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338 lines
8.0 KiB
338 lines
8.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver |
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* |
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* Copyright (c) 2016 Akinobu Mita <[email protected]> |
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* |
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* Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf |
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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/regulator/consumer.h> |
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#include <linux/iio/buffer.h> |
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#include <linux/iio/trigger.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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enum { |
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adc0831, |
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adc0832, |
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adc0834, |
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adc0838, |
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}; |
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struct adc0832 { |
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struct spi_device *spi; |
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struct regulator *reg; |
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struct mutex lock; |
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u8 mux_bits; |
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/* |
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* Max size needed: 16x 1 byte ADC data + 8 bytes timestamp |
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* May be shorter if not all channels are enabled subject |
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* to the timestamp remaining 8 byte aligned. |
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*/ |
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u8 data[24] __aligned(8); |
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u8 tx_buf[2] ____cacheline_aligned; |
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u8 rx_buf[2]; |
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}; |
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#define ADC0832_VOLTAGE_CHANNEL(chan) \ |
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{ \ |
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.type = IIO_VOLTAGE, \ |
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.indexed = 1, \ |
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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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.scan_index = chan, \ |
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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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#define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \ |
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{ \ |
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.type = IIO_VOLTAGE, \ |
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.indexed = 1, \ |
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.channel = (chan1), \ |
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.channel2 = (chan2), \ |
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.differential = 1, \ |
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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 = si, \ |
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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 adc0831_channels[] = { |
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ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0), |
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IIO_CHAN_SOFT_TIMESTAMP(1), |
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}; |
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static const struct iio_chan_spec adc0832_channels[] = { |
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ADC0832_VOLTAGE_CHANNEL(0), |
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ADC0832_VOLTAGE_CHANNEL(1), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3), |
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IIO_CHAN_SOFT_TIMESTAMP(4), |
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}; |
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static const struct iio_chan_spec adc0834_channels[] = { |
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ADC0832_VOLTAGE_CHANNEL(0), |
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ADC0832_VOLTAGE_CHANNEL(1), |
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ADC0832_VOLTAGE_CHANNEL(2), |
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ADC0832_VOLTAGE_CHANNEL(3), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7), |
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IIO_CHAN_SOFT_TIMESTAMP(8), |
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}; |
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static const struct iio_chan_spec adc0838_channels[] = { |
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ADC0832_VOLTAGE_CHANNEL(0), |
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ADC0832_VOLTAGE_CHANNEL(1), |
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ADC0832_VOLTAGE_CHANNEL(2), |
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ADC0832_VOLTAGE_CHANNEL(3), |
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ADC0832_VOLTAGE_CHANNEL(4), |
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ADC0832_VOLTAGE_CHANNEL(5), |
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ADC0832_VOLTAGE_CHANNEL(6), |
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ADC0832_VOLTAGE_CHANNEL(7), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14), |
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ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15), |
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IIO_CHAN_SOFT_TIMESTAMP(16), |
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}; |
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static int adc0831_adc_conversion(struct adc0832 *adc) |
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{ |
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struct spi_device *spi = adc->spi; |
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int ret; |
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ret = spi_read(spi, &adc->rx_buf, 2); |
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if (ret) |
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return ret; |
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/* |
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* Skip TRI-STATE and a leading zero |
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*/ |
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return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6); |
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} |
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static int adc0832_adc_conversion(struct adc0832 *adc, int channel, |
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bool differential) |
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{ |
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struct spi_device *spi = adc->spi; |
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struct spi_transfer xfer = { |
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.tx_buf = adc->tx_buf, |
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.rx_buf = adc->rx_buf, |
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.len = 2, |
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}; |
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int ret; |
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if (!adc->mux_bits) |
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return adc0831_adc_conversion(adc); |
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/* start bit */ |
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adc->tx_buf[0] = 1 << (adc->mux_bits + 1); |
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/* single-ended or differential */ |
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adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits); |
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/* odd / sign */ |
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adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1); |
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/* select */ |
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if (adc->mux_bits > 1) |
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adc->tx_buf[0] |= channel / 2; |
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/* align Data output BIT7 (MSB) to 8-bit boundary */ |
