547 lines
13 KiB
C
Executable File
547 lines
13 KiB
C
Executable File
/*
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* AD7606 SPI ADC driver
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*
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* Copyright 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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*/
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#include <linux/interrupt.h>
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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/regulator/consumer.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/delay.h>
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#include <linux/sched.h>
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#include <linux/module.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 "ad7606.h"
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/*
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* Scales are computed as 5000/32768 and 10000/32768 respectively,
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* so that when applied to the raw values they provide mV values
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*/
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static const unsigned int scale_avail[2][2] = {
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{0, 152588}, {0, 305176}
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};
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static int ad7606_reset(struct ad7606_state *st)
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{
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if (st->gpio_reset) {
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gpiod_set_value(st->gpio_reset, 1);
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ndelay(100); /* t_reset >= 100ns */
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gpiod_set_value(st->gpio_reset, 0);
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return 0;
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}
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return -ENODEV;
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}
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static int ad7606_read_samples(struct ad7606_state *st)
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{
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unsigned int num = st->chip_info->num_channels;
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u16 *data = st->data;
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int ret;
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/*
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* The frstdata signal is set to high while and after reading the sample
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* of the first channel and low for all other channels. This can be used
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* to check that the incoming data is correctly aligned. During normal
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* operation the data should never become unaligned, but some glitch or
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* electrostatic discharge might cause an extra read or clock cycle.
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* Monitoring the frstdata signal allows to recover from such failure
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* situations.
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*/
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if (st->gpio_frstdata) {
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ret = st->bops->read_block(st->dev, 1, data);
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if (ret)
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return ret;
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if (!gpiod_get_value(st->gpio_frstdata)) {
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ad7606_reset(st);
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return -EIO;
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}
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data++;
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num--;
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}
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return st->bops->read_block(st->dev, num, data);
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}
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static irqreturn_t ad7606_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 ad7606_state *st = iio_priv(pf->indio_dev);
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gpiod_set_value(st->gpio_convst, 1);
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return IRQ_HANDLED;
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}
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/**
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* ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
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* @work_s: the work struct through which this was scheduled
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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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* I think the one copy of this at a time was to avoid problems if the
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* trigger was set far too high and the reads then locked up the computer.
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**/
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static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
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{
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struct ad7606_state *st = container_of(work_s, struct ad7606_state,
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poll_work);
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struct iio_dev *indio_dev = iio_priv_to_dev(st);
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int ret;
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ret = ad7606_read_samples(st);
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if (ret == 0)
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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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gpiod_set_value(st->gpio_convst, 0);
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iio_trigger_notify_done(indio_dev->trig);
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}
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static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
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{
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struct ad7606_state *st = iio_priv(indio_dev);
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int ret;
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st->done = false;
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gpiod_set_value(st->gpio_convst, 1);
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ret = wait_event_interruptible(st->wq_data_avail, st->done);
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if (ret)
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goto error_ret;
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ret = ad7606_read_samples(st);
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if (ret == 0)
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ret = st->data[ch];
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error_ret:
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gpiod_set_value(st->gpio_convst, 0);
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return ret;
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}
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static int ad7606_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 ad7606_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 = ad7606_scan_direct(indio_dev, 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 = (short)ret;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = scale_avail[st->range][0];
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*val2 = scale_avail[st->range][1];
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return IIO_VAL_INT_PLUS_MICRO;
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case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
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*val = st->oversampling;
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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 ssize_t in_voltage_scale_available_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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int i, len = 0;
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for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
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len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
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scale_avail[i][0], scale_avail[i][1]);
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buf[len - 1] = '\n';
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return len;
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}
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static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
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static int ad7606_oversampling_get_index(unsigned int val)
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{
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unsigned char supported[] = {1, 2, 4, 8, 16, 32, 64};
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int i;
