1 files changed, 141 insertions, 274 deletions

diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index fbcff96f4ca1..3d8d36b0ad12 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -1,5 +1,5 @@
 This is a small guide for those who want to write kernel drivers for I2C
-or SMBus devices.
+or SMBus devices, using Linux as the protocol host/master (not slave).
 
 To set up a driver, you need to do several things. Some are optional, and
 some things can be done slightly or completely different. Use this as a
@@ -29,8 +29,16 @@ static struct i2c_driver foo_driver = {
         .driver = {
                 .name   = "foo",
         },
+
+        /* iff driver uses driver model ("new style") binding model: */
+        .probe          = foo_probe,
+        .remove         = foo_remove,
+
+        /* else, driver uses "legacy" binding model: */
         .attach_adapter = foo_attach_adapter,
         .detach_client  = foo_detach_client,
+
+        /* these may be used regardless of the driver binding model */
         .shutdown       = foo_shutdown, /* optional */
         .suspend        = foo_suspend,  /* optional */
         .resume         = foo_resume,   /* optional */
@@ -40,7 +48,8 @@ static struct i2c_driver foo_driver = {
 The name field is the driver name, and must not contain spaces.  It
 should match the module name (if the driver can be compiled as a module),
 although you can use MODULE_ALIAS (passing "foo" in this example) to add
-another name for the module.
+another name for the module.  If the driver name doesn't match the module
+name, the module won't be automatically loaded (hotplug/coldplug).
 
 All other fields are for call-back functions which will be explained 
 below.
@@ -65,16 +74,13 @@ An example structure is below.
 
   struct foo_data {
     struct i2c_client client;
-    struct semaphore lock; /* For ISA access in `sensors' drivers. */
-    int sysctl_id;         /* To keep the /proc directory entry for 
-                              `sensors' drivers. */
     enum chips type;       /* To keep the chips type for `sensors' drivers. */
    
     /* Because the i2c bus is slow, it is often useful to cache the read
        information of a chip for some time (for example, 1 or 2 seconds).
        It depends of course on the device whether this is really worthwhile
        or even sensible. */
-    struct semaphore update_lock; /* When we are reading lots of information,
+    struct mutex update_lock;     /* When we are reading lots of information,
                                      another process should not update the
                                      below information */
     char valid;                   /* != 0 if the following fields are valid. */
@@ -95,8 +101,7 @@ some obscure clients). But we need generic reading and writing routines.
 I have found it useful to define foo_read and foo_write function for this.
 For some cases, it will be easier to call the i2c functions directly,
 but many chips have some kind of register-value idea that can easily
-be encapsulated. Also, some chips have both ISA and I2C interfaces, and
-it useful to abstract from this (only for `sensors' drivers).
+be encapsulated.
 
 The below functions are simple examples, and should not be copied
 literally.
@@ -119,28 +124,101 @@ literally.
       return i2c_smbus_write_word_data(client,reg,value);
   }
 
-For sensors code, you may have to cope with ISA registers too. Something
-like the below often works. Note the locking! 
-
-  int foo_read_value(struct i2c_client *client, u8 reg)
-  {
-    int res;
-    if (i2c_is_isa_client(client)) {
-      down(&(((struct foo_data *) (client->data)) -> lock));
-      outb_p(reg,client->addr + FOO_ADDR_REG_OFFSET);
-      res = inb_p(client->addr + FOO_DATA_REG_OFFSET);
-      up(&(((struct foo_data *) (client->data)) -> lock));
-      return res;
-    } else
-      return i2c_smbus_read_byte_data(client,reg);
-  }
-
-Writing is done the same way.
-
 
