Staging: iio: add driver for MAX517/518/519 (6ddc5fb4) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/staging/iio/Documentation/dac/max517

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		Kernel driver max517
		====================

		Supported chips:
		* Maxim MAX517, MAX518, MAX519
		Prefix: 'max517'
		Datasheet: Publicly available at the Maxim website
		http://www.maxim-ic.com/

		Author:
		Roland Stigge <stigge@antcom.de>

		Description
		-----------

		The Maxim MAX517/518/519 is an 8-bit DAC on the I2C bus. The following table
		shows the different feature sets of the variants MAX517, MAX518 and MAX519:

		Feature MAX517 MAX518 MAX519
		--------------------------------------------------------------------------
		One output channel X
		Two output channels X X
		Simultaneous output updates X X
		Supply voltage as reference X
		Separate reference input X
		Reference input for each DAC X

		Via the iio sysfs interface, there are three attributes available: out1_raw,
		out2_raw and out12_raw. With out1_raw and out2_raw, the current output values
		(0..255) of the DACs can be written to the device. out12_raw can be used to set
		both output channel values simultaneously.

		With MAX517, only out1_raw is available.

		Via out1_scale (and where appropriate, out2_scale), the current scaling factor
		in mV can be read.

		When the operating system goes to a power down state, the Power Down function
		of the chip is activated, reducing the supply current to 4uA.

		On power-up, the device is in 0V-output state.

drivers/staging/iio/dac/Kconfig

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		@@ -19,3 +19,13 @@ config AD5446

		To compile this driver as a module, choose M here: the
		module will be called ad5446.

		config MAX517
		tristate "Maxim MAX517/518/519 DAC driver"
		depends on I2C && EXPERIMENTAL
		help
		If you say yes here you get support for the Maxim chips MAX517,
		MAX518 and MAX519 (I2C 8-Bit DACs with rail-to-rail outputs).

		This driver can also be built as a module. If so, the module
		will be called max517.

drivers/staging/iio/dac/Makefile

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		@@ -4,3 +4,4 @@

		obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
		obj-$(CONFIG_AD5446) += ad5446.o
		obj-$(CONFIG_MAX517) += max517.o

drivers/staging/iio/dac/max517.c

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		/*
		* max517.c - Support for Maxim MAX517, MAX518 and MAX519
		*
		* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
		*/

		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/slab.h>
		#include <linux/jiffies.h>
		#include <linux/i2c.h>
		#include <linux/err.h>

		#include "../iio.h"
		#include "dac.h"

		#include "max517.h"

		#define MAX517_DRV_NAME "max517"

		/* Commands */
		#define COMMAND_CHANNEL0 0x00
		#define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
		#define COMMAND_PD 0x08 /* Power Down */

		enum max517_device_ids {
		ID_MAX517,
		ID_MAX518,
		ID_MAX519,
		};

		struct max517_data {
		struct iio_dev *indio_dev;
		unsigned short vref_mv[2];
		};

		/*
		* channel: bit 0: channel 1
		* bit 1: channel 2
		* (this way, it's possible to set both channels at once)
		*/
		static ssize_t max517_set_value(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count, int channel)
		{
		struct i2c_client *client = to_i2c_client(dev);
		u8 outbuf[4]; /* 1x or 2x command + value */
		int outbuf_size = 0;
		int res;
		long val;

		res = strict_strtol(buf, 10, &val);

		if (res)
		return res;

		if (val < 0 \|\| val > 255)
		return -EINVAL;

		if (channel & 1) {
		outbuf[outbuf_size++] = COMMAND_CHANNEL0;
		outbuf[outbuf_size++] = val;
		}
		if (channel & 2) {
		outbuf[outbuf_size++] = COMMAND_CHANNEL1;
		outbuf[outbuf_size++] = val;
		}

		/*
		* At this point, there are always 1 or 2 two-byte commands in
		* outbuf. With 2 commands, the device can set two outputs
		* simultaneously, latching the values upon the end of the I2C
		* transfer.
		*/

		res = i2c_master_send(client, outbuf, outbuf_size);
		if (res < 0)
		return res;

		return count;
		}

		static ssize_t max517_set_value_1(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count)
		{
		return max517_set_value(dev, attr, buf, count, 1);
		}
		static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);

		static ssize_t max517_set_value_2(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count)
		{
		return max517_set_value(dev, attr, buf, count, 2);
		}
		static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);

		static ssize_t max517_set_value_both(struct device *dev,
		struct device_attribute *attr,
		const char *buf, size_t count)
		{
		return max517_set_value(dev, attr, buf, count, 3);
		}
		static IIO_DEVICE_ATTR_NAMED(out1and2_raw, out1&2_raw, S_IWUSR, NULL,
		max517_set_value_both, -1);

		static ssize_t max517_show_scale(struct device *dev,
		struct device_attribute *attr,
		char *buf, int channel)
		{
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct max517_data *data = iio_dev_get_devdata(dev_info);
		/* Corresponds to Vref / 2^(bits) */
		unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;

		return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
		}

		static ssize_t max517_show_scale1(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		return max517_show_scale(dev, attr, buf, 1);
		}
		static IIO_DEVICE_ATTR(out1_scale, S_IRUGO, max517_show_scale1, NULL, 0);

		static ssize_t max517_show_scale2(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		return max517_show_scale(dev, attr, buf, 2);
		}
		static IIO_DEVICE_ATTR(out2_scale, S_IRUGO, max517_show_scale2, NULL, 0);

