Implement generic GPIO-based I2C bus recovery for the PXA I2C driver.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Merge tag 'for-5.8-i2c' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into i2c/for-5.8

i2c: tegra: Changes for v5.8-rc1

This includes a few improvements to make the Tegra I2C controller behave
properly on suspend/resume, does a bit of cleanup and adds support for
the VI-variant of the I2C controller that is used primarily for video
capture purposes.

Protect altr_i2c_int_enable() by the mutex and remove unneeded spinlock.
Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Although in the most platforms, the bus power of i2c
are alway on, some platforms disable the i2c bus power
in order to meet low power request.

We get and enable bulk regulator in i2c adapter device.
Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

In some platforms, they disable the power-supply of i2c due
to power consumption reduction. This patch add bus-supply property.
Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
[wsa: rebased to i2c/for-next]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Atomic transfers are not only about sending messages like the original
wording suggested. Speak of 'accessing' now like in i2c.h.
Reported-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

I don't plan to support every EEPROM type, but the 24c512 ones need a
tiny code update, so let's have that upstream.
Reported-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

This patch adds a algorithm to calculate some ac-timing parameters
which can fully meet I2C Spec.
Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add Qii Wang as maintainer for mediatek i2c controller driver.
Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

A call to 'i2c_demux_deactivate_master()' is missing in the error handling
path, as already done in the remove function.

Fixes: 50a5ba87 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Use a mutex to protect access to idev->msg_len, idev->buf, etc. which
are modified by both altr_i2c_xfer_msg() and altr_i2c_isr().

This is the minimal fix for easy backporting. A cleanup to remove the
spinlock will be added later.
Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Acked-by: Thor Thayer <thor.thayer@linux.intel.com>
[wsa: updated commit message]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The 'pengutronix' address is defunct for years. Use the proper contact
address.
Signed-off-by: Wolfram Sang <wsa@kernel.org>

devm_gpiod_get() usually calls gpio_request_enable() for non-strict pinmux
drivers. These puts the pins in GPIO mode, whithout notifying the pinctrl
driver. At this point, the I2C bus no longer owns the pins. To mux the
pins back to the I2C bus, we use the pinctrl driver to change the state
of the pins to GPIO, before using devm_gpiod_get(). After the pins are
received as GPIOs, we switch theer pinctrl state back to the default
one,

Fixes: d3d3fdcc ("i2c: at91: implement i2c bus recovery")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Allow slave mode for PCI enumerated devices by calling a common i2c_dw_probe()
instead of i2c_dw_probe_master().

While dropping dependency to platform driver in slave module, move its
configuration section above, closer to core.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

As a preparatory patch to support slave mode for PCI enumerated devices rename
i2c_dw_probe() to i2c_dw_probe_master() and split common i2c_dw_probe() as
inline helper.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Since we have available helper to configure master mode, let's use it
in the PCI driver instead of spread open-coded variant.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Move configuration routines to respective modules, i.e. master and slave.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Use devm_platform_ioremap_resource() instead of
platform_get_resource() + devm_ioremap_resource().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Tegra210 has an extra instance of the I2C controller that is in the
domain of host1x and usually used for camera use-cases. The programming
model for the VI variant of the controller is roughly the same as for
the other variants, except that the I2C registers start at an offset
and are spaced further apart. VI I2C also doesn't support slave mode.
Signed-off-by: Thierry Reding <treding@nvidia.com>

Using these macros helps increase readability of the code.
Signed-off-by: Thierry Reding <treding@nvidia.com>

Use master-abort to send the stop condition after an address cycle
rather than resetting the controller.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

If we timeout during a message transfer, the control register may
contain bits that cause an action to be set. Read-modify-writing the
register leaving these bits set may trigger the hardware to attempt
one of these actions unintentionally.

Always clear these bits when cleaning up after a message or after
a timeout.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Remove unnecessary show_state() in the loop inside
i2c_pxa_pio_set_master(), which can be unnecessarily verbose.

Remove the i2c_pxa_scream_blue_murder() in i2c_pxa_pio_xfer(), which
will trigger if we are probing the I2C bus and a slave does not
respond; this is a normal event, and not something to report.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Ensure that the various timeout messages can identify where in the code
they were produced from to aid debugging.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Running i2cdetect on a PXA I2C adapter is very noisy; it complains
whenever a slave fails to respond to the address cycle.  Since it is
normal to probe for slaves in this way, we should not fill the kernel
log.  This is especially true with SFP modules that take a while to
respond on the I2C bus, and probing via the I2C bus is the only way to
detect that they are ready.

