There is a race between the TWSI interrupt and the condition
that is required before proceeding:

Low-level: interrupt flag bit must be set
High-level controller: valid bit must be clear

If the interrupt comes too early and the condition is not met
the wait will time out, and the transfer is aborted leading
to very poor performance.

To avoid this race retry for the condition ~80 µs later.
The retry is avoided on the very first invocation of
wait_event_timeout() (which tests the condition before entering
the wait and is therefore always wrong in this case).

EEPROM reads on 100kHz i2c now measure ~5.2kB/s, about 1/2 what's
achievable, and much better than the worst-case 100 bytes/sec before.

While at it remove the debug print from the low-level wait function.
Signed-off-by: Peter Swain <pswain@cavium.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Zero-length message support (SMBUS QUICK or i2c) never worked with
the Octeon hardware. Disable SMBUS QUICK support and bail out in
case of a zero-length i2c request.

After this change 'i2c-detect -q' will return an error on Octeon but
the previously reported results were wrong anyway.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

The clk_prepare_enable() function can fail so check the return
value and propagate the error in case of a failure.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

The driver not always prints the error code in case of a failure but this
information can be very useful for debugging. So let's print if available.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Improve the readability by:
 - fixing indentation,
 - switching to proper block comments,
 - removing spurious blank lines,
 - checkpatch: void function return statements are not generally useful,
 - checkpatch: braces {} are not necessary for any arm of this
   statement,
 - checkpatch: missing a blank line after declarations.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Cleanup the weird function-level comments and remove obvious
documentation for probe/remove.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

If during probe() the s3c24xx_i2c_init() failed, the clock was left in
disabled but prepared state.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

cn78xx has a different interrupt architecture, so we have to manage
the interrupts differently.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Use High-Level Controller (HLC) when possible. The HLC can read/write
up to 8 bytes and is completely optional. The most important difference
of the HLC is that it only requires one interrupt for a transfer
(up to 8 bytes) where the low-level read/write requires 2 interrupts
plus one interrupt per transferred byte. Since the interrupts are costly
using the HLC improves the performance. Also, the HLC provides improved
error handling.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[wsa: fixed trivial checkpatch warnings]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Add helper function that reads back a value after writing to
make sure the write is finished and use it in octeon_i2c_write_int().
Signed-off-by: Peter Swain <pswain@cavium.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Switch to the i2c bus recovery framework using generic SCL recovery.
If this fails try to reset the hardware. The recovery is triggered
during START on timeout of the interrupt or failure to reach
the START / repeated-START condition.

The START function is moved to xfer and while at it remove the
xfer debug message (i2c core already provides a debug message
for this).
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[wsa: removed one empty line]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Introduce a function that checks for valid status codes depending
on the phase of a transmit or receive. Also add all existing status
codes and improve error handling for various states.

The Octeon TWSI has an "assert acknowledge" bit (TWSI_CTL_AAK) that
is required to be set in master receive mode until the last byte is
requested. The state check needs to consider if this bit was set.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS to simplify the code.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS to simplify the code.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

smatch rightfully says:

drivers/i2c/muxes/i2c-mux-pinctrl.c:175 i2c_mux_pinctrl_probe() warn: inconsistent indenting
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

The lock is taken while reading two registers. On RT the first lock is
taken in hard irq where it might sleep and in the threaded irq.
The threaded irq runs in oneshot mode so the hard irq does not run until
the thread the completes so there is no reason to grab the lock.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[grygorii.strashko@ti.com: drop locking from isr completely and remove
lock field from struct omap_i2c_dev]
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Share the ACPI companion for the platform device with the
i2c adapter, so that the adapter has access to the properties
defined in ACPI tables.
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

All i2c mux users are using an explicit i2c mux core, drop support
for implicit i2c mux cores.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.
Tested-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Tested-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Tested-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.
Tested-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select op to be in terms of the i2c mux core instead
of the child adapter.
Tested-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Acked-by: Jonathan Cameron <jic23@kernel.org>
Tested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.

Add a mask to handle the case where not all child adapters should
cause a mux deselect to happen, now that there is a common deselect op
for all child adapters.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Allocate an explicit i2c mux core to handle parent and child adapters
etc. Update the select/deselect ops to be in terms of the i2c mux core
instead of the child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

All i2c-muxes have a parent adapter and one or many child
adapters. A mux also has some means of selection. Previously,
this was stored per child adapter, but it is only needed
to keep track of this per mux.

Add an i2c mux core, that keeps track of this consistently.

Also add some glue for users of the old interface, which will
create one implicit mux core per child adapter.
Signed-off-by: Peter Rosin <peda@axentia.se>
Tested-by: Antti Palosaari <crope@iki.fi>
Tested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

We cannot expect msleep(1) to actually sleep for a period shorter than
20 ms. Replace all calls to msleep() with usleep_range().
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

The second check for I2C_FUNC_I2C is reduntant, so remove it.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
[wsa: reworded commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Switch to the new generic functions: i2c_parse_fw_timings().
Signed-off-by: David Wu <david.wu@rock-chips.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Remove superfluous check and stray newline.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Add helper functions for control, data and status register access.
This simplifies the code and makes the purpose of the register
access clearer.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Rename the [read|write]_sw functions to make it clearer they access
the TWSI registers.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

No functional change, just moving the functions upward in
preparation of improving the recovery.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Convert the adapter timeout to 2 ms independently of depending on CONFIG_HZ.
CONFIG_HZ is 100 for MIPS Cavium-Octeon so the timeout value is not changed.

Also set retries to 5 to improve robustness.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>