linux/drivers/hwmon/lm70.c
Thomas Gleixner 74ba9207e1 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:36:45 +02:00

208 lines
4.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*/
#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;
}
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);
}
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");