Can be used during probe to double check that the probed device is
what is expected.

Loosely based on code from Adrian Fiergolski <adrian.fiergolski@cern.ch>.
Tested-by: NAdrian Fiergolski <adrian.fiergolski@cern.ch>
Reviewed-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NPeter Rosin <peda@axentia.se>

GPIO library can return -ENOSYS for the failed request.
Instead of failing ->probe() in this case override error code to 0.

Fixes: ca382f5b ("i2c: designware: add i2c gpio recovery option")
Reported-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Fix spelling.
Signed-off-by: NPatryk Kocielnik <patryk.kocielnik@gmail.com>
[wsa: fixed "Initialization", too]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

We were leaving them in the power on state (or the state the firmware
had set up for some client, if we were taking over from them).  The
boot state was 30 core clocks, when we actually want to sample some
time after (to make sure that the new input bit has actually arrived).
Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

Commits adding PCI IDs for Intel Braswell and Kaby Lake PCH-H lacked the
respective Kconfig and Documentation/i2c/busses/i2c-i801 change. Add
them now.
Signed-off-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

One I2C bus on my Atom E3845 board has been broken since 4.9.
It has two devices, both declared by ACPI and with built-in drivers.

There are two back-to-back transactions originating from the kernel, one
targeting each device. The first transaction works, the second one locks
up the I2C controller. The controller never recovers.

These kernel logs show up whenever an I2C transaction is attempted after
this failure.
i2c-designware-pci 0000:00:18.3: timeout in disabling adapter
i2c-designware-pci 0000:00:18.3: timeout waiting for bus ready

Waiting for the I2C controller status to indicate that it is enabled
before programming it fixes the issue.

I have tested this patch on 4.14 and 4.15.

Fixes: commit 2702ea7d ("i2c: designware: wait for disable/enable only if necessary")
Cc: linux-stable <stable@vger.kernel.org> #4.13+
Signed-off-by: NBen Gardner <gardner.ben@gmail.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock
is optional because not all the SoCs need them but at least for Armada
7K/8K it is actually mandatory.

The binding documentation is updating accordingly.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

clk_disable_unprepare() already checks that the clock pointer is valid.
No need to test it before calling it.
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Assign true or false to boolean variables instead of an integer value.

This issue was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add description for 'data' parameter and drop unused 'irq' memeber.

Here is the warnings:
drivers/i2c/busses/i2c-meson.c:103: warning: No description found for
parameter 'data'
drivers/i2c/busses/i2c-meson.c:103: warning: Excess struct member 'irq'
description in 'meson_i2c'
Reported-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NYixun Lan <yixun.lan@amlogic.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch try to add support for I2C controller in Meson-AXG SoC,
Due to the IP changes between I2C controller, we need to introduce
a compatible data to make the divider factor configurable.
Reviewed-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NJian Hu <jian.hu@amlogic.com>
Signed-off-by: NYixun Lan <yixun.lan@amlogic.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add runtime pm support to dynamically manage the clock to avoid enable/disable
clock in frequently that can improve the i2c bus transfer performance.

And use pm_runtime_force_suspend/resume() instead of lpi2c_imx_suspend/resume().
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Nothing big, but they get annoying after a while ;)
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

i2c_davinci_cpufreq_transition() is implemented in a way that will
block if it ever gets called while no transfer is in progress.

Not only that, but reinit_completion() is never called for xfr_complete.

Use the fact that cpufreq uses an srcu_notifier (running in process
context) for transitions and that the bus_lock is taken during the call
to master_xfer() and simplify the code by removing the transfer
completion entirely and protecting i2c_davinci_cpufreq_transition()
with i2c_lock/unlock_adapter().
Reported-by: NDavid Lechner <david@lechnology.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: NSekhar Nori <nsekhar@ti.com>
Tested-by: NDavid Lechner <david@lechnology.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

gcc noticed the kerneldoc was wrongly formatted. Fix it!

drivers/i2c/busses/i2c-rk3x.c:164: warning:
  Cannot understand  * @grf_offset: ...
  on line 164 - I thought it was a doc line
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Reviewed-by: NHeiko Stuebner <heiko@sntech.de>

This driver creates a number of const structures that it stores in
the data field of an of_device_id array.

