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hwmon: add Maxim MAX197 support

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The MAX197 is an A/D converter, made by Maxim. This driver currently
supports the MAX197, and MAX199. They are both 8-Channel, Multi-Range,
5V, 12-Bit DAS with 8+4 Bus Interface and Fault Protection.

The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to
10V, while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Vivien Didelot 2012-08-30 21:42:57 -04:00 committed by Guenter Roeck
parent 37f9648b27
commit 6c1fe725fd
5 changed files with 440 additions and 0 deletions
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60
Documentation/hwmon/max197 Normal file
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@ -0,0 +1,60 @@
Maxim MAX197 driver
===================
Author:
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Supported chips:
* Maxim MAX197
Prefix: 'max197'
Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX197.pdf
* Maxim MAX199
Prefix: 'max199'
Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX199.pdf
Description
-----------
The A/D converters MAX197, and MAX199 are both 8-Channel, Multi-Range, 5V,
12-Bit DAS with 8+4 Bus Interface and Fault Protection.
The available ranges for the MAX197 are {0,-5V} to 5V, and {0,-10V} to 10V,
while they are {0,-2V} to 2V, and {0,-4V} to 4V on the MAX199.
Platform data
-------------
The MAX197 platform data (defined in linux/platform_data/max197.h) should be
filled with a pointer to a conversion function, defined like:
int convert(u8 ctrl);
ctrl is the control byte to write to start a new conversion.
On success, the function must return the 12-bit raw value read from the chip,
or a negative error code otherwise.
Control byte format:
Bit Name Description
7,6 PD1,PD0 Clock and Power-Down modes
5 ACQMOD Internal or External Controlled Acquisition
4 RNG Full-scale voltage magnitude at the input
3 BIP Unipolar or Bipolar conversion mode
2,1,0 A2,A1,A0 Channel
Sysfs interface
---------------
* in[0-7]_input: The conversion value for the corresponding channel.
RO
* in[0-7]_min: The lower limit (in mV) for the corresponding channel.
For the MAX197, it will be adjusted to -10000, -5000, or 0.
For the MAX199, it will be adjusted to -4000, -2000, or 0.
RW
* in[0-7]_max: The higher limit (in mV) for the corresponding channel.
For the MAX197, it will be adjusted to 0, 5000, or 10000.
For the MAX199, it will be adjusted to 0, 2000, or 4000.
RW

9
drivers/hwmon/Kconfig
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@ -813,6 +813,15 @@ config SENSORS_MAX1668
This driver can also be built as a module. If so, the module
will be called max1668.
config SENSORS_MAX197
tristate "Maxim MAX197 and compatibles"
help
Support for the Maxim MAX197 A/D converter.
Support will include, but not be limited to, MAX197, and MAX199.
This driver can also be built as a module. If so, the module
will be called max197.
config SENSORS_MAX6639
tristate "Maxim MAX6639 sensor chip"
depends on I2C && EXPERIMENTAL

1
drivers/hwmon/Makefile
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@ -95,6 +95,7 @@ obj-$(CONFIG_SENSORS_MAX1111) += max1111.o
obj-$(CONFIG_SENSORS_MAX16065) += max16065.o
obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
obj-$(CONFIG_SENSORS_MAX1668) += max1668.o
obj-$(CONFIG_SENSORS_MAX197) += max197.o
obj-$(CONFIG_SENSORS_MAX6639) += max6639.o
obj-$(CONFIG_SENSORS_MAX6642) += max6642.o
obj-$(CONFIG_SENSORS_MAX6650) += max6650.o

