Previously the duty cycle was divided equally into h_scl_l, t_scl_h.
This makes the low period of the SCL clock in Fast Mode is only 1.25us
which is way lower than the minimal value (1.3) specified in i2c
specification. In order to make sure t_scl_l, t_scl_h always fullfill
i2c specification, this commit calculates t_scl_l using this formula:

t_scl_l = clk_cycle *
    ((t_low_min + (scl_clock - t_low_min - t_high_min) / 2) / scl_clock)

where:
t_low_min is the minimal value of low period of the SCL clock in us;
t_high_min is the minimal value of high period of the SCL clock in us;
scl_clock is converted from SCL clock frequency into us.
Signed-off-by: Camel Guo <camel.guo@axis.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Now that the legacy eeprom driver was removed, the only remaining i2c
client driver with class SPD autodetection is jc42, and this driver
supports also class HWMON. Therefore we can remove class SPD from the
supported classes of the i801 adapter driver.
Legacy class-based instantiation shouldn't be used in new code, so I
think we can remove also the generic logic that ensures that supported
classes of parent and muxed adapters don't overlap.

Note: i801 parent supports just class HWMON now, and muxed childs
class SPD, so the supported classes don't overlap.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add support for atomic transfers using polling mode with interrupts
intentionally disabled. This removes the warning introduced by commit
63b96983 ("i2c: core: introduce callbacks for atomic transfers")
during system reboot and power-off.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Replace the pair of functions, devm_clk_get() and
clk_prepare_enable(), with a single function
devm_clk_get_enabled().
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
[wsa: rebased]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Merge tag 'at24-updates-for-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into i2c/for-mergewindow

at24 updates for v6.7

- support the write-lockable pages on two more models
- drop at24_get_chip_data()
- use the new __counted_by() attribute in struct at24_data

The ST M24C64-D behaves as a regular M24C64, except for the -D variant
which uses up another I2C address for Additional Write lockable page.
This page is 32 Bytes long and can contain additional data. Add entry
for it, so users can describe that page in DT. Note that users still
have to describe the main M24C64 area separately as that is on separate
I2C address from this page.
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The ST M24C64-D behaves as a regular M24C64, except for the -D variant
which uses up another I2C address for Additional Write lockable page.
This page is 32 Bytes long and can contain additional data. Document
compatible string for it, so users can describe that page in DT. Note
that users still have to describe the main M24C64 area separately as
that is on separate I2C address from this page.
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The ST M24C32-D behaves as a regular M24C32, except for the -D variant
which uses up another I2C address for Additional Write lockable page.
This page is 32 Bytes long and can contain additional data. Add entry
for it, so users can describe that page in DT. Note that users still
have to describe the main M24C32 area separately as that is on separate
I2C address from this page.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The ST M24C32-D behaves as a regular M24C32, except for the -D variant
which uses up another I2C address for Additional Write lockable page.
This page is 32 Bytes long and can contain additional data. Document
compatible string for it, so users can describe that page in DT. Note
that users still have to describe the main M24C32 area separately as
that is on separate I2C address from this page.
Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This reverts commit ae2a1f0f. An updated
series was sent. And this patch was not needed anymore because another
compatible entry was reused.
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add support for atomic transfers using polling mode with interrupts
intentionally disabled to get rid of the warning introduced by commit
63b96983 ("i2c: core: introduce callbacks for atomic transfers")
during system reboot and power-off.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add SMBus PCI ID on Intel Birch Stream SoC.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add sc8280xp compatible consistent with recent CAMSS CCI interfaces.
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
[wsa: rebased]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Use preferred device_get_match_data() instead of of_match_device() to
get the driver match data. With this, adjust the includes to explicitly
include the correct headers.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Document the compatible for the CCI block found on SC7280 SoC.
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Return an error code if devm_reset_control_get_exclusive() fails.
The current code returns success.

Fixes: 0e864b55 ("i2c: rcar: reset controller is mandatory for Gen3+")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Add an atomic_xfer method to the driver so that it behaves correctly
when controlling a PMIC that is responsible for device shutdown.

The atomic_xfer method added is similar to the one from the i2c-mv64xxx
driver. When running an atomic_xfer a bool flag in the driver data is
set, the interrupt is not unmasked on transfer start, and the IRQ
handler is manually invoked while waiting for pending transfers to
complete.
Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct at24_data.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocciSigned-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct i2c_atr.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocciSigned-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct i2c_demux_pinctrl_priv.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocciSigned-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
[wsa: improved blank lines]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

`info.type` is expected to be NUL-terminated judging by its use in
`i2c_new_client_device()` wherein it is used to populate `client->name`:
|	strscpy(client->name, info->type, sizeof(client->name));

NUL-padding is not required and even if it was, `client` is already
zero-initialized.