The data field of an of_device_id structure has type const void *, so
there is no need for a const-discarding cast when putting const values
into such a structure.

Furthermore, adding const to the declaration of the location that
receives a const value from such a field ensures that the compiler
will continue to check that the value is not modified.  The
const-discarding cast on the extraction from the data field is thus
no longer needed.

Done using Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

That path has gone away for a long time. Move the HW name upwards for a
proper header.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

As of v4.15, Kbuild warns about missing MODULE_LICENSE tags:

WARNING: modpost: missing MODULE_LICENSE() in drivers/i2c/busses/i2c-acorn.o

This adds a license, author and description tag, matching the
comment at the start of the acorn i2c driver.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

On a I2C_SMBUS_I2C_BLOCK_DATA read request, if data->block[0] is
greater than I2C_SMBUS_BLOCK_MAX + 1, the underlying I2C driver writes
data out of the msgbuf1 array boundary.

It is possible from a user application to run into that issue by
calling the I2C_SMBUS ioctl with data.block[0] greater than
I2C_SMBUS_BLOCK_MAX + 1.

This patch makes the code compliant with
Documentation/i2c/dev-interface by raising an error when the requested
size is larger than 32 bytes.

Call Trace:
 [<ffffffff8139f695>] dump_stack+0x67/0x92
 [<ffffffff811802a4>] panic+0xc5/0x1eb
 [<ffffffff810ecb5f>] ? vprintk_default+0x1f/0x30
 [<ffffffff817456d3>] ? i2cdev_ioctl_smbus+0x303/0x320
 [<ffffffff8109a68b>] __stack_chk_fail+0x1b/0x20
 [<ffffffff817456d3>] i2cdev_ioctl_smbus+0x303/0x320
 [<ffffffff81745aed>] i2cdev_ioctl+0x4d/0x1e0
 [<ffffffff811f761a>] do_vfs_ioctl+0x2ba/0x490
 [<ffffffff81336e43>] ? security_file_ioctl+0x43/0x60
 [<ffffffff811f7869>] SyS_ioctl+0x79/0x90
 [<ffffffff81a22e97>] entry_SYSCALL_64_fastpath+0x12/0x6a
Signed-off-by: NJeremy Compostella <jeremy.compostella@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

Reference count of device node was increased in of_i2c_register_device,
but without decreasing it in i2c_unregister_device. Then the added
device node will never be released. Fix this by adding the of_node_put.
Signed-off-by: NLixin Wang <alan.1.wang@nokia-sbell.com>
Tested-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

We can force levels of SCL and SDA, so we can use that for bus recovery.
Note that we cannot read SDA back, because we will only get the internal
state of the bus free detection.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If we managed to get a client release SDA again, send a STOP afterwards
to make sure we have a consistent state on the bus again.
Tested-by: NPhil Reid <preid@electromag.com.au>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

If we have a function to control SDA, we should ensure that SDA is not
held down by us. So, release the GPIO in this case.
Tested-by: NPhil Reid <preid@electromag.com.au>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This will be needed when we want to create STOP conditions, too, later.
Create the needed fields and populate them for the GPIO case if the GPIO
is set to output.
Tested-by: NPhil Reid <preid@electromag.com.au>
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Exynos-I2C uses default timeout of 1 second for the whole transaction,
including re-transmissions due to arbitration lost errors (-EAGAIN).
To allow re-transmissions driver's internal timeout should be significantly
lower, 100ms seems to be good candidate.
Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Use only a portion of the data buffer for DMA transfers, which is always
16-byte aligned. This makes the DMA buffer address 16-byte aligned and
compensates for spurious hardware parity errors that may appear when the
DMA buffer address is not 16-byte aligned.

The data buffer is enlarged in order to accommodate any possible 16-byte
alignment offset and changes the DMA code to only use a portion of the
data buffer, which is 16-byte aligned.

The symptom of the hardware issue is the same as the one addressed in
v3.12-rc2-5-gbf416910 and manifests by transfers failing with EIO, with
bit 9 being set in the ERRSTS register.
Signed-off-by: NRadu Rendec <radu.rendec@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Remove the facility for setting the prescaler value at compile time
entirely. It was only used for two SoCs, duplicating the actual value
for one of them and setting sometimes bogus value for another. Make all
MPC8xxx SoCs obtain their actual I2C clock prescaler from a single place
in the code.