 Probing and attaching
 =====================
 
+The Linux I2C stack was originally written to support access to hardware
+monitoring chips on PC motherboards, and thus it embeds some assumptions
+that are more appropriate to SMBus (and PCs) than to I2C.  One of these
+assumptions is that most adapters and devices drivers support the SMBUS_QUICK
+protocol to probe device presence.  Another is that devices and their drivers
+can be sufficiently configured using only such probe primitives.
+
+As Linux and its I2C stack became more widely used in embedded systems
+and complex components such as DVB adapters, those assumptions became more
+problematic.  Drivers for I2C devices that issue interrupts need more (and
+different) configuration information, as do drivers handling chip variants
+that can't be distinguished by protocol probing, or which need some board
+specific information to operate correctly.
+
+Accordingly, the I2C stack now has two models for associating I2C devices
+with their drivers:  the original "legacy" model, and a newer one that's
+fully compatible with the Linux 2.6 driver model.  These models do not mix,
+since the "legacy" model requires drivers to create "i2c_client" device
+objects after SMBus style probing, while the Linux driver model expects
+drivers to be given such device objects in their probe() routines.
+
+
+Standard Driver Model Binding ("New Style")
+-------------------------------------------
+
+System infrastructure, typically board-specific initialization code or
+boot firmware, reports what I2C devices exist.  For example, there may be
+a table, in the kernel or from the boot loader, identifying I2C devices
+and linking them to board-specific configuration information about IRQs
+and other wiring artifacts, chip type, and so on.  That could be used to
+create i2c_client objects for each I2C device.
+
+I2C device drivers using this binding model work just like any other
+kind of driver in Linux:  they provide a probe() method to bind to
+those devices, and a remove() method to unbind.
+
+        static int foo_probe(struct i2c_client *client);
+        static int foo_remove(struct i2c_client *client);
+
+Remember that the i2c_driver does not create those client handles.  The
+handle may be used during foo_probe().  If foo_probe() reports success
+(zero not a negative status code) it may save the handle and use it until
+foo_remove() returns.  That binding model is used by most Linux drivers.
+
+Drivers match devices when i2c_client.driver_name and the driver name are
+the same; this approach is used in several other busses that don't have
+device typing support in the hardware.  The driver and module name should
+match, so hotplug/coldplug mechanisms will modprobe the driver.
+
+
+Device Creation (Standard driver model)
+---------------------------------------
+
+If you know for a fact that an I2C device is connected to a given I2C bus,
+you can instantiate that device by simply filling an i2c_board_info
+structure with the device address and driver name, and calling
+i2c_new_device().  This will create the device, then the driver core will
+take care of finding the right driver and will call its probe() method.
+If a driver supports different device types, you can specify the type you
+want using the type field.  You can also specify an IRQ and platform data
+if needed.
+
+Sometimes you know that a device is connected to a given I2C bus, but you
+don't know the exact address it uses.  This happens on TV adapters for
+example, where the same driver supports dozens of slightly different
+models, and I2C device addresses change from one model to the next.  In
+that case, you can use the i2c_new_probed_device() variant, which is
+similar to i2c_new_device(), except that it takes an additional list of
+possible I2C addresses to probe.  A device is created for the first
+responsive address in the list.  If you expect more than one device to be
+present in the address range, simply call i2c_new_probed_device() that
+many times.
+
+The call to i2c_new_device() or i2c_new_probed_device() typically happens
+in the I2C bus driver. You may want to save the returned i2c_client
+reference for later use.
+
+
+Device Deletion (Standard driver model)
+---------------------------------------
+
+Each I2C device which has been created using i2c_new_device() or
+i2c_new_probed_device() can be unregistered by calling
+i2c_unregister_device().  If you don't call it explicitly, it will be
+called automatically before the underlying I2C bus itself is removed, as a
+device can't survive its parent in the device driver model.
+
+
+Legacy Driver Binding Model
+---------------------------
+
 Most i2c devices can be present on several i2c addresses; for some this
 is determined in hardware (by soldering some chip pins to Vcc or Ground),
 for others this can be changed in software (by writing to specific client
@@ -157,13 +235,9 @@ detection algorithm.
 You do not have to use this parameter interface; but don't try to use
 function i2c_probe() if you don't.
 
