Properly terminate the DMA transfer in case the DMA PIO transfer
or setup fails for any reason.
Signed-off-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

This I2C master can do DMA and PIOQUEUE (PIO with FIFO). Originally,
only PIOQUEUE was supported and it had issues, then DMA support was added
this cycle. The original intention was to keep PIOQUEUE since it has
less overhead what is nice for small transfers. However, runtime
switching between PIOQEUE and DMA depending on the transfer size never
worked despite a lot of trying. Since PIOQUEUE mode itself was flaky
(polling at places where interrupts failed to work) and the
implementation also imposed a size limit for transfers, it is best to
remove the support, so users don't fall over its limitations. It also
makes the driver a lot cleaner and more robust. If somebody really wants
less overhead, plain PIO mode could still be implemented with the
addidtional advantage that this mode is also available on MX23, too.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Reviewed-by: NMarek Vasut <marex@denx.de>

This patch implements DMA support into mxs-i2c. DMA transfers are now enabled
via DT. The DMA operation is enabled by default.
Signed-off-by: NMarek Vasut <marex@denx.de>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>

[wsa: rebased to 3.6-rc7]
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

Commit cd4f2d4a (i2c: mxs: Set I2C timing registers for mxs-i2c) only
covered the case for devicetree and made platform_data based boards
bail out with -EINVAL. Correctly support the latter one, too.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

This patch configures the I2C bus timing registers according
to information passed via DT. Currently, 100kHz and 400kHz
modes are supported.

The TIMING2 register value is wrong in the documentation for
i.MX28! This was found and fixed by:
  Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

This patch mutes the false positive compiler warning:

drivers/i2c/busses/i2c-mxs.c: In function 'mxs_i2c_xfer_msg':
drivers/i2c/busses/i2c-mxs.c:206:8: warning: 'data' may be used uninitialized in this function [-Wuninitialized]
drivers/i2c/busses/i2c-mxs.c:196:6: note: 'data' was declared here
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

Add device tree probe support for i2c-mxs driver.  So far, it's only
been tested on imx28.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Cc: linux-i2c@vger.kernel.org
Cc: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

Since the last fixes to this driver ensure now the queue termination is
done correctly, we can finally disable the queue after a transfer
without problems. The gain is that it will only be reenabled after the
next transfer is fully set up. Before, the queue was running all the
time and if the setup of the next message was interrupted by another
thread, an incomplete buffer could have been sent, padded with zeroes.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

After an error interrupt setting cmd->err, I see another interrupt that
the data engine is empty which clears cmd->err before being processed.
So, clear cmd->err at the beginning of a transfer only to handle these
consecutive interrupts.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

The former mach specific reset_block function has been converted to a global
one. Use the new one to remove mach dependency from the driver.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

The hardware generates an interrupt for every completed command in the
queue while the code assumed that it will only generate one interrupt
when the queue is empty. So, explicitly check if the queue is really
empty. This patch fixed problems which occurred due to high traffic on
the bus. While we are here, move the completion-initialization after the
parameter error checking.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Lothar Waßmann <LW@KARO-electronics.de>
Cc: stable@kernel.org

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

mxs_reset_block() clears the PIO_QUEUE_MODE bit. So we have
to set it again after a controller reset.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

Currently only supporting the PIOQUEUE-mode, because DMA-support for
this platform is not yet in mainline. When it becomes available and
support has been added to this driver, it will also be suitable for
i.MX23 and STMP3xxx.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: NBen Dooks <ben-linux@fluff.org>