[net-next-2.6.git] / drivers / hwmon / lm70.c

/*
 * lm70.c
 *
 * The LM70 is a temperature sensor chip from National Semiconductor (NS).
 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
 *
 * The LM70 communicates with a host processor via an SPI/Microwire Bus
 * interface. The complete datasheet is available at National's website
 * here:
 * http://www.national.com/pf/LM/LM70.html
 *
 * 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 <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/hwmon.h>
#include <linux/mutex.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>


#define DRVNAME		"lm70"

#define LM70_CHIP_LM70		0	/* original NS LM70 */
#define LM70_CHIP_TMP121	1	/* TI TMP121/TMP123 */

struct lm70 {
	struct device *hwmon_dev;
	struct mutex lock;
	unsigned int chip;
};

/* sysfs hook function */
static ssize_t lm70_sense_temp(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct spi_device *spi = to_spi_device(dev);
	int status, val = 0;
	u8 rxbuf[2];
	s16 raw=0;
	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);

	if (mutex_lock_interruptible(&p_lm70->lock))
		return -ERESTARTSYS;

	/*
	 * spi_read() requires a DMA-safe buffer; so we use
	 * spi_write_then_read(), transmitting 0 bytes.
	 */
	status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
	if (status < 0) {
		printk(KERN_WARNING
		"spi_write_then_read failed with status %d\n", status);
		goto out;
	}
	raw = (rxbuf[0] << 8) + rxbuf[1];
	dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
		rxbuf[0], rxbuf[1], raw);

	/*
	 * LM70:
	 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
	 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
	 * bits) are meaningful; the LSB 5 bits are to be discarded.
	 * See the datasheet.
	 *
	 * Further, each bit represents 0.25 degrees Celsius; so, multiply
	 * by 0.25. Also multiply by 1000 to represent in millidegrees
	 * Celsius.
	 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
	 *
	 * TMP121/TMP123:
	 * 13 bits of 2's complement data, discard LSB 3 bits,
	 * resolution 0.0625 degrees celsius.
	 */
	switch (p_lm70->chip) {
	case LM70_CHIP_LM70:
		val = ((int)raw / 32) * 250;
		break;

	case LM70_CHIP_TMP121:
		val = ((int)raw / 8) * 625 / 10;
		break;
	}

	status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
out:
	mutex_unlock(&p_lm70->lock);
	return status;
}

static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);

static ssize_t lm70_show_name(struct device *dev, struct device_attribute
			      *devattr, char *buf)
{
	struct lm70 *p_lm70 = dev_get_drvdata(dev);
	int ret;

	switch (p_lm70->chip) {
	case LM70_CHIP_LM70:
		ret = sprintf(buf, "lm70\n");
		break;
	case LM70_CHIP_TMP121:
		ret = sprintf(buf, "tmp121\n");
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}

static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);

/*----------------------------------------------------------------------*/

static int __devinit lm70_probe(struct spi_device *spi)
{
	int chip = spi_get_device_id(spi)->driver_data;
	struct lm70 *p_lm70;
	int status;

	/* signaling is SPI_MODE_0 for both LM70 and TMP121 */
	if (spi->mode & (SPI_CPOL | SPI_CPHA))
		return -EINVAL;

	/* 3-wire link (shared SI/SO) for LM70 */
	if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
		return -EINVAL;

	/* NOTE:  we assume 8-bit words, and convert to 16 bits manually */

	p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
	if (!p_lm70)
		return -ENOMEM;

	mutex_init(&p_lm70->lock);
	p_lm70->chip = chip;

	/* sysfs hook */
	p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
	if (IS_ERR(p_lm70->hwmon_dev)) {
		dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
		status = PTR_ERR(p_lm70->hwmon_dev);
		goto out_dev_reg_failed;
	}
	dev_set_drvdata(&spi->dev, p_lm70);

	if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
	 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
		dev_dbg(&spi->dev, "device_create_file failure.\n");
		goto out_dev_create_file_failed;
	}

	return 0;

out_dev_create_file_failed:
	device_remove_file(&spi->dev, &dev_attr_temp1_input);
	hwmon_device_unregister(p_lm70->hwmon_dev);
out_dev_reg_failed:
	dev_set_drvdata(&spi->dev, NULL);
	kfree(p_lm70);
	return status;
}

static int __devexit lm70_remove(struct spi_device *spi)
{
	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);

	device_remove_file(&spi->dev, &dev_attr_temp1_input);
	device_remove_file(&spi->dev, &dev_attr_name);
	hwmon_device_unregister(p_lm70->hwmon_dev);
	dev_set_drvdata(&spi->dev, NULL);
	kfree(p_lm70);

	return 0;
}


static const struct spi_device_id lm70_ids[] = {
	{ "lm70",   LM70_CHIP_LM70 },
	{ "tmp121", LM70_CHIP_TMP121 },
	{ },
};
MODULE_DEVICE_TABLE(spi, lm70_ids);

static struct spi_driver lm70_driver = {
	.driver = {
		.name	= "lm70",
		.owner	= THIS_MODULE,
	},
	.id_table = lm70_ids,
	.probe	= lm70_probe,
	.remove	= __devexit_p(lm70_remove),
};

static int __init init_lm70(void)
{
	return spi_register_driver(&lm70_driver);
}

static void __exit cleanup_lm70(void)
{
	spi_unregister_driver(&lm70_driver);
}

module_init(init_lm70);
module_exit(cleanup_lm70);