-NOTE: If you want to write a `sensors' driver, the interface is slightly
-      different! See below.
-
 
-
-Probing classes
----------------
+Probing classes (Legacy model)
+------------------------------
 
 All parameters are given as lists of unsigned 16-bit integers. Lists are
 terminated by I2C_CLIENT_END.
@@ -210,8 +284,8 @@ Note that you *have* to call the defined variable `normal_i2c',
 without any prefix!
 
 
-Attaching to an adapter
------------------------
+Attaching to an adapter (Legacy model)
+--------------------------------------
 
 Whenever a new adapter is inserted, or for all adapters if the driver is
 being registered, the callback attach_adapter() is called. Now is the
@@ -237,17 +311,13 @@ them (unless a `force' parameter was used). In addition, addresses that
 are already in use (by some other registered client) are skipped.
 
 
-The detect client function
---------------------------
+The detect client function (Legacy model)
+-----------------------------------------
 
 The detect client function is called by i2c_probe. The `kind' parameter
 contains -1 for a probed detection, 0 for a forced detection, or a positive
 number for a forced detection with a chip type forced.
 
-Below, some things are only needed if this is a `sensors' driver. Those
-parts are between /* SENSORS ONLY START */ and /* SENSORS ONLY END */
-markers. 
-
 Returning an error different from -ENODEV in a detect function will cause
 the detection to stop: other addresses and adapters won't be scanned.
 This should only be done on fatal or internal errors, such as a memory
@@ -256,64 +326,20 @@ shortage or i2c_attach_client failing.
 For now, you can ignore the `flags' parameter. It is there for future use.
 
   int foo_detect_client(struct i2c_adapter *adapter, int address, 
-                        unsigned short flags, int kind)
+                        int kind)
   {
     int err = 0;
     int i;
-    struct i2c_client *new_client;
+    struct i2c_client *client;
     struct foo_data *data;
-    const char *client_name = ""; /* For non-`sensors' drivers, put the real
-                                     name here! */
+    const char *name = "";
    
     /* Let's see whether this adapter can support what we need.
-       Please substitute the things you need here! 
-       For `sensors' drivers, add `! is_isa &&' to the if statement */
+       Please substitute the things you need here! */
     if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA |
                                         I2C_FUNC_SMBUS_WRITE_BYTE))
        goto ERROR0;
 
-    /* SENSORS ONLY START */
-    const char *type_name = "";
-    int is_isa = i2c_is_isa_adapter(adapter);
-
-    /* Do this only if the chip can additionally be found on the ISA bus
-       (hybrid chip). */
-
-    if (is_isa) {
-
-      /* Discard immediately if this ISA range is already used */
-      /* FIXME: never use check_region(), only request_region() */
-      if (check_region(address,FOO_EXTENT))
-        goto ERROR0;
-
-      /* Probe whether there is anything on this address.
-         Some example code is below, but you will have to adapt this
-         for your own driver */
-
-      if (kind < 0) /* Only if no force parameter was used */ {
-        /* We may need long timeouts at least for some chips. */
-        #define REALLY_SLOW_IO
-        i = inb_p(address + 1);
-        if (inb_p(address + 2) != i)
-          goto ERROR0;
-        if (inb_p(address + 3) != i)
-          goto ERROR0;
-        if (inb_p(address + 7) != i)
-          goto ERROR0;
-        #undef REALLY_SLOW_IO
-
-        /* Let's just hope nothing breaks here */
-        i = inb_p(address + 5) & 0x7f;
-        outb_p(~i & 0x7f,address+5);
-        if ((inb_p(address + 5) & 0x7f) != (~i & 0x7f)) {
-          outb_p(i,address+5);
-          return 0;
-        }
-      }
-    }
-
-    /* SENSORS ONLY END */
-
     /* OK. For now, we presume we have a valid client. We now create the
        client structure, even though we cannot fill it completely yet.
        But it allows us to access several i2c functions safely */
@@ -323,13 +349,12 @@ For now, you can ignore the `flags' parameter. It is there for future use.
       goto ERROR0;
     }
 
