Clock stretching is not supposed to last long, so asking to be
rescheduled while waiting for the clock line to be released by a slave
makes little sense. Odds are that the clock line will long have been
released when we run again, so we will have lost time and may even
get an SMBus timeout because of this.

So just busy-wait in that case. This also participates in the effort
to make i2c-algo-bit usable in contexts that can't sleep.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Ben Skeggs <bskeggs@redhat.com>

Signed-off-by: NJean Delvare <khali@linux-fr.org>

When the system is under heavy load, there can be a significant delay
between the getscl() and time_after() calls inside sclhi(). That delay
may cause the time_after() check to trigger after SCL has gone high,
causing sclhi() to return -ETIMEDOUT.

To fix the problem, double check that SCL is still low after the
timeout has been reached, before deciding to return -ETIMEDOUT.
Signed-off-by: NVille Syrjala <syrjala@sci.fi>
Cc: stable@vger.kernel.org
Signed-off-by: NJean Delvare <khali@linux-fr.org>

i915 has a hw i2c controller (gmbus) but for a bunch of stupid reasons
we need to be able to fall back to the bit-banging algo on gpio pins.

The current code sets up a 2nd i2c controller for the same i2c bus using
the bit-banging algo. This has a bunch of issues, the major one being
that userspace can directly access this fallback i2c adaptor behind
the drivers back.

But we need to frob a few registers before and after using fallback
gpio bit-banging, so this horribly fails.

The new plan is to only set up one i2c adaptor and transparently fall
back to bit-banging by directly calling the xfer function of the bit-
banging algo in the i2c core.

To make that possible, export the 2 i2c algo functions.

v2: As suggested by Jean Delvare, simply export the i2c_bit_algo
vtable instead of the individual functions.
Acked-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The wrong bits were put on the wire, fix that.

This fixes kernel bug #42562.
Signed-off-by: NSheng-Hui J. Chu <jeffchu@broadcom.com>
Cc: stable@kernel.org
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Adjust i2c-algo-bit to return fault codes compliant with
Documentation/i2c/fault-codes, rather than the undocumented and
vague -EREMOTEIO.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

If bus testing fails due to the bus being seen as busy, it might be
helpful for developers to know which line is unexpectedly low.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Reviewed-by: NAlex Deucher <alexdeucher@gmail.com>

Always failing to register I2C buses when the line testing fails is a
little harsh. While such a failure is definitely a bug in the driver
that exposes the affected I2C bus, things may still work fine if the
missing initialization steps are done later, before the I2C bus is
used. So it seems a better debugging tool to just report the test
failure by default. I introduce bit_test=2 if anyone really misses the
original behavior of bit_test=1.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Reviewed-by: NAlex Deucher <alexdeucher@gmail.com>

Apparently some distros set i2c-algo-bit.bit_test to 1 by
default.  In some cases this causes i2c_bit_add_bus
to fail and prevents the i2c bus from being added.  In the
radeon case, we fail to add the ddc i2c buses which prevents
the driver from being able to detect attached monitors.
The i2c bus works fine even if bit_test fails.  This is likely
due to gpio switching that is required and handled in the
pre/post_xfer hooks, so call the pre/post_xfer hooks in the
bit test as well.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=36221Signed-off-by: NAlex Deucher <alexdeucher@gmail.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org [.38 down to .34]

The I2C specification explicitly describes both SDA and SCL as
bidirectional lines. An I2C master with a read-only SCL is thus not
compliant. If a slow slave stretches the clock, errors will happen,
so the bus can't be considered as reliable.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Use a function pointer to decide whether to call i2c_add_adapter or
i2c_add_numbered_adapter. This makes the code more compact than the
current strategy of having the common code in a separate function.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Drivers might have to do random things before and/or after I2C
transfers. Add hooks to the i2c-algo-bit implementation to let them do
so.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Alex Deucher <alexdeucher@gmail.com>

When fetching DDC using i2c algo bit, we were often seeing timeouts
before getting valid EDID on a retry. The VESA spec states 2ms is the
DDC timeout, so when this translates into 1 jiffie and we are close
to the end of the time period, it could return with a timeout less than
2ms.

Change this code to use time_after instead of time_after_eq.
Signed-off-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Setting a default timeout value on a per-algo basis doesn't make any
sense. Move the default value setting to i2c-core. Individual adapter
drivers can specify a different (non-zero) value if they wish.

Also express the timeout value in a way which results in the same
duration regarless of the value of HZ.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Tighten error paths used by various i2c adapters (mostly x86) so
they return real fault/errno codes instead of a "-1" (which is
most often interpreted as "-EPERM").  Build tested, with eyeball
review.

One minor initial goal is to have adapters consistently return
the code "-ENXIO" when addressing a device doesn't get an ACK
response, at least in the probe paths where they are already
good at stifling related logspam.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Update comments and logging on return path for byte writes.  NAK is
an error, to be reported or optionally ignored.  Timeouts are always
errors.  Lost arbitration is not currently handled, so don't even list
it as an option in the error message.

