drivers/hwmon/max197.c - pub/scm/linux/kernel/git/lee/backlight - Git at Google

 /*
  * 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 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) {
 		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 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 = 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");
	/*
	* 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 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) {
	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 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 = 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");