linux/drivers/hwmon/lm70.c

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/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#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 = spi_get_drvdata(spi);
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) {
pr_warn("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;
}
spi_set_drvdata(spi, 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:
spi_set_drvdata(spi, NULL);
kfree(p_lm70);
return status;
}
static int __devexit lm70_remove(struct spi_device *spi)
{
struct lm70 *p_lm70 = spi_get_drvdata(spi);
device_remove_file(&spi->dev, &dev_attr_temp1_input);
device_remove_file(&spi->dev, &dev_attr_name);
hwmon_device_unregister(p_lm70->hwmon_dev);
spi_set_drvdata(spi, 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");