Staging: iio: add driver for MAX517/518/519
IIO Driver for Maxim MAX517, MAX518 and MAX519 DAC Signed-off-by: Roland Stigge <stigge@antcom.de> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>hifive-unleashed-5.1
Roland Stigge
Greg Kroah-Hartman
parent
18545cfd36
commit
6ddc5fb43e
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@ -0,0 +1,41 @@
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Kernel driver max517
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====================
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Supported chips:
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* Maxim MAX517, MAX518, MAX519
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Prefix: 'max517'
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Datasheet: Publicly available at the Maxim website
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http://www.maxim-ic.com/
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Author:
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Roland Stigge <stigge@antcom.de>
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Description
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-----------
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The Maxim MAX517/518/519 is an 8-bit DAC on the I2C bus. The following table
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shows the different feature sets of the variants MAX517, MAX518 and MAX519:
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Feature MAX517 MAX518 MAX519
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--------------------------------------------------------------------------
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One output channel X
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Two output channels X X
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Simultaneous output updates X X
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Supply voltage as reference X
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Separate reference input X
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Reference input for each DAC X
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Via the iio sysfs interface, there are three attributes available: out1_raw,
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out2_raw and out12_raw. With out1_raw and out2_raw, the current output values
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(0..255) of the DACs can be written to the device. out12_raw can be used to set
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both output channel values simultaneously.
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With MAX517, only out1_raw is available.
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Via out1_scale (and where appropriate, out2_scale), the current scaling factor
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in mV can be read.
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When the operating system goes to a power down state, the Power Down function
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of the chip is activated, reducing the supply current to 4uA.
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On power-up, the device is in 0V-output state.
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@ -19,3 +19,13 @@ config AD5446
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To compile this driver as a module, choose M here: the
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module will be called ad5446.
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config MAX517
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tristate "Maxim MAX517/518/519 DAC driver"
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depends on I2C && EXPERIMENTAL
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help
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If you say yes here you get support for the Maxim chips MAX517,
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MAX518 and MAX519 (I2C 8-Bit DACs with rail-to-rail outputs).
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This driver can also be built as a module. If so, the module
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will be called max517.
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@ -4,3 +4,4 @@
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obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
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obj-$(CONFIG_AD5446) += ad5446.o
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obj-$(CONFIG_MAX517) += max517.o
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@ -0,0 +1,293 @@
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/*
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* max517.c - Support for Maxim MAX517, MAX518 and MAX519
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*
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* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
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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/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/err.h>
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#include "../iio.h"
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#include "dac.h"
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#include "max517.h"
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#define MAX517_DRV_NAME "max517"
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/* Commands */
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#define COMMAND_CHANNEL0 0x00
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#define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
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#define COMMAND_PD 0x08 /* Power Down */
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enum max517_device_ids {
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ID_MAX517,
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ID_MAX518,
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ID_MAX519,
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};
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struct max517_data {
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struct iio_dev *indio_dev;
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unsigned short vref_mv[2];
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};
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/*
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* channel: bit 0: channel 1
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* bit 1: channel 2
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* (this way, it's possible to set both channels at once)
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*/
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static ssize_t max517_set_value(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count, int channel)
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{
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struct i2c_client *client = to_i2c_client(dev);
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u8 outbuf[4]; /* 1x or 2x command + value */
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int outbuf_size = 0;
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int res;
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long val;
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res = strict_strtol(buf, 10, &val);
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if (res)
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return res;
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if (val < 0 || val > 255)
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return -EINVAL;
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if (channel & 1) {
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outbuf[outbuf_size++] = COMMAND_CHANNEL0;
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outbuf[outbuf_size++] = val;
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}
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if (channel & 2) {
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outbuf[outbuf_size++] = COMMAND_CHANNEL1;
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outbuf[outbuf_size++] = val;
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}
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/*
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* At this point, there are always 1 or 2 two-byte commands in
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* outbuf. With 2 commands, the device can set two outputs
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* simultaneously, latching the values upon the end of the I2C
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* transfer.