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for (i = 0; i < ARRAY_SIZE(supported); i++)
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if (val == supported[i])
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return i;
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return -EINVAL;
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}
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static int ad7606_write_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 mask)
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{
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struct ad7606_state *st = iio_priv(indio_dev);
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int values[3];
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int ret, i;
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switch (mask) {
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case IIO_CHAN_INFO_SCALE:
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ret = -EINVAL;
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mutex_lock(&st->lock);
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for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
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if (val2 == scale_avail[i][1]) {
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gpiod_set_value(st->gpio_range, i);
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st->range = i;
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ret = 0;
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break;
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}
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mutex_unlock(&st->lock);
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return ret;
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case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
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if (val2)
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return -EINVAL;
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ret = ad7606_oversampling_get_index(val);
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if (ret < 0)
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return ret;
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values[0] = (ret >> 0) & 1;
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values[1] = (ret >> 1) & 1;
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values[2] = (ret >> 2) & 1;
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mutex_lock(&st->lock);
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gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
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values);
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st->oversampling = val;
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mutex_unlock(&st->lock);
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return 0;
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default:
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return -EINVAL;
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}
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}
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static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");
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static struct attribute *ad7606_attributes_os_and_range[] = {
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&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
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&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad7606_attribute_group_os_and_range = {
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.attrs = ad7606_attributes_os_and_range,
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};
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static struct attribute *ad7606_attributes_os[] = {
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&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad7606_attribute_group_os = {
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.attrs = ad7606_attributes_os,
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};
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static struct attribute *ad7606_attributes_range[] = {
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&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad7606_attribute_group_range = {
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.attrs = ad7606_attributes_range,
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};
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#define AD7606_CHANNEL(num) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = num, \
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.address = num, \
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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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.info_mask_shared_by_all = \
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BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
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.scan_index = num, \
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.scan_type = { \
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.sign = 's', \
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.realbits = 16, \
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.storagebits = 16, \
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.endianness = IIO_CPU, \
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}, \
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}
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static const struct iio_chan_spec ad7606_channels[] = {
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IIO_CHAN_SOFT_TIMESTAMP(8),
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AD7606_CHANNEL(0),
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AD7606_CHANNEL(1),
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AD7606_CHANNEL(2),
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AD7606_CHANNEL(3),
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AD7606_CHANNEL(4),
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AD7606_CHANNEL(5),
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AD7606_CHANNEL(6),
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AD7606_CHANNEL(7),
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};
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static const struct ad7606_chip_info ad7606_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_AD7606_8] = {
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.channels = ad7606_channels,
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.num_channels = 9,
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},
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[ID_AD7606_6] = {
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.channels = ad7606_channels,
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.num_channels = 7,
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},
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[ID_AD7606_4] = {
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.channels = ad7606_channels,
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.num_channels = 5,
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},
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};
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static int ad7606_request_gpios(struct ad7606_state *st)
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{
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struct device *dev = st->dev;
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st->gpio_convst = devm_gpiod_get(dev, "conversion-start",
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GPIOD_OUT_LOW);
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if (IS_ERR(st->gpio_convst))
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return PTR_ERR(st->gpio_convst);
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st->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
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if (IS_ERR(st->gpio_reset))
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return PTR_ERR(st->gpio_reset);
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st->gpio_range = devm_gpiod_get_optional(dev, "range", GPIOD_OUT_LOW);
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if (IS_ERR(st->gpio_range))
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return PTR_ERR(st->gpio_range);
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st->gpio_standby = devm_gpiod_get_optional(dev, "standby",
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GPIOD_OUT_HIGH);
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if (IS_ERR(st->gpio_standby))
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return PTR_ERR(st->gpio_standby);
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st->gpio_frstdata = devm_gpiod_get_optional(dev, "first-data",
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GPIOD_IN);
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if (IS_ERR(st->gpio_frstdata))
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return PTR_ERR(st->gpio_frstdata);
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st->gpio_os = devm_gpiod_get_array_optional(dev, "oversampling-ratio",
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GPIOD_OUT_LOW);
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return PTR_ERR_OR_ZERO(st->gpio_os);
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}
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/**
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* Interrupt handler