-    new_client = &data->client;
-    i2c_set_clientdata(new_client, data);
+    client = &data->client;
+    i2c_set_clientdata(client, data);
 
-    new_client->addr = address;
-    new_client->adapter = adapter;
-    new_client->driver = &foo_driver;
-    new_client->flags = 0;
+    client->addr = address;
+    client->adapter = adapter;
+    client->driver = &foo_driver;
 
     /* Now, we do the remaining detection. If no `force' parameter is used. */
 
@@ -337,19 +362,17 @@ For now, you can ignore the `flags' parameter. It is there for future use.
        parameter was used. */
     if (kind < 0) {
       /* The below is of course bogus */
-      if (foo_read(new_client,FOO_REG_GENERIC) != FOO_GENERIC_VALUE)
+      if (foo_read(client, FOO_REG_GENERIC) != FOO_GENERIC_VALUE)
          goto ERROR1;
     }
 
-    /* SENSORS ONLY START */
-
     /* Next, specific detection. This is especially important for `sensors'
        devices. */
 
     /* Determine the chip type. Not needed if a `force_CHIPTYPE' parameter
        was used. */
     if (kind <= 0) {
-      i = foo_read(new_client,FOO_REG_CHIPTYPE);
+      i = foo_read(client, FOO_REG_CHIPTYPE);
       if (i == FOO_TYPE_1) 
         kind = chip1; /* As defined in the enum */
       else if (i == FOO_TYPE_2)
@@ -363,63 +386,31 @@ For now, you can ignore the `flags' parameter. It is there for future use.
 
     /* Now set the type and chip names */
     if (kind == chip1) {
-      type_name = "chip1"; /* For /proc entry */
-      client_name = "CHIP 1";
+      name = "chip1";
     } else if (kind == chip2) {
-      type_name = "chip2"; /* For /proc entry */
-      client_name = "CHIP 2";
+      name = "chip2";
     }
    
-    /* Reserve the ISA region */
-    if (is_isa)
-      request_region(address,FOO_EXTENT,type_name);
-
-    /* SENSORS ONLY END */
-
     /* Fill in the remaining client fields. */
-    strcpy(new_client->name,client_name);
-
-    /* SENSORS ONLY BEGIN */
+    strlcpy(client->name, name, I2C_NAME_SIZE);
     data->type = kind;
-    /* SENSORS ONLY END */
-
-    data->valid = 0; /* Only if you use this field */
-    init_MUTEX(&data->update_lock); /* Only if you use this field */
+    mutex_init(&data->update_lock); /* Only if you use this field */
 
     /* Any other initializations in data must be done here too. */
 
-    /* Tell the i2c layer a new client has arrived */
-    if ((err = i2c_attach_client(new_client)))
-      goto ERROR3;
-
-    /* SENSORS ONLY BEGIN */
-    /* Register a new directory entry with module sensors. See below for
-       the `template' structure. */
-    if ((i = i2c_register_entry(new_client, type_name,
-                                    foo_dir_table_template,THIS_MODULE)) < 0) {
-      err = i;
-      goto ERROR4;
-    }
-    data->sysctl_id = i;
-
-    /* SENSORS ONLY END */
-
     /* This function can write default values to the client registers, if
        needed. */
-    foo_init_client(new_client);
+    foo_init_client(client);
+
+    /* Tell the i2c layer a new client has arrived */
+    if ((err = i2c_attach_client(client)))
+      goto ERROR1;
+
     return 0;
 
     /* OK, this is not exactly good programming practice, usually. But it is
        very code-efficient in this case. */
 
-    ERROR4:
-      i2c_detach_client(new_client);
-    ERROR3:
-    ERROR2:
-    /* SENSORS ONLY START */
-      if (is_isa)
-        release_region(address,FOO_EXTENT);
-    /* SENSORS ONLY END */
     ERROR1:
       kfree(data);
     ERROR0:
@@ -427,8 +418,8 @@ For now, you can ignore the `flags' parameter. It is there for future use.
   }
 
