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OpenCloudOS-Kernel/drivers/i2c/chips/pcf8591.c

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/*
pcf8591.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
the help of Jean Delvare <khali@linux-fr.org>
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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD_1(pcf8591);
static int input_mode;
module_param(input_mode, int, 0);
MODULE_PARM_DESC(input_mode,
"Analog input mode:\n"
" 0 = four single ended inputs\n"
" 1 = three differential inputs\n"
" 2 = single ended and differential mixed\n"
" 3 = two differential inputs\n");
/* The PCF8591 control byte
7 6 5 4 3 2 1 0
| 0 |AOEF| AIP | 0 |AINC| AICH | */
/* Analog Output Enable Flag (analog output active if 1) */
#define PCF8591_CONTROL_AOEF 0x40
/* Analog Input Programming
0x00 = four single ended inputs
0x10 = three differential inputs
0x20 = single ended and differential mixed
0x30 = two differential inputs */
#define PCF8591_CONTROL_AIP_MASK 0x30
/* Autoincrement Flag (switch on if 1) */
#define PCF8591_CONTROL_AINC 0x04
/* Channel selection
0x00 = channel 0
0x01 = channel 1
0x02 = channel 2
0x03 = channel 3 */
#define PCF8591_CONTROL_AICH_MASK 0x03
/* Initial values */
#define PCF8591_INIT_CONTROL ((input_mode << 4) | PCF8591_CONTROL_AOEF)
#define PCF8591_INIT_AOUT 0 /* DAC out = 0 */
/* Conversions */
#define REG_TO_SIGNED(reg) (((reg) & 0x80)?((reg) - 256):(reg))
struct pcf8591_data {
struct i2c_client client;
struct mutex update_lock;
u8 control;
u8 aout;
};
static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
static int pcf8591_detach_client(struct i2c_client *client);
static void pcf8591_init_client(struct i2c_client *client);
static int pcf8591_read_channel(struct device *dev, int channel);
/* This is the driver that will be inserted */
static struct i2c_driver pcf8591_driver = {
.driver = {
.name = "pcf8591",
},
.id = I2C_DRIVERID_PCF8591,
.attach_adapter = pcf8591_attach_adapter,
.detach_client = pcf8591_detach_client,
};
/* following are the sysfs callback functions */
#define show_in_channel(channel) \
static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
} \
static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
show_in##channel##_input, NULL);
show_in_channel(0);
show_in_channel(1);
show_in_channel(2);
show_in_channel(3);
static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
{
struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
return sprintf(buf, "%d\n", data->aout * 10);
}
static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
unsigned int value;
struct i2c_client *client = to_i2c_client(dev);
struct pcf8591_data *data = i2c_get_clientdata(client);
if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
data->aout = value;
i2c_smbus_write_byte_data(client, data->control, data->aout);
return count;
}
return -EINVAL;
}
static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
show_out0_ouput, set_out0_output);
static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
{
struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
}
static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct pcf8591_data *data = i2c_get_clientdata(client);
unsigned long val = simple_strtoul(buf, NULL, 10);
mutex_lock(&data->update_lock);
if (val)
data->control |= PCF8591_CONTROL_AOEF;
else
data->control &= ~PCF8591_CONTROL_AOEF;
i2c_smbus_write_byte(client, data->control);
mutex_unlock(&data->update_lock);
return count;
}
static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
show_out0_enable, set_out0_enable);
static struct attribute *pcf8591_attributes[] = {
&dev_attr_out0_enable.attr,
&dev_attr_out0_output.attr,
&dev_attr_in0_input.attr,
&dev_attr_in1_input.attr,
NULL
};
static const struct attribute_group pcf8591_attr_group = {
.attrs = pcf8591_attributes,
};
static struct attribute *pcf8591_attributes_opt[] = {
&dev_attr_in2_input.attr,
&dev_attr_in3_input.attr,
NULL
};
static const struct attribute_group pcf8591_attr_group_opt = {
.attrs = pcf8591_attributes_opt,
};
/*
* Real code
*/
static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
{
return i2c_probe(adapter, &addr_data, pcf8591_detect);
}
/* This function is called by i2c_probe */
static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *new_client;
struct pcf8591_data *data;
int err = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
| I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
goto exit;
/* OK. For now, we presume we have a valid client. We now create the
client structure, even though we cannot fill it completely yet. */
if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
new_client = &data->client;
i2c_set_clientdata(new_client, data);
new_client->addr = address;
new_client->adapter = adapter;
new_client->driver = &pcf8591_driver;
new_client->flags = 0;
/* Now, we would do the remaining detection. But the PCF8591 is plainly
impossible to detect! Stupid chip. */
/* Determine the chip type - only one kind supported! */
if (kind <= 0)
kind = pcf8591;
/* Fill in the remaining client fields and put it into the global
list */
strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
mutex_init(&data->update_lock);
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(new_client)))
goto exit_kfree;
/* Initialize the PCF8591 chip */
pcf8591_init_client(new_client);
/* Register sysfs hooks */
err = sysfs_create_group(&new_client->dev.kobj, &pcf8591_attr_group);
if (err)
goto exit_detach;
/* Register input2 if not in "two differential inputs" mode */
if (input_mode != 3) {
if ((err = device_create_file(&new_client->dev,
&dev_attr_in2_input)))
goto exit_sysfs_remove;
}
/* Register input3 only in "four single ended inputs" mode */
if (input_mode == 0) {
if ((err = device_create_file(&new_client->dev,
&dev_attr_in3_input)))
goto exit_sysfs_remove;
}
return 0;
exit_sysfs_remove:
sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group_opt);
sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group);
exit_detach:
i2c_detach_client(new_client);
exit_kfree:
kfree(data);
exit:
return err;
}
static int pcf8591_detach_client(struct i2c_client *client)
{
int err;
sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
if ((err = i2c_detach_client(client)))
return err;
kfree(i2c_get_clientdata(client));
return 0;
}
/* Called when we have found a new PCF8591. */
static void pcf8591_init_client(struct i2c_client *client)
{
struct pcf8591_data *data = i2c_get_clientdata(client);
data->control = PCF8591_INIT_CONTROL;
data->aout = PCF8591_INIT_AOUT;
i2c_smbus_write_byte_data(client, data->control, data->aout);
/* The first byte transmitted contains the conversion code of the
previous read cycle. FLUSH IT! */
i2c_smbus_read_byte(client);
}
static int pcf8591_read_channel(struct device *dev, int channel)
{
u8 value;
struct i2c_client *client = to_i2c_client(dev);
struct pcf8591_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
| channel;
i2c_smbus_write_byte(client, data->control);
/* The first byte transmitted contains the conversion code of
the previous read cycle. FLUSH IT! */
i2c_smbus_read_byte(client);
}
value = i2c_smbus_read_byte(client);
mutex_unlock(&data->update_lock);
if ((channel == 2 && input_mode == 2) ||
(channel != 3 && (input_mode == 1 || input_mode == 3)))
return (10 * REG_TO_SIGNED(value));
else
return (10 * value);
}
static int __init pcf8591_init(void)
{
if (input_mode < 0 || input_mode > 3) {
printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
input_mode);
input_mode = 0;
}
return i2c_add_driver(&pcf8591_driver);
}
static void __exit pcf8591_exit(void)
{
i2c_del_driver(&pcf8591_driver);
}
MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
MODULE_DESCRIPTION("PCF8591 driver");
MODULE_LICENSE("GPL");
module_init(pcf8591_init);
module_exit(pcf8591_exit);
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