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