 
-Removing the client
-===================
+Removing the client (Legacy model)
+==================================
 
 The detach_client call back function is called when a client should be
 removed. It may actually fail, but only when panicking. This code is
@@ -436,22 +427,12 @@ much simpler than the attachment code, fortunately!
 
   int foo_detach_client(struct i2c_client *client)
   {
-    int err,i;
-
-    /* SENSORS ONLY START */
-    /* Deregister with the `i2c-proc' module. */
-    i2c_deregister_entry(((struct lm78_data *)(client->data))->sysctl_id);
-    /* SENSORS ONLY END */
+    int err;
 
     /* Try to detach the client from i2c space */
     if ((err = i2c_detach_client(client)))
       return err;
 
-    /* HYBRID SENSORS CHIP ONLY START */
-    if i2c_is_isa_client(client)
-      release_region(client->addr,LM78_EXTENT);
-    /* HYBRID SENSORS CHIP ONLY END */
-
     kfree(i2c_get_clientdata(client));
     return 0;
   }
@@ -464,45 +445,34 @@ When the kernel is booted, or when your foo driver module is inserted,
 you have to do some initializing. Fortunately, just attaching (registering)
 the driver module is usually enough.
 
-  /* Keep track of how far we got in the initialization process. If several
-     things have to initialized, and we fail halfway, only those things
-     have to be cleaned up! */
-  static int __initdata foo_initialized = 0;
-
   static int __init foo_init(void)
   {
     int res;
-    printk("foo version %s (%s)\n",FOO_VERSION,FOO_DATE);
     
     if ((res = i2c_add_driver(&foo_driver))) {
       printk("foo: Driver registration failed, module not inserted.\n");
-      foo_cleanup();
       return res;
     }
-    foo_initialized ++;
     return 0;
   }
 
-  void foo_cleanup(void)
+  static void __exit foo_cleanup(void)
   {
-    if (foo_initialized == 1) {
-      if ((res = i2c_del_driver(&foo_driver))) {
-        printk("foo: Driver registration failed, module not removed.\n");
-        return;
-      }
-      foo_initialized --;
-    }
+    i2c_del_driver(&foo_driver);
   }
 
   /* Substitute your own name and email address */
   MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"
   MODULE_DESCRIPTION("Driver for Barf Inc. Foo I2C devices");
 
+  /* a few non-GPL license types are also allowed */
+  MODULE_LICENSE("GPL");
+
   module_init(foo_init);
   module_exit(foo_cleanup);
 
 Note that some functions are marked by `__init', and some data structures
-by `__init_data'.  Hose functions and structures can be removed after
+by `__initdata'.  These functions and structures can be removed after
 kernel booting (or module loading) is completed.
 
 
@@ -632,110 +602,7 @@ General purpose routines
 Below all general purpose routines are listed, that were not mentioned
 before.
 
-  /* This call returns a unique low identifier for each registered adapter,
-   * or -1 if the adapter was not registered.
+  /* This call returns a unique low identifier for each registered adapter.
    */
   extern int i2c_adapter_id(struct i2c_adapter *adap);
 
