7 files changed, 169 insertions, 116 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 46ece3fba6f9..65a1482457a8 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -222,13 +222,6 @@ Who:	Thomas Gleixner <tglx@linutronix.de>
 
 ---------------------------
 
-What:   i2c-i810, i2c-prosavage and i2c-savage4
-When:   May 2008
-Why:    These drivers are superseded by i810fb, intelfb and savagefb.
-Who:    Jean Delvare <khali@linux-fr.org>
-
----------------------------
-
 What (Why):
         - include/linux/netfilter_ipv4/ipt_TOS.h ipt_tos.h header files
           (superseded by xt_TOS/xt_tos target & match)
diff --git a/Documentation/i2c/busses/i2c-i810 b/Documentation/i2c/busses/i2c-i810
deleted file mode 100644
index 778210ee1583..000000000000
--- a/Documentation/i2c/busses/i2c-i810
+++ /dev/null
@@ -1,47 +0,0 @@
-Kernel driver i2c-i810
-
-Supported adapters:
-  * Intel 82810, 82810-DC100, 82810E, and 82815 (GMCH)
-  * Intel 82845G (GMCH)
-
-Authors: 
-        Frodo Looijaard <frodol@dds.nl>, 
-        Philip Edelbrock <phil@netroedge.com>,
-        Kyösti Mälkki <kmalkki@cc.hut.fi>,
-        Ralph Metzler <rjkm@thp.uni-koeln.de>,
-        Mark D. Studebaker <mdsxyz123@yahoo.com>
-
-Main contact: Mark Studebaker <mdsxyz123@yahoo.com>
-
-Description 
------------ 
-
-WARNING: If you have an '810' or '815' motherboard, your standard I2C
-temperature sensors are most likely on the 801's I2C bus. You want the
-i2c-i801 driver for those, not this driver.
-
-Now for the i2c-i810...
-
-The GMCH chip contains two I2C interfaces.
-
-The first interface is used for DDC (Data Display Channel) which is a
-serial channel through the VGA monitor connector to a DDC-compliant
-monitor. This interface is defined by the Video Electronics Standards
-Association (VESA). The standards are available for purchase at
-http://www.vesa.org .
-
-The second interface is a general-purpose I2C bus. It may be connected to a
-TV-out chip such as the BT869 or possibly to a digital flat-panel display.
-
-Features
--------- 
-
-Both busses use the i2c-algo-bit driver for 'bit banging'
-and support for specific transactions is provided by i2c-algo-bit.
-
-Issues
-------
-
-If you enable bus testing in i2c-algo-bit (insmod i2c-algo-bit bit_test=1),
-the test may fail; if so, the i2c-i810 driver won't be inserted. However,
-we think this has been fixed.
diff --git a/Documentation/i2c/busses/i2c-prosavage b/Documentation/i2c/busses/i2c-prosavage
deleted file mode 100644
index 703687902511..000000000000
--- a/Documentation/i2c/busses/i2c-prosavage
+++ /dev/null
@@ -1,23 +0,0 @@
-Kernel driver i2c-prosavage
-
-Supported adapters:
-        
-        S3/VIA KM266/VT8375 aka ProSavage8 
-        S3/VIA KM133/VT8365 aka Savage4 
-
-Author: Henk Vergonet <henk@god.dyndns.org>
-
-Description
------------
-
-The Savage4 chips contain two I2C interfaces (aka a I2C 'master' or
-'host'). 
-
-The first interface is used for DDC (Data Display Channel) which is a
-serial channel through the VGA monitor connector to a DDC-compliant
-monitor. This interface is defined by the Video Electronics Standards
-Association (VESA). The standards are available for purchase at
-http://www.vesa.org . The second interface is a general-purpose I2C bus.
-
-Usefull for gaining access to the TV Encoder chips.
-
diff --git a/Documentation/i2c/busses/i2c-savage4 b/Documentation/i2c/busses/i2c-savage4
deleted file mode 100644
index 6ecceab618d3..000000000000
--- a/Documentation/i2c/busses/i2c-savage4
+++ /dev/null
@@ -1,26 +0,0 @@
-Kernel driver i2c-savage4
-
-Supported adapters:
-  * Savage4
-  * Savage2000
-
-Authors: 
-        Alexander Wold <awold@bigfoot.com>,
-        Mark D. Studebaker <mdsxyz123@yahoo.com> 
-
-Description
------------
-
-The Savage4 chips contain two I2C interfaces (aka a I2C 'master'
-or 'host'). 
-
-The first interface is used for DDC (Data Display Channel) which is a
-serial channel through the VGA monitor connector to a DDC-compliant
-monitor. This interface is defined by the Video Electronics Standards
-Association (VESA). The standards are available for purchase at
-http://www.vesa.org . The DDC bus is not yet supported because its register
-is not directly memory-mapped.
-
-The second interface is a general-purpose I2C bus. This is the only
-interface supported by the driver at the moment.
-
diff --git a/Documentation/i2c/fault-codes b/Documentation/i2c/fault-codes
new file mode 100644
index 000000000000..045765c0b9b5
--- /dev/null
+++ b/Documentation/i2c/fault-codes
@@ -0,0 +1,127 @@
+This is a summary of the most important conventions for use of fault
+codes in the I2C/SMBus stack.
+
+
+A "Fault" is not always an "Error"
+----------------------------------
+Not all fault reports imply errors; "page faults" should be a familiar
+example.  Software often retries idempotent operations after transient
+faults.  There may be fancier recovery schemes that are appropriate in
+some cases, such as re-initializing (and maybe resetting).  After such
+recovery, triggered by a fault report, there is no error.
+
+In a similar way, sometimes a "fault" code just reports one defined
+result for an operation ... it doesn't indicate that anything is wrong
+at all, just that the outcome wasn't on the "golden path".
+
