/*
* adcxx.c
*
* The adcxx4s is an AD converter family from National Semiconductor (NS).
*
* Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
*
* The adcxx4s communicates with a host processor via an SPI/Microwire Bus
* interface. This driver supports the whole family of devices with name
* ADC<bb><c>S<sss>, where
* * bb is the resolution in number of bits (8, 10, 12)
* * c is the number of channels (1, 2, 4, 8)
* * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
* and 101 for 1 MSPS)
*
* Complete datasheets are available at National's website here:
* http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
*
* Handling of 8, 10 and 12 bits converters are the same, the
* unavailable bits are 0 :)
*
* 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/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/sysfs.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/mutex.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#define DRVNAME "adcxx"
struct adcxx {
struct device *hwmon_dev;
struct mutex lock;
u32 channels;
u32 reference; /* in millivolts */
};
/* sysfs hook function */
static ssize_t adcxx_read(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct adcxx *adc = spi_get_drvdata(spi);
u8 tx_buf[2];
u8 rx_buf[2];
int status;
u32 value;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
if (adc->channels == 1) {
status = spi_read(spi, rx_buf, sizeof(rx_buf));
} else {
tx_buf[0] = attr->index << 3; /* other bits are don't care */
status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
rx_buf, sizeof(rx_buf));
}
if (status < 0) {
dev_warn(dev, "SPI synch. transfer failed with status %d\n",
status);
goto out;
}
value = (rx_buf[0] << 8) + rx_buf[1];
dev_dbg(dev, "raw value = 0x%x\n", value);
value = value * adc->reference >> 12;
status = sprintf(buf, "%d\n", value);
out:
mutex_unlock(&adc->lock);
return status;
}
static ssize_t adcxx_show_min(struct device *dev,
struct device_attribute *devattr, char *buf)
{
/* The minimum reference is 0 for this chip family */
return sprintf(buf, "0\n");
}
static ssize_t adcxx_show_max(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct adcxx *adc = spi_get_drvdata(spi);
u32 reference;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
reference = adc->reference;
mutex_unlock(&adc->lock);
return sprintf(buf, "%d\n", reference);
}
static ssize_t adcxx_set_max(struct device *dev,
struct device_attribute *devattr, const char *buf, size_t count)
{
struct spi_device *spi = to_spi_device(dev);
struct adcxx *adc = spi_get_drvdata(spi);
unsigned long value;
if (kstrtoul(buf, 10, &value))
return -EINVAL;
if (mutex_lock_interruptible(&adc->lock))
return -ERESTARTSYS;
adc->reference = value;
mutex_unlock(&adc->lock);
return count;
}
static ssize_t adcxx_show_name(struct device *dev, struct device_attribute
*devattr, char *buf)
{
struct spi_device *spi = to_spi_device(dev);
struct adcxx *adc = spi_get_drvdata(spi);
return sprintf(buf, "adcxx%ds\n", adc->channels);
}
static struct sensor_device_attribute ad_input[] = {
SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
adcxx_set_max, 0),
SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
SENSOR_ATTR(in4_input, S_IRUGO, adcxx_read, NULL, 4),
SENSOR_ATTR(in5_input, S_IRUGO, adcxx_read, NULL, 5),
SENSOR_ATTR(in6_input, S_IRUGO, adcxx_read, NULL, 6),
SENSOR_ATTR(in7_input, S_IRUGO, adcxx_read, NULL, 7),
};
/*----------------------------------------------------------------------*/
static int __devinit adcxx_probe(struct spi_device *spi)
{
int channels = spi_get_device_id(spi)->driver_data;
struct adcxx *adc;
int status;
int i;
adc = kzalloc(sizeof *adc, GFP_KERNEL);
if (!adc)
return -ENOMEM;
/* set a default value for the reference */
adc->reference = 3300;
adc->channels = channels;
mutex_init(&adc->lock);
mutex_lock(&adc->lock);
spi_set_drvdata(spi, adc);
for (i = 0; i < 3 + adc->channels; i++) {
status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
if (status) {
dev_err(&spi->dev, "device_create_file failed.\n");
goto out_err;
}
}
adc->hwmon_dev = hwmon_device_register(&spi->dev);
if (IS_ERR(adc->hwmon_dev)) {
dev_err(&spi->dev, "hwmon_device_register failed.\n");
status = PTR_ERR(adc->hwmon_dev);
goto out_err;
}
mutex_unlock(&adc->lock);
return 0;
out_err:
for (i--; i >= 0; i--)
device_remove_file(&spi->dev, &ad_input[i].dev_attr);
spi_set_drvdata(spi, NULL);
mutex_unlock(&adc->lock);
kfree(adc);
return status;
}
static int __devexit adcxx_remove(struct spi_device *spi)
{
struct adcxx *adc = spi_get_drvdata(spi);
int i;
mutex_lock(&adc->lock);
hwmon_device_unregister(adc->hwmon_dev);
for (i = 0; i < 3 + adc->channels; i++)
device_remove_file(&spi->dev, &ad_input[i].dev_attr);
spi_set_drvdata(spi, NULL);
mutex_unlock(&adc->lock);
kfree(adc);
return 0;
}
static const struct spi_device_id adcxx_ids[] = {
{ "adcxx1s", 1 },
{ "adcxx2s", 2 },
{ "adcxx4s", 4 },
{ "adcxx8s", 8 },
{ },
};
MODULE_DEVICE_TABLE(spi, adcxx_ids);
static struct spi_driver adcxx_driver = {
.driver = {
.name = "adcxx",
.owner = THIS_MODULE,
},
.id_table = adcxx_ids,
.probe = adcxx_probe,
.remove = __devexit_p(adcxx_remove),
};
module_spi_driver(adcxx_driver);
MODULE_AUTHOR("Marc Pignat");
MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
MODULE_LICENSE("GPL");
