The changes in "i2c-s3c2410: use exponential back off while polling for
bus idle" remove the initial busy wait for I2C transfers to complete and
replace it with usleep_range() calls which will schedule.

Since for older SoCs I2C transfers would usually complete within an
extremely small number of CPU cycles there is a win from not having to
schedule.  This happens because on the older SoCs the cores run at a
smaller multiple of the speeds that the I2C bus is operating at; on more
modern SoCs the busy wait is less likely to be effective.

Fix the issue by restoring the busy wait, reducing the number of spins
from 20 to 3 which covers the overwhelming majority of I2C transfers on
the SoCs where the busy wait is effective.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

This moves the grlib set and get functions into the #ifdef CONFIG_OF block to
avoid warnings of unimplemented functions when compiling with -Wunused-function
when CONFIG_OF is not defined.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The I2C driver makes a gpio_request during initialization. This request
happens again on resume and fails due to the earlier successful request.
Re-factor the code to only initialize the gpios during probe.

Errors on resume without this:
[   16.020000] s3c-i2c s3c2440-i2c.0: gpio [42] request failed
[   16.020000] s3c-i2c s3c2440-i2c.1: gpio [44] request failed
[   16.020000] s3c-i2c s3c2440-i2c.2: gpio [6] request failed
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Store the requested gpios so that they can be freed on error/removal.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Add i2c driver to enable access to devices behind CBUS on Nokia Internet
Tablets.

The patch also adds CBUS I2C configuration for N8x0 which is one of the
users of this driver.
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

i2c: ocores: Add support for the GRLIB port of the controller and use function pointers for getreg and setreg functions

The registers in the GRLIB port of the controller are 32-bit and in big endian
byte order. The PRELOW and PREHIGH registers are merged into one register. The
subsequent registers have their offset decreased accordingly. Hence the register
access needs to be handled in a non-standard manner using custom getreg and
setreg functions.

Add setreg and getreg functions for different register widths and let oc_setreg
and oc_getreg use function pointers to call the appropriate functions.

A type is added as the data of the of match table entries. A new entry with a
different compatible string is added to the table. The type of that entry
triggers usage of the custom grlib functions by setting the setreg and getreg
function pointers.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Add sparc support by using platform_get_irq instead of platform_get_resource.
There are no platform resources of type IORESOURCE_IRQ for sparc, but
platform_get_irq works for sparc. In the non-sparc case platform_get_irq
internally uses platform_get_resource.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Currently we just queue the transfer and release the
qos constraints, however we do not wait for the transfer
to complete to release the constraint. Move the remove
constraint after the bus busy as we are sure that the
transfers are completed by then.
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

This will allow to add the 3 Nuvoton NAU7802 ADCs and the NXP PCA9555
GPIO expander eventually.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Commit "i2c-s3c2410: Add HDMIPHY quirk for S3C2440" added support for
HDMIPHY with some special handling in s3c24xx_i2c_set_master:

"due to unknown reason (probably HW bug in HDMIPHY and/or the controller)
a transfer fails to finish. The controller hangs after sending the last
byte, the workaround for this bug is resetting the controller after each
transfer"

The "unknown reason" was that the proper sequence for generating a STOP
condition wasn't being followed as per the datasheet. Since this is fixed
by "PATCH: i2c-s3c2410: do not generate STOP for QUIRK_HDMIPHY buses",
remove the special handling.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Usually, the i2c controller has finished emitting the i2c STOP before the
driver reaches the bus idle polling loop.  Optimize for this most common
case by reading IICSTAT first and potentially skipping the loop.

If the cpu is faster than the hardware, we wait for bus idle in a polling
loop.  However, since the duration of one iteration of the loop is
dependent on cpu freq, and this i2c IP is used on many different systems,
use a time based loop timeout (5 ms).