MODULE_AUTHOR("Kaiwan N Billimoria");
MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
e1a8e913 KB	1	/*
	2	* lm70.c
	3	*
	4	* The LM70 is a temperature sensor chip from National Semiconductor (NS).
	5	* Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
	6	*
	7	* The LM70 communicates with a host processor via an SPI/Microwire Bus
	8	* interface. The complete datasheet is available at National's website
	9	* here:
	10	* http://www.national.com/pf/LM/LM70.html
	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	* This program is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	20	* GNU General Public License for more details.
	21	*
	22	* You should have received a copy of the GNU General Public License
	23	* along with this program; if not, write to the Free Software
	24	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	25	*/
	26
	27	#include <linux/init.h>
	28	#include <linux/module.h>
	29	#include <linux/kernel.h>
	30	#include <linux/device.h>
	31	#include <linux/err.h>
	32	#include <linux/sysfs.h>
	33	#include <linux/hwmon.h>
4bfe6604	34	#include <linux/mutex.h>
8cec03ee	35	#include <linux/mod_devicetable.h>
e1a8e913	36	#include <linux/spi/spi.h>
5a0e3ad6	37	#include <linux/slab.h>
4bfe6604	38
e1a8e913 KB	39
	40	#define DRVNAME "lm70"
	41
c8ac32e4 ML	42	#define LM70_CHIP_LM70 0 /* original NS LM70 */
	43	#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
	44
e1a8e913	45	struct lm70 {
1beeffe4	46	struct device *hwmon_dev;
4bfe6604	47	struct mutex lock;
c8ac32e4	48	unsigned int chip;
e1a8e913 KB	49	};
	50
	51	/* sysfs hook function */
	52	static ssize_t lm70_sense_temp(struct device *dev,
	53	struct device_attribute attr, char buf)
	54	{
	55	struct spi_device *spi = to_spi_device(dev);
c8ac32e4	56	int status, val = 0;
e1a8e913 KB	57	u8 rxbuf[2];
	58	s16 raw=0;
	59	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
	60
4bfe6604	61	if (mutex_lock_interruptible(&p_lm70->lock))
e1a8e913 KB	62	return -ERESTARTSYS;
	63
	64	/*
	65	* spi_read() requires a DMA-safe buffer; so we use
	66	* spi_write_then_read(), transmitting 0 bytes.
	67	*/
	68	status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
	69	if (status < 0) {
	70	printk(KERN_WARNING
	71	"spi_write_then_read failed with status %d\n", status);
	72	goto out;
	73	}
2b730051 KB	74	raw = (rxbuf[0] << 8) + rxbuf[1];
	75	dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
	76	rxbuf[0], rxbuf[1], raw);
e1a8e913 KB	77
e1a8e913 KB	78	/*
c8ac32e4	79	* LM70:
e1a8e913 KB	80	* The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
	81	* complement value. Only the MSB 11 bits (1 sign + 10 temperature
	82	* bits) are meaningful; the LSB 5 bits are to be discarded.
	83	* See the datasheet.
	84	*
	85	* Further, each bit represents 0.25 degrees Celsius; so, multiply
	86	* by 0.25. Also multiply by 1000 to represent in millidegrees
	87	* Celsius.
	88	* So it's equivalent to multiplying by 0.25 * 1000 = 250.
c8ac32e4 ML	89	*
	90	* TMP121/TMP123:
	91	* 13 bits of 2's complement data, discard LSB 3 bits,
	92	* resolution 0.0625 degrees celsius.
e1a8e913	93	*/
c8ac32e4 ML	94	switch (p_lm70->chip) {
	95	case LM70_CHIP_LM70:
	96	val = ((int)raw / 32) * 250;
	97	break;
	98
	99	case LM70_CHIP_TMP121:
	100	val = ((int)raw / 8) * 625 / 10;
	101	break;
	102	}
	103
67f921d1	104	status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
e1a8e913	105	out:
4bfe6604	106	mutex_unlock(&p_lm70->lock);
e1a8e913 KB	107	return status;
	108	}
	109
	110	static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
	111
67f921d1 JD	112	static ssize_t lm70_show_name(struct device *dev, struct device_attribute