-
-The sensors sysctl/proc interface
-=================================
-
-This section only applies if you write `sensors' drivers.
-
-Each sensors driver creates a directory in /proc/sys/dev/sensors for each
-registered client. The directory is called something like foo-i2c-4-65.
-The sensors module helps you to do this as easily as possible.
-
-The template
-------------
-
-You will need to define a ctl_table template. This template will automatically
-be copied to a newly allocated structure and filled in where necessary when
-you call sensors_register_entry.
-
-First, I will give an example definition.
-  static ctl_table foo_dir_table_template[] = {
-    { FOO_SYSCTL_FUNC1, "func1", NULL, 0, 0644, NULL, &i2c_proc_real,
-      &i2c_sysctl_real,NULL,&foo_func },
-    { FOO_SYSCTL_FUNC2, "func2", NULL, 0, 0644, NULL, &i2c_proc_real,
-      &i2c_sysctl_real,NULL,&foo_func },
-    { FOO_SYSCTL_DATA, "data", NULL, 0, 0644, NULL, &i2c_proc_real,
-      &i2c_sysctl_real,NULL,&foo_data },
-    { 0 }
-  };
-
-In the above example, three entries are defined. They can either be
-accessed through the /proc interface, in the /proc/sys/dev/sensors/*
-directories, as files named func1, func2 and data, or alternatively 
-through the sysctl interface, in the appropriate table, with identifiers
-FOO_SYSCTL_FUNC1, FOO_SYSCTL_FUNC2 and FOO_SYSCTL_DATA.
-
-The third, sixth and ninth parameters should always be NULL, and the
-fourth should always be 0. The fifth is the mode of the /proc file;
-0644 is safe, as the file will be owned by root:root. 
-
-The seventh and eighth parameters should be &i2c_proc_real and
-&i2c_sysctl_real if you want to export lists of reals (scaled
-integers). You can also use your own function for them, as usual.
-Finally, the last parameter is the call-back to gather the data
-(see below) if you use the *_proc_real functions. 
-
-
-Gathering the data
-------------------
-
-The call back functions (foo_func and foo_data in the above example)
-can be called in several ways; the operation parameter determines
-what should be done:
-
-  * If operation == SENSORS_PROC_REAL_INFO, you must return the
-    magnitude (scaling) in nrels_mag;
-  * If operation == SENSORS_PROC_REAL_READ, you must read information
-    from the chip and return it in results. The number of integers
-    to display should be put in nrels_mag;
-  * If operation == SENSORS_PROC_REAL_WRITE, you must write the
-    supplied information to the chip. nrels_mag will contain the number
-    of integers, results the integers themselves.
-
-The *_proc_real functions will display the elements as reals for the
-/proc interface. If you set the magnitude to 2, and supply 345 for
-SENSORS_PROC_REAL_READ, it would display 3.45; and if the user would
-write 45.6 to the /proc file, it would be returned as 4560 for
-SENSORS_PROC_REAL_WRITE. A magnitude may even be negative!
-
-An example function:
-
-  /* FOO_FROM_REG and FOO_TO_REG translate between scaled values and
-     register values. Note the use of the read cache. */
-  void foo_in(struct i2c_client *client, int operation, int ctl_name, 
-              int *nrels_mag, long *results)
-  {
-    struct foo_data *data = client->data;
-    int nr = ctl_name - FOO_SYSCTL_FUNC1; /* reduce to 0 upwards */
-    
-    if (operation == SENSORS_PROC_REAL_INFO)
-      *nrels_mag = 2;
-    else if (operation == SENSORS_PROC_REAL_READ) {
-      /* Update the readings cache (if necessary) */
-      foo_update_client(client);
-      /* Get the readings from the cache */
-      results[0] = FOO_FROM_REG(data->foo_func_base[nr]);
-      results[1] = FOO_FROM_REG(data->foo_func_more[nr]);
-      results[2] = FOO_FROM_REG(data->foo_func_readonly[nr]);
-      *nrels_mag = 2;
-    } else if (operation == SENSORS_PROC_REAL_WRITE) {
-      if (*nrels_mag >= 1) {
-        /* Update the cache */
-        data->foo_base[nr] = FOO_TO_REG(results[0]);
-        /* Update the chip */
-        foo_write_value(client,FOO_REG_FUNC_BASE(nr),data->foo_base[nr]);
-      }
-      if (*nrels_mag >= 2) {
-        /* Update the cache */
-        data->foo_more[nr] = FOO_TO_REG(results[1]);
-        /* Update the chip */
-        foo_write_value(client,FOO_REG_FUNC_MORE(nr),data->foo_more[nr]);
-      }
-    }
-  }