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356 lines
8.6 KiB
356 lines
8.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* AD7887 SPI ADC driver |
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* |
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* Copyright 2010-2011 Analog Devices Inc. |
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*/ |
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#include <linux/device.h> |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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#include <linux/spi/spi.h> |
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#include <linux/regulator/consumer.h> |
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#include <linux/err.h> |
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#include <linux/module.h> |
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#include <linux/interrupt.h> |
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#include <linux/bitops.h> |
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#include <linux/iio/iio.h> |
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#include <linux/iio/sysfs.h> |
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#include <linux/iio/buffer.h> |
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#include <linux/iio/trigger_consumer.h> |
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#include <linux/iio/triggered_buffer.h> |
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#include <linux/platform_data/ad7887.h> |
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#define AD7887_REF_DIS BIT(5) /* on-chip reference disable */ |
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#define AD7887_DUAL BIT(4) /* dual-channel mode */ |
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#define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */ |
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#define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */ |
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#define AD7887_PM_MODE1 0 /* CS based shutdown */ |
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#define AD7887_PM_MODE2 1 /* full on */ |
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#define AD7887_PM_MODE3 2 /* auto shutdown after conversion */ |
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#define AD7887_PM_MODE4 3 /* standby mode */ |
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enum ad7887_channels { |
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AD7887_CH0, |
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AD7887_CH0_CH1, |
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AD7887_CH1, |
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}; |
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/** |
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* struct ad7887_chip_info - chip specifc information |
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* @int_vref_mv: the internal reference voltage |
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* @channels: channels specification |
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* @num_channels: number of channels |
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* @dual_channels: channels specification in dual mode |
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* @num_dual_channels: number of channels in dual mode |
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*/ |
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struct ad7887_chip_info { |
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u16 int_vref_mv; |
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const struct iio_chan_spec *channels; |
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unsigned int num_channels; |
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const struct iio_chan_spec *dual_channels; |
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unsigned int num_dual_channels; |
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}; |
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struct ad7887_state { |
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struct spi_device *spi; |
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const struct ad7887_chip_info *chip_info; |
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struct regulator *reg; |
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struct spi_transfer xfer[4]; |
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struct spi_message msg[3]; |
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struct spi_message *ring_msg; |
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unsigned char tx_cmd_buf[4]; |
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/* |
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* DMA (thus cache coherency maintenance) requires the |
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* transfer buffers to live in their own cache lines. |
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* Buffer needs to be large enough to hold two 16 bit samples and a |
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* 64 bit aligned 64 bit timestamp. |
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*/ |
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unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)] |
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____cacheline_aligned; |
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}; |
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enum ad7887_supported_device_ids { |
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ID_AD7887 |
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}; |
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static int ad7887_ring_preenable(struct iio_dev *indio_dev) |
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{ |
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struct ad7887_state *st = iio_priv(indio_dev); |
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/* We know this is a single long so can 'cheat' */ |
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switch (*indio_dev->active_scan_mask) { |
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case (1 << 0): |
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st->ring_msg = &st->msg[AD7887_CH0]; |
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break; |
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case (1 << 1): |
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st->ring_msg = &st->msg[AD7887_CH1]; |
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/* Dummy read: push CH1 setting down to hardware */ |
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spi_sync(st->spi, st->ring_msg); |
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break; |
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case ((1 << 1) | (1 << 0)): |
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st->ring_msg = &st->msg[AD7887_CH0_CH1]; |
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break; |
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} |
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return 0; |
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} |
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static int ad7887_ring_postdisable(struct iio_dev *indio_dev) |
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{ |
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struct ad7887_state *st = iio_priv(indio_dev); |
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/* dummy read: restore default CH0 settin */ |
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return spi_sync(st->spi, &st->msg[AD7887_CH0]); |
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} |
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/* |
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* ad7887_trigger_handler() bh of trigger launched polling to ring buffer |
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* |
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* Currently there is no option in this driver to disable the saving of |
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* timestamps within the ring. |
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**/ |
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static irqreturn_t ad7887_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 ad7887_state *st = iio_priv(indio_dev); |
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int b_sent; |
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b_sent = spi_sync(st->spi, st->ring_msg); |
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if (b_sent) |
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goto done; |
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iio_push_to_buffers_with_timestamp(indio_dev, st->data, |
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iio_get_time_ns(indio_dev)); |
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done: |
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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 const struct iio_buffer_setup_ops ad7887_ring_setup_ops = { |
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.preenable = &ad7887_ring_preenable, |
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.postdisable = &ad7887_ring_postdisable, |
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}; |
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static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch) |
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{ |
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int ret = spi_sync(st->spi, &st->msg[ch]); |
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if (ret) |
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return ret; |
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return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1]; |
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} |
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static int ad7887_read_raw(struct iio_dev *indio_dev, |
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struct iio_chan_spec const *chan, |
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int *val, |
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int *val2, |
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long m) |
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{ |
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int ret; |
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struct ad7887_state *st = iio_priv(indio_dev); |
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switch (m) { |
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case IIO_CHAN_INFO_RAW: |
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ret = iio_device_claim_direct_mode(indio_dev); |
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if (ret) |
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return ret; |
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ret = ad7887_scan_direct(st, chan->address); |
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iio_device_release_direct_mode(indio_dev); |
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if (ret < 0) |
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return ret; |
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*val = ret >> chan->scan_type.shift; |