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*/
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static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
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{
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struct iio_dev *indio_dev = dev_id;
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struct ad7606_state *st = iio_priv(indio_dev);
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if (iio_buffer_enabled(indio_dev)) {
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schedule_work(&st->poll_work);
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} else {
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st->done = true;
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wake_up_interruptible(&st->wq_data_avail);
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}
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return IRQ_HANDLED;
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};
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static const struct iio_info ad7606_info_no_os_or_range = {
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.driver_module = THIS_MODULE,
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.read_raw = &ad7606_read_raw,
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};
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static const struct iio_info ad7606_info_os_and_range = {
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.driver_module = THIS_MODULE,
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.read_raw = &ad7606_read_raw,
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.write_raw = &ad7606_write_raw,
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.attrs = &ad7606_attribute_group_os_and_range,
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};
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static const struct iio_info ad7606_info_os = {
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.driver_module = THIS_MODULE,
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.read_raw = &ad7606_read_raw,
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.write_raw = &ad7606_write_raw,
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.attrs = &ad7606_attribute_group_os,
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};
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static const struct iio_info ad7606_info_range = {
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.driver_module = THIS_MODULE,
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.read_raw = &ad7606_read_raw,
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.write_raw = &ad7606_write_raw,
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.attrs = &ad7606_attribute_group_range,
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};
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int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
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const char *name, unsigned int id,
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const struct ad7606_bus_ops *bops)
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{
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struct ad7606_state *st;
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int ret;
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struct iio_dev *indio_dev;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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st->dev = dev;
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mutex_init(&st->lock);
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st->bops = bops;
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st->base_address = base_address;
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/* tied to logic low, analog input range is +/- 5V */
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st->range = 0;
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st->oversampling = 1;
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INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
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st->reg = devm_regulator_get(dev, "avcc");
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if (IS_ERR(st->reg))
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return PTR_ERR(st->reg);
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ret = regulator_enable(st->reg);
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if (ret) {
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dev_err(dev, "Failed to enable specified AVcc supply\n");
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return ret;
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}
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ret = ad7606_request_gpios(st);
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if (ret)
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goto error_disable_reg;
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st->chip_info = &ad7606_chip_info_tbl[id];
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indio_dev->dev.parent = dev;
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if (st->gpio_os) {
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if (st->gpio_range)
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indio_dev->info = &ad7606_info_os_and_range;
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else
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indio_dev->info = &ad7606_info_os;
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} else {
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if (st->gpio_range)
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indio_dev->info = &ad7606_info_range;
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else
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indio_dev->info = &ad7606_info_no_os_or_range;
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}
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->name = name;
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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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init_waitqueue_head(&st->wq_data_avail);
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ret = ad7606_reset(st);
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if (ret)
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dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
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ret = request_irq(irq, ad7606_interrupt, IRQF_TRIGGER_FALLING, name,
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indio_dev);
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if (ret)
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goto error_disable_reg;
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ret = iio_triggered_buffer_setup(indio_dev, &ad7606_trigger_handler,
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NULL, NULL);
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if (ret)
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goto error_free_irq;
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_unregister_ring;
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dev_set_drvdata(dev, indio_dev);
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return 0;
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error_unregister_ring:
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iio_triggered_buffer_cleanup(indio_dev);
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error_free_irq:
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free_irq(irq, indio_dev);
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error_disable_reg:
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regulator_disable(st->reg);
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return ret;
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}
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EXPORT_SYMBOL_GPL(ad7606_probe);
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int ad7606_remove(struct device *dev, int irq)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct ad7606_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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free_irq(irq, indio_dev);
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regulator_disable(st->reg);
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return 0;
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}
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EXPORT_SYMBOL_GPL(ad7606_remove);
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#ifdef CONFIG_PM_SLEEP
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static int ad7606_suspend(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct ad7606_state *st = iio_priv(indio_dev);
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if (st->gpio_standby) {
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gpiod_set_value(st->gpio_range, 1);
|
|
gpiod_set_value(st->gpio_standby, 0);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ad7606_resume(struct device *dev)
|
|
{
|
|
struct iio_dev *indio_dev = dev_get_drvdata(dev);
|
|
struct ad7606_state *st = iio_priv(indio_dev);
|
|
|
|
if (st->gpio_standby) {
|
|
gpiod_set_value(st->gpio_range, st->range);
|
|
gpiod_set_value(st->gpio_standby, 1);
|
|
ad7606_reset(st);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
SIMPLE_DEV_PM_OPS(ad7606_pm_ops, ad7606_suspend, ad7606_resume);
|
|
EXPORT_SYMBOL_GPL(ad7606_pm_ops);
|
|
|
|
#endif
|
|
|
|
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
|
|
MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
|
|
MODULE_LICENSE("GPL v2");
|