Fix this by changing the internal transfer return code from I2C_RETRY
to a new NO_SLAVE code (mapped to -ENXIO, as per the I2C documentation
for this condition, but we still return -EREMOTEIO to the I2C stack to
maintain long established driver behaviour.)
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Most of i2c_pxa_pio_xfer() and i2c_pxa_xfer() are identical; the only
differences are that i2c_pxa_pio_xfer() may reset the bus, and they
use different underlying transfer functions. The retry loop is the
same. Consolidate these two functions.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Use a shorter SPDX identifier instead of pasting the whole license.

While here, replace duplicating PCA954x with PCA984x.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

device_create_file() is called the last in ->probe() but pca954x_cleanup(),
which is called earlier in error path, tries to remove never created file.
Move device_remove_file() call outside of pca954x_cleanup() to make it
slightly closer to what pca954x_init() is doing.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Device property API allows to gather device resources from different sources,
such as ACPI. Convert the drivers to unleash the power of device property API.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Refactor pca954x_irq_handler() to:
  - use for_each_set_bit() macro
  - use IRQ_RETVAL() macro

Above change makes code easy to read and understand.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

DMA transfer could be completed, but CPU (which handles DMA interrupt)
may get too busy and can't handle the interrupt in a timely manner,
despite of DMA IRQ being raised. In this case the DMA state needs to
synchronized before terminating DMA transfer in order not to miss the
DMA transfer completion.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Boot CPU0 always handle I2C interrupt and under some rare circumstances
(like running KASAN + NFS root) it may stuck in uninterruptible state for
a significant time. In this case we will get timeout if I2C transfer is
running on a sibling CPU, despite of IRQ being raised. In order to handle
this rare condition, the IRQ status needs to be checked after completion
timeout.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

One of the I2C controllers on Tegra SoCs is typically connected to a
system PMIC, which provides controls for critical power supplies for
most platforms.

Some drivers, such as PCI, need to disable these regulators during a
very late stage during suspend and resume them at a very early stage
during resume.

To support these use-cases, keep interrupts disabled during suspend/
resume.
Suggested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Depending on the board design, the I2C controllers found on Tegra SoCs
may require pinmuxing in order to function. This is done as part of the
driver's runtime suspend/resume operations. However, the PM core does
not allow devices to go into runtime suspend during system sleep to
avoid potential races with the suspend/resume of their parents.

As a result of this, when Tegra SoCs resume from system suspend, their
I2C controllers may have lost the pinmux state in hardware, whereas the
pinctrl subsystem is not aware of this. To fix this, make sure that if
the I2C controller is not runtime suspended, the runtime suspend code is
still executed in order to disable the module clock (which we don't need
to be enabled during sleep) and set the pinmux to the idle state.

Conversely, make sure that the I2C controller is properly resumed when
waking up from sleep so that pinmux settings are properly restored.

This fixes a bug seen with DDC transactions to an HDMI monitor timing
out when resuming from system suspend.
Signed-off-by: Thierry Reding <treding@nvidia.com>

This reverts commit 9f42de8d.

It's not safe to use pm_runtime_force_{suspend,resume}(), especially
during the noirq phase of suspend. See also the guidance provided in
commit 1e2ef05b ("PM: Limit race conditions between runtime PM
and system sleep (v2)").
Signed-off-by: Thierry Reding <treding@nvidia.com>

After a transfer timeout, some faulty I2C slave devices might hold down
the SDA pin. We can generate a bus clear command, hoping that the slave
might release the pins.
If the CLEAR command is not supported, we will use gpio recovery, if
available, to reset the bus.
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The old email is still active, but for easier handling, I am going to
use my kernel.org address from now on. Also, add a mailmap for the now
defunct Pengutronix address.
Signed-off-by: Wolfram Sang <wsa@kernel.org>

In case of the I2C client exposes the flag I2C_CLIENT_HOST_NOTIFY,
pm_runtime_get_sync is called in order to always keep active the
adapter. However later on, pm_runtime_put_sync is never called
within the function in case of an error. This commit add this
error handling.

Fixes: 72bfcee1 ("i2c: Prevent runtime suspend of adapter when Host Notify is required")
Signed-off-by: Alain Volmat <alain.volmat@st.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>