i2c: Convert the pcf8575 driver to a new-style i2c driver

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>

diff --git a/Documentation/i2c/chips/pcf8575 b/Documentation/i2c/chips/pcf8575
index 25f5698..40b268e 100644 (file)
--- a/Documentation/i2c/chips/pcf8575
+++ b/Documentation/i2c/chips/pcf8575
@@ -40,12 +40,9 @@ Detection
 ---------
 
 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
 --------------

diff --git a/drivers/i2c/chips/pcf8575.c b/drivers/i2c/chips/pcf8575.c
index 3ea08ac..07fd7cb 100644 (file)
--- a/drivers/i2c/chips/pcf8575.c
+++ b/drivers/i2c/chips/pcf8575.c
@@ -32,11 +32,8 @@
 #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;
@@ -44,24 +41,9 @@ I2C_CLIENT_INSMOD;
 
 /* Each client has this additional data */
 struct pcf8575_data {
-       struct i2c_client client;
        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)
@@ -126,75 +108,77 @@ static const struct attribute_group pcf8575_attr_group = {
  * Real code
  */
 
-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;
-       int err = 0;
-
-       if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
-               goto exit;
+       int err;
 
-       /* 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;
        }
 
-       client = &data->client;
        i2c_set_clientdata(client, data);
-       client->addr = address;
-       client->adapter = adapter;
-       client->driver = &pcf8575_driver;
-       strlcpy(client->name, "pcf8575", I2C_NAME_SIZE);
        data->write = -EAGAIN;
 
-       /* 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)
-               goto exit_detach;
+               goto exit_free;
 
        return 0;
 
-exit_detach:
-       i2c_detach_client(client);
 exit_free:
        kfree(data);
 exit:
        return err;
 }
 
-static int pcf8575_detach_client(struct i2c_client *client)
+static int pcf8575_remove(struct i2c_client *client)
 {
-       int err;
-
        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;
 }
 
+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);