<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/linux/i2c.h, branch v3.19-rc5</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Merge branch 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux</title>
<updated>2014-12-14T20:54:40+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2014-12-14T20:54:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=96895199c8648db475b38aac5fe6a04ec14a49c4'/>
<id>96895199c8648db475b38aac5fe6a04ec14a49c4</id>
<content type='text'>
Pull i2c updates from Wolfram Sang:
 "For 3.19, the I2C subsystem has to offer special candy this time.
  Right in time for Christmas :)

   - I2C slave framework: finally, a generic mechanism for Linux being
     an I2C slave (if the bus driver supports that).  Docs are still
     missing but will come later this cycle, the code is good enough to
     go.
   - I2C muxes represent their topology in sysfs much more detailed.
     This will help users to navigate around much easier.
   - irq population of i2c clients is now done at probe time, not device
     creation time, to have better support for deferred probing.
   - new drivers for Imagination SCB, Amlogic Meson
   - DMA support added for Freescale IMX, Renesas SHMobile
   - slightly bigger driver updates to OMAP, i801, AT91, and rk3x
     (mostly quirk handling, timing updates, and using better kernel
     interfaces)
   - eeprom driver can now write with byte-access (very slow, but OK to
     have)
   - and the bunch of smaller fixes, cleanups, ID updates..."

* 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits)
  i2c: sh_mobile: remove unneeded DMA mask
  i2c: rcar: add slave support
  i2c: slave-eeprom: add eeprom simulator driver
  i2c: core changes for slave support
  MAINTAINERS: add I2C dt bindings also to I2C realm
  i2c: designware: Fix falling time bindings doc
  i2c: davinci: switch to use platform_get_irq
  Documentation: i2c: Use PM ops instead of legacy suspend/resume
  i2c: sh_mobile: optimize irq entry
  i2c: pxa: add support for SCCB devices
  omap: i2c: don't check bus state IP rev3.3 and earlier
  i2c: s3c2410: Handle i2c sys_cfg register in i2c driver
  i2c: rk3x: add Kconfig dependency on COMMON_CLK
  i2c: omap: add notes related to i2c multimaster mode
  i2c: omap: don't reset controller if Arbitration Lost detected
  i2c: omap: implement workaround for handling invalid BB-bit values
  i2c: omap: cleanup register definitions
  i2c: rk3x: handle dynamic clock rate changes correctly
  i2c: at91: enable probe deferring on dma channel request
  i2c: at91: remove legacy DMA support
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull i2c updates from Wolfram Sang:
 "For 3.19, the I2C subsystem has to offer special candy this time.
  Right in time for Christmas :)

   - I2C slave framework: finally, a generic mechanism for Linux being
     an I2C slave (if the bus driver supports that).  Docs are still
     missing but will come later this cycle, the code is good enough to
     go.
   - I2C muxes represent their topology in sysfs much more detailed.
     This will help users to navigate around much easier.
   - irq population of i2c clients is now done at probe time, not device
     creation time, to have better support for deferred probing.
   - new drivers for Imagination SCB, Amlogic Meson
   - DMA support added for Freescale IMX, Renesas SHMobile
   - slightly bigger driver updates to OMAP, i801, AT91, and rk3x
     (mostly quirk handling, timing updates, and using better kernel
     interfaces)
   - eeprom driver can now write with byte-access (very slow, but OK to
     have)
   - and the bunch of smaller fixes, cleanups, ID updates..."