We would like very low latencies to detect bus idle for the normal
'fast' case.  However, if a device is slow to release the bus for some
reason, it could hold off the STOP generation for up to several
milliseconds.  Rapidly polling for bus idle would seriously load the CPU
while waiting for it to release the bus.  So, use a partial exponential
backoff as a compromise between idle detection latency and cpu load.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The datasheet says that the STOP sequence should be:
 1) I2CSTAT.5 = 0	- Clear BUSY (or 'generate STOP')
 2) I2CCON.4 = 0	- Clear IRQPEND
 3) Wait until the stop condition takes effect.
 4*) I2CSTAT.4 = 0 	- Clear TXRXEN

Where, step "4*" is only for buses with the "HDMIPHY" quirk.

However, after much experimentation, it appears that:
 a) normal buses automatically clear BUSY and transition from
    Master->Slave when they complete generating a STOP condition.
    Therefore, step (3) can be done in doxfer() by polling I2CCON.4
    after starting the STOP generation here.
 b) HDMIPHY bus does neither, so there is no way to do step 3.
    There is no indication when this bus has finished generating STOP.

In fact, we have found that as soon as the IRQPEND bit is cleared in
step 2, the HDMIPHY bus generates the STOP condition, and then immediately
starts transferring another data byte, even though the bus is supposedly
stopped.  This is presumably because the bus is still in "Master" mode,
and its BUSY bit is still set.

To avoid these extra post-STOP transactions on HDMI phy devices, we just
disable Serial Output on the bus (I2CSTAT.4 = 0) directly, instead of
first generating a proper STOP condition.  This should float SDA & SCK
terminating the transfer.  Subsequent transfers start with a proper START
condition, and proceed normally.

The HDMIPHY bus is an internal bus that always has exactly two devices,
the host as Master and the HDMIPHY device as the slave. Skipping the STOP
condition has been tested on this bus and works.

Also, since we disable the bus directly from the isr, we can skip the bus
idle polling loop at the end of doxfer().
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

We probably don't want to change I2C frequency while a transfer is in
progress.  The current implementation grabs a spinlock, but that only
protected the writes to IICCON when starting a message, it didn't protect
against clock changes in the middle of a transaction.

Note: The i2c-core already grabs the adapter lock before calling
s3c24xx_i2c_doxfer(), which ensures that only one caller is issuing a
xfer at a time. This means it is not necessary to disable interrupts
(spin_lock_irqsave) when changing frequencies, since there won't be
any i2c interrupts if there is no on-going xfer.

Lastly, i2c_lock_adapter() may cause the cpufreq_transition to sleep if
if a xfer is in progress, but this is ok since cpufreq notifiers are
called in a kernel thread, and there are already cases where it could
sleep, such as when using i2c to update the output of a voltage
regulator.

Note: the cpufreq part of this change has no functional affect on
	exynos, where the i2c clock is independent of the cpufreq.
	But, there is a slight perfomance boost since we no longer need to
	lock/unlock an additional spinlock.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

This patch adds support for pin configuration using pinctrl subsystem
to the i2c-s3c2410 driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

A small code saving and less error handling to worry about.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Use the PM_SLEEP ifdef for system suspend and resume. This is partly
in preparation for adding runtime operations and partly because a user
may in theory choose to enable runtime suspend but not system suspend.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Allow the i2c-mux-gpio to be used by a device tree enabled device. The
bindings are inspired by the one found in the i2c-mux-pinctrl driver.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>

[wsa: fixed some whitespace]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Ensure that any of preceding register write operations to the I2C
hardware block reached the module, and the write data is reflected
in the registers, before leaving the interrupt handler.

Otherwise, we'll suffer from spurious WAIT interrupts that lead to
'Transfer request timed out' message, and the transaction failed.
Reported-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

On newer SH-/R-Mobile SoCs, a clock supply to the I2C hardware block,
which is used to generate the SCL clock output, is getting faster than
before, while on the other hand, the SCL clock control registers, ICCH
and ICCL, stay unchanged in 9-bit-wide (8+1).

On such silicons, the internal SCL clock counter gets incremented every
2 clocks of the operating clock.