349
drivers/hwmon/max197.c Normal file
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@ -0,0 +1,349 @@
/*
* Maxim MAX197 A/D Converter driver
*
* Copyright (c) 2012 Savoir-faire Linux Inc.
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* For further information, see the Documentation/hwmon/max197 file.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/platform_device.h>
#include <linux/platform_data/max197.h>
#define MAX199_LIMIT 4000 /* 4V */
#define MAX197_LIMIT 10000 /* 10V */
#define MAX197_NUM_CH 8 /* 8 Analog Input Channels */
/* Control byte format */
#define MAX197_BIP (1 << 3) /* Bipolarity */
#define MAX197_RNG (1 << 4) /* Full range */
#define MAX197_SCALE 12207 /* Scale coefficient for raw data */
/* List of supported chips */
enum max197_chips { max197, max199 };
/**
* struct max197_data - device instance specific data
* @pdata: Platform data.
* @hwmon_dev: The hwmon device.
* @lock: Read/Write mutex.
* @limit: Max range value (10V for MAX197, 4V for MAX199).
* @scale: Need to scale.
* @ctrl_bytes: Channels control byte.
*/
struct max197_data {
struct max197_platform_data *pdata;
struct device *hwmon_dev;
struct mutex lock;
int limit;
bool scale;
u8 ctrl_bytes[MAX197_NUM_CH];
};
static inline void max197_set_unipolarity(struct max197_data *data, int channel)
{
data->ctrl_bytes[channel] &= ~MAX197_BIP;
}
static inline void max197_set_bipolarity(struct max197_data *data, int channel)
{
data->ctrl_bytes[channel] |= MAX197_BIP;
}
static inline void max197_set_half_range(struct max197_data *data, int channel)
{
data->ctrl_bytes[channel] &= ~MAX197_RNG;
}
static inline void max197_set_full_range(struct max197_data *data, int channel)
{
data->ctrl_bytes[channel] |= MAX197_RNG;
}
static inline bool max197_is_bipolar(struct max197_data *data, int channel)
{
return data->ctrl_bytes[channel] & MAX197_BIP;
}
static inline bool max197_is_full_range(struct max197_data *data, int channel)
{
return data->ctrl_bytes[channel] & MAX197_RNG;
}
/* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */
static ssize_t max197_show_range(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct max197_data *data = dev_get_drvdata(dev);
struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
int channel = attr->index;
bool is_min = attr->nr;
int range;
if (mutex_lock_interruptible(&data->lock))
return -ERESTARTSYS;
range = max197_is_full_range(data, channel) ?
data->limit : data->limit / 2;
if (is_min) {
if (max197_is_bipolar(data, channel))
range = -range;
else
range = 0;
}
mutex_unlock(&data->lock);
return sprintf(buf, "%d\n", range);
}
/* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */
static ssize_t max197_store_range(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max197_data *data = dev_get_drvdata(dev);
struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
int channel = attr->index;
bool is_min = attr->nr;
long value;
int half = data->limit / 2;
int full = data->limit;
if (kstrtol(buf, 10, &value))
return -EINVAL;
if (is_min) {
if (value <= -full)
value = -full;
else if (value < 0)
value = -half;
else
value = 0;
} else {
if (value >= full)
value = full;
else
value = half;
}
if (mutex_lock_interruptible(&data->lock))
return -ERESTARTSYS;
if (value == 0) {
/* We can deduce only the polarity */
max197_set_unipolarity(data, channel);
} else if (value == -half) {
max197_set_bipolarity(data, channel);
max197_set_half_range(data, channel);
} else if (value == -full) {
max197_set_bipolarity(data, channel);
max197_set_full_range(data, channel);
} else if (value == half) {
/* We can deduce only the range */
max197_set_half_range(data, channel);
} else if (value == full) {
/* We can deduce only the range */
max197_set_full_range(data, channel);
}
mutex_unlock(&data->lock);
return count;
}
/* Function called on read access on in{0,1,2,3,4,5,6,7}_input */
static ssize_t max197_show_input(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct max197_data *data = dev_get_drvdata(dev);
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
int channel = attr->index;
s32 value;
int ret;
if (mutex_lock_interruptible(&data->lock))
return -ERESTARTSYS;
ret = data->pdata->convert(data->ctrl_bytes[channel]);
if (ret < 0) {
dev_err(dev, "conversion failed\n");
