[deliverable/linux.git] / drivers / hwmon / mcp3021.c

/*
 * mcp3021.c - driver for the Microchip MCP3021 chip
 *
 * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
 * Author: Mingkai Hu <Mingkai.hu@freescale.com>
 *
 * This driver export the value of analog input voltage to sysfs, the
 * voltage unit is mV. Through the sysfs interface, lm-sensors tool
 * can also display the input voltage.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hwmon.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/device.h>

/* Vdd info */
#define MCP3021_VDD_MAX		5500
#define MCP3021_VDD_MIN		2700
#define MCP3021_VDD_REF		3300

/* output format */
#define MCP3021_SAR_SHIFT	2
#define MCP3021_SAR_MASK	0x3ff

#define MCP3021_OUTPUT_RES	10	/* 10-bit resolution */
#define MCP3021_OUTPUT_SCALE	4

/*
 * Client data (each client gets its own)
 */
struct mcp3021_data {
	struct device *hwmon_dev;
	u32 vdd;	/* device power supply */
};

static int mcp3021_read16(struct i2c_client *client)
{
	int ret;
	u16 reg;
	__be16 buf;

	ret = i2c_master_recv(client, (char *)&buf, 2);
	if (ret < 0)
		return ret;
	if (ret != 2)
		return -EIO;

	/* The output code of the MCP3021 is transmitted with MSB first. */
	reg = be16_to_cpu(buf);

	/*
	 * The ten-bit output code is composed of the lower 4-bit of the
	 * first byte and the upper 6-bit of the second byte.
	 */
	reg = (reg >> MCP3021_SAR_SHIFT) & MCP3021_SAR_MASK;

	return reg;
}

static inline u16 volts_from_reg(u16 vdd, u16 val)
{
	if (val == 0)
		return 0;

	val = val * MCP3021_OUTPUT_SCALE - MCP3021_OUTPUT_SCALE / 2;

	return val * DIV_ROUND_CLOSEST(vdd,
			(1 << MCP3021_OUTPUT_RES) * MCP3021_OUTPUT_SCALE);
}

static ssize_t show_in_input(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct mcp3021_data *data = i2c_get_clientdata(client);
	int reg, in_input;

	reg = mcp3021_read16(client);
	if (reg < 0)
		return reg;

	in_input = volts_from_reg(data->vdd, reg);
	return sprintf(buf, "%d\n", in_input);
}

static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);

static int mcp3021_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	int err;
	struct mcp3021_data *data = NULL;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);

	if (client->dev.platform_data) {
		data->vdd = *(u32 *)client->dev.platform_data;
		if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN)
			return -EINVAL;
	} else
		data->vdd = MCP3021_VDD_REF;

	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	if (err)
		return err;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return 0;

exit_remove:
	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	return err;
}

static int mcp3021_remove(struct i2c_client *client)
{
	struct mcp3021_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);

	return 0;
}

static const struct i2c_device_id mcp3021_id[] = {
	{ "mcp3021", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mcp3021_id);

static struct i2c_driver mcp3021_driver = {
	.driver = {
		.name = "mcp3021",
	},
	.probe = mcp3021_probe,
	.remove = mcp3021_remove,
	.id_table = mcp3021_id,
};

module_i2c_driver(mcp3021_driver);

MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
MODULE_DESCRIPTION("Microchip MCP3021 driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
5510e62a XX	1	/*
	2	* mcp3021.c - driver for the Microchip MCP3021 chip
	3	*
	4	* Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
	5	* Author: Mingkai Hu <Mingkai.hu@freescale.com>
	6	*
	7	* This driver export the value of analog input voltage to sysfs, the
	8	* voltage unit is mV. Through the sysfs interface, lm-sensors tool
	9	* can also display the input voltage.
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*/
	16
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/hwmon.h>
	20	#include <linux/slab.h>
	21	#include <linux/i2c.h>
	22	#include <linux/err.h>
	23	#include <linux/device.h>
	24
	25	/* Vdd info */
	26	#define MCP3021_VDD_MAX 5500
	27	#define MCP3021_VDD_MIN 2700
	28	#define MCP3021_VDD_REF 3300
	29
	30	/* output format */
	31	#define MCP3021_SAR_SHIFT 2
	32	#define MCP3021_SAR_MASK 0x3ff
	33
	34	#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
	35	#define MCP3021_OUTPUT_SCALE 4
	36
	37	/*
	38	* Client data (each client gets its own)
	39	*/
	40	struct mcp3021_data {
	41	struct device *hwmon_dev;
	42	u32 vdd; /* device power supply */
	43	};
	44
	45	static int mcp3021_read16(struct i2c_client *client)
	46	{
	47	int ret;
	48	u16 reg;
	49	__be16 buf;
	50
	51	ret = i2c_master_recv(client, (char *)&buf, 2);
	52	if (ret < 0)
	53	return ret;
	54	if (ret != 2)
	55	return -EIO;
	56
	57	/* The output code of the MCP3021 is transmitted with MSB first. */
	58	reg = be16_to_cpu(buf);
	59
	60	/*
	61	* The ten-bit output code is composed of the lower 4-bit of the
	62	* first byte and the upper 6-bit of the second byte.
	63	*/
	64	reg = (reg >> MCP3021_SAR_SHIFT) & MCP3021_SAR_MASK;
65
66	return reg;
67	}
68
69	static inline u16 volts_from_reg(u16 vdd, u16 val)
70	{
71	if (val == 0)
72	return 0;
73
74	val = val * MCP3021_OUTPUT_SCALE - MCP3021_OUTPUT_SCALE / 2;
75
76	return val * DIV_ROUND_CLOSEST(vdd,
77	(1 << MCP3021_OUTPUT_RES) * MCP3021_OUTPUT_SCALE);
78	}
79
80	static ssize_t show_in_input(struct device dev, struct device_attribute attr,
81	char *buf)
82	{
83	struct i2c_client *client = to_i2c_client(dev);
84	struct mcp3021_data *data = i2c_get_clientdata(client);
85	int reg, in_input;
86
87	reg = mcp3021_read16(client);
88	if (reg < 0)
89	return reg;
90
91	in_input = volts_from_reg(data->vdd, reg);
92	return sprintf(buf, "%d\n", in_input);
93	}
94
95	static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
96
97	static int mcp3021_probe(struct i2c_client *client,
98	const struct i2c_device_id *id)
99	{
100	int err;
101	struct mcp3021_data *data = NULL;
102
103	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
104	return -ENODEV;
105
79831fd4 GR	106	data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
79831fd4 GR	107	GFP_KERNEL);
5510e62a XX	108	if (!data)
	109	return -ENOMEM;
	110
	111	i2c_set_clientdata(client, data);
	112
	113	if (client->dev.platform_data) {
	114	data->vdd = (u32 )client->dev.platform_data;
79831fd4 GR	115	if (data->vdd > MCP3021_VDD_MAX \|\| data->vdd < MCP3021_VDD_MIN)
79831fd4 GR	116	return -EINVAL;
5510e62a XX	117	} else
	118	data->vdd = MCP3021_VDD_REF;
	119
	120	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	121	if (err)
79831fd4	122	return err;
5510e62a XX	123
	124	data->hwmon_dev = hwmon_device_register(&client->dev);
	125	if (IS_ERR(data->hwmon_dev)) {
	126	err = PTR_ERR(data->hwmon_dev);
	127	goto exit_remove;
	128	}
	129
	130	return 0;
	131
	132	exit_remove:
	133	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	134	return err;
	135	}
	136
	137	static int mcp3021_remove(struct i2c_client *client)
	138	{
	139	struct mcp3021_data *data = i2c_get_clientdata(client);
	140
	141	hwmon_device_unregister(data->hwmon_dev);
	142	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	143
	144	return 0;
	145	}
	146
	147	static const struct i2c_device_id mcp3021_id[] = {
	148	{ "mcp3021", 0 },
	149	{ }
	150	};
	151	MODULE_DEVICE_TABLE(i2c, mcp3021_id);
	152
	153	static struct i2c_driver mcp3021_driver = {
	154	.driver = {
	155	.name = "mcp3021",
	156	},
	157	.probe = mcp3021_probe,
	158	.remove = mcp3021_remove,
	159	.id_table = mcp3021_id,
	160	};
	161
	162	module_i2c_driver(mcp3021_driver);
	163
	164	MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
	165	MODULE_DESCRIPTION("Microchip MCP3021 driver");
	166	MODULE_LICENSE("GPL");