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372 lines
8.7 KiB
372 lines
8.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* AD7298 SPI ADC driver |
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* |
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* Copyright 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/delay.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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#define AD7298_WRITE BIT(15) /* write to the control register */ |
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#define AD7298_REPEAT BIT(14) /* repeated conversion enable */ |
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#define AD7298_CH(x) BIT(13 - (x)) /* channel select */ |
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#define AD7298_TSENSE BIT(5) /* temperature conversion enable */ |
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#define AD7298_EXTREF BIT(2) /* external reference enable */ |
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#define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */ |
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#define AD7298_PDD BIT(0) /* partial power down enable */ |
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#define AD7298_MAX_CHAN 8 |
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#define AD7298_INTREF_mV 2500 |
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#define AD7298_CH_TEMP 9 |
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struct ad7298_state { |
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struct spi_device *spi; |
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struct regulator *reg; |
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unsigned ext_ref; |
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struct spi_transfer ring_xfer[10]; |
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struct spi_transfer scan_single_xfer[3]; |
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struct spi_message ring_msg; |
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struct spi_message scan_single_msg; |
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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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*/ |
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__be16 rx_buf[12] ____cacheline_aligned; |
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__be16 tx_buf[2]; |
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}; |
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#define AD7298_V_CHAN(index) \ |
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{ \ |
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.type = IIO_VOLTAGE, \ |
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.indexed = 1, \ |
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.channel = index, \ |
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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 = index, \ |
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.scan_index = index, \ |
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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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.endianness = IIO_BE, \ |
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}, \ |
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} |
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static const struct iio_chan_spec ad7298_channels[] = { |
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{ |
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.type = IIO_TEMP, |
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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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BIT(IIO_CHAN_INFO_OFFSET), |
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.address = AD7298_CH_TEMP, |
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.scan_index = -1, |
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.scan_type = { |
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.sign = 's', |
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.realbits = 32, |
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.storagebits = 32, |
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}, |
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}, |
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AD7298_V_CHAN(0), |
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AD7298_V_CHAN(1), |
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AD7298_V_CHAN(2), |
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AD7298_V_CHAN(3), |
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AD7298_V_CHAN(4), |
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AD7298_V_CHAN(5), |
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AD7298_V_CHAN(6), |
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AD7298_V_CHAN(7), |
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IIO_CHAN_SOFT_TIMESTAMP(8), |
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}; |
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/* |
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* ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask |
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*/ |
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static int ad7298_update_scan_mode(struct iio_dev *indio_dev, |
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const unsigned long *active_scan_mask) |
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{ |
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struct ad7298_state *st = iio_priv(indio_dev); |
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int i, m; |
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unsigned short command; |
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int scan_count; |
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/* Now compute overall size */ |
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scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength); |
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command = AD7298_WRITE | st->ext_ref; |
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for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1) |
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if (test_bit(i, active_scan_mask)) |
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command |= m; |
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st->tx_buf[0] = cpu_to_be16(command); |
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/* build spi ring message */ |
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st->ring_xfer[0].tx_buf = &st->tx_buf[0]; |
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st->ring_xfer[0].len = 2; |
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st->ring_xfer[0].cs_change = 1; |
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st->ring_xfer[1].tx_buf = &st->tx_buf[1]; |
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st->ring_xfer[1].len = 2; |
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st->ring_xfer[1].cs_change = 1; |
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spi_message_init(&st->ring_msg); |
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spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg); |
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spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg); |
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for (i = 0; i < scan_count; i++) { |
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st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i]; |
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st->ring_xfer[i + 2].len = 2; |
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st->ring_xfer[i + 2].cs_change = 1; |
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spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg); |
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} |
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/* make sure last transfer cs_change is not set */ |
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st->ring_xfer[i + 1].cs_change = 0; |
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return 0; |
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} |
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/* |
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* ad7298_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 ad7298_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 ad7298_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->rx_buf, |
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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 int ad7298_scan_direct(struct ad7298_state *st, unsigned ch) |
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{ |
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int ret; |
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st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref | |
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(AD7298_CH(0) >> ch)); |
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ret = spi_sync(st->spi, &st->scan_single_msg); |
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if (ret) |
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return ret; |