+In short, your I2C driver code may need to know these codes in order
+to respond correctly.  Other code may need to rely on YOUR code reporting
+the right fault code, so that it can (in turn) behave correctly.
+
+
+I2C and SMBus fault codes
+-------------------------
+These are returned as negative numbers from most calls, with zero or
+some positive number indicating a non-fault return.  The specific
+numbers associated with these symbols differ between architectures,
+though most Linux systems use <asm-generic/errno*.h> numbering.
+
+Note that the descriptions here are not exhaustive.  There are other
+codes that may be returned, and other cases where these codes should
+be returned.  However, drivers should not return other codes for these
+cases (unless the hardware doesn't provide unique fault reports).
+
+Also, codes returned by adapter probe methods follow rules which are
+specific to their host bus (such as PCI, or the platform bus).
+
+
+EAGAIN
+        Returned by I2C adapters when they lose arbitration in master
+        transmit mode:  some other master was transmitting different
+        data at the same time.
+
+        Also returned when trying to invoke an I2C operation in an
+        atomic context, when some task is already using that I2C bus
+        to execute some other operation.
+
+EBADMSG
+        Returned by SMBus logic when an invalid Packet Error Code byte
+        is received.  This code is a CRC covering all bytes in the
+        transaction, and is sent before the terminating STOP.  This
+        fault is only reported on read transactions; the SMBus slave
+        may have a way to report PEC mismatches on writes from the
+        host.  Note that even if PECs are in use, you should not rely
+        on these as the only way to detect incorrect data transfers.
+
+EBUSY
+        Returned by SMBus adapters when the bus was busy for longer
+        than allowed.  This usually indicates some device (maybe the
+        SMBus adapter) needs some fault recovery (such as resetting),
+        or that the reset was attempted but failed.
+
+EINVAL
+        This rather vague error means an invalid parameter has been
+        detected before any I/O operation was started.  Use a more
+        specific fault code when you can.
+
+        One example would be a driver trying an SMBus Block Write
+        with block size outside the range of 1-32 bytes.
+
+EIO
+        This rather vague error means something went wrong when
+        performing an I/O operation.  Use a more specific fault
+        code when you can.
+
+ENODEV
+        Returned by driver probe() methods.  This is a bit more
+        specific than ENXIO, implying the problem isn't with the
+        address, but with the device found there.  Driver probes
+        may verify the device returns *correct* responses, and
+        return this as appropriate.  (The driver core will warn
+        about probe faults other than ENXIO and ENODEV.)
+
+ENOMEM
+        Returned by any component that can't allocate memory when
+        it needs to do so.
+
+ENXIO
+        Returned by I2C adapters to indicate that the address phase
+        of a transfer didn't get an ACK.  While it might just mean
+        an I2C device was temporarily not responding, usually it
+        means there's nothing listening at that address.
+
+        Returned by driver probe() methods to indicate that they
+        found no device to bind to.  (ENODEV may also be used.)
+
+EOPNOTSUPP
+        Returned by an adapter when asked to perform an operation
+        that it doesn't, or can't, support.
+
+        For example, this would be returned when an adapter that
+        doesn't support SMBus block transfers is asked to execute
+        one.  In that case, the driver making that request should
+        have verified that functionality was supported before it
+        made that block transfer request.
+
+        Similarly, if an I2C adapter can't execute all legal I2C
+        messages, it should return this when asked to perform a
+        transaction it can't.  (These limitations can't be seen in
+        the adapter's functionality mask, since the assumption is
+        that if an adapter supports I2C it supports all of I2C.)
+
+EPROTO
+        Returned when slave does not conform to the relevant I2C
+        or SMBus (or chip-specific) protocol specifications.  One
+        case is when the length of an SMBus block data response
+        (from the SMBus slave) is outside the range 1-32 bytes.
+
+ETIMEDOUT
+        This is returned by drivers when an operation took too much
+        time, and was aborted before it completed.
+
+        SMBus adapters may return it when an operation took more
+        time than allowed by the SMBus specification; for example,
+        when a slave stretches clocks too far.  I2C has no such
+        timeouts, but it's normal for I2C adapters to impose some
+        arbitrary limits (much longer than SMBus!) too.
+
diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol
index 03f08fb491cc..24bfb65da17d 100644
--- a/Documentation/i2c/smbus-protocol
+++ b/Documentation/i2c/smbus-protocol
@@ -42,8 +42,8 @@ Count (8 bits): A data byte containing the length of a block operation.
 [..]: Data sent by I2C device, as opposed to data sent by the host adapter.
 