goto unlock;
}
value = ret;
/*
* Coefficient to apply on raw value.
* See Table 1. Full Scale and Zero Scale in the MAX197 datasheet.
*/
if (data->scale) {
value *= MAX197_SCALE;
if (max197_is_full_range(data, channel))
value *= 2;
value /= 10000;
}
ret = sprintf(buf, "%d\n", value);
unlock:
mutex_unlock(&data->lock);
return ret;
}
static ssize_t max197_show_name(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
return sprintf(buf, "%s\n", pdev->name);
}
#define MAX197_SENSOR_DEVICE_ATTR_CH(chan) \
static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO, \
max197_show_input, NULL, chan); \
static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR, \
max197_show_range, \
max197_store_range, \
true, chan); \
static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR, \
max197_show_range, \
max197_store_range, \
false, chan)
#define MAX197_SENSOR_DEV_ATTR_IN(chan) \
&sensor_dev_attr_in##chan##_input.dev_attr.attr, \
&sensor_dev_attr_in##chan##_max.dev_attr.attr, \
&sensor_dev_attr_in##chan##_min.dev_attr.attr
static DEVICE_ATTR(name, S_IRUGO, max197_show_name, NULL);
MAX197_SENSOR_DEVICE_ATTR_CH(0);
MAX197_SENSOR_DEVICE_ATTR_CH(1);
MAX197_SENSOR_DEVICE_ATTR_CH(2);
MAX197_SENSOR_DEVICE_ATTR_CH(3);
MAX197_SENSOR_DEVICE_ATTR_CH(4);
MAX197_SENSOR_DEVICE_ATTR_CH(5);
MAX197_SENSOR_DEVICE_ATTR_CH(6);
MAX197_SENSOR_DEVICE_ATTR_CH(7);
static const struct attribute_group max197_sysfs_group = {
.attrs = (struct attribute *[]) {
&dev_attr_name.attr,
MAX197_SENSOR_DEV_ATTR_IN(0),
MAX197_SENSOR_DEV_ATTR_IN(1),
MAX197_SENSOR_DEV_ATTR_IN(2),
MAX197_SENSOR_DEV_ATTR_IN(3),
MAX197_SENSOR_DEV_ATTR_IN(4),
MAX197_SENSOR_DEV_ATTR_IN(5),
MAX197_SENSOR_DEV_ATTR_IN(6),
MAX197_SENSOR_DEV_ATTR_IN(7),
NULL
},
};
static int __devinit max197_probe(struct platform_device *pdev)
{
int ch, ret;
struct max197_data *data;
struct max197_platform_data *pdata = pdev->dev.platform_data;
enum max197_chips chip = platform_get_device_id(pdev)->driver_data;
if (pdata == NULL) {
dev_err(&pdev->dev, "no platform data supplied\n");
return -EINVAL;
}
if (pdata->convert == NULL) {
dev_err(&pdev->dev, "no convert function supplied\n");
return -EINVAL;
}
data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL);
if (!data) {
dev_err(&pdev->dev, "devm_kzalloc failed\n");
return -ENOMEM;
}
data->pdata = pdata;
mutex_init(&data->lock);
if (chip == max197) {
data->limit = MAX197_LIMIT;
data->scale = true;
} else {
data->limit = MAX199_LIMIT;
data->scale = false;
}
for (ch = 0; ch < MAX197_NUM_CH; ch++)
data->ctrl_bytes[ch] = (u8) ch;
platform_set_drvdata(pdev, data);
ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group);
if (ret) {
dev_err(&pdev->dev, "sysfs create group failed\n");
return ret;
}
data->hwmon_dev = hwmon_device_register(&pdev->dev);
if (IS_ERR(data->hwmon_dev)) {
ret = PTR_ERR(data->hwmon_dev);
dev_err(&pdev->dev, "hwmon device register failed\n");
goto error;
}
return 0;
error:
sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
return ret;
}
static int __devexit max197_remove(struct platform_device *pdev)
{
struct max197_data *data = platform_get_drvdata(pdev);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
return 0;
}
static struct platform_device_id max197_device_ids[] = {
{ "max197", max197 },
{ "max199", max199 },
{ }
};
MODULE_DEVICE_TABLE(platform, max197_device_ids);
static struct platform_driver max197_driver = {
.driver = {
.name = "max197",
.owner = THIS_MODULE,
},
.probe = max197_probe,
.remove = __devexit_p(max197_remove),
.id_table = max197_device_ids,
};
module_platform_driver(max197_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>");
MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");

21
include/linux/platform_data/max197.h Normal file
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@ -0,0 +1,21 @@
/*
* Maxim MAX197 A/D Converter Driver
*
* Copyright (c) 2012 Savoir-faire Linux Inc.
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* For further information, see the Documentation/hwmon/max197 file.
*/
/**
* struct max197_platform_data - MAX197 connectivity info
* @convert: Function used to start a conversion with control byte ctrl.
* It must return the raw data, or a negative error code.
*/
struct max197_platform_data {
int (*convert)(u8 ctrl);
};