[linux-2.6-block.git] / drivers / hwmon / mcp3021.c

/*
 * mcp3021.c - driver for Microchip MCP3021 and MCP3221
 *
 * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
 * Author: Mingkai Hu <Mingkai.hu@freescale.com>
 * Reworked by Sven Schuchmann <schuchmann@schleissheimer.de>
 *
 * 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 MCP3221_SAR_SHIFT	0
#define MCP3221_SAR_MASK	0xfff
#define MCP3221_OUTPUT_RES	12	/* 12-bit resolution */

enum chips {
	mcp3021,
	mcp3221
};

/*
 * Client data (each client gets its own)
 */
struct mcp3021_data {
	struct device *hwmon_dev;
	u32 vdd;	/* device power supply */
	u16 sar_shift;
	u16 sar_mask;
	u8 output_res;
};

static int mcp3021_read16(struct i2c_client *client)
{
	struct mcp3021_data *data = i2c_get_clientdata(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 >> data->sar_shift) & data->sar_mask;

	return reg;
}

static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
{
	return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
}

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, 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);

	switch (id->driver_data) {
	case mcp3021:
		data->sar_shift = MCP3021_SAR_SHIFT;
		data->sar_mask = MCP3021_SAR_MASK;
		data->output_res = MCP3021_OUTPUT_RES;
		break;

	case mcp3221:
		data->sar_shift = MCP3221_SAR_SHIFT;
		data->sar_mask = MCP3221_SAR_MASK;
		data->output_res = MCP3221_OUTPUT_RES;
		break;
	}