Considering the two points from above, a suitable replacement is
`strscpy` [2] due to the fact that it guarantees NUL-termination on the
destination buffer without unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

We expect name to be NUL-terminated based on its numerous uses with
functions that expect NUL-terminated strings.

For example in i2c-core-base.c +1533:
| dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

NUL-padding is not required as `adap` is already zero-alloacted with:
| adap = devm_kzalloc(&usbif->dev, sizeof(struct i2c_adapter), GFP_KERNEL);

With the above in mind, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Advertise our coding style by following it :)
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

debugfs can handle error pointers in subsequent calls. So, remove the
error checks as suggested by kerneldoc of this function.
Reported-by: Minjie Du <duminjie@vivo.com>
Closes: http://patchwork.ozlabs.org/project/linux-i2c/patch/20230713101829.15548-1-duminjie@vivo.com/Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

With some new registers, SCL can be calculated to be closer to the
desired rate. Apply the new formula for R-Car Gen3 device types.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Initially, we only needed a reset controller to make sure RXDMA works at
least once per transfer. Meanwhile, documentation has been updated. It
now says that a reset has to be performed prior every transaction, even
if it is non-DMA. So, make the reset controller a requirement instead of
being optional. And bail out if resetting fails.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

I2C core ensures in i2c_smbus_xfer() that the I2C bus lock is held when
calling the smbus_xfer callback. That's i801_access() in our case.
I think it's safe in general to assume that the I2C bus lock is held
when the smbus_xfer callback is called.
Therefore I see no need to define an own mutex.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

When entering the suspend callback, at first we should ensure that
transfers are finished and I2C core can't start further transfers.
Use i2c_mark_adapter_suspended() for this purpose, and complement it
with a call to i2c_mark_adapter_resumed() in the resume path.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Now that the driver core allows for struct class to be in read-only
memory, move the i2c_dev_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Using the I2C host controller on the MT7981 SoC requires 4 clocks to
be enabled. One of them, the pmic clk, is only enabled in case
'mediatek,have-pmic' is also set which has other consequences which
are not desired in this case.

Allow defining a pmic clk even in case the 'mediatek,have-pmic' propterty
is not present and the bus is not used to connect to a pmic, but may
still require to enable the pmic clock.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Simplify the module boilerplate code.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

In few places relevant registers are reset to their initial value on
driver load. Factor this out to new helper i801_restore_regs to avoid
code duplication.
Even though no actual problems are known, this patch may contribute
to avoiding potential issues by:
- restoring register values also in the error path of i2c_add_adapter
- making restoring registers the last step (especially in i801_remove)
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The DesignWare IP can be synthesized with the IC_EMPTYFIFO_HOLD_MASTER_EN
parameter.
In this case, when the TX FIFO gets empty and the last command didn't have
the STOP bit (IC_DATA_CMD[9]), the controller will hold SCL low until
a new command is pushed into the TX FIFO or the transfer is aborted.

When the controller is holding SCL low, it cannot be disabled.
The transfer must first be aborted.
Also, the bus recovery won't work because SCL is held low by the master.

Check if the master is holding SCL low in __i2c_dw_disable() before trying
to disable the controller. If SCL is held low, an abort is initiated.
When the abort is done, then proceed with disabling the controller.

This whole situation can happen for instance during SMBus read data block
if the slave just responds with "byte count == 0".
This puts the driver in an unrecoverable state, because the controller is
holding SCL low and the current __i2c_dw_disable() procedure is not
working. In this situation only a SoC reset can fix the i2c bus.
Co-developed-by: Jonathan Borne <jborne@kalray.eu>
Signed-off-by: Jonathan Borne <jborne@kalray.eu>
Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Merge tag 'ib-mfd-i2c-reboot-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into i2c/for-mergewindow

Immutable branch between MFD, I2C and Reboot due for the v6.7 merge window

Value comes from DT, so it could be 0. Unlikely, but could be.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

It improves readability if we use the available helper.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Instead of trying all values, we can actually compute it as the comment
suggests. It is unclear what the comment means with "involved", it works
nicely.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Use proper types and spacing.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Kernel functions goto somewhere on error conditions. Using goto for the
default path is irritating. Let's bail out on error instead and use a
proper retval.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>