/*
* 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/mod_devicetable.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 name_show(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_RO(name);
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 max197_probe(struct platform_device *pdev)
{
int ch, ret;
struct max197_data *data;
struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev);
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)
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 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 const 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",
},
.probe = max197_probe,
.remove = 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");
