_handler(int irq, void *p) |
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{ |
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struct iio_poll_func *pf = p; |
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struct iio_dev *indio_dev = pf->indio_dev; |
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struct max1118 *adc = iio_priv(indio_dev); |
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int scan_index; |
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int i = 0; |
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mutex_lock(&adc->lock); |
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for_each_set_bit(scan_index, indio_dev->active_scan_mask, |
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indio_dev->masklength) { |
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const struct iio_chan_spec *scan_chan = |
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&indio_dev->channels[scan_index]; |
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int ret = max1118_read(adc->spi, scan_chan->channel); |
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if (ret < 0) { |
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dev_warn(&adc->spi->dev, |
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"failed to get conversion data\n"); |
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goto out; |
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} |
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adc->scan.channels[i] = ret; |
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i++; |
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} |
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iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan, |
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iio_get_time_ns(indio_dev)); |
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out: |
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mutex_unlock(&adc->lock); |
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iio_trigger_notify_done(indio_dev->trig); |
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return IRQ_HANDLED; |
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} |
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static int max1118_probe(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev; |
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struct max1118 *adc; |
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const struct spi_device_id *id = spi_get_device_id(spi); |
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int ret; |
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indio_dev = devm_iio_device_alloc(&spi->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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if (id->driver_data == max1118) { |
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adc->reg = devm_regulator_get(&spi->dev, "vref"); |
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if (IS_ERR(adc->reg)) { |
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dev_err(&spi->dev, "failed to get vref regulator\n"); |
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return PTR_ERR(adc->reg); |
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} |
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ret = regulator_enable(adc->reg); |
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if (ret) |
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return ret; |
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} |
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spi_set_drvdata(spi, indio_dev); |
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indio_dev->name = spi_get_device_id(spi)->name; |
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indio_dev->info = &max1118_info; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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indio_dev->channels = max1118_channels; |
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indio_dev->num_channels = ARRAY_SIZE(max1118_channels); |
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/* |
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* To reinitiate a conversion on CH0, it is necessary to allow for a |
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* conversion to be complete and all of the data to be read out. Once |
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* a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go |
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* into AutoShutdown mode until the next conversion is initiated. |
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*/ |
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max1118_read(spi, 0); |
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ret = iio_triggered_buffer_setup(indio_dev, NULL, |
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max1118_trigger_handler, NULL); |
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if (ret) |
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goto err_reg_disable; |
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ret = iio_device_register(indio_dev); |
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if (ret) |
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goto err_buffer_cleanup; |
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return 0; |
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err_buffer_cleanup: |
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iio_triggered_buffer_cleanup(indio_dev); |
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err_reg_disable: |
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if (id->driver_data == max1118) |
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regulator_disable(adc->reg); |
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return ret; |
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} |
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static int max1118_remove(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev = spi_get_drvdata(spi); |
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struct max1118 *adc = iio_priv(indio_dev); |
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const struct spi_device_id *id = spi_get_device_id(spi); |
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iio_device_unregister(indio_dev); |
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iio_triggered_buffer_cleanup(indio_dev); |
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if (id->driver_data == max1118) |
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return regulator_disable(adc->reg); |
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return 0; |
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} |
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static const struct spi_device_id max1118_id[] = { |
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{ "max1117", max1117 }, |
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{ "max1118", max1118 }, |
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{ "max1119", max1119 }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(spi, max1118_id); |
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static const struct of_device_id max1118_dt_ids[] = { |
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{ .compatible = "maxim,max1117" }, |
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{ .compatible = "maxim,max1118" }, |
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{ .compatible = "maxim,max1119" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, max1118_dt_ids); |
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static struct spi_driver max1118_spi_driver = { |
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.driver = { |
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.name = "max1118", |
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.of_match_table = max1118_dt_ids, |
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}, |
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.probe = max1118_probe, |
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.remove = max1118_remove, |
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.id_table = max1118_id, |
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}; |
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module_spi_driver(max1118_spi_driver); |
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MODULE_AUTHOR("Akinobu Mita <[email protected]>"); |
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MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver"); |
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MODULE_LICENSE("GPL v2");
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