356 lines
9.3 KiB
C
Executable File
356 lines
9.3 KiB
C
Executable File
/**
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* Copyright (C) 2017 Axis Communications AB
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*
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* Driver for Texas Instruments' ADC084S021 ADC chip.
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* Datasheets can be found here:
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* http://www.ti.com/lit/ds/symlink/adc084s021.pdf
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/err.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include <linux/interrupt.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/events.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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#define MODULE_NAME "adc084s021"
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#define DRIVER_VERSION "1.0"
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#define ADC_RESOLUTION 8
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#define ADC_N_CHANNELS 4
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struct adc084s021_configuration {
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const struct iio_chan_spec *channels;
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u8 num_channels;
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};
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struct adc084s021 {
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struct spi_device *spi;
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struct spi_message message;
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struct spi_transfer spi_trans[2];
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struct regulator *reg;
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struct mutex lock;
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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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union {
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u8 tx_buf[2];
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u8 rx_buf[2];
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} ____cacheline_aligned;
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u8 cur_adc_values[ADC_N_CHANNELS];
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};
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/**
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* Event triggered when value changes on a channel
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*/
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static const struct iio_event_spec adc084s021_event = {
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.type = IIO_EV_TYPE_CHANGE,
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.dir = IIO_EV_DIR_NONE,
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};
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/**
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* Channel specification
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*/
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#define ADC084S021_VOLTAGE_CHANNEL(num) \
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{ \
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.type = IIO_VOLTAGE, \
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.channel = (num), \
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.address = (num << 3), \
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.indexed = 1, \
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.scan_index = num, \
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.scan_type = { \
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.sign = 'u', \
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.realbits = 8, \
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.storagebits = 32, \
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.shift = 24 - ((num << 3)), \
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}, \
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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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.event_spec = &adc084s021_event, \
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.num_event_specs = 1, \
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}
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static const struct iio_chan_spec adc084s021_channels[] = {
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ADC084S021_VOLTAGE_CHANNEL(0),
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ADC084S021_VOLTAGE_CHANNEL(1),
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ADC084S021_VOLTAGE_CHANNEL(2),
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ADC084S021_VOLTAGE_CHANNEL(3),
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IIO_CHAN_SOFT_TIMESTAMP(4),
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};
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static const struct adc084s021_configuration adc084s021_config[] = {
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{ adc084s021_channels, ARRAY_SIZE(adc084s021_channels) },
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};
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/**
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* Read an ADC channel and return its value.
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*
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* @adc: The ADC SPI data.
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* @channel: The IIO channel data structure.
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*/
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static int adc084s021_adc_conversion(struct adc084s021 *adc,
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struct iio_chan_spec const *channel)
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{
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u16 value;
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int ret;
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mutex_lock(&adc->lock);
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adc->tx_buf[0] = channel->address;
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/* Do the transfer */
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ret = spi_sync(adc->spi, &adc->message);
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if (ret < 0) {
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mutex_unlock(&adc->lock);
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return ret;
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}
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value = (adc->rx_buf[0] << 4) | (adc->rx_buf[1] >> 4);
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mutex_unlock(&adc->lock);
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dev_dbg(&adc->spi->dev, "value 0x%02X on channel %d\n",
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value, channel->channel);
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return value;
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}
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/**
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* Make a readout of requested IIO channel info.
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*
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* @indio_dev: The industrial I/O device.
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* @channel: The IIO channel data structure.
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* @val: First element of value (integer).
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* @val2: Second element of value (fractional).
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* @mask: The info_mask to read.
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*/
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static int adc084s021_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *channel, int *val,
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int *val2, long mask)
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{
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struct adc084s021 *adc = iio_priv(indio_dev);
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int retval;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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retval = adc084s021_adc_conversion(adc, channel);
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if (retval < 0)
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return retval;
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*val = retval;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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retval = regulator_get_voltage(adc->reg);
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*val = retval / 1000;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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/**
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* Read enabled ADC channels and push data to the buffer.
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*
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* @irq: The interrupt number (not used).
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* @pollfunc: Pointer to the poll func.
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*/
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#ifdef BUFFER_USED
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static irqreturn_t adc084s021_trigger_handler(int irq, void *pollfunc)
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{
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struct iio_poll_func *pf = pollfunc;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct adc084s021 *adc = iio_priv(indio_dev);
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u8 *data;
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s64 timestamp;
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int value, scan_index;
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data = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
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if (!data) {
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_NONE;
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}
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timestamp = iio_get_time_ns();
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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 *channel =
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&indio_dev->channels[scan_index];
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value = adc084s021_adc_conversion(adc, channel);
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data[scan_index] = value;
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/*
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* Compare read data to previous read. If it differs send
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* event notification for affected channel.