	113	devattr, char buf)
	114	{
c8ac32e4 ML	115	struct lm70 *p_lm70 = dev_get_drvdata(dev);
	116	int ret;
	117
	118	switch (p_lm70->chip) {
	119	case LM70_CHIP_LM70:
	120	ret = sprintf(buf, "lm70\n");
	121	break;
	122	case LM70_CHIP_TMP121:
	123	ret = sprintf(buf, "tmp121\n");
	124	break;
	125	default:
	126	ret = -EINVAL;
	127	}
	128	return ret;
67f921d1 JD	129	}
	130
	131	static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
	132
e1a8e913 KB	133	/----------------------------------------------------------------------/
e1a8e913 KB	134
8cec03ee	135	static int __devinit lm70_probe(struct spi_device *spi)
e1a8e913	136	{
8cec03ee	137	int chip = spi_get_device_id(spi)->driver_data;
e1a8e913 KB	138	struct lm70 *p_lm70;
	139	int status;
	140
8cec03ee AV	141	/* signaling is SPI_MODE_0 for both LM70 and TMP121 */
	142	if (spi->mode & (SPI_CPOL \| SPI_CPHA))
	143	return -EINVAL;
	144
	145	/* 3-wire link (shared SI/SO) for LM70 */
	146	if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
	147	return -EINVAL;
	148
2b730051 KB	149	/* NOTE: we assume 8-bit words, and convert to 16 bits manually */
2b730051 KB	150
e1a8e913 KB	151	p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
	152	if (!p_lm70)
	153	return -ENOMEM;
	154
4bfe6604	155	mutex_init(&p_lm70->lock);
c8ac32e4	156	p_lm70->chip = chip;
e1a8e913 KB	157
e1a8e913 KB	158	/* sysfs hook */
1beeffe4 TJ	159	p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
1beeffe4 TJ	160	if (IS_ERR(p_lm70->hwmon_dev)) {
e1a8e913	161	dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
1beeffe4	162	status = PTR_ERR(p_lm70->hwmon_dev);
e1a8e913 KB	163	goto out_dev_reg_failed;
	164	}
	165	dev_set_drvdata(&spi->dev, p_lm70);
	166
67f921d1 JD	167	if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
67f921d1 JD	168	\|\| (status = device_create_file(&spi->dev, &dev_attr_name))) {
e1a8e913 KB	169	dev_dbg(&spi->dev, "device_create_file failure.\n");
	170	goto out_dev_create_file_failed;
	171	}
	172
	173	return 0;
	174
	175	out_dev_create_file_failed:
67f921d1	176	device_remove_file(&spi->dev, &dev_attr_temp1_input);
1beeffe4	177	hwmon_device_unregister(p_lm70->hwmon_dev);
e1a8e913 KB	178	out_dev_reg_failed:
	179	dev_set_drvdata(&spi->dev, NULL);
	180	kfree(p_lm70);
	181	return status;
	182	}
	183
41be722b	184	static int __devexit lm70_remove(struct spi_device *spi)
e1a8e913 KB	185	{
	186	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
	187
	188	device_remove_file(&spi->dev, &dev_attr_temp1_input);
67f921d1	189	device_remove_file(&spi->dev, &dev_attr_name);
1beeffe4	190	hwmon_device_unregister(p_lm70->hwmon_dev);
e1a8e913 KB	191	dev_set_drvdata(&spi->dev, NULL);
	192	kfree(p_lm70);
	193
	194	return 0;
	195	}
	196
8cec03ee AV	197
	198	static const struct spi_device_id lm70_ids[] = {
	199	{ "lm70", LM70_CHIP_LM70 },
	200	{ "tmp121", LM70_CHIP_TMP121 },
	201	{ },
c8ac32e4	202	};
8cec03ee	203	MODULE_DEVICE_TABLE(spi, lm70_ids);
c8ac32e4	204
e1a8e913 KB	205	static struct spi_driver lm70_driver = {
	206	.driver = {
	207	.name = "lm70",
	208	.owner = THIS_MODULE,
	209	},
8cec03ee	210	.id_table = lm70_ids,
e1a8e913 KB	211	.probe = lm70_probe,
	212	.remove = __devexit_p(lm70_remove),
	213	};
	214
	215	static int __init init_lm70(void)
	216	{
8cec03ee	217	return spi_register_driver(&lm70_driver);
e1a8e913 KB	218	}
	219
	220	static void __exit cleanup_lm70(void)
	221	{
	222	spi_unregister_driver(&lm70_driver);
	223	}
	224
	225	module_init(init_lm70);
	226	module_exit(cleanup_lm70);
	227
	228	MODULE_AUTHOR("Kaiwan N Billimoria");
c8ac32e4	229	MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
e1a8e913	230	MODULE_LICENSE("GPL");