Changes from v2:
- left Device Tree compatibles in place
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

According to the reference manuals for the corresponding SoCs, SEC
frequency ratio configuration is indicated by bit 26 of the POR Device
Status Register 2. Consequently, SEC_CFG bit should be tested by mask 0x20,
not 0x80. Testing the wrong bit leads to selection of wrong I2C clock
prescaler on those SoCs.
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Commit 8ce795cb ("i2c: mpc: assign the correct prescaler from SVR")
introduced the common helper function for obtaining the actual clock
prescaler value for MPC85xx. However, getting the prescaler for MPC8544
which depends on the SEC frequency ratio on this platform, has been always
performed separately based on the corresponding Device Tree configuration.

Move special handling of MPC8544 into that common helper. Make it dependent
on the SoC version and not on Device Tree compatible node, as is the case
with all other SoCs. Handle MPC8533 the same way which is similar
to MPC8544 in this regard, according to AN2919 "Determining the I2C
Frequency Divider Ratio for SCL".
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Obtaining the actual I2C clock prescaler value in mpc_i2c_setup_8xxx() only
happens when the clock parameter is set to something other than
MPC_I2C_CLOCK_LEGACY. When the clock parameter is exactly
MPC_I2C_CLOCK_LEGACY, the prescaler parameter is used in arithmetic
division as provided by the caller, resulting in a division by zero
for the majority of processors supported by the module.

Avoid division by zero by obtaining the actual I2C clock prescaler
in mpc_i2c_setup_8xxx() unconditionally regardless of the passed clock
value.
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch dumps general and master registers at the end of transactions
when debugging is enabled. Previously, registers were only dumped before
submitting new descriptors (at the beginning of transactions).

This helps debugging if some registers change as result of a failed
transaction (e.g. bits are set in the ERRSTS general register).
Signed-off-by: NRadu Rendec <radu.rendec@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
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>

Optimize the power management in i2c-designware-platdrv by making it
set the DPM_FLAG_SMART_SUSPEND and DPM_FLAG_LEAVE_SUSPENDED which
allows some code to be dropped from its PM callbacks.

First, setting DPM_FLAG_SMART_SUSPEND causes the intel-lpss driver
to avoid resuming i2c-designware-platdrv devices in its ->prepare
callback, so they can stay in runtime suspend after that point even
if the direct-complete feature is not used for them.

It also causes the ACPI PM domain and the PM core to avoid invoking
"late" and "noirq" suspend callbacks for these devices if they are
in runtime suspend at the beginning of the "late" phase of device
suspend during system suspend.  That guarantees dw_i2c_plat_suspend()
to be called for a device only if it is not in runtime suspend.

Moreover, it causes the device's runtime PM status to be set to
"active" after calling dw_i2c_plat_resume() for it, so the
driver doesn't need internal flags to avoid invoking either
dw_i2c_plat_suspend() or dw_i2c_plat_resume() twice in a row.

Second, setting DPM_FLAG_LEAVE_SUSPENDED enables the optimization
allowing the device to stay suspended after system resume under
suitable conditions, so again the driver doesn't need to take
care of that by itself.

Accordingly, the internal "suspended" and "skip_resume" flags
used by the driver are not necessary any more, so drop them and
simplify the driver's PM callbacks.

Additionally, notice that dw_i2c_plat_complete() only needs to
schedule runtime PM resume for the device if platform firmware
has been involved in resuming the system, so make it call
pm_resume_via_firmware() to check that.  Also make it check the
runtime PM status of the device instead of its direct_complete
flag which also works if the device remained suspended due to
the DPM_FLAG_LEAVE_SUSPENDED driver flag.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Tested-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>

Modify i2c-designware-platdrv to set DPM_FLAG_SMART_PREPARE for its
devices and return 0 from the system suspend ->prepare callback
if the device has an ACPI companion object in order to tell the PM
core and middle layers to avoid skipping system suspend/resume
callbacks for the device in that case (which may be problematic,
because the device may be accessed during suspend and resume of
other devices via I2C operation regions then).

Also the pm_runtime_suspended() check in dw_i2c_plat_prepare()
is not necessary any more, because the core does it when setting
power.direct_complete for the device, so drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Tested-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>