Don't return bogus EFAULT code for inappropriate NAK; EIO is better,
there is no bad userspace address in question.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Fix *LOTS* of whitespace goofs and checkpatch.pl warnings, strangely
parenthesized ternary expressions, and other CodingStyle glitches.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

* Convert files to UTF-8.

  * Also correct some people's names
    (one example is Eißfeldt, which was found in a source file.
    Given that the author used an ß at all in a source file
    indicates that the real name has in fact a 'ß' and not an 'ss',
    which is commonly used as a substitute for 'ß' when limited to
    7bit.)

  * Correct town names (Goettingen -> Göttingen)

  * Update Eberhard Mönkeberg's address (http://lkml.org/lkml/2007/1/8/313)
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Signed-off-by: NAdrian Bunk <bunk@kernel.org>

This fixes a bug in the way i2c-algo-bit handles I2C_M_RECV_LEN,
used to implement i2c_smbus_read_block_data().  Previously, in the
absence of PEC (rarely used!) it would NAK the "length" byte:

	S addr Rd [A] [length] NA

That prevents the subsequent data bytes from being read:

	S addr Rd [A] [length] { A [data] }* NA

The primary fix just reorders two code blocks, so the length used
in the "should I NAK now?" check incorporates the data which it
just read from the slave device.

However, that move also highlighted other fault handling glitches.
This fixes those by abstracting the RX path ack/nak logic, so it
can be used in more than one location.  Also, a few CodingStyle
issues were also resolved.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Improve the debugging features of the i2c-algo-bit driver:
* Make it possible to compile the driver without debugging support
  at all, making it much smaller.
* Use dev_dbg() for debugging messages where possible, and dev_err()
  for error messages.
* Remove redundant debugging messages.

These changes allowed for minor code cleanups, which are included
as well.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

The original i2c-algo-bit implementation uses a 33/66 SCL duty cycle
when bits are being written on the bus. While the I2C specification
doesn't forbid it, this prevents us from driving the I2C bus to its
max speed, limiting us to 66 kbps max on standard I2C busses.

Implementing a 50/50 duty cycle instead lets us max out the bandwidth
up to the theoretical max of 100 kbps on standard I2C busses. This is
particularly important when large amounts of data need to be transfered
over the bus, as is the case with some TV adapters when the firmware is
being uploaded.

In fact this change even allows, at least in theory, fast-mode I2C
support at 125, 166 and 250 kbps. There's no way to reach the
theoretical max of 400 kbps with this implementation. But I don't
think we want to put efforts in that direction anyway: software-driven
I2C is very CPU-intensive and bad for latency.

Other timing changes:
* Don't set SDA high explicitly on error, we're going to issue a stop
  condition before we leave anyway.
* If an error occurs when sending the slave address, yield the CPU
  before retrying, and remove the additional delay after the new start
  condition.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Add i2c_bit_add_numbered_bus(), which is equivalent to i2c_bit_add_bus
except that it calls i2c_add_numbered_adapter() at the end instead of
i2c_add_adapter().
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Now that i2c-core lets the i2c bus drivers emulate the SMBus block read
and SMBus block process call transaction types, let's implement that in
the popular i2c bit-banging driver. This will also act as a reference
implementation for other bus drivers which want to do the same.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

The i2c-algo-bit driver doesn't behave well on read errors: it'll
bail out without even sending a stop condition on the bus, so the bus
will be stuck. So make sure that we always send a stop condition on
the bus before we leave. The best way to make sure is to always send
it at the end of function bit_xfer.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

They are all only calling i2c_del_adapter, so we may as well do
it directly.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

i2c: Constify i2c_algorithm declarations, part 1

Make struct i2c_algorithm declarations const in all i2c algorithm
drivers.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

i2c-algo-bit: Cleanups

* Uninline long functions (saves around 1 kB or 15%)
* Refactor code in sclhi()
* Drop redundant udelay on repeated start
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

i2c-algo-bit: Discard the mdelay data struct member

The i2c_algo_bit_data structure has an mdelay member, which is not
used by the algorithm code (the code has always been ifdef'd out.)
Let's discard it to save some code and memory.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NMauro Carvalho Chehab <mchehab@brturbo.com.br>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

i2c-algo-bit: Wipe out dead code
Signed-off-by: NUwe Bugla <uwe.bugla@gmx.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Content-Disposition: inline; filename=i2c-algo-error-handling-fix.patch

It is possible for i2c_add_adapter() to fail.  Several I2C algorithm
drivers ignore that fact.  This (compile-tested only) patch fixes them.
Signed-off-by: NMark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Merge the algorithm id part (16 upper bits) of the i2c adapters ids
into the definition of the adapters ids directly. After that, we don't
need to OR both ids together for each i2c_adapter structure.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

There are no more users of i2c_algorithm.id, so we can finally drop
this structure member.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Don't rely on i2c_algorithm.id to alter the i2c adapter's id, use the
I2C_ALGO_* value directly instead, because i2c_algorithm will soon
have no id member no more.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The name member of the i2c_algorithm is never used, although all
drivers conscientiously fill it. We can drop it completely, this
structure doesn't need to have a name.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!