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adc->tx_buf[0] <<= 1; |
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ret = spi_sync_transfer(spi, &xfer, 1); |
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if (ret) |
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return ret; |
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return adc->rx_buf[1]; |
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} |
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static int adc0832_read_raw(struct iio_dev *iio, |
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struct iio_chan_spec const *channel, int *value, |
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int *shift, long mask) |
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{ |
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struct adc0832 *adc = iio_priv(iio); |
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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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*value = adc0832_adc_conversion(adc, channel->channel, |
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channel->differential); |
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mutex_unlock(&adc->lock); |
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if (*value < 0) |
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return *value; |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_SCALE: |
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*value = regulator_get_voltage(adc->reg); |
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if (*value < 0) |
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return *value; |
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/* convert regulator output voltage to mV */ |
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*value /= 1000; |
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*shift = 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 adc0832_info = { |
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.read_raw = adc0832_read_raw, |
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}; |
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static irqreturn_t adc0832_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 adc0832 *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 = adc0832_adc_conversion(adc, scan_chan->channel, |
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scan_chan->differential); |
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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->data[i] = ret; |
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i++; |
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} |
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iio_push_to_buffers_with_timestamp(indio_dev, adc->data, |
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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 void adc0832_reg_disable(void *reg) |
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{ |
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regulator_disable(reg); |
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} |
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static int adc0832_probe(struct spi_device *spi) |
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{ |
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struct iio_dev *indio_dev; |
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struct adc0832 *adc; |
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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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indio_dev->name = spi_get_device_id(spi)->name; |
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indio_dev->info = &adc0832_info; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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switch (spi_get_device_id(spi)->driver_data) { |
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case adc0831: |
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adc->mux_bits = 0; |
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indio_dev->channels = adc0831_channels; |
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indio_dev->num_channels = ARRAY_SIZE(adc0831_channels); |
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break; |
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case adc0832: |
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adc->mux_bits = 1; |
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indio_dev->channels = adc0832_channels; |
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indio_dev->num_channels = ARRAY_SIZE(adc0832_channels); |
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break; |
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case adc0834: |
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adc->mux_bits = 2; |
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indio_dev->channels = adc0834_channels; |
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indio_dev->num_channels = ARRAY_SIZE(adc0834_channels); |
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break; |
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case adc0838: |
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adc->mux_bits = 3; |
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indio_dev->channels = adc0838_channels; |
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indio_dev->num_channels = ARRAY_SIZE(adc0838_channels); |
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break; |
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default: |
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return -EINVAL; |
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} |
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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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return PTR_ERR(adc->reg); |
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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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ret = devm_add_action_or_reset(&spi->dev, adc0832_reg_disable, |
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adc->reg); |
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if (ret) |
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return ret; |
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ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, |
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adc0832_trigger_handler, NULL); |
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if (ret) |
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return ret; |
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return devm_iio_device_register(&spi->dev, indio_dev); |
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} |
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static const struct of_device_id adc0832_dt_ids[] = { |
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{ .compatible = "ti,adc0831", }, |
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{ .compatible = "ti,adc0832", }, |
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{ .compatible = "ti,adc0834", }, |
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{ .compatible = "ti,adc0838", }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, adc0832_dt_ids); |
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static const struct spi_device_id adc0832_id[] = { |
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{ "adc0831", adc0831 }, |
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{ "adc0832", adc0832 }, |
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{ "adc0834", adc0834 }, |
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{ "adc0838", adc0838 }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(spi, adc0832_id); |
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static struct spi_driver adc0832_driver = { |
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.driver = { |
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.name = "adc0832", |
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.of_match_table = adc0832_dt_ids, |
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}, |
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.probe = adc0832_probe, |
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.id_table = adc0832_id, |
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}; |
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module_spi_driver(adc0832_driver); |
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MODULE_AUTHOR("Akinobu Mita <[email protected]>"); |
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MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver"); |
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MODULE_LICENSE("GPL v2");
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