 
-SMBus Quick Command:  i2c_smbus_write_quick()
-=============================================
+SMBus Quick Command
+===================
 
 This sends a single bit to the device, at the place of the Rd/Wr bit.
 
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients
index d4cd4126d1ad..6b61b3a2e90b 100644
--- a/Documentation/i2c/writing-clients
+++ b/Documentation/i2c/writing-clients
@@ -44,6 +44,10 @@ static struct i2c_driver foo_driver = {
         .id_table       = foo_ids,
         .probe          = foo_probe,
         .remove         = foo_remove,
+        /* if device autodetection is needed: */
+        .class          = I2C_CLASS_SOMETHING,
+        .detect         = foo_detect,
+        .address_data   = &addr_data,
 
         /* else, driver uses "legacy" binding model: */
         .attach_adapter = foo_attach_adapter,
@@ -217,6 +221,31 @@ in the I2C bus driver. You may want to save the returned i2c_client
 reference for later use.
 
 
+Device Detection (Standard driver model)
+----------------------------------------
+
+Sometimes you do not know in advance which I2C devices are connected to
+a given I2C bus.  This is for example the case of hardware monitoring
+devices on a PC's SMBus.  In that case, you may want to let your driver
+detect supported devices automatically.  This is how the legacy model
+was working, and is now available as an extension to the standard
+driver model (so that we can finally get rid of the legacy model.)
+
+You simply have to define a detect callback which will attempt to
+identify supported devices (returning 0 for supported ones and -ENODEV
+for unsupported ones), a list of addresses to probe, and a device type
+(or class) so that only I2C buses which may have that type of device
+connected (and not otherwise enumerated) will be probed.  The i2c
+core will then call you back as needed and will instantiate a device
+for you for every successful detection.
+
+Note that this mechanism is purely optional and not suitable for all
+devices.  You need some reliable way to identify the supported devices
+(typically using device-specific, dedicated identification registers),
+otherwise misdetections are likely to occur and things can get wrong
+quickly.
+
+
 Device Deletion (Standard driver model)
 ---------------------------------------
 
@@ -569,7 +598,6 @@ SMBus communication
   in terms of it. Never use this function directly!
 
 
-  extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);
   extern s32 i2c_smbus_read_byte(struct i2c_client * client);
   extern s32 i2c_smbus_write_byte(struct i2c_client * client, u8 value);
   extern s32 i2c_smbus_read_byte_data(struct i2c_client * client, u8 command);
@@ -578,30 +606,31 @@ SMBus communication
   extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
   extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
                                        u8 command, u16 value);
+  extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
+                                       u8 command, u8 *values);
   extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
                                         u8 command, u8 length,
                                         u8 *values);
   extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
                                            u8 command, u8 length, u8 *values);
-
-These ones were removed in Linux 2.6.10 because they had no users, but could
-be added back later if needed:
-
-  extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
-                                       u8 command, u8 *values);
   extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client,
                                             u8 command, u8 length,
                                             u8 *values);
+
+These ones were removed from i2c-core because they had no users, but could
+be added back later if needed:
+
+  extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);
   extern s32 i2c_smbus_process_call(struct i2c_client * client,
                                     u8 command, u16 value);
   extern s32 i2c_smbus_block_process_call(struct i2c_client *client,
                                           u8 command, u8 length,
                                           u8 *values)
 
-All these transactions return -1 on failure. The 'write' transactions 
-return 0 on success; the 'read' transactions return the read value, except 
-for read_block, which returns the number of values read. The block buffers 
-need not be longer than 32 bytes.
+All these transactions return a negative errno value on failure. The 'write'
+transactions return 0 on success; the 'read' transactions return the read
+value, except for block transactions, which return the number of values
+read. The block buffers need not be longer than 32 bytes.
 
 You can read the file `smbus-protocol' for more information about the
 actual SMBus protocol.