* 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits)
  i2c: sh_mobile: remove unneeded DMA mask
  i2c: rcar: add slave support
  i2c: slave-eeprom: add eeprom simulator driver
  i2c: core changes for slave support
  MAINTAINERS: add I2C dt bindings also to I2C realm
  i2c: designware: Fix falling time bindings doc
  i2c: davinci: switch to use platform_get_irq
  Documentation: i2c: Use PM ops instead of legacy suspend/resume
  i2c: sh_mobile: optimize irq entry
  i2c: pxa: add support for SCCB devices
  omap: i2c: don't check bus state IP rev3.3 and earlier
  i2c: s3c2410: Handle i2c sys_cfg register in i2c driver
  i2c: rk3x: add Kconfig dependency on COMMON_CLK
  i2c: omap: add notes related to i2c multimaster mode
  i2c: omap: don't reset controller if Arbitration Lost detected
  i2c: omap: implement workaround for handling invalid BB-bit values
  i2c: omap: cleanup register definitions
  i2c: rk3x: handle dynamic clock rate changes correctly
  i2c: at91: enable probe deferring on dma channel request
  i2c: at91: remove legacy DMA support
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: core changes for slave support</title>
<updated>2014-12-11T21:25:53+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2014-11-18T16:04:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4b1acc43331d6c716c331a61477660dc20c8b59c'/>
<id>4b1acc43331d6c716c331a61477660dc20c8b59c</id>
<content type='text'>
Finally(!), make Linux support being an I2C slave. Most of the existing
infrastructure is reused. We mainly add i2c_slave_register/unregister()
calls which tells i2c bus drivers to activate the slave mode. Then, they
also get a callback to report slave events to.

Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Finally(!), make Linux support being an I2C slave. Most of the existing
infrastructure is reused. We mainly add i2c_slave_register/unregister()
calls which tells i2c bus drivers to activate the slave mode. Then, they
also get a callback to report slave events to.

Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Fix typo in Documentation/DocBook/device-drivers</title>
<updated>2014-11-03T16:53:34+00:00</updated>
<author>
<name>Masanari Iida</name>
<email>standby24x7@gmail.com</email>
</author>
<published>2014-10-21T15:00:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f353d71f75394e518b4d939aea2030d8e239dd41'/>
<id>f353d71f75394e518b4d939aea2030d8e239dd41</id>
<content type='text'>
This patch fix speeling typo found in html files within
Documentation/DocBook/device-drivers.
It is because html files are generated from comments in source,
so I have to fix comments in the source.

Signed-off-by: Masanari Iida &lt;standby24x7@gmail.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Acked-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch fix speeling typo found in html files within
Documentation/DocBook/device-drivers.
It is because html files are generated from comments in source,
so I have to fix comments in the source.

Signed-off-by: Masanari Iida &lt;standby24x7@gmail.com&gt;
Acked-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Acked-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: move acpi code back into the core</title>
<updated>2014-09-25T14:07:15+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa@the-dreams.de</email>
</author>
<published>2014-09-22T17:41:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=17f4a5c47f28de9ea59182f48d07f8c44ee5dcc9'/>
<id>17f4a5c47f28de9ea59182f48d07f8c44ee5dcc9</id>
<content type='text'>
Commit 5d98e61d337c ("I2C/ACPI: Add i2c ACPI operation region support")
renamed the i2c-core module. This may cause regressions for
distributions, so put the ACPI code back into the core.

Reported-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Tested-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Tested-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 5d98e61d337c ("I2C/ACPI: Add i2c ACPI operation region support")
renamed the i2c-core module. This may cause regressions for
distributions, so put the ACPI code back into the core.

Reported-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
Tested-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Tested-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: rework kernel config I2C_ACPI</title>
<updated>2014-08-19T15:19:39+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2014-08-15T05:38:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=366047515c6eab2ff886bc28d1c2b0ad041d040a'/>
<id>366047515c6eab2ff886bc28d1c2b0ad041d040a</id>
<content type='text'>
Commit da3c6647(I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI
config) adds a new kernel config I2C_ACPI and make I2C core built in
when the config is selected. This is wrong because distributions
etc generally compile I2C as a module and the commit broken that.
This patch is to rename I2C_ACPI to ACPI_I2C_OPREGION. New config
only controls ACPI I2C operation region code and depends on I2C=y.

Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
[wsa: removed unrelated change for Kconfig]
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit da3c6647(I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI
config) adds a new kernel config I2C_ACPI and make I2C core built in
when the config is selected. This is wrong because distributions
etc generally compile I2C as a module and the commit broken that.
This patch is to rename I2C_ACPI to ACPI_I2C_OPREGION. New config
only controls ACPI I2C operation region code and depends on I2C=y.

Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
[wsa: removed unrelated change for Kconfig]
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI config</title>
<updated>2014-06-27T12:50:41+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2014-05-20T12:59:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=da3c6647ee08711c7edc28d7fea4ad69fc5ffcca'/>
<id>da3c6647ee08711c7edc28d7fea4ad69fc5ffcca</id>
<content type='text'>
Clean up ACPI related code in the i2c core and add CONFIG_I2C_ACPI
to enable I2C ACPI code.

Current there is a race between removing I2C ACPI operation region
and ACPI AML code accessing. So make i2c core built-in if CONFIG_I2C_ACPI
is set.

Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Clean up ACPI related code in the i2c core and add CONFIG_I2C_ACPI
to enable I2C ACPI code.

Current there is a race between removing I2C ACPI operation region
and ACPI AML code accessing. So make i2c core built-in if CONFIG_I2C_ACPI
is set.

Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>I2C/ACPI: Add i2c ACPI operation region support</title>
<updated>2014-06-27T12:50:40+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2014-05-20T12:59:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5d98e61d337c181f199a6cb864569cc4e116ef4c'/>
<id>5d98e61d337c181f199a6cb864569cc4e116ef4c</id>
<content type='text'>
ACPI 5.0 spec(5.5.2.4.5) defines GenericSerialBus(i2c, spi, uart) operation region.
It allows ACPI aml code able to access such kind of devices to implement
some ACPI standard method.

ACPI Spec defines some access attribute to associate with i2c protocol.
AttribQuick 	       	       		Read/Write Quick Protocol
AttribSendReceive			Send/Receive Byte Protocol
AttribByte 			 	Read/Write Byte Protocol
AttribWord				Read/Write Word Protocol
AttribBlock				Read/Write Block Protocol
AttribBytes				Read/Write N-Bytes Protocol
AttribProcessCall			Process Call Protocol
AttribBlockProcessCall			Write Block-Read Block Process Call Protocol
AttribRawBytes 				Raw Read/Write N-BytesProtocol
AttribRawProcessBytes			Raw Process Call Protocol

On the Asus T100TA, Bios use GenericSerialBus operation region to access
i2c device to get battery info.

Sample code From Asus T100TA

    Scope (_SB.I2C1)
    {
        Name (UMPC, ResourceTemplate ()
        {
            I2cSerialBus (0x0066, ControllerInitiated, 0x00061A80,
                AddressingMode7Bit, "\\_SB.I2C1",
                0x00, ResourceConsumer, ,
                )
        })

	...

        OperationRegion (DVUM, GenericSerialBus, Zero, 0x0100)
        Field (DVUM, BufferAcc, NoLock, Preserve)
        {
            Connection (UMPC),
            Offset (0x81),
            AccessAs (BufferAcc, AttribBytes (0x3E)),
            FGC0,   8
        }
	...
     }

     Device (BATC)
     {
         Name (_HID, EisaId ("PNP0C0A"))  // _HID: Hardware ID
         Name (_UID, One)  // _UID: Unique ID
	 ...

            Method (_BST, 0, NotSerialized)  // _BST: Battery Status
            {
                If (LEqual (AVBL, One))
                {
                    Store (FGC0, BFFG)
                    If (LNotEqual (STAT, One))
                    {
                        ShiftRight (CHST, 0x04, Local0)
                        And (Local0, 0x03, Local0)
                        If (LOr (LEqual (Local0, One), LEqual (Local0, 0x02)))
                        {
                            Store (0x02, Local1)
                        }
	...

