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path: root/drivers/aiodev/lm75.c
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/*
 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
 *	 monitoring
 * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <common.h>
#include <driver.h>
#include <xfuncs.h>
#include <i2c/i2c.h>
#include <aiodev.h>

/*
 * This driver handles the LM75 and compatible digital temperature sensors.
 */

/* straight from the datasheet */
#define LM75_TEMP_MIN (-55000)
#define LM75_TEMP_MAX 125000
#define LM75_SHUTDOWN 0x01

enum lm75_type {		/* keep sorted in alphabetical order */
	adt75,
	ds1775,
	ds75,
	ds7505,
	g751,
	lm75,
	lm75a,
	lm75b,
	max6625,
	max6626,
	mcp980x,
	stds75,
	tcn75,
	tmp100,
	tmp101,
	tmp105,
	tmp112,
	tmp175,
	tmp275,
	tmp75,
	tmp75c,
};

/* The LM75 registers */
#define LM75_REG_CONF		0x01
static const u8 LM75_REG_TEMP[3] = {
	0x00,		/* input */
	0x03,		/* max */
	0x02,		/* hyst */
};

/* Each client has this additional data */
struct lm75_data {
	struct i2c_client	*client;
	struct device_d		dev;
	u8			resolution;	/* In bits, between 9 and 12 */
	struct aiochannel	aiochan;
	struct aiodevice	aiodev;
};

static int lm75_read_value(struct lm75_data *data, u8 reg)
{
	if (reg == LM75_REG_CONF)
		return i2c_smbus_read_byte_data(data->client, reg);
	else
		return i2c_smbus_read_word_swapped(data->client, reg);
}

static int lm75_write_value(struct lm75_data *data, u8 reg, u16 value)
{
	if (reg == LM75_REG_CONF)
		return i2c_smbus_write_byte_data(data->client, reg, value);
	else
		return i2c_smbus_write_word_swapped(data->client, reg, value);
}

static long lm75_reg_to_mc(s16 temp, u8 resolution)
{
	return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
}

static int lm75_get_temp(struct aiochannel *chan, int *val)
{
	struct lm75_data *data = container_of(chan, struct lm75_data, aiochan);
	int status;

	status = lm75_read_value(data, LM75_REG_TEMP[0]);
	if (status < 0) {
		dev_err(&data->client->dev,
			"LM75: Failed to read value: reg %d, error %d\n",
			LM75_REG_TEMP[0], status);
		return status;
	}

	*val = lm75_reg_to_mc(status, data->resolution);

	return 0;
}

static int lm75_probe(struct device_d *dev)
{
	struct lm75_data *data;
	int status;
	u8 set_mask, clr_mask;
	int new, ret;
	enum lm75_type kind;

	ret = dev_get_drvdata(dev, (const void **)&kind);
	if (ret)
		return ret;

	data = xzalloc(sizeof(*data));

	data->client = to_i2c_client(dev);

	/* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
	 * Then tweak to be more precise when appropriate.
	 */
	set_mask = 0;
	clr_mask = LM75_SHUTDOWN;		/* continuous conversions */

	switch (kind) {
	case adt75:
		clr_mask |= 1 << 5;		/* not one-shot mode */
		data->resolution = 12;
		break;
	case ds1775:
	case ds75:
	case stds75:
		clr_mask |= 3 << 5;
		set_mask |= 2 << 5;		/* 11-bit mode */
		data->resolution = 11;
		break;
	case ds7505:
		set_mask |= 3 << 5;		/* 12-bit mode */
		data->resolution = 12;
		break;
	case g751:
	case lm75:
	case lm75a:
		data->resolution = 9;
		break;
	case lm75b:
		data->resolution = 11;
		break;
	case max6625:
		data->resolution = 9;
		break;
	case max6626:
		data->resolution = 12;
		break;
	case tcn75:
		data->resolution = 9;
		break;
	case mcp980x:
		/* fall through */
	case tmp100:
	case tmp101:
		set_mask |= 3 << 5;		/* 12-bit mode */
		data->resolution = 12;
		clr_mask |= 1 << 7;		/* not one-shot mode */
		break;
	case tmp112:
		set_mask |= 3 << 5;		/* 12-bit mode */
		clr_mask |= 1 << 7;		/* not one-shot mode */
		data->resolution = 12;
		break;
	case tmp105:
	case tmp175:
	case tmp275:
	case tmp75:
		set_mask |= 3 << 5;		/* 12-bit mode */
		clr_mask |= 1 << 7;		/* not one-shot mode */
		data->resolution = 12;
		break;
	case tmp75c:
		clr_mask |= 1 << 5;		/* not one-shot mode */
		data->resolution = 12;
		break;
	}

	/* configure as specified */
	status = lm75_read_value(data, LM75_REG_CONF);
	if (status < 0) {
		dev_dbg(dev, "Can't read config? %d\n", status);
		return status;
	}

	new = status & ~clr_mask;
	new |= set_mask;
	if (status != new)
		lm75_write_value(data, LM75_REG_CONF, new);

	data->aiodev.num_channels = 1;
	data->aiodev.hwdev = dev;
	data->aiodev.read = lm75_get_temp;
	data->aiodev.channels = xmalloc(sizeof(void *));
	data->aiodev.channels[0] = &data->aiochan;
	data->aiochan.unit = "mC";

	ret = aiodevice_register(&data->aiodev);
	if (ret)
		return ret;

	return 0;
}

static const struct platform_device_id lm75_ids[] = {
	{ .name = "adt75", .driver_data = adt75, },
	{ .name = "ds1775", .driver_data = ds1775, },
	{ .name = "ds75", .driver_data = ds75, },
	{ .name = "ds7505", .driver_data = ds7505, },
	{ .name = "g751", .driver_data = g751, },
	{ .name = "lm75", .driver_data = lm75, },
	{ .name = "lm75a", .driver_data = lm75a, },
	{ .name = "lm75b", .driver_data = lm75b, },
	{ .name = "max6625", .driver_data = max6625, },
	{ .name = "max6626", .driver_data = max6626, },
	{ .name = "mcp980x", .driver_data = mcp980x, },
	{ .name = "stds75", .driver_data = stds75, },
	{ .name = "tcn75", .driver_data = tcn75, },
	{ .name = "tmp100", .driver_data = tmp100, },
	{ .name = "tmp101", .driver_data = tmp101, },
	{ .name = "tmp105", .driver_data = tmp105, },
	{ .name = "tmp112", .driver_data = tmp112, },
	{ .name = "tmp175", .driver_data = tmp175, },
	{ .name = "tmp275", .driver_data = tmp275, },
	{ .name = "tmp75", .driver_data = tmp75, },
	{ .name = "tmp75c", .driver_data = tmp75c, },
	{ /* LIST END */ }
};

static struct driver_d lm75_driver = {
	.name  = "lm75",
	.probe = lm75_probe,
	.id_table = lm75_ids,
};
device_i2c_driver(lm75_driver);