We don't need to init HW before every transfer since we know the HW
state then. HW init at probe time is enough. While here, add setting the
clock register which belongs to init HW. Also, set MDBS bit since not
setting it is prohibited according to the manual.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

When calculating the bus speed, the clock should be on, of course. Most
bootloaders left them on, so this went unnoticed so far.

Move the ioremapping out of this clock-enabled-block and prepare for
adding hw initialization there, too.
Reported-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This whole series caused sometimes timeouts and even OOPSes on some
r8a7791 Koelsch boards. We need to understand and fix those first.

Revert "i2c: rcar: clean up after refactoring"
Revert "i2c: rcar: revoke START request early"
Revert "i2c: rcar: check master irqs before slave irqs"
Revert "i2c: rcar: don't issue stop when HW does it automatically"
Revert "i2c: rcar: init new messages in irq"
Revert "i2c: rcar: refactor setup of a msg"
Revert "i2c: rcar: remove spinlock"
Revert "i2c: rcar: remove unused IOERROR state"
Revert "i2c: rcar: rework hw init"
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Since commit 4baadb9e ("ARM: shmobile: r8a7778: remove obsolete
setup code"), Renesas R-Car SoCs are only supported in generic DT-only
ARM multi-platform builds.  The driver doesn't need to use platform data
anymore, hence remove platform data configuration.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
[wsa: removed now unused ret value and cast to proper enum type]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Enable the I2C core for this SoC. I add a new type because this version
has new features (e.g. DMA) which will be added somewhen later.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The core may register clients attached to this master which may use
funtionality from the master. So, RuntimePM must be enabled before, otherwise
this will fail. While here, move drvdata, too.
Reported-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

Update the comments to match current behaviour. Shorten some comments.
Update copyrights.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If we don't clear START generation as soon as possible, it may cause
another message to be generated. To keep the race window as small as
possible, we clear it right at the beginning of the interrupt. We don't
need checking since we always want to stop START and STOP generation on
the next occasion after we started it.

This patch improves the situation but sadly does not completely fix it.
It is still to be researched if we can do better given this HW design.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Due to broken HW design, master IRQs are more timing critical, so give
them precedence over slave IRQ.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The manual says (55.4.8.6) that HW does automatically send STOP after
NACK was received. My measuerments confirm that.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Setting up new messages was done in process context while handling a
message was in interrupt context. Because of the HW design, this IP core
is sensitive to timing, so the context switches were too expensive. Move
this setup to interrupt context as well.

In my test setup, this fixed the occasional 'data byte sent twice' issue
which a number of people have seen. It also fixes to send REP_START
after a read message which was wrongly send as a STOP + START sequence
before.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We want to reuse this function later.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We make sure to reinit the HW in the timeout case; then we know that
interrupts are always disabled in the sections protected by the
spinlock. Thus, we can simply remove it which is a preparation for
further refactoring. While here, rename the timeout variable to
time_left which is way more readable.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We don't need to init HW before every transfer since we know the HW
state then. HW init at probe time is enough. While here, add setting the
clock register which belongs to init HW. Also, set MDBS bit since not
setting it is prohibited according to the manual.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

wait_event_timeout returns long, not int.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

5 seconds is a very large timeout, and it is hardcoded. Use the default
timeout from 'struct adapter' which is 1 second. It can also be modified
from userspace for specific workloads via i2c-dev.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The platform_device_id is not modified by these drivers and core uses it
as const.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

After more discussion, brave users, and additional datasheet evaluation,
some API updates for the new I2C slave framework became imminent. The
slave events now get some easier to understand naming. Also, the event
handling has been simplified to only need a single call to the slave
callback when an action by the backend is required.
Reported-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The first I2C slave provider using the new generic interface.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

A platform_driver does not need to set an owner, it will be populated by the
driver core.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

gcc rightfully says:

drivers/i2c/busses/i2c-rcar.c:198:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Check if the ICMSR register (masked with the ICMIER register) evaluates to 0  in
the driver's interrupt handler and return IRQ_NONE in that case, like many other
drivers do.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

rcar_i2c_prepare_msg() always returns 0, so we can make this function return
*void* and thus remove the result check in rcar_i2c_master_xfer().
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

rcar_i2c_master_xfer() needlessly compares the message pointers (using indirect
addressing) in order to detect the last I2C message, while it's enough to only
compare the message indexes.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Bits 8-31 of all registers reflect the value of bits 0-7 on reads and should be
0 on writes, according to the manuals. RCAR_IRQ_ACK_{RECV|SEND} macros have all
1's in bits 8-31, thus going against the manuals, so fix them.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: stable@vger.kernel.org
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This reverts commit 150b8be3.

The I2C core's per-adapter locks can't protect from IRQs, so the driver still
needs a spinlock to protect the register accesses.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Sometimes the MNR and MST interrupts happen simultaneously  (stop  automatically
follows NACK, according to the manuals) and in such case the ID_NACK flag  isn't
set since the MST interrupt handling precedes MNR and all interrupts are cleared
and disabled then, so that MNR interrupt is never noticed -- this causes NACK'ed
transfers to be falsely reported as successful. Exchanging MNR and  MST handlers
fixes this issue, however the MNR bit  somehow  gets set again even after  being
explicitly cleared, so I decided to completely suppress handling of all disabled
interrupts (which is a good thing anyway)...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: stable@vger.kernel.org
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This driver has been flagged to drop class based instantiation. The removal
improves boot-up time and is unneeded for embedded controllers. Users have been
warned to switch for some time now, so we can actually do the removal. Keep the
DEPRECATED flag, so the core can inform users that the behaviour finally
changed now. After another transition period, this flag can go, too.
While we are here, remove the indentation for the array setup because
such things always break after some time.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message. For example,
k.alloc and v.alloc failures use dump_stack().
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Acked-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NFelipe Balbi <balbi@ti.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Make clear that the driver is GPL v2 only. Remove FSF address. Remove
filename in comment. Update copyright information.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Remove some obvious comments, remove some superfluous debug output (the
error code carries the same information), some white space fixing...
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Status register and enable register are identical regarding their
layout. Use the bit definitions for both.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The i2c core has per-adapter locks, so no need to protect again.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The old macros made it harder to see what was actually happening.
Replace them with something more readable.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Setting up a read or write message is similar enough to be done in one
function. Also, move a helper function into the new function since it is
only used here.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We should always check if the bus is free, independently if it is a read
or write. It should be done before the first message, though. After
that, we ourselves keep the bus busy. Remove a 'ret' assignment which
only silenced a build warning.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Remove the seperate functions and use designated constants. As readable
but less overhead. Actually, this is even more readable since the old
function used a mix of "=" and "|=".
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Remove the seperate functions and use designated constants. As readable
but less overhead.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>