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

/*
 * mcp3021.c - driver for Microchip MCP3021 and MCP3221
 *
 * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
 * Author: Mingkai Hu <[email protected]>
 * Reworked by Sven Schuchmann <[email protected]>
 *
 * 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

#define MCP3221_SAR_SHIFT	0
#define MCP3221_SAR_MASK	0xfff
#define MCP3221_OUTPUT_RES	12	/* 12-bit resolution */
#define MCP3221_OUTPUT_SCALE	1

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;
	u8 output_scale;
};

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)
{
	if (val == 0)
		return 0;

	val = val * data->output_scale - data->output_scale / 2;

	return val * DIV_ROUND_CLOSEST(data->vdd,
			(1 << data->output_res) * data->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, 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;
		data->output_scale = MCP3021_OUTPUT_SCALE;
		break;

	case mcp3221:
		data->sar_shift = MCP3221_SAR_SHIFT;
		data->sar_mask = MCP3221_SAR_MASK;
		data->output_res = MCP3221_OUTPUT_RES;
		data->output_scale = MCP3221_OUTPUT_SCALE;
		break;
	}

	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", 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 <[email protected]>");
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 <[email protected]>
8b662f38	6	* Reworked by Sven Schuchmann <[email protected]>
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
	34
	35	#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
	36	#define MCP3021_OUTPUT_SCALE 4
	37
592758b1 SS	38	#define MCP3221_SAR_SHIFT 0
	39	#define MCP3221_SAR_MASK 0xfff
	40	#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */
	41	#define MCP3221_OUTPUT_SCALE 1
	42
8b662f38	43	enum chips {
592758b1 SS	44	mcp3021,
592758b1 SS	45	mcp3221
8b662f38	46	};
592758b1	47
5510e62a XX	48	/*
	49	* Client data (each client gets its own)
	50	*/
	51	struct mcp3021_data {
	52	struct device *hwmon_dev;
	53	u32 vdd; /* device power supply */
8b662f38 SS	54	u16 sar_shift;
	55	u16 sar_mask;
	56	u8 output_res;
	57	u8 output_scale;
5510e62a XX	58	};
	59
	60	static int mcp3021_read16(struct i2c_client *client)
	61	{
8b662f38	62	struct mcp3021_data *data = i2c_get_clientdata(client);
5510e62a XX	63	int ret;
	64	u16 reg;
	65	__be16 buf;
	66
	67	ret = i2c_master_recv(client, (char *)&buf, 2);
	68	if (ret < 0)
	69	return ret;
	70	if (ret != 2)
	71	return -EIO;
	72
	73	/* The output code of the MCP3021 is transmitted with MSB first. */
	74	reg = be16_to_cpu(buf);
	75
	76	/*
	77	* The ten-bit output code is composed of the lower 4-bit of the
	78	* first byte and the upper 6-bit of the second byte.
	79	*/
8b662f38	80	reg = (reg >> data->sar_shift) & data->sar_mask;
5510e62a XX	81
	82	return reg;
	83	}
	84
8b662f38	85	static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
5510e62a XX	86	{
	87	if (val == 0)
	88	return 0;
	89
8b662f38	90	val = val * data->output_scale - data->output_scale / 2;
5510e62a	91
8b662f38 SS	92	return val * DIV_ROUND_CLOSEST(data->vdd,
8b662f38 SS	93	(1 << data->output_res) * data->output_scale);
5510e62a XX	94	}
	95
	96	static ssize_t show_in_input(struct device dev, struct device_attribute attr,
	97	char *buf)
	98	{
	99	struct i2c_client *client = to_i2c_client(dev);
	100	struct mcp3021_data *data = i2c_get_clientdata(client);
	101	int reg, in_input;
	102
	103	reg = mcp3021_read16(client);
	104	if (reg < 0)
	105	return reg;
	106
8b662f38 SS	107	in_input = volts_from_reg(data, reg);
8b662f38 SS	108
5510e62a XX	109	return sprintf(buf, "%d\n", in_input);
	110	}
	111
	112	static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
	113
	114	static int mcp3021_probe(struct i2c_client *client,
	115	const struct i2c_device_id *id)
	116	{
	117	int err;
	118	struct mcp3021_data *data = NULL;
	119
	120	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	121	return -ENODEV;
	122
79831fd4 GR	123	data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
79831fd4 GR	124	GFP_KERNEL);
5510e62a XX	125	if (!data)
	126	return -ENOMEM;
	127
	128	i2c_set_clientdata(client, data);
	129
8b662f38 SS	130	switch (id->driver_data) {
	131	case mcp3021:
	132	data->sar_shift = MCP3021_SAR_SHIFT;
	133	data->sar_mask = MCP3021_SAR_MASK;
	134	data->output_res = MCP3021_OUTPUT_RES;
	135	data->output_scale = MCP3021_OUTPUT_SCALE;
	136	break;
592758b1 SS	137
	138	case mcp3221:
	139	data->sar_shift = MCP3221_SAR_SHIFT;
	140	data->sar_mask = MCP3221_SAR_MASK;
	141	data->output_res = MCP3221_OUTPUT_RES;
	142	data->output_scale = MCP3221_OUTPUT_SCALE;
	143	break;
8b662f38 SS	144	}
8b662f38 SS	145
5510e62a XX	146	if (client->dev.platform_data) {
5510e62a XX	147	data->vdd = (u32 )client->dev.platform_data;
79831fd4 GR	148	if (data->vdd > MCP3021_VDD_MAX \|\| data->vdd < MCP3021_VDD_MIN)
79831fd4 GR	149	return -EINVAL;
5510e62a XX	150	} else
	151	data->vdd = MCP3021_VDD_REF;
	152
	153	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	154	if (err)
79831fd4	155	return err;
5510e62a XX	156
	157	data->hwmon_dev = hwmon_device_register(&client->dev);
	158	if (IS_ERR(data->hwmon_dev)) {
	159	err = PTR_ERR(data->hwmon_dev);
	160	goto exit_remove;
	161	}
	162
	163	return 0;
	164
	165	exit_remove:
	166	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	167	return err;
	168	}
	169
	170	static int mcp3021_remove(struct i2c_client *client)
	171	{
	172	struct mcp3021_data *data = i2c_get_clientdata(client);
	173
	174	hwmon_device_unregister(data->hwmon_dev);
	175	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
5510e62a XX	176
	177	return 0;
	178	}
	179
	180	static const struct i2c_device_id mcp3021_id[] = {
8b662f38	181	{ "mcp3021", mcp3021 },
592758b1	182	{ "mcp3221", mcp3221 },
5510e62a XX	183	{ }
	184	};
	185	MODULE_DEVICE_TABLE(i2c, mcp3021_id);
	186
	187	static struct i2c_driver mcp3021_driver = {
	188	.driver = {
	189	.name = "mcp3021",
	190	},
	191	.probe = mcp3021_probe,
	192	.remove = mcp3021_remove,
	193	.id_table = mcp3021_id,
	194	};
	195
	196	module_i2c_driver(mcp3021_driver);
	197
	198	MODULE_AUTHOR("Mingkai Hu <[email protected]>");
592758b1	199	MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver");
5510e62a	200	MODULE_LICENSE("GPL");