![Sachin Kamat](/assets/img/avatar_default.png)
devm_* APIs are device managed and make code simpler. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Cc: Oskar Andero <oskar.andero@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
250 lines
5.5 KiB
C
250 lines
5.5 KiB
C
/*
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* Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
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*
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* Driver for Microchip Technology's MCP3204 and MCP3208 ADC chips.
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* Datasheet can be found here:
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* http://ww1.microchip.com/downloads/en/devicedoc/21298c.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/iio/iio.h>
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#include <linux/regulator/consumer.h>
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#define MCP_SINGLE_ENDED (1 << 3)
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#define MCP_START_BIT (1 << 4)
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enum {
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mcp3204,
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mcp3208,
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};
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struct mcp320x {
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struct spi_device *spi;
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struct spi_message msg;
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struct spi_transfer transfer[2];
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u8 tx_buf;
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u8 rx_buf[2];
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struct regulator *reg;
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struct mutex lock;
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};
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static int mcp320x_adc_conversion(struct mcp320x *adc, u8 msg)
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{
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int ret;
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adc->tx_buf = msg;
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ret = spi_sync(adc->spi, &adc->msg);
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if (ret < 0)
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return ret;
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return ((adc->rx_buf[0] & 0x3f) << 6) |
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(adc->rx_buf[1] >> 2);
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}
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static int mcp320x_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 mcp320x *adc = iio_priv(indio_dev);
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int ret = -EINVAL;
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mutex_lock(&adc->lock);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (channel->differential)
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ret = mcp320x_adc_conversion(adc,
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MCP_START_BIT | channel->address);
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else
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ret = mcp320x_adc_conversion(adc,
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MCP_START_BIT | MCP_SINGLE_ENDED |
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channel->address);
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if (ret < 0)
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goto out;
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*val = ret;
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ret = IIO_VAL_INT;
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break;
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case IIO_CHAN_INFO_SCALE:
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/* Digital output code = (4096 * Vin) / Vref */
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ret = regulator_get_voltage(adc->reg);
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if (ret < 0)
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goto out;
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*val = ret / 1000;
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*val2 = 12;
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ret = IIO_VAL_FRACTIONAL_LOG2;
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break;
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default:
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break;
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}
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out:
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mutex_unlock(&adc->lock);
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return ret;
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}
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#define MCP320X_VOLTAGE_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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}
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#define MCP320X_VOLTAGE_CHANNEL_DIFF(num) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = (num * 2), \
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.channel2 = (num * 2 + 1), \
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.address = (num * 2), \
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.differential = 1, \
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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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}
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static const struct iio_chan_spec mcp3204_channels[] = {
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MCP320X_VOLTAGE_CHANNEL(0),
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MCP320X_VOLTAGE_CHANNEL(1),
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MCP320X_VOLTAGE_CHANNEL(2),
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MCP320X_VOLTAGE_CHANNEL(3),
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MCP320X_VOLTAGE_CHANNEL_DIFF(0),
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MCP320X_VOLTAGE_CHANNEL_DIFF(1),
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};
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static const struct iio_chan_spec mcp3208_channels[] = {
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MCP320X_VOLTAGE_CHANNEL(0),
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MCP320X_VOLTAGE_CHANNEL(1),
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MCP320X_VOLTAGE_CHANNEL(2),
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MCP320X_VOLTAGE_CHANNEL(3),
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MCP320X_VOLTAGE_CHANNEL(4),
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MCP320X_VOLTAGE_CHANNEL(5),
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MCP320X_VOLTAGE_CHANNEL(6),
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MCP320X_VOLTAGE_CHANNEL(7),
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MCP320X_VOLTAGE_CHANNEL_DIFF(0),
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MCP320X_VOLTAGE_CHANNEL_DIFF(1),
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MCP320X_VOLTAGE_CHANNEL_DIFF(2),
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MCP320X_VOLTAGE_CHANNEL_DIFF(3),
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};
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static const struct iio_info mcp320x_info = {
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.read_raw = mcp320x_read_raw,
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.driver_module = THIS_MODULE,
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};
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struct mcp3208_chip_info {
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const struct iio_chan_spec *channels;
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unsigned int num_channels;
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};
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static const struct mcp3208_chip_info mcp3208_chip_infos[] = {
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[mcp3204] = {
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.channels = mcp3204_channels,
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.num_channels = ARRAY_SIZE(mcp3204_channels)
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},
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[mcp3208] = {
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.channels = mcp3208_channels,
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.num_channels = ARRAY_SIZE(mcp3208_channels)
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},
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};
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static int mcp320x_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct mcp320x *adc;
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const struct mcp3208_chip_info *chip_info;
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int ret;
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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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return -ENOMEM;
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adc = iio_priv(indio_dev);
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adc->spi = spi;
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indio_dev->dev.parent = &spi->dev;
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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->info = &mcp320x_info;
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chip_info = &mcp3208_chip_infos[spi_get_device_id(spi)->driver_data];
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indio_dev->channels = chip_info->channels;
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indio_dev->num_channels = chip_info->num_channels;
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adc->transfer[0].tx_buf = &adc->tx_buf;
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adc->transfer[0].len = sizeof(adc->tx_buf);
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adc->transfer[1].rx_buf = adc->rx_buf;
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adc->transfer[1].len = sizeof(adc->rx_buf);
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spi_message_init_with_transfers(&adc->msg, adc->transfer,
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ARRAY_SIZE(adc->transfer));
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adc->reg = devm_regulator_get(&spi->dev, "vref");
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if (IS_ERR(adc->reg))
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return PTR_ERR(adc->reg);
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ret = regulator_enable(adc->reg);
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if (ret < 0)
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return ret;
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mutex_init(&adc->lock);
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ret = iio_device_register(indio_dev);
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if (ret < 0)
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goto reg_disable;
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return 0;
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reg_disable:
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regulator_disable(adc->reg);
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return ret;
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}
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static int mcp320x_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 mcp320x *adc = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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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 spi_device_id mcp320x_id[] = {
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{ "mcp3204", mcp3204 },
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{ "mcp3208", mcp3208 },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, mcp320x_id);
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static struct spi_driver mcp320x_driver = {
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.driver = {
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.name = "mcp320x",
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.owner = THIS_MODULE,
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},
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.probe = mcp320x_probe,
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.remove = mcp320x_remove,
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.id_table = mcp320x_id,
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};
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module_spi_driver(mcp320x_driver);
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MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
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MODULE_DESCRIPTION("Microchip Technology MCP3204/08");
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MODULE_LICENSE("GPL v2");
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