linux/drivers/i2c/chips/pcf8591.c
Jean Delvare 7d9db67feb i2c: __must_check fixes (chip drivers)
i2c: __must_check fixes (chip drivers)

Check for error on sysfs file creation.
Delete sysfs files on device removal.

The approach taken for the most complex case (pcf8591) is similar to
what Mark M. Hoffman proposed for hardware monitoring chip drivers.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Ben Gardner <bgardner@wabtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:51 -07:00

343 lines
9.7 KiB
C

/*
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);