Release 4.12 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.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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>
#include <linux/of_device.h>



#define DRVNAME		"lm70"


#define LM70_CHIP_LM70		0	
/* original NS LM70 */

#define LM70_CHIP_TMP121	1	
/* TI TMP121/TMP123 */

#define LM70_CHIP_LM71		2	
/* NS LM71 */

#define LM70_CHIP_LM74		3	
/* NS LM74 */

#define LM70_CHIP_TMP122	4	
/* TI TMP122/TMP124 */


struct lm70 {
	
struct spi_device *spi;
	
struct mutex lock;
	
unsigned int chip;
};

/* sysfs hook function */


static ssize_t temp1_input_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct lm70 *p_lm70 = dev_get_drvdata(dev);
	struct spi_device *spi = p_lm70->spi;
	int status, val = 0;
	u8 rxbuf[2];
	s16 raw = 0;

	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) {
		dev_warn(dev, "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.
         *
         * LM74 and TMP121/TMP122/TMP123/TMP124:
         * 13 bits of 2's complement data, discard LSB 3 bits,
         * resolution 0.0625 degrees celsius.
         *
         * LM71:
         * 14 bits of 2's complement data, discard LSB 2 bits,
         * resolution 0.0312 degrees celsius.
         */
	switch (p_lm70->chip) {
	case LM70_CHIP_LM70:
		val = ((int)raw / 32) * 250;
		break;

	case LM70_CHIP_TMP121:
	case LM70_CHIP_TMP122:
	case LM70_CHIP_LM74:
		val = ((int)raw / 8) * 625 / 10;
		break;

	case LM70_CHIP_LM71:
		val = ((int)raw / 4) * 3125 / 100;
		break;
	}

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

Contributors
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CommitProp
Kaiwan N Billimoria
161
66.80%
2
20.00%
Manuel Lauss
33
13.69%
1
10.00%
Christophe Leroy
22
9.13%
1
10.00%
Guenter Roeck
12
4.98%
1
10.00%
Florian Fainelli
7
2.90%
2
20.00%
Matthias Kaehlcke
4
1.66%
1
10.00%
Julia Lawall
1
0.41%
1
10.00%
Jean Delvare
1
0.41%
1
10.00%
Total
241
100.00%
10
100.00%

static DEVICE_ATTR_RO(temp1_input);


static struct attribute *lm70_attrs[] = {
	&dev_attr_temp1_input.attr,
	NULL
};


ATTRIBUTE_GROUPS(lm70);

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

#ifdef CONFIG_OF

static const struct of_device_id lm70_of_ids[] = {
	{
		.compatible = "ti,lm70",
		.data = (void *) LM70_CHIP_LM70,
        },
	{
		.compatible = "ti,tmp121",
		.data = (void *) LM70_CHIP_TMP121,
        },
	{
		.compatible = "ti,tmp122",
		.data = (void *) LM70_CHIP_TMP122,
        },
	{
		.compatible = "ti,lm71",
		.data = (void *) LM70_CHIP_LM71,
        },
	{
		.compatible = "ti,lm74",
		.data = (void *) LM70_CHIP_LM74,
        },
	{},
};
MODULE_DEVICE_TABLE(of, lm70_of_ids);
#endif



static int lm70_probe(struct spi_device *spi)
{
	const struct of_device_id *match;
	struct device *hwmon_dev;
	struct lm70 *p_lm70;
	int chip;

	match = of_match_device(lm70_of_ids, &spi->dev);
	if (match)
		chip = (int)(uintptr_t)match->data;
	else
		chip = spi_get_device_id(spi)->driver_data;

	/* signaling is SPI_MODE_0 */
	if (spi->mode & (SPI_CPOL | SPI_CPHA))
		return -EINVAL;

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

	p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
	if (!p_lm70)
		return -ENOMEM;

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

	hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev,
							   spi->modalias,
							   p_lm70, lm70_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

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CommitProp
Kaiwan N Billimoria
48
30.57%
2
18.18%
Rabin Vincent
46
29.30%
1
9.09%
Guenter Roeck
27
17.20%
3
27.27%
Anton Vorontsov
18
11.46%
1
9.09%
Jean Delvare
9
5.73%
1
9.09%
Manuel Lauss
6
3.82%
1
9.09%
Matthias Kaehlcke
2
1.27%
1
9.09%
Christophe Leroy
1
0.64%
1
9.09%
Total
157
100.00%
11
100.00%


static const struct spi_device_id lm70_ids[] = {
	{ "lm70",   LM70_CHIP_LM70 },
	{ "tmp121", LM70_CHIP_TMP121 },
	{ "tmp122", LM70_CHIP_TMP122 },
	{ "lm71",   LM70_CHIP_LM71 },
	{ "lm74",   LM70_CHIP_LM74 },
	{ },
};
MODULE_DEVICE_TABLE(spi, lm70_ids);


static struct spi_driver lm70_driver = {
	.driver = {
		.name	= "lm70",
		.of_match_table	= of_match_ptr(lm70_of_ids),
        },
	.id_table = lm70_ids,
	.probe	= lm70_probe,
};


module_spi_driver(lm70_driver);

MODULE_AUTHOR("Kaiwan N Billimoria");
MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
MODULE_LICENSE("GPL");
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Kaiwan N Billimoria
297
41.02%
2
11.76%
Rabin Vincent
142
19.61%
1
5.88%
Manuel Lauss
63
8.70%
1
5.88%
Guenter Roeck
54
7.46%
3
17.65%
Christophe Leroy
46
6.35%
1
5.88%
Anton Vorontsov
46
6.35%
1
5.88%
Florian Fainelli
34
4.70%
2
11.76%
Jean Delvare
18
2.49%
1
5.88%
Matthias Kaehlcke
10
1.38%
1
5.88%
Joe Perches
7
0.97%
1
5.88%
Tejun Heo
3
0.41%
1
5.88%
Axel Lin
2
0.28%
1
5.88%
Julia Lawall
2
0.28%
1
5.88%
Total
724
100.00%
17
100.00%
Directory: drivers/hwmon

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