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*/
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if (adc->cur_adc_values[scan_index] != (u8)value) {
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adc->cur_adc_values[scan_index] = (u8)value;
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iio_push_event(indio_dev,
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IIO_EVENT_CODE(IIO_VOLTAGE, 0,
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IIO_NO_MOD, IIO_EV_DIR_NONE,
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IIO_EV_TYPE_CHANGE,
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channel->channel, 0, 0),
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timestamp);
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dev_dbg(&indio_dev->dev,
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"new value on ch%d: 0x%02X (ts %llu)\n",
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channel->channel, value, timestamp);
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}
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}
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iio_push_to_buffers_with_timestamp(indio_dev, data, timestamp);
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iio_trigger_notify_done(indio_dev->trig);
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kfree(data);
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return IRQ_HANDLED;
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}
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#endif
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static const struct iio_info adc084s021_info = {
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.read_raw = adc084s021_read_raw,
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.driver_module = THIS_MODULE,
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};
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/**
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* Create and register ADC IIO device for SPI.
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*/
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static int adc084s021_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct adc084s021 *adc;
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int config = spi_get_device_id(spi)->driver_data;
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int retval;
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/* Allocate an Industrial I/O device */
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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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dev_err(&spi->dev, "Failed to allocate IIO device\n");
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return -ENOMEM;
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}
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adc = iio_priv(indio_dev);
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adc->spi = spi;
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spi->bits_per_word = ADC_RESOLUTION;
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/* Update the SPI device with config and connect the iio dev */
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retval = spi_setup(spi);
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if (retval) {
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dev_err(&spi->dev, "Failed to update SPI device\n");
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return retval;
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}
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spi_set_drvdata(spi, indio_dev);
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/* Initiate the Industrial I/O device */
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indio_dev->dev.parent = &spi->dev;
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indio_dev->dev.of_node = spi->dev.of_node;
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->modes = INDIO_BUFFER_TRIGGERED; //INDIO_DIRECT_MODE;
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indio_dev->info = &adc084s021_info;
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indio_dev->channels = adc084s021_config[config].channels;
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indio_dev->num_channels = adc084s021_config[config].num_channels;
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/* Create SPI transfer for channel reads */
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adc->spi_trans[0].tx_buf = &adc->tx_buf[0];
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adc->spi_trans[0].len = 2;
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adc->spi_trans[0].speed_hz = spi->max_speed_hz;
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adc->spi_trans[0].bits_per_word = spi->bits_per_word;
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adc->spi_trans[1].rx_buf = &adc->rx_buf[0];
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adc->spi_trans[1].len = 2;
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adc->spi_trans[1].speed_hz = spi->max_speed_hz;
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adc->spi_trans[1].bits_per_word = spi->bits_per_word;
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/* Setup SPI message for channel reads */
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spi_message_init(&adc->message);
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spi_message_add_tail(&adc->spi_trans[0], &adc->message);
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spi_message_add_tail(&adc->spi_trans[1], &adc->message);
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adc->reg = devm_regulator_get(&spi->dev, "vcc-adc");
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if (IS_ERR(adc->reg))
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return PTR_ERR(adc->reg);
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retval = regulator_enable(adc->reg);
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if (retval < 0)
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return retval;
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mutex_init(&adc->lock);
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/* Setup triggered buffer with pollfunction */
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#ifdef BUFFER_USED
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retval = iio_triggered_buffer_setup(indio_dev, NULL,
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adc084s021_trigger_handler, NULL);
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if (retval) {
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dev_err(&spi->dev, "Failed to setup triggered buffer\n");
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goto buffer_setup_failed;
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}
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#endif
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retval = iio_device_register(indio_dev);
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if (retval) {
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dev_err(&spi->dev, "Failed to register IIO device\n");
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goto device_register_failed;
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}
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dev_info(&spi->dev, "adc084s021 probed succeed!\n");
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return 0;
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device_register_failed:
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iio_triggered_buffer_cleanup(indio_dev);
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#ifdef BUFFER_USED
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buffer_setup_failed:
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#endif
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regulator_disable(adc->reg);
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return retval;
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}
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/**
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* Unregister ADC IIO device for SPI.
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*/
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static int adc084s021_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 adc084s021 *adc = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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#ifdef BUFFER_USED
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iio_triggered_buffer_cleanup(indio_dev);
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#endif
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regulator_disable(adc->reg);
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return 0;
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}
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static const struct of_device_id adc084s021_of_match[] = {
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{ .compatible = "ti,adc084s021", },
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{},
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};
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MODULE_DEVICE_TABLE(of, adc084s021_of_match);
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static const struct spi_device_id adc084s021_id[] = {
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{ MODULE_NAME, 0},
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{}
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};
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MODULE_DEVICE_TABLE(spi, adc084s021_id);
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static struct spi_driver adc084s021_driver = {
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.driver = {
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.name = MODULE_NAME,
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.of_match_table = of_match_ptr(adc084s021_of_match),
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},
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.probe = adc084s021_probe,
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.remove = adc084s021_remove,
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.id_table = adc084s021_id,
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};
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module_spi_driver(adc084s021_driver);
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MODULE_AUTHOR("Marten Lindahl <martenli@xxxxxxxx>");
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MODULE_DESCRIPTION("Texas Instruments ADC084S021");
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MODULE_LICENSE("GPL v2");
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MODULE_VERSION(DRIVER_VERSION);
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