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661f020f56
Convert to use devm_ functions to reduce code size and simplify the code. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Jean Delvare <khali@linux-fr.org>
234 lines
5.4 KiB
C
234 lines
5.4 KiB
C
/*
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* max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
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*
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* Based on arch/arm/mach-pxa/corgi_ssp.c
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*
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* Copyright (C) 2004-2005 Richard Purdie
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*
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* Copyright (C) 2008 Marvell International Ltd.
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* Eric Miao <eric.miao@marvell.com>
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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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* publishhed by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#define MAX1111_TX_BUF_SIZE 1
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#define MAX1111_RX_BUF_SIZE 2
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/* MAX1111 Commands */
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#define MAX1111_CTRL_PD0 (1u << 0)
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#define MAX1111_CTRL_PD1 (1u << 1)
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#define MAX1111_CTRL_SGL (1u << 2)
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#define MAX1111_CTRL_UNI (1u << 3)
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#define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
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#define MAX1111_CTRL_STR (1u << 7)
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struct max1111_data {
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struct spi_device *spi;
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struct device *hwmon_dev;
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struct spi_message msg;
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struct spi_transfer xfer[2];
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uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
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uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
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struct mutex drvdata_lock;
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/* protect msg, xfer and buffers from multiple access */
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};
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static int max1111_read(struct device *dev, int channel)
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{
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struct max1111_data *data = dev_get_drvdata(dev);
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uint8_t v1, v2;
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int err;
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/* writing to drvdata struct is not thread safe, wait on mutex */
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mutex_lock(&data->drvdata_lock);
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data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) |
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MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
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MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
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err = spi_sync(data->spi, &data->msg);
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if (err < 0) {
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dev_err(dev, "spi_sync failed with %d\n", err);
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mutex_unlock(&data->drvdata_lock);
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return err;
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}
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v1 = data->rx_buf[0];
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v2 = data->rx_buf[1];
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mutex_unlock(&data->drvdata_lock);
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if ((v1 & 0xc0) || (v2 & 0x3f))
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return -EINVAL;
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return (v1 << 2) | (v2 >> 6);
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}
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#ifdef CONFIG_SHARPSL_PM
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static struct max1111_data *the_max1111;
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int max1111_read_channel(int channel)
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{
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return max1111_read(&the_max1111->spi->dev, channel);
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}
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EXPORT_SYMBOL(max1111_read_channel);
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#endif
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/*
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* NOTE: SPI devices do not have a default 'name' attribute, which is
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* likely to be used by hwmon applications to distinguish between
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* different devices, explicitly add a name attribute here.
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*/
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static ssize_t show_name(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "max1111\n");
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}
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static ssize_t show_adc(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int channel = to_sensor_dev_attr(attr)->index;
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int ret;
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ret = max1111_read(dev, channel);
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if (ret < 0)
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return ret;
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/*
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* assume the reference voltage to be 2.048V, with an 8-bit sample,
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* the LSB weight is 8mV
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*/
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return sprintf(buf, "%d\n", ret * 8);
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}
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#define MAX1111_ADC_ATTR(_id) \
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SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
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static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
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static MAX1111_ADC_ATTR(0);
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static MAX1111_ADC_ATTR(1);
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static MAX1111_ADC_ATTR(2);
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static MAX1111_ADC_ATTR(3);
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static struct attribute *max1111_attributes[] = {
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&dev_attr_name.attr,
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&sensor_dev_attr_in0_input.dev_attr.attr,
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&sensor_dev_attr_in1_input.dev_attr.attr,
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&sensor_dev_attr_in2_input.dev_attr.attr,
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&sensor_dev_attr_in3_input.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group max1111_attr_group = {
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.attrs = max1111_attributes,
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};
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static int __devinit setup_transfer(struct max1111_data *data)
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{
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struct spi_message *m;
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struct spi_transfer *x;
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m = &data->msg;
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x = &data->xfer[0];
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spi_message_init(m);
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x->tx_buf = &data->tx_buf[0];
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x->len = MAX1111_TX_BUF_SIZE;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &data->rx_buf[0];
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x->len = MAX1111_RX_BUF_SIZE;
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spi_message_add_tail(x, m);
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return 0;
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}
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static int __devinit max1111_probe(struct spi_device *spi)
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{
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struct max1111_data *data;
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int err;
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spi->bits_per_word = 8;
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spi->mode = SPI_MODE_0;
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err = spi_setup(spi);
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if (err < 0)
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return err;
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data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
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if (data == NULL) {
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dev_err(&spi->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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err = setup_transfer(data);
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if (err)
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return err;
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mutex_init(&data->drvdata_lock);
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data->spi = spi;
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spi_set_drvdata(spi, data);
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err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
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if (err) {
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dev_err(&spi->dev, "failed to create attribute group\n");
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return err;
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}
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data->hwmon_dev = hwmon_device_register(&spi->dev);
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if (IS_ERR(data->hwmon_dev)) {
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dev_err(&spi->dev, "failed to create hwmon device\n");
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err = PTR_ERR(data->hwmon_dev);
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goto err_remove;
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}
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#ifdef CONFIG_SHARPSL_PM
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the_max1111 = data;
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#endif
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return 0;
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err_remove:
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sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
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return err;
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}
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static int __devexit max1111_remove(struct spi_device *spi)
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{
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struct max1111_data *data = spi_get_drvdata(spi);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
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mutex_destroy(&data->drvdata_lock);
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return 0;
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}
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static struct spi_driver max1111_driver = {
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.driver = {
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.name = "max1111",
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.owner = THIS_MODULE,
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},
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.probe = max1111_probe,
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.remove = __devexit_p(max1111_remove),
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};
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module_spi_driver(max1111_driver);
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MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
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MODULE_DESCRIPTION("MAX1111 ADC Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("spi:max1111");
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