	if (dev_get_platdata(&client->dev)) {
		data->vdd = *(u32 *)dev_get_platdata(&client->dev);
		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", mcp3021 },
	{ "mcp3221", mcp3221 },
	{ }
};
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/MCP3221 driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
5510e62a	1	/*
592758b1	2	* mcp3021.c - driver for Microchip MCP3021 and MCP3221
5510e62a XX	3	*
	4	* Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
	5	* Author: Mingkai Hu <Mingkai.hu@freescale.com>
8b662f38	6	* Reworked by Sven Schuchmann <schuchmann@schleissheimer.de>
5510e62a XX	7	*
	8	* This driver export the value of analog input voltage to sysfs, the
	9	* voltage unit is mV. Through the sysfs interface, lm-sensors tool
	10	* can also display the input voltage.
	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License as published by
	14	* the Free Software Foundation; either version 2 of the License, or
	15	* (at your option) any later version.
	16	*/
	17
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/hwmon.h>
	21	#include <linux/slab.h>
	22	#include <linux/i2c.h>
	23	#include <linux/err.h>
	24	#include <linux/device.h>
	25
	26	/* Vdd info */
	27	#define MCP3021_VDD_MAX 5500
	28	#define MCP3021_VDD_MIN 2700
	29	#define MCP3021_VDD_REF 3300
	30
	31	/* output format */
	32	#define MCP3021_SAR_SHIFT 2
	33	#define MCP3021_SAR_MASK 0x3ff
5510e62a	34	#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
5510e62a	35
592758b1 SS	36	#define MCP3221_SAR_SHIFT 0
	37	#define MCP3221_SAR_MASK 0xfff
	38	#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */
592758b1	39
8b662f38	40	enum chips {
592758b1 SS	41	mcp3021,
592758b1 SS	42	mcp3221
8b662f38	43	};
592758b1	44
5510e62a XX	45	/*
	46	* Client data (each client gets its own)
	47	*/
	48	struct mcp3021_data {
	49	struct device *hwmon_dev;
	50	u32 vdd; /* device power supply */
8b662f38 SS	51	u16 sar_shift;
	52	u16 sar_mask;
	53	u8 output_res;
5510e62a XX	54	};
	55
	56	static int mcp3021_read16(struct i2c_client *client)
	57	{
8b662f38	58	struct mcp3021_data *data = i2c_get_clientdata(client);
5510e62a XX	59	int ret;
	60	u16 reg;
	61	__be16 buf;
	62
	63	ret = i2c_master_recv(client, (char *)&buf, 2);
	64	if (ret < 0)
	65	return ret;
	66	if (ret != 2)
	67	return -EIO;
	68
	69	/* The output code of the MCP3021 is transmitted with MSB first. */
	70	reg = be16_to_cpu(buf);
	71
	72	/*
	73	* The ten-bit output code is composed of the lower 4-bit of the
	74	* first byte and the upper 6-bit of the second byte.
	75	*/
8b662f38	76	reg = (reg >> data->sar_shift) & data->sar_mask;
5510e62a XX	77
	78	return reg;
	79	}
	80
8b662f38	81	static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
5510e62a	82	{
347d7e45	83	return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
5510e62a XX	84	}
	85
	86	static ssize_t show_in_input(struct device dev, struct device_attribute attr,
	87	char *buf)
	88	{
	89	struct i2c_client *client = to_i2c_client(dev);
	90	struct mcp3021_data *data = i2c_get_clientdata(client);
	91	int reg, in_input;
	92
	93	reg = mcp3021_read16(client);
	94	if (reg < 0)
	95	return reg;
	96
8b662f38 SS	97	in_input = volts_from_reg(data, reg);
8b662f38 SS	98
5510e62a XX	99	return sprintf(buf, "%d\n", in_input);
	100	}
	101
	102	static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
	103
	104	static int mcp3021_probe(struct i2c_client *client,
	105	const struct i2c_device_id *id)
	106	{
	107	int err;
	108	struct mcp3021_data *data = NULL;
	109
	110	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	111	return -ENODEV;
	112
79831fd4 GR	113	data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
79831fd4 GR	114	GFP_KERNEL);
5510e62a XX	115	if (!data)
	116	return -ENOMEM;
	117
	118	i2c_set_clientdata(client, data);
	119
8b662f38 SS	120	switch (id->driver_data) {
	121	case mcp3021:
	122	data->sar_shift = MCP3021_SAR_SHIFT;
	123	data->sar_mask = MCP3021_SAR_MASK;
	124	data->output_res = MCP3021_OUTPUT_RES;
8b662f38	125	break;
592758b1 SS	126
	127	case mcp3221:
	128	data->sar_shift = MCP3221_SAR_SHIFT;
	129	data->sar_mask = MCP3221_SAR_MASK;
	130	data->output_res = MCP3221_OUTPUT_RES;
592758b1	131	break;
8b662f38 SS	132	}
8b662f38 SS	133
a8b3a3a5 JH	134	if (dev_get_platdata(&client->dev)) {
a8b3a3a5 JH	135	data->vdd = (u32 )dev_get_platdata(&client->dev);
79831fd4 GR	136	if (data->vdd > MCP3021_VDD_MAX \|\| data->vdd < MCP3021_VDD_MIN)
79831fd4 GR	137	return -EINVAL;
a8b3a3a5	138	} else {
5510e62a	139	data->vdd = MCP3021_VDD_REF;
a8b3a3a5	140	}
5510e62a XX	141
	142	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	143	if (err)
79831fd4	144	return err;
5510e62a XX	145
	146	data->hwmon_dev = hwmon_device_register(&client->dev);
	147	if (IS_ERR(data->hwmon_dev)) {
	148	err = PTR_ERR(data->hwmon_dev);
	149	goto exit_remove;
	150	}
	151
	152	return 0;
	153
	154	exit_remove:
	155	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	156	return err;
	157	}
	158
	159	static int mcp3021_remove(struct i2c_client *client)
	160	{
	161	struct mcp3021_data *data = i2c_get_clientdata(client);
	162
	163	hwmon_device_unregister(data->hwmon_dev);
	164	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	165
	166	return 0;
	167	}
	168
	169	static const struct i2c_device_id mcp3021_id[] = {
8b662f38	170	{ "mcp3021", mcp3021 },
592758b1	171	{ "mcp3221", mcp3221 },
5510e62a XX	172	{ }
	173	};
	174	MODULE_DEVICE_TABLE(i2c, mcp3021_id);
	175
	176	static struct i2c_driver mcp3021_driver = {
	177	.driver = {
	178	.name = "mcp3021",
	179	},
	180	.probe = mcp3021_probe,
	181	.remove = mcp3021_remove,
	182	.id_table = mcp3021_id,
	183	};
	184
	185	module_i2c_driver(mcp3021_driver);
	186
	187	MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
592758b1	188	MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver");
5510e62a	189	MODULE_LICENSE("GPL");