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return be16_to_cpu(st->rx_buf[0]); |
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} |
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static int ad7298_scan_temp(struct ad7298_state *st, int *val) |
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{ |
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int ret; |
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__be16 buf; |
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buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE | |
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AD7298_TAVG | st->ext_ref); |
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ret = spi_write(st->spi, (u8 *)&buf, 2); |
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if (ret) |
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return ret; |
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buf = cpu_to_be16(0); |
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ret = spi_write(st->spi, (u8 *)&buf, 2); |
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if (ret) |
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return ret; |
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usleep_range(101, 1000); /* sleep > 100us */ |
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ret = spi_read(st->spi, (u8 *)&buf, 2); |
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if (ret) |
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return ret; |
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*val = sign_extend32(be16_to_cpu(buf), 11); |
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return 0; |
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} |
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static int ad7298_get_ref_voltage(struct ad7298_state *st) |
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{ |
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int vref; |
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if (st->reg) { |
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vref = regulator_get_voltage(st->reg); |
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if (vref < 0) |
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return vref; |
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return vref / 1000; |
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} else { |
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return AD7298_INTREF_mV; |
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} |
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} |
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static int ad7298_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 ad7298_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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if (chan->address == AD7298_CH_TEMP) |
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ret = ad7298_scan_temp(st, val); |
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else |
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ret = ad7298_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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if (chan->address != AD7298_CH_TEMP) |
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*val = ret & 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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switch (chan->type) { |
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case IIO_VOLTAGE: |
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*val = ad7298_get_ref_voltage(st); |
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*val2 = chan->scan_type.realbits; |
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return IIO_VAL_FRACTIONAL_LOG2; |
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case IIO_TEMP: |
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*val = ad7298_get_ref_voltage(st); |
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*val2 = 10; |
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return IIO_VAL_FRACTIONAL; |
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default: |
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return -EINVAL; |
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} |
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case IIO_CHAN_INFO_OFFSET: |
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*val = 1093 - 2732500 / ad7298_get_ref_voltage(st); |
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return IIO_VAL_INT; |
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} |
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return -EINVAL; |
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} |
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static const struct iio_info ad7298_info = { |
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.read_raw = &ad7298_read_raw, |
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.update_scan_mode = ad7298_update_scan_mode, |
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}; |
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static void ad7298_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 ad7298_probe(struct spi_device *spi) |
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{ |
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struct ad7298_state *st; |
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struct iio_dev *indio_dev; |
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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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st->ext_ref = AD7298_EXTREF; |
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} else { |
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ret = PTR_ERR(st->reg); |
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if (ret != -ENODEV) |
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return ret; |
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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, ad7298_reg_disable, |
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st->reg); |
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if (ret) |
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return ret; |
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} |
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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->modes = INDIO_DIRECT_MODE; |
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indio_dev->channels = ad7298_channels; |
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indio_dev->num_channels = ARRAY_SIZE(ad7298_channels); |
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indio_dev->info = &ad7298_info; |
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/* Setup default message */ |
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st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; |
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st->scan_single_xfer[0].len = 2; |
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st->scan_single_xfer[0].cs_change = 1; |
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st->scan_single_xfer[1].tx_buf = &st->tx_buf[1]; |
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st->scan_single_xfer[1].len = 2; |
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st->scan_single_xfer[1].cs_change = 1; |
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st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; |
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st->scan_single_xfer[2].len = 2; |
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spi_message_init(&st->scan_single_msg); |
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spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); |
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spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); |
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spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg); |
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ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, |
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&ad7298_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 spi_device_id ad7298_id[] = { |
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{"ad7298", 0}, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(spi, ad7298_id); |
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static struct spi_driver ad7298_driver = { |
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.driver = { |
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.name = "ad7298", |
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}, |
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.probe = ad7298_probe, |
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.id_table = ad7298_id, |
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}; |
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module_spi_driver(ad7298_driver); |
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MODULE_AUTHOR("Michael Hennerich <[email protected]>"); |
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MODULE_DESCRIPTION("Analog Devices AD7298 ADC"); |
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MODULE_LICENSE("GPL v2");
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