hwmon: add Maxim MAX197 support
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>
diff --git a/drivers/hwmon/max197.c b/drivers/hwmon/max197.c
new file mode 100644
index 0000000..6304f26
--- /dev/null
+++ b/drivers/hwmon/max197.c
@@ -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");