After various refactoring over the years, start_ch() doesn't return
errno anymore, so make the function return void. This saves the error
handling when calling it which in turn eases cleanup of resources of a
future patch.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

a) rename to 'put' instead of 'release' to match 'get' when obtaining
   the buffer
b) change the argument order to have the buffer as first argument
c) add a new argument telling the function if the message was
   transferred. This allows the function to be used also in cases
   where setting up DMA failed, so the buffer needs to be freed without
   syncing to the message buffer.

Also convert the only user.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

And don't reimplement in the driver.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

These days, the I2C core ensures that the embedded adapter device
ignores the PM states of its children already. Because the adapter
device is an opaque logical device, there is no need for drivers to
repeat that again.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Make use of the new formula for more precise bus frequencies.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The formula to generate the desired bus speeds has changed a little over
time. Implement the new formula and allow drivers to opt-in by changing
to this new config set. Ensure in probe that we don't divide by zero.
The returned values on a R-Car H2 (r8a7790/Lager board) match the
suggested values in the datasheet.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Because we will add a second formula soon, put the sanity checks for the
computed results into a separate function.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Start RuntimePM a bit earlier, so we can use it to enable the clock
during probe for frequency calculations. Make sure it is enabled before
calling setup().
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Require the setup callback and move the frequency calculation into it.
This is in preparation for supporting multiple formulas.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The setup callback will be more generic and, thus, need to be able to
return error codes. Change the return type to 'int' for that.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

For refactoring reasons, we will need this information before the setup
callback. Also, simplify the comment to a oneliner.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This ensures that we fall back to PIO if the message length is too small
for DMA being useful. Otherwise, we use DMA. A bounce buffer might be
applied by the helper if the original message buffer is not DMA safe.
Reviewed-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The datasheet was a bit vague, but after consultation with HW designers,
we came to the conclusion that we should set the SCP bit always when
dealing only with the ICE bit. A set SCP bit is ignored, and thus fine,
a cleared one may trigger STOP on the bus.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We initiate STOP (or REP_START) on the second last WAIT interrupt
currently. This works fine but is not according to the datasheet which
says to do it on the last WAIT interrupt. This also simplifies the code
quite a lot, so let's do it.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

There is no data when the first WAIT interrupt arrives. No need to read
something then.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

No need to do it manually.
Reported-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We can use the ternary operator for easier reading.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

ICE bit is for resetting the module. Other bits don't matter then, so we
don't need to use the iic_set_clr() function but can use iic_wr().
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Those two functions are very short and only called once. The code
becomes easier to understand if the code is directly put into the main
xfer function.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

No need to clear the interrupt registers because right after that we
disable the IP core which will reload registers with their initial
values anyhow.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Following the documentation, we initialize the HW before each START in
start_ch(). No need to do the same in activate_ch().
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Use the of_device_get_match_data() helper instead of open coding.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Fix smatch warning:
drivers/i2c/busses/i2c-sh_mobile.c:564 \
  sh_mobile_i2c_request_dma_chan() warn: unused return: ret = PTR_ERR()
Signed-off-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

After removal of platform_data support, we can simplify OF handling.
of_match_device() evaluates to NULL if !CONFIG_OF or if there is no node
pointer for that device, so we can remove the check for the node ptr.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

No platform currently upstream makes use of this platform_data anymore.
The ones that did are converted to DT meanwhile. So, remove it. The old
platforms likely don't have the 'clks_per_cnt' feature, otherwise it
would have been implemented by now. And in the unlikely case they need
to setup a different bus speed, we should rather go for a generic i2c
platform data just for that.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Declare i2c_algorithm structures as const as they are only stored in the
algo field of an i2c_adapter structure. This field is of type const, so
i2c_algorithm structures having this property can be made const too.
Signed-off-by: NBhumika Goyal <bhumirks@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> for
Acked-by: NPatrice Chotard <patrice.chotard@st.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NLudovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add per-Generation fallback bindings for R-Car SoCs.

This is in keeping with the compatibility string scheme is being adopted
for drivers for Renesas SoCs.

Also, improve readability by listing the rmobile fallback compatibility
string after the more-specific compatibility strings they provide a
fallback for.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We must use the same device we used for mapping.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The core will do this for us now.
Signed-off-by: NWolfram Sang <wsa-dev@sang-engineering.com>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Acked-by: NPeter Korsgaard <peter@korsgaard.com>
Acked-by: NHeiko Stuebner <heiko@sntech.de>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NThierry Reding <treding@nvidia.com>
Acked-by: NRay Jui <ray.jui@broadcom.com>
Acked-by: NVladimir Zapolskiy <vz@mleia.com>
Acked-by: NLudovic Desroches <ludovic.desroches@atmel.com>
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Enable the I2C core for this SoC. It is compitable to Gen2 SoCs, so
reuse the settings.
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>

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>

This used to be in platform init code. We want it to do in the driver
now. This is basically a code move and a new compatible added.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

DMA read requests could miss proper termination, so two more bytes would
have been read via PIO overwriting the end of the buffer with wrong
data. Make DMA stop handling more readable while we are here.
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>

DMA is opt-in for this driver. So, we can't use deferred probing for
requesting DMA channels in probe, because our driver would get endlessly
deferred if DMA support is compiled in AND the DMA driver is missing.
Because we can't know when the DMA driver might show up, we always try
again when a DMA transfer would be possible. The downside is that there
is more overhead for setting up PIO transfers under the above scenario.
But well, having DMA enabled and the proper DMA driver missing looks
like a broken or test config anyhow.
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>

Refactor DMA setup to keep the errno so we can implement better
deferred probe support in the next step.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We don't need the mask since we obtain the channels via DT.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>