Instead of checking for i2c parent adapters for every lock/unlock, simply
override the locking for muxes to always lock/unlock the parent adapter
directly.
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add i2c_lock_bus() and i2c_unlock_bus(), which call the new lock_bus and
unlock_bus ops in the adapter. These funcs/ops take an additional flags
argument that indicates for what purpose the adapter is locked.

There are two flags, I2C_LOCK_ROOT_ADAPTER and I2C_LOCK_SEGMENT, but they
are both implemented the same. For now. Locking the root adapter means
that the whole bus is locked, locking the segment means that only the
current bus segment is locked (i.e. i2c traffic on the parent side of
a mux is still allowed even if the child side of the mux is locked).

Also support a trylock_bus op (but no function to call it, as it is not
expected to be needed outside of the i2c core).

Implement i2c_lock_adapter/i2c_unlock_adapter in terms of the new locking
scheme (i.e. lock with the I2C_LOCK_ROOT_ADAPTER flag).

Locking the root adapter and locking the segment is the same thing for
all root adapters (e.g. in the normal case of a simple topology with no
i2c muxes). The two locking variants are also the same for traditional
muxes (aka parent-locked muxes). These muxes traverse the tree, locking
each level as they go until they reach the root. This patch is preparatory
for a later patch in the series introducing mux-locked muxes, which behave
differently depending on the requested locking. Since all current users
are using i2c_lock_adapter, which is a wrapper for I2C_LOCK_ROOT_ADAPTER,
we only need to annotate the calls that will not need to lock the root
adapter for mux-locked muxes. I.e. the instances that needs to use
I2C_LOCK_SEGMENT instead of i2c_lock_adapter/I2C_LOCK_ROOT_ADAPTER. Those
instances are in the i2c_transfer and i2c_smbus_xfer functions, so that
mux-locked muxes can single out normal i2c accesses to its slave side
and adjust the locking for those accesses.
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Just in case.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

When clock support was added to the i2c-mv64xxx, not all clk functions
had stubs when for !CONFIG_HAVE_CLK configurations. However, nowadays,
both "struct clk" and all the clock framework functions have stubs
when CONFIG_HAVE_CLK is not enabled, so it no longer makes sense to
carry such compile-time conditionals in the driver.

This commit was compile tested on both ARM64 (which has both
CONFIG_OF=y and CONFIG_HAVE_CLK=y) and PowerPC c2k_defconfig (which
has CONFIG_OF=y, CONFIG_HAVE_CLK disabled, and the i2c-mv64xxx driver
enabled).

The only non-trivial change is in the mv64xxx_of_config() function,
which was returning -ENODEV unconditionally if CONFIG_HAVE_CLK was
disabled. Simply removing this condition works fine because the first
test done by the function is to verify if drv_data->clk points to a
valid clock, and if it doesn't, we return -ENODEV. When
CONFIG_HAVE_CLK is disabled, devm_clk_get() unconditionally returns
NULL, so mv64xxx_of_config() will return -ENODEV when no clock is
provided, which is the intended behavior.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Instead of separately calling clk_prepare()/clk_enable(), use
clk_prepare_enable(), and instead of calling
clk_disable()/clk_unprepare(), use clk_disable_unprepare(). Those
handy shortcuts have been introduced specifically to simplify the
numerous call sites were both functions were called in sequence.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If a clock is registered by a platform driver and not by the
OF_CLK_DECLARE() mechanism, it might show up after the first attempt
to probe i2c-mv64xxx. In order to solve this, we need to handle
-EPROBE_PREFER as a special return value of devm_clk_get(), and return
the same error code from probe().

This gives us three situations:

 - There is no reference to a clock in the DT. In this case,
   devm_clk_get() returns an error that is not -EPROBE_DEFER
   (something like -ENODEV), and we continue the probing without
   enabling the clock.

