The new-style pcf8575 driver implements the optional detect() callback
to cover the use cases of the legacy driver.
Warning: users will now have to use the force module parameter to get
the driver to attach to their device. That's not a bad thing as these
devices can't be detected anyway.
Note that this doesn't change the fact that this driver is deprecated
in favor of gpio/pcf857x.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
---------
There is no method known to detect whether a chip on a given I2C address is
---------
There is no method known to detect whether a chip on a given I2C address is
-a PCF8575 or whether it is any other I2C device. So there are two alternatives
-to let the driver find the installed PCF8575 devices:
-- Load this driver after any other I2C driver for I2C devices with addresses
- in the range 0x20 .. 0x27.
-- Pass the I2C bus and address of the installed PCF8575 devices explicitly to
- the driver at load time via the probe=... or force=... parameters.
+a PCF8575 or whether it is any other I2C device, so you have to pass the I2C
+bus and address of the installed PCF8575 devices explicitly to the driver at
+load time via the force=... parameter.
/sys interface
--------------
/sys interface
--------------
#include <linux/slab.h> /* kzalloc() */
#include <linux/sysfs.h> /* sysfs_create_group() */
#include <linux/slab.h> /* kzalloc() */
#include <linux/sysfs.h> /* sysfs_create_group() */
-/* Addresses to scan */
-static const unsigned short normal_i2c[] = {
- 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
- I2C_CLIENT_END
-};
+/* Addresses to scan: none, device can't be detected */
+static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD;
/* Insmod parameters */
I2C_CLIENT_INSMOD;
/* Each client has this additional data */
struct pcf8575_data {
/* Each client has this additional data */
struct pcf8575_data {
- struct i2c_client client;
int write; /* last written value, or error code */
};
int write; /* last written value, or error code */
};
-static int pcf8575_attach_adapter(struct i2c_adapter *adapter);
-static int pcf8575_detect(struct i2c_adapter *adapter, int address, int kind);
-static int pcf8575_detach_client(struct i2c_client *client);
-
-/* This is the driver that will be inserted */
-static struct i2c_driver pcf8575_driver = {
- .driver = {
- .owner = THIS_MODULE,
- .name = "pcf8575",
- },
- .attach_adapter = pcf8575_attach_adapter,
- .detach_client = pcf8575_detach_client,
-};
-
/* following are the sysfs callback functions */
static ssize_t show_read(struct device *dev, struct device_attribute *attr,
char *buf)
/* following are the sysfs callback functions */
static ssize_t show_read(struct device *dev, struct device_attribute *attr,
char *buf)
-static int pcf8575_attach_adapter(struct i2c_adapter *adapter)
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int pcf8575_detect(struct i2c_client *client, int kind,
+ struct i2c_board_info *info)
- return i2c_probe(adapter, &addr_data, pcf8575_detect);
+ struct i2c_adapter *adapter = client->adapter;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ /* This is the place to detect whether the chip at the specified
+ address really is a PCF8575 chip. However, there is no method known
+ to detect whether an I2C chip is a PCF8575 or any other I2C chip. */
+
+ strlcpy(info->type, "pcf8575", I2C_NAME_SIZE);
+
+ return 0;
-/* This function is called by i2c_probe */
-static int pcf8575_detect(struct i2c_adapter *adapter, int address, int kind)
+static int pcf8575_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
- struct i2c_client *client;
struct pcf8575_data *data;
struct pcf8575_data *data;
- int err = 0;
-
- if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
- 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. */
data = kzalloc(sizeof(struct pcf8575_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
data = kzalloc(sizeof(struct pcf8575_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
- client = &data->client;
i2c_set_clientdata(client, data);
i2c_set_clientdata(client, data);
- client->addr = address;
- client->adapter = adapter;
- client->driver = &pcf8575_driver;
- strlcpy(client->name, "pcf8575", I2C_NAME_SIZE);
- /* This is the place to detect whether the chip at the specified
- address really is a PCF8575 chip. However, there is no method known
- to detect whether an I2C chip is a PCF8575 or any other I2C chip. */
-
- /* Tell the I2C layer a new client has arrived */
- err = i2c_attach_client(client);
- if (err)
- goto exit_free;
-
/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &pcf8575_attr_group);
if (err)
/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &pcf8575_attr_group);
if (err)
-exit_detach:
- i2c_detach_client(client);
exit_free:
kfree(data);
exit:
return err;
}
exit_free:
kfree(data);
exit:
return err;
}
-static int pcf8575_detach_client(struct i2c_client *client)
+static int pcf8575_remove(struct i2c_client *client)
sysfs_remove_group(&client->dev.kobj, &pcf8575_attr_group);
sysfs_remove_group(&client->dev.kobj, &pcf8575_attr_group);
-
- err = i2c_detach_client(client);
- if (err)
- return err;
-
kfree(i2c_get_clientdata(client));
return 0;
}
kfree(i2c_get_clientdata(client));
return 0;
}
+static const struct i2c_device_id pcf8575_id[] = {
+ { "pcf8575", 0 },
+ { }
+};
+
+static struct i2c_driver pcf8575_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "pcf8575",
+ },
+ .probe = pcf8575_probe,
+ .remove = pcf8575_remove,
+ .id_table = pcf8575_id,
+
+ .detect = pcf8575_detect,
+ .address_data = &addr_data,
+};
+
static int __init pcf8575_init(void)
{
return i2c_add_driver(&pcf8575_driver);
static int __init pcf8575_init(void)
{
return i2c_add_driver(&pcf8575_driver);