		/* On MAX517 variant, we have two outputs */
		static struct attribute *max517_attributes[] = {
		&iio_dev_attr_out1_raw.dev_attr.attr,
		&iio_dev_attr_out1_scale.dev_attr.attr,
		NULL
		};

		static struct attribute_group max517_attribute_group = {
		.attrs = max517_attributes,
		};

		/* On MAX518 and MAX518 variant, we have two outputs */
		static struct attribute *max518_attributes[] = {
		&iio_dev_attr_out1_raw.dev_attr.attr,
		&iio_dev_attr_out1_scale.dev_attr.attr,
		&iio_dev_attr_out2_raw.dev_attr.attr,
		&iio_dev_attr_out2_scale.dev_attr.attr,
		&iio_dev_attr_out1and2_raw.dev_attr.attr,
		NULL
		};

		static struct attribute_group max518_attribute_group = {
		.attrs = max518_attributes,
		};

		static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
		{
		u8 outbuf = COMMAND_PD;

		return i2c_master_send(client, &outbuf, 1);
		}

		static int max517_resume(struct i2c_client *client)
		{
		u8 outbuf = 0;

		return i2c_master_send(client, &outbuf, 1);
		}

		static int max517_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct max517_data *data;
		struct max517_platform_data *platform_data = client->dev.platform_data;
		int err;

		data = kzalloc(sizeof(struct max517_data), GFP_KERNEL);
		if (!data) {
		err = -ENOMEM;
		goto exit;
		}

		i2c_set_clientdata(client, data);

		data->indio_dev = iio_allocate_device();
		if (data->indio_dev == NULL) {
		err = -ENOMEM;
		goto exit_free_data;
		}

		/* establish that the iio_dev is a child of the i2c device */
		data->indio_dev->dev.parent = &client->dev;

		/* reduced attribute set for MAX517 */
		if (id->driver_data == ID_MAX517)
		data->indio_dev->attrs = &max517_attribute_group;
		else
		data->indio_dev->attrs = &max518_attribute_group;
		data->indio_dev->dev_data = (void *)(data);
		data->indio_dev->driver_module = THIS_MODULE;
		data->indio_dev->modes = INDIO_DIRECT_MODE;

		/*
		* Reference voltage on MAX518 and default is 5V, else take vref_mv
		* from platform_data
		*/
		if (id->driver_data == ID_MAX518 \|\| !platform_data) {
		data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
		} else {
		data->vref_mv[0] = platform_data->vref_mv[0];
		data->vref_mv[1] = platform_data->vref_mv[1];
		}

		err = iio_device_register(data->indio_dev);
		if (err)
		goto exit_free_device;

		dev_info(&client->dev, "DAC registered\n");

		return 0;

		exit_free_device:
		iio_free_device(data->indio_dev);
		exit_free_data:
		kfree(data);
		exit:
		return err;
		}

		static int max517_remove(struct i2c_client *client)
		{
		struct max517_data *data = i2c_get_clientdata(client);

		iio_free_device(data->indio_dev);
		kfree(data);

		return 0;
		}

		static const struct i2c_device_id max517_id[] = {
		{ "max517", ID_MAX517 },
		{ "max518", ID_MAX518 },
		{ "max519", ID_MAX519 },
		{ }
		};
		MODULE_DEVICE_TABLE(i2c, max517_id);

		static struct i2c_driver max517_driver = {
		.driver = {
		.name = MAX517_DRV_NAME,
		},
		.probe = max517_probe,
		.remove = max517_remove,
		.suspend = max517_suspend,
		.resume = max517_resume,
		.id_table = max517_id,
		};

		static int __init max517_init(void)
		{
		return i2c_add_driver(&max517_driver);
		}

		static void __exit max517_exit(void)
		{
		i2c_del_driver(&max517_driver);
		}

		MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
		MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
		MODULE_LICENSE("GPL");

		module_init(max517_init);
		module_exit(max517_exit);

drivers/staging/iio/dac/max517.h

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		/*
		* MAX517 DAC driver
		*
		* Copyright 2011 Roland Stigge <stigge@antcom.de>
		*
		* Licensed under the GPL-2 or later.
		*/
		#ifndef IIO_DAC_MAX517_H_
		#define IIO_DAC_MAX517_H_

		/*
		* TODO: struct max517_platform_data needs to go into include/linux/iio
		*/

		struct max517_platform_data {
		u16 vref_mv[2];
		};

		#endif /* IIO_DAC_MAX517_H_ */