 - There is a reference to the clock in the DT, and the clock is
   ready. devm_clk_get() returns a valid reference to the clock, and
   we prepare/enable it.

 - There is a reference to the clock in the DT, but the clock is not
   ready. devm_clk_get() returns -EPROBE_DEFER, and we exit from
   probe() with the same error code so that probe() is tried again
   later.

This is needed for Marvell Armada 7K/8K, where the clock driver is a
platform driver.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The new ARM64 Marvell Armada 7K/8K SoC family is using the same I2C
controller as the 32-bits Marvell EBU SoCs, so this commit allows
mv64xxx to be enabled when ARCH_MVEBU=y.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

CN3860 does not interrupt the CPU when the i2c status changes. If
we get a timeout, and see the status has in fact changed, we know we
have this problem, and drop back to polling.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Documentation/timers/timers-howto.txt recommends to use
usleep_range on delays > 10usec. According to my test results
with Neonode zForce touchscreen driver, usleep_range indeed
reduces CPU load.

Stats collected with "./perf record -a -g -F 1000 sleep 10"

i2c-imx with udelay(50):
34.19% 0.00% irq/220-Neonode [kernel.kallsyms] [k] irq_thread
    ---irq_thread
       |--33.75%--irq_thread_fn
       |    |--19.27%--0x7f08a878
       |    |     i2c_master_recv
       |    |     i2c_transfer
       |    |     __i2c_transfer
       |    |     i2c_imx_xfer
       |    |     |--11.71%--i2c_imx_trx_complete
       |    |     |--5.70%--i2c_imx_start <<<<----------------
       |    |     |     |--5.38%--__timer_const_udelay
       |    |     |     |      __timer_delay
       |    |     |     |      --5.07%--read_current_timer

i2c-imx with usleep_range(50,100)
29.08% 0.00% irq/220-Neonode  [kernel.kallsyms] [k] irq_thread
    ---irq_thread
       |--28.89%--irq_thread_fn
       |    |--17.21%--0x7f08a878
       |    |     i2c_master_recv
       |    |     |--17.14%--i2c_transfer
       |    |     |     __i2c_transfer
       |    |     |     i2c_imx_xfer
       |    |     |     |--14.29%--i2c_imx_trx_complete
       |    |     |     |--1.42%--i2c_imx_start <<<<----------
       |    |     |     |      |--0.71%--usleep_range
       |    |     |     |      |--0.53%--i2c_imx_bus_busy
Signed-off-by: NOleksij Rempel <linux@rempel-privat.de>
Signed-off-by: NDirk Behme <dirk.behme@de.bosch.com>
Reviewed-by: NVladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

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: NPeter Swain <pswain@cavium.com>
Signed-off-by: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram 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: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram 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: NJavier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NWolfram 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: NJavier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NWolfram 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: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

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

cn78xx has a different interrupt architecture, so we have to manage
the interrupts differently.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram 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: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NJan Glauber <jglauber@cavium.com>
[wsa: fixed trivial checkpatch warnings]
Signed-off-by: NWolfram 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: NPeter Swain <pswain@cavium.com>
Signed-off-by: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram 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: NJan Glauber <jglauber@cavium.com>
[wsa: removed one empty line]
Signed-off-by: NWolfram 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: NJan Glauber <jglauber@cavium.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

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

Use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS to simplify the code.
Signed-off-by: NAxel Lin <axel.lin@ingics.com>
Reviewed-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NWolfram 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: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NSebastian 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: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NWolfram 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: NIrina Tirdea <irina.tirdea@intel.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NAntti Palosaari <crope@iki.fi>
Reviewed-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NAntti Palosaari <crope@iki.fi>
Reviewed-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NAntti Palosaari <crope@iki.fi>
Reviewed-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NAntti Palosaari <crope@iki.fi>
Reviewed-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NJonathan Cameron <jic23@kernel.org>
Tested-by: NCrestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram 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: NPeter Rosin <peda@axentia.se>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>