This patch makes it configurable through platform data.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

ICCH/ICCL values is supposed to be calculated/optimized to strictly meet
the timing specs required by the I2C standard. The resulting I2C bus
speed does not matter at all, if it's less than 100 or 400 kHz.

With this change, sh_mobile_i2c_icch() is virtually identical to
sh_mobile_i2c_iccl(), but they're providing good descriptions of
SH-/R-Mobile I2C hardware spec, and I'd leave them as separated.

Also fix a typo in the comment, print icch/iccl values at probe, etc.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>

[wsa: squashed two patches for bisectability]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Currently SCL clock parameters (ICCH/ICCL) are calculated in
activate_ch(), which gets called every time sh_mobile_i2c_xfer() is
processed, while each I2C bus speed is system-defined and in general
those parameters do not have to be updated over I2C transactions.

The only reason I could see having it transaction-time is to adjust
ICCH/ICCL values according to the operating frequency of the I2C
hardware block, in the face of DFS (Dynamic Frequency Scaling).

However, this won't be necessary.

The operating frequency of the I2C hardware block can change _even_
in the middle of I2C transactions.  There is no way to prevent it
from happening, and I2C hardware block can work with such dynamic
frequency change, of course.

Another is that ICCH/ICCL clock parameters optimized for the faster
operating frequency, can also be applied to the slower operating
frequency, as long as slave devices work.  However, the converse is
not true.  It would violate SCL timing specs of the I2C standard.

What we can do now is to calculate the ICCH/ICCL clock parameters
according to the fastest operating clock of the I2C hardware block.
And if that's the case, that calculation should be done just once
at driver-module-init time.

This patch moves ICCH/ICCL calculating part from activate_ch() into
sh_mobile_i2c_init(), and call it from sh_mobile_i2c_probe().

Note that sh_mobile_i2c_init() just prepares clock parameters using
the clock rate and platform data provided, but does _not_ make any
hardware I/O accesses.  We don't have to care about run-time PM
maintenance here.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>

Currently after the reset the sysc is written with hardcoded values.
The patch reads the sysc register and writes back the same value
after reset.

- Some unnecessary rev checks can be optimised.
- Also due to whatever reason the hwmod flags are changed
we will not reset the values.
- In some of the cases the minor values of the 2430 register
is different(0x37) in that case the autoidle setting may be missed.
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Currently the restore is done based on the flag
OMAP_I2C_FLAG_RESET_REGS_POSTIDLE.

This helps the following
- The driver is always capable of restoring regardless
of the off mode support being there or not.

- While testing omap2430 it is found that in case of certain
error paths (timeout) a reset is done. However the restore
never happens as it is dependent on the POSTIDLE flag.
The other option would be to call a restore in the reset
case. As there are only a few registers to be restored
the penalty in the idle case should not be much.
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Implement reset as a separate function.
This will enable us to make sure that we don't do the
calculation again on every transfer.
Also at probe the reset is not added as the hwmod is doing that
for us.
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

re-factor omap_i2c_init() so that we can re-use it for resume.
While at it also remove the bufstate variable as we write it
in omap_i2c_resize_fifo for every transfer.
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The commit [i2c: omap: use revision check for OMAP_I2C_FLAG_APPLY_ERRATA_I207]
uses the revision id instead of the flag. So the flag can be safely removed.
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The dtrev is used only for the comments. Remove the same and use
the scheme instead to know if it is version2.
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The errata i207 is enabled for 2430 and 3xxx. Use the revision check
to enable the erratum instead.
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The revision register on OMAP4 is a 16-bit lo and a 16-bit
hi. Currently the driver reads only the lower 8-bits.
Fix the same by preventing the truncating of the rev register
for OMAP4.

Also use the scheme bit ie bit-14 of the hi register to know if it
is OMAP_I2C_IP_VERSION_2.

On platforms previous to OMAP4 the offset 0x04 is IE register whose
bit-14 reset value is 0, the code uses the same to its advantage.

