248 lines
6.4 KiB
C
248 lines
6.4 KiB
C
/*
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* adcxx.c
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*
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* The adcxx4s is an AD converter family from National Semiconductor (NS).
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*
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* Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
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*
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* The adcxx4s communicates with a host processor via an SPI/Microwire Bus
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* interface. This driver supports the whole family of devices with name
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* ADC<bb><c>S<sss>, where
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* * bb is the resolution in number of bits (8, 10, 12)
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* * c is the number of channels (1, 2, 4, 8)
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* * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
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* and 101 for 1 MSPS)
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*
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* Complete datasheets are available at National's website here:
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* http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
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*
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* Handling of 8, 10 and 12 bits converters are the same, the
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* unavailable bits are 0 :)
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/sysfs.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/mutex.h>
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#include <linux/mod_devicetable.h>
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#include <linux/spi/spi.h>
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#define DRVNAME "adcxx"
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struct adcxx {
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struct device *hwmon_dev;
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struct mutex lock;
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u32 channels;
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u32 reference; /* in millivolts */
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};
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/* sysfs hook function */
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static ssize_t adcxx_read(struct device *dev,
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struct device_attribute *devattr, char *buf)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
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struct adcxx *adc = spi_get_drvdata(spi);
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u8 tx_buf[2];
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u8 rx_buf[2];
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int status;
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u32 value;
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if (mutex_lock_interruptible(&adc->lock))
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return -ERESTARTSYS;
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if (adc->channels == 1) {
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status = spi_read(spi, rx_buf, sizeof(rx_buf));
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} else {
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tx_buf[0] = attr->index << 3; /* other bits are don't care */
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status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
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rx_buf, sizeof(rx_buf));
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}
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if (status < 0) {
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dev_warn(dev, "SPI synch. transfer failed with status %d\n",
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status);
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goto out;
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}
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value = (rx_buf[0] << 8) + rx_buf[1];
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dev_dbg(dev, "raw value = 0x%x\n", value);
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value = value * adc->reference >> 12;
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status = sprintf(buf, "%d\n", value);
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out:
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mutex_unlock(&adc->lock);
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return status;
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}
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static ssize_t adcxx_show_min(struct device *dev,
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struct device_attribute *devattr, char *buf)
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{
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/* The minimum reference is 0 for this chip family */
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return sprintf(buf, "0\n");
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}
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static ssize_t adcxx_show_max(struct device *dev,
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struct device_attribute *devattr, char *buf)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct adcxx *adc = spi_get_drvdata(spi);
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u32 reference;
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if (mutex_lock_interruptible(&adc->lock))
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return -ERESTARTSYS;
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reference = adc->reference;
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mutex_unlock(&adc->lock);
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return sprintf(buf, "%d\n", reference);
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}
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static ssize_t adcxx_set_max(struct device *dev,
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struct device_attribute *devattr, const char *buf, size_t count)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct adcxx *adc = spi_get_drvdata(spi);
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unsigned long value;
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if (kstrtoul(buf, 10, &value))
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return -EINVAL;
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if (mutex_lock_interruptible(&adc->lock))
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return -ERESTARTSYS;
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adc->reference = value;
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mutex_unlock(&adc->lock);
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return count;
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}
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static ssize_t adcxx_show_name(struct device *dev, struct device_attribute
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*devattr, char *buf)
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{
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return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
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}
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static struct sensor_device_attribute ad_input[] = {
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SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
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SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
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SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
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adcxx_set_max, 0),
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SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
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SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
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SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
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SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
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SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4),
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SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5),
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SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6),
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SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7),
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};
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/*----------------------------------------------------------------------*/
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static int adcxx_probe(struct spi_device *spi)
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{
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int channels = spi_get_device_id(spi)->driver_data;
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struct adcxx *adc;
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int status;
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int i;
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adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);
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if (!adc)
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return -ENOMEM;
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/* set a default value for the reference */
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adc->reference = 3300;
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adc->channels = channels;
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mutex_init(&adc->lock);
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mutex_lock(&adc->lock);
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spi_set_drvdata(spi, adc);
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for (i = 0; i < 3 + adc->channels; i++) {
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status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
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if (status) {
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dev_err(&spi->dev, "device_create_file failed.\n");
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goto out_err;
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}
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}
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adc->hwmon_dev = hwmon_device_register(&spi->dev);
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if (IS_ERR(adc->hwmon_dev)) {
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dev_err(&spi->dev, "hwmon_device_register failed.\n");
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status = PTR_ERR(adc->hwmon_dev);
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goto out_err;
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}
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mutex_unlock(&adc->lock);
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return 0;
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out_err:
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for (i--; i >= 0; i--)
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device_remove_file(&spi->dev, &ad_input[i].dev_attr);
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mutex_unlock(&adc->lock);
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return status;
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}
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static int adcxx_remove(struct spi_device *spi)
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{
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struct adcxx *adc = spi_get_drvdata(spi);
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int i;
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mutex_lock(&adc->lock);
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hwmon_device_unregister(adc->hwmon_dev);
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for (i = 0; i < 3 + adc->channels; i++)
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device_remove_file(&spi->dev, &ad_input[i].dev_attr);
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mutex_unlock(&adc->lock);
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return 0;
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}
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static const struct spi_device_id adcxx_ids[] = {
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{ "adcxx1s", 1 },
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{ "adcxx2s", 2 },
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{ "adcxx4s", 4 },
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{ "adcxx8s", 8 },
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{ },
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};
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MODULE_DEVICE_TABLE(spi, adcxx_ids);
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static struct spi_driver adcxx_driver = {
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.driver = {
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.name = "adcxx",
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},
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.id_table = adcxx_ids,
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.probe = adcxx_probe,
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.remove = adcxx_remove,
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};
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module_spi_driver(adcxx_driver);
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MODULE_AUTHOR("Marc Pignat");
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MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
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MODULE_LICENSE("GPL");
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