    }

The i2c operation region is defined under I2C1 scope. _BST method under
battery device BATC read battery status from the field "FCG0". The request
would be sent to i2c operation region handler.

This patch is to add i2c ACPI operation region support. Due to there are
only "Byte" and "Bytes" protocol access on the Asus T100TA, other protocols
have not been tested.

About RawBytes and RawProcessBytes protocol, they needs specific drivers to interpret
reference data from AML code according ACPI 5.0 SPEC(5.5.2.4.5.3.9 and 5.5.2.4.5.3.10).
So far, not found such case and will add when find real case.

Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ACPI 5.0 spec(5.5.2.4.5) defines GenericSerialBus(i2c, spi, uart) operation region.
It allows ACPI aml code able to access such kind of devices to implement
some ACPI standard method.

ACPI Spec defines some access attribute to associate with i2c protocol.
AttribQuick 	       	       		Read/Write Quick Protocol
AttribSendReceive			Send/Receive Byte Protocol
AttribByte 			 	Read/Write Byte Protocol
AttribWord				Read/Write Word Protocol
AttribBlock				Read/Write Block Protocol
AttribBytes				Read/Write N-Bytes Protocol
AttribProcessCall			Process Call Protocol
AttribBlockProcessCall			Write Block-Read Block Process Call Protocol
AttribRawBytes 				Raw Read/Write N-BytesProtocol
AttribRawProcessBytes			Raw Process Call Protocol

On the Asus T100TA, Bios use GenericSerialBus operation region to access
i2c device to get battery info.

Sample code From Asus T100TA

    Scope (_SB.I2C1)
    {
        Name (UMPC, ResourceTemplate ()
        {
            I2cSerialBus (0x0066, ControllerInitiated, 0x00061A80,
                AddressingMode7Bit, "\\_SB.I2C1",
                0x00, ResourceConsumer, ,
                )
        })

	...

        OperationRegion (DVUM, GenericSerialBus, Zero, 0x0100)
        Field (DVUM, BufferAcc, NoLock, Preserve)
        {
            Connection (UMPC),
            Offset (0x81),
            AccessAs (BufferAcc, AttribBytes (0x3E)),
            FGC0,   8
        }
	...
     }

     Device (BATC)
     {
         Name (_HID, EisaId ("PNP0C0A"))  // _HID: Hardware ID
         Name (_UID, One)  // _UID: Unique ID
	 ...

            Method (_BST, 0, NotSerialized)  // _BST: Battery Status
            {
                If (LEqual (AVBL, One))
                {
                    Store (FGC0, BFFG)
                    If (LNotEqual (STAT, One))
                    {
                        ShiftRight (CHST, 0x04, Local0)
                        And (Local0, 0x03, Local0)
                        If (LOr (LEqual (Local0, One), LEqual (Local0, 0x02)))
                        {
                            Store (0x02, Local1)
                        }
	...

    }

The i2c operation region is defined under I2C1 scope. _BST method under
battery device BATC read battery status from the field "FCG0". The request
would be sent to i2c operation region handler.

This patch is to add i2c ACPI operation region support. Due to there are
only "Byte" and "Bytes" protocol access on the Asus T100TA, other protocols
have not been tested.

About RawBytes and RawProcessBytes protocol, they needs specific drivers to interpret
reference data from AML code according ACPI 5.0 SPEC(5.5.2.4.5.3.9 and 5.5.2.4.5.3.10).
So far, not found such case and will add when find real case.

Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: add deprecation warning for class based instantiation</title>
<updated>2014-03-05T16:16:45+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa@the-dreams.de</email>
</author>
<published>2014-02-10T10:03:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0c176170089c3a7f2a891f9860f5cdc5f481ff78'/>
<id>0c176170089c3a7f2a891f9860f5cdc5f481ff78</id>
<content type='text'>
Class based instantiation can cause noticeable delays when booting. This
mechanism is used when it is not possible to describe slaves on I2C
busses. As we do have other mechanisms, most embedded I2C will not need
classes and for embedded it is explicitly not recommended to use them. Add
a deprecation warning for drivers which want to disable class based
instantiation in the near future to gain boot-up time, so users relying
on this technique can switch to something better. They really should.

Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Class based instantiation can cause noticeable delays when booting. This
mechanism is used when it is not possible to describe slaves on I2C
busses. As we do have other mechanisms, most embedded I2C will not need
classes and for embedded it is explicitly not recommended to use them. Add
a deprecation warning for drivers which want to disable class based
instantiation in the near future to gain boot-up time, so users relying
on this technique can switch to something better. They really should.

Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: update i2c_algorithm documentation</title>
<updated>2014-01-26T21:48:35+00:00</updated>
<author>
<name>Ben Dooks</name>
<email>ben.dooks@codethink.co.uk</email>
</author>
<published>2014-01-26T16:05:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=25ee33fb824eb46ae77f6c962007492603d39772'/>
<id>25ee33fb824eb46ae77f6c962007492603d39772</id>
<content type='text'>
Add some kerneldoc style documentaton to the i2c_algorithm
structure, and point the master_xfer return codes at the
right place in Documentation/i2c/fault_codes

Signed-off-by: Ben Dooks &lt;ben.dooks@codethink.co.uk&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add some kerneldoc style documentaton to the i2c_algorithm
structure, and point the master_xfer return codes at the
right place in Documentation/i2c/fault_codes

Signed-off-by: Ben Dooks &lt;ben.dooks@codethink.co.uk&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>i2c: Re-instate body of i2c_parent_is_i2c_adapter()</title>
<updated>2014-01-14T16:11:13+00:00</updated>
<author>
<name>Stephen Warren</name>
<email>swarren@nvidia.com</email>
</author>
<published>2014-01-13T21:29:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2fac2b891f287691c27ee8d2eeecf39571b27fea'/>
<id>2fac2b891f287691c27ee8d2eeecf39571b27fea</id>
<content type='text'>
The body of i2c_parent_is_i2c_adapter() is currently guarded by
I2C_MUX. It should be CONFIG_I2C_MUX instead.

Among potentially other problems, this resulted in i2c_lock_adapter()
only locking I2C mux child adapters, and not the parent adapter. In
turn, this could allow inter-mingling of mux child selection and I2C
transactions, which could result in I2C transactions being directed to
the wrong I2C bus, and possibly even switching between busses in the
middle of a transaction.

One concrete issue caused by this bug was corrupted HDMI EDID reads
during boot on the NVIDIA Tegra Seaboard system, although this only
became apparent in recent linux-next, when the boot timing was changed
just enough to trigger the race condition.

Fixes: 3923172b3d70 ("i2c: reduce parent checking to a NOOP in non-I2C_MUX case")
Cc: Phil Carmody &lt;phil.carmody@partner.samsung.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Stephen Warren &lt;swarren@nvidia.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The body of i2c_parent_is_i2c_adapter() is currently guarded by
I2C_MUX. It should be CONFIG_I2C_MUX instead.

Among potentially other problems, this resulted in i2c_lock_adapter()
only locking I2C mux child adapters, and not the parent adapter. In
turn, this could allow inter-mingling of mux child selection and I2C
transactions, which could result in I2C transactions being directed to
the wrong I2C bus, and possibly even switching between busses in the
middle of a transaction.

One concrete issue caused by this bug was corrupted HDMI EDID reads
during boot on the NVIDIA Tegra Seaboard system, although this only
became apparent in recent linux-next, when the boot timing was changed
just enough to trigger the race condition.

Fixes: 3923172b3d70 ("i2c: reduce parent checking to a NOOP in non-I2C_MUX case")
Cc: Phil Carmody &lt;phil.carmody@partner.samsung.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Stephen Warren &lt;swarren@nvidia.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@the-dreams.de&gt;
</pre>
</div>
</content>
</entry>
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