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*val &= GENMASK(chan->scan_type.realbits - 1, 0); |
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return IIO_VAL_INT; |
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case IIO_CHAN_INFO_SCALE: |
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if (st->reg) { |
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*val = regulator_get_voltage(st->reg); |
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if (*val < 0) |
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return *val; |
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*val /= 1000; |
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} else { |
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*val = st->chip_info->int_vref_mv; |
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} |
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*val2 = chan->scan_type.realbits; |
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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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#define AD7887_CHANNEL(x) { \ |
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.type = IIO_VOLTAGE, \ |
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.indexed = 1, \ |
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.channel = (x), \ |
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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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.address = (x), \ |
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.scan_index = (x), \ |
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.scan_type = { \ |
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.sign = 'u', \ |
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.realbits = 12, \ |
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.storagebits = 16, \ |
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.shift = 0, \ |
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.endianness = IIO_BE, \ |
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}, \ |
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} |
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static const struct iio_chan_spec ad7887_channels[] = { |
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AD7887_CHANNEL(0), |
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IIO_CHAN_SOFT_TIMESTAMP(1), |
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}; |
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static const struct iio_chan_spec ad7887_dual_channels[] = { |
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AD7887_CHANNEL(0), |
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AD7887_CHANNEL(1), |
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IIO_CHAN_SOFT_TIMESTAMP(2), |
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}; |
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static const struct ad7887_chip_info ad7887_chip_info_tbl[] = { |
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/* |
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* More devices added in future |
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*/ |
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[ID_AD7887] = { |
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.channels = ad7887_channels, |
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.num_channels = ARRAY_SIZE(ad7887_channels), |
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.dual_channels = ad7887_dual_channels, |
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.num_dual_channels = ARRAY_SIZE(ad7887_dual_channels), |
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.int_vref_mv = 2500, |
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}, |
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}; |
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static const struct iio_info ad7887_info = { |
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.read_raw = &ad7887_read_raw, |
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}; |
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static void ad7887_reg_disable(void *data) |
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{ |
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struct regulator *reg = data; |
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regulator_disable(reg); |
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} |
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static int ad7887_probe(struct spi_device *spi) |
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{ |
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struct ad7887_platform_data *pdata = spi->dev.platform_data; |
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struct ad7887_state *st; |
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struct iio_dev *indio_dev; |
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uint8_t mode; |
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int ret; |
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); |
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if (indio_dev == NULL) |
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return -ENOMEM; |
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st = iio_priv(indio_dev); |
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st->reg = devm_regulator_get_optional(&spi->dev, "vref"); |
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if (IS_ERR(st->reg)) { |
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if (PTR_ERR(st->reg) != -ENODEV) |
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return PTR_ERR(st->reg); |
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st->reg = NULL; |
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} |
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if (st->reg) { |
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ret = regulator_enable(st->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, ad7887_reg_disable, st->reg); |
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if (ret) |
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return ret; |
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} |
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st->chip_info = |
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&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data]; |
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spi_set_drvdata(spi, indio_dev); |
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st->spi = spi; |
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indio_dev->name = spi_get_device_id(spi)->name; |
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indio_dev->info = &ad7887_info; |
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indio_dev->modes = INDIO_DIRECT_MODE; |
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/* Setup default message */ |
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mode = AD7887_PM_MODE4; |
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if (!st->reg) |
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mode |= AD7887_REF_DIS; |
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if (pdata && pdata->en_dual) |
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mode |= AD7887_DUAL; |
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st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode; |
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st->xfer[0].rx_buf = &st->data[0]; |
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st->xfer[0].tx_buf = &st->tx_cmd_buf[0]; |
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st->xfer[0].len = 2; |
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spi_message_init(&st->msg[AD7887_CH0]); |
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spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]); |
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if (pdata && pdata->en_dual) { |
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st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode; |
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st->xfer[1].rx_buf = &st->data[0]; |
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st->xfer[1].tx_buf = &st->tx_cmd_buf[2]; |
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st->xfer[1].len = 2; |
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st->xfer[2].rx_buf = &st->data[2]; |
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st->xfer[2].tx_buf = &st->tx_cmd_buf[0]; |
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st->xfer[2].len = 2; |
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spi_message_init(&st->msg[AD7887_CH0_CH1]); |
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spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]); |
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spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]); |
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st->xfer[3].rx_buf = &st->data[2]; |
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st->xfer[3].tx_buf = &st->tx_cmd_buf[2]; |
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st->xfer[3].len = 2; |
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spi_message_init(&st->msg[AD7887_CH1]); |
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spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]); |
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indio_dev->channels = st->chip_info->dual_channels; |
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indio_dev->num_channels = st->chip_info->num_dual_channels; |
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} else { |
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indio_dev->channels = st->chip_info->channels; |
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indio_dev->num_channels = st->chip_info->num_channels; |
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} |
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ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, |
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&iio_pollfunc_store_time, |
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&ad7887_trigger_handler, &ad7887_ring_setup_ops); |
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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 spi_device_id ad7887_id[] = { |
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{"ad7887", ID_AD7887}, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(spi, ad7887_id); |
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static struct spi_driver ad7887_driver = { |
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.driver = { |
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.name = "ad7887", |
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}, |
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.probe = ad7887_probe, |
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.id_table = ad7887_id, |
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}; |
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module_spi_driver(ad7887_driver); |
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MODULE_AUTHOR("Michael Hennerich <[email protected]>"); |
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MODULE_DESCRIPTION("Analog Devices AD7887 ADC"); |
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MODULE_LICENSE("GPL v2");
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