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*/
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res = i2c_master_send(client, outbuf, outbuf_size);
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if (res < 0)
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return res;
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return count;
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}
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static ssize_t max517_set_value_1(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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return max517_set_value(dev, attr, buf, count, 1);
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}
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static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
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static ssize_t max517_set_value_2(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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return max517_set_value(dev, attr, buf, count, 2);
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}
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static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
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static ssize_t max517_set_value_both(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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return max517_set_value(dev, attr, buf, count, 3);
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}
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static IIO_DEVICE_ATTR_NAMED(out1and2_raw, out1&2_raw, S_IWUSR, NULL,
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max517_set_value_both, -1);
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static ssize_t max517_show_scale(struct device *dev,
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struct device_attribute *attr,
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char *buf, int channel)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct max517_data *data = iio_dev_get_devdata(dev_info);
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/* Corresponds to Vref / 2^(bits) */
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unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;
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return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
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}
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static ssize_t max517_show_scale1(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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return max517_show_scale(dev, attr, buf, 1);
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}
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static IIO_DEVICE_ATTR(out1_scale, S_IRUGO, max517_show_scale1, NULL, 0);
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static ssize_t max517_show_scale2(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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return max517_show_scale(dev, attr, buf, 2);
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}
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static IIO_DEVICE_ATTR(out2_scale, S_IRUGO, max517_show_scale2, NULL, 0);
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/* On MAX517 variant, we have two outputs */
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static struct attribute *max517_attributes[] = {
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&iio_dev_attr_out1_raw.dev_attr.attr,
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&iio_dev_attr_out1_scale.dev_attr.attr,
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NULL
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};
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static struct attribute_group max517_attribute_group = {
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.attrs = max517_attributes,
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};
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/* On MAX518 and MAX518 variant, we have two outputs */
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static struct attribute *max518_attributes[] = {
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&iio_dev_attr_out1_raw.dev_attr.attr,
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&iio_dev_attr_out1_scale.dev_attr.attr,
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&iio_dev_attr_out2_raw.dev_attr.attr,
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&iio_dev_attr_out2_scale.dev_attr.attr,
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&iio_dev_attr_out1and2_raw.dev_attr.attr,
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NULL
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};
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static struct attribute_group max518_attribute_group = {
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.attrs = max518_attributes,
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};
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static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
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{
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u8 outbuf = COMMAND_PD;
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return i2c_master_send(client, &outbuf, 1);
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}
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static int max517_resume(struct i2c_client *client)
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{
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u8 outbuf = 0;
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return i2c_master_send(client, &outbuf, 1);
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}
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static int max517_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct max517_data *data;
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struct max517_platform_data *platform_data = client->dev.platform_data;
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int err;
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data = kzalloc(sizeof(struct max517_data), GFP_KERNEL);
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if (!data) {
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err = -ENOMEM;
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goto exit;
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}
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i2c_set_clientdata(client, data);
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data->indio_dev = iio_allocate_device();
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if (data->indio_dev == NULL) {
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err = -ENOMEM;
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goto exit_free_data;
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}
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/* establish that the iio_dev is a child of the i2c device */
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data->indio_dev->dev.parent = &client->dev;
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/* reduced attribute set for MAX517 */
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if (id->driver_data == ID_MAX517)
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data->indio_dev->attrs = &max517_attribute_group;
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else
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data->indio_dev->attrs = &max518_attribute_group;
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data->indio_dev->dev_data = (void *)(data);
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data->indio_dev->driver_module = THIS_MODULE;
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data->indio_dev->modes = INDIO_DIRECT_MODE;
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/*
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* Reference voltage on MAX518 and default is 5V, else take vref_mv
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* from platform_data
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*/
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if (id->driver_data == ID_MAX518 || !platform_data) {
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data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
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} else {
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data->vref_mv[0] = platform_data->vref_mv[0];
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data->vref_mv[1] = platform_data->vref_mv[1];
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}
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err = iio_device_register(data->indio_dev);
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if (err)
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goto exit_free_device;
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dev_info(&client->dev, "DAC registered\n");
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return 0;
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exit_free_device:
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iio_free_device(data->indio_dev);
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exit_free_data:
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kfree(data);
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exit:
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return err;
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}
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static int max517_remove(struct i2c_client *client)
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{
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struct max517_data *data = i2c_get_clientdata(client);
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iio_free_device(data->indio_dev);
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kfree(data);
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return 0;
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}
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static const struct i2c_device_id max517_id[] = {
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{ "max517", ID_MAX517 },
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{ "max518", ID_MAX518 },
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{ "max519", ID_MAX519 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, max517_id);
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static struct i2c_driver max517_driver = {
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.driver = {
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.name = MAX517_DRV_NAME,
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},
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.probe = max517_probe,
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.remove = max517_remove,
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.suspend = max517_suspend,
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.resume = max517_resume,
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.id_table = max517_id,
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};
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static int __init max517_init(void)
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{
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return i2c_add_driver(&max517_driver);
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}
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static void __exit max517_exit(void)
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{
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i2c_del_driver(&max517_driver);
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}
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MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
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MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
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MODULE_LICENSE("GPL");
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module_init(max517_init);
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module_exit(max517_exit);
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@ -0,0 +1,19 @@
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/*
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* MAX517 DAC driver
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*
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* Copyright 2011 Roland Stigge <stigge@antcom.de>
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*
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* Licensed under the GPL-2 or later.
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*/
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#ifndef IIO_DAC_MAX517_H_
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#define IIO_DAC_MAX517_H_
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/*
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* TODO: struct max517_platform_data needs to go into include/linux/iio
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*/
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struct max517_platform_data {
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u16 vref_mv[2];
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};
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#endif /* IIO_DAC_MAX517_H_ */
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