Also since the omap_i2c_read_reg uses reg_map_ip_* a raw_readw is done
to fetch the revision register.

The dev->regs is populated after reading the rev_hi. A NULL check
has been added in the resume handler to prevent the access before
the setting of the regs.
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Some GPIO expanders need some early pin control muxing. Due to
legacy boards sometimes the driver uses subsys_initcall instead of
module_init. This patch takes advantage of defer probe feature
and pin control in order to wait until pin control probing before
GPIO driver probing. It has been tested on OMAP5 board with TCA6424
driver.
Signed-off-by: Sebastien Guiriec <s-guiriec@ti.com>
Acked-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

if we allow compiler reorder our writes, we could
fall into a situation where dev->buf_len is reset
for no apparent reason.

This bug was found with a simple script which would
transfer data to an i2c client from 1 to 1024 bytes
(a simple for loop), when we got to transfer sizes
bigger than the fifo size, dev->buf_len was reset
to zero before we had an oportunity to handle XDR
Interrupt. Because dev->buf_len was zero, we entered
omap_i2c_transmit_data() to transfer zero bytes,
which would mean we would just silently exit
omap_i2c_transmit_data() without actually writing
anything to DATA register. That would cause XDR
IRQ to trigger forever and we would never transfer
the remaining bytes.

After adding the memory barrier, we also drop resetting
dev->buf_len to zero in omap_i2c_xfer_msg() because
both omap_i2c_transmit_data() and omap_i2c_receive_data()
will act until dev->buf_len reaches zero, rendering the
other write in omap_i2c_xfer_msg() redundant.

This patch has been tested with pandaboard for a few
iterations of the script mentioned above.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

This reverts commit 3db11fef
(ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints).
This commit causes I2C timeouts to appear on several OMAP3430/3530-based
boards:

  http://marc.info/?l=linux-arm-kernel&m=135071372426971&w=2
  http://marc.info/?l=linux-arm-kernel&m=135067558415214&w=2
  http://marc.info/?l=linux-arm-kernel&m=135216013608196&w=2

and appears to have been sent for merging before one of its prerequisites
was merged:

  http://marc.info/?l=linux-arm-kernel&m=135219411617621&w=2Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The driver claims to support SMBus quick command but it was not the
case. This patch fixes this issue. Without it, i2cdetect finds imaginary
devices. And with some IP versions, trying to send 0 byte can cause
issue when writing data to an EEPROM.
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

[wsa: improved the commit message]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

When having multiple i2c-gpio nodes, the name for each is same.
So add the patch to fix it.

The adap->name printing information was added by myself

without this patch the log information is as following
---<8---
adap->name = i2c-gpio-1
i2c-gpio i2c.2: using pins 30 (SDA) and 31 (SCL)
adap->name = i2c-gpio-1
i2c-gpio i2c.3: using pins 64 (SDA) and 65 (SCL)
--->8---

with this patch, the log information is as following
---<8---
adap->name = i2c.2
i2c-gpio i2c.2: using pins 30 (SDA) and 31 (SCL)
adap->name = i2c.3
i2c-gpio i2c.3: using pins 64 (SDA) and 65 (SCL)
--->8---
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>

[wsa: minor fixes to the commit mesage]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Replacing the devm_request_mem_region() and devm_ioremap_nocache() calls
by a single call to devm_request_and_ioremap() simplifies the code.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Give the driver struct a name according to the 'standard' to fix:

WARNING: vmlinux.o(.data+0x11798): Section mismatch in reference from the variable rcar_i2c_drv to the function .devinit.text:rcar_i2c_probe()
...
WARNING: vmlinux.o(.data+0x1179c): Section mismatch in reference from the variable rcar_i2c_drv to the function .devexit.text:rcar_i2c_remove()
Reported-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

The return value of wait_for_completion_timeout() is always
>= 0 with unsigned int type.

So the condition "ret < 0" or "ret >= 0" is pointless.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>