Tegra194 supports maximum 64K Bytes transfer per packet.
Tegra186 and prior supports maximum 4K Bytes transfer per packet.
This patch fixes this payload difference between Tegra194 and prior
Tegra chipsets using separate i2c_adapter_quirks.
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull i2c updates from Wolfram Sang:
"I2C has only driver updates for you this time.
Mostly new IDs/DT compatibles, also SPDX conversions, small cleanups.
STM32F7 got FastMode+ and PM support, Axxia some reliabilty
improvements"
* 'i2c/for-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (26 commits)
i2c: Add Actions Semiconductor Owl family S700 I2C support
dt-bindings: i2c: Add S700 support for Actions Semi Soc's
i2c: ismt: Add support for Intel Cedar Fork
i2c: tegra: Switch to SPDX identifier
i2c: tegra: Add missing kerneldoc for some fields
i2c: tegra: Cleanup kerneldoc comments
i2c: axxia: support sequence command mode
dt-bindings: i2c: rcar: Add r8a774c0 support
dt-bindings: i2c: sh_mobile: Add r8a774c0 support
i2c: sh_mobile: Add support for r8a774c0 (RZ/G2E)
i2c: i2c-cros-ec-tunnel: Switch to SPDX identifier.
i2c: powermac: Use of_node_name_eq for node name comparisons
i2c-axxia: check for error conditions first
i2c-axxia: dedicated function to set client addr
dt-bindings: i2c: Use correct vendor prefix for Atmel
i2c: tegra: replace spin_lock_irqsave with spin_lock in ISR
eeprom: at24: add support for 24c2048
dt-bindings: eeprom: at24: add "atmel,24c2048" compatible string
i2c: i2c-stm32f7: add PM Runtime support
i2c: sh_mobile: add support for r8a77990 (R-Car E3)
...
Add S700 to the list of devices supported by Owl I2C driver.
Add Actions Semiconductor Owl family S700 I2C driver.
Signed-off-by: Parthiban Nallathambi <pn@denx.de>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add PCI ID for the Intel Cedar Fork iSMT SMBus controller.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
[wsa: kept sorting]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Not all fields were properly documented. Add kerneldoc for the missing
fields to prevent the build from flagging them.
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Some of the kerneldoc uses a strange spelling for abbreviations. Turn
them into all-uppercase and clean up some whitespace issues while at it.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
In order to comply with SMBus specification, the Axxia I²C module will
abort the multi message transfer if the delay between finishing sending
one message and starting another is longer than 25ms. Unfortunately it
isn't that hard to trigger this situation on a busy system. In order to
fix this problem, we should make sure hardware does whole transaction
without waiting for software to fill some data.
Fortunately, in addition to Manual mode that is currently used by the
driver to perform I²C transfers, the module supports also so called
Sequence mode. In this mode, the module automatically performs
predefined sequence of operations - it sends a slave address, transmits
specified number of bytes from the FIFO, changes transfer direction,
resends the slave address and then reads specified number of bytes to
FIFO. While very inflexible, this does fit a most common case of multi
message transfer - the one where you first write a register number you
want to read and then read it.
To use this mode effectively, a number of conditions must be met to
ensure the transaction does fit the predefined sequence. In case this is
not the case, a fallback to manual mode is used.
The initialization of this mode is very similar to Manual mode. The most
notable difference is different bit in the Master Interrupt Status
designating finishing of transaction. Also some of the errors, like TSS,
cannot happen in this mode.
While it is possible to support transactions requesting a read of any
size (RFL interrupt will be generated when FIFO size is not enough) the
TFL interrupt is not available in this mode, thus the write part of the
transaction cannot exceed FIFO_SIZE (8).
Note that in case of a NAK during transaction, the NA/ND status bits
will be set before STOP command is generated, triggering an interrupt
while the controller is still busy. Current solution for this problem is
to actively wait for this command to stop before leaving xfer callback.
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
[wsa: added braces around else branch spotted by checkpatch]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Similarly to R-Car E3, RZ/G2E doesn't come with automatic
transmission registers, as such it is not considered compatible
with the existing fallback bindings.
Add SoC specific binding compatibility to allow for later
support for automatic transmission.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When CONFIG_PM is disabled, this is needed to avoid a harmless
unused-function warning:
drivers/i2c/busses/i2c-nvidia-gpu.c:345:12: error: 'gpu_i2c_resume' defined but not used [-Werror=unused-function]
Fixes: c71bcdcb42 ("i2c: add i2c bus driver for NVIDIA GPU")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Convert string compares of DT node names to use of_node_name_eq helper
instead. This removes direct access to the node name pointer.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
It was observed that when using seqentional mode contrary to the
documentation, the SS bit (which is supposed to only be set if
automatic/sequence command completed normally), is sometimes set
together with NA (NAK in address phase) causing transfer to falsely be
considered successful.
My assumption is that this does not happen during manual mode since the
controller is stopping its work the moment it sets NA/ND bit in status
register. This is not the case in Automatic/Sequentional mode where it
is still working to send STOP condition and the actual status we get
depends on the time when the ISR is run.
This patch changes the order of checking status bits in ISR - error
conditions are checked first and only if none of them occurred, the
transfer may be considered successful. This is required to introduce
using of sequentional mode in next patch.
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch moves configuration of hardware registers used for setting
i2c client address to separate function. It is preparatory change for
next commit.
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
As you are already in ISR, it is unnecessary to call spin_lock_irqsave.
Signed-off-by: jun qian <hangdianqj@163.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently, the clock duty is set as tLOW/tHIGH = 1/1. For Fast-mode,
tLOW is set to 1.25 us while the I2C spec requires tLOW >= 1.3 us.
tLOW/tHIGH = 5/4 would meet both Standard-mode and Fast-mode:
Standard-mode: tLOW = 5.56 us, tHIGH = 4.44 us
Fast-mode: tLOW = 1.39 us, tHIGH = 1.11 us
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently, the clock duty is set as tLOW/tHIGH = 1/1. For Fast-mode,
tLOW is set to 1.25 us while the I2C spec requires tLOW >= 1.3 us.
tLOW/tHIGH = 5/4 would meet both Standard-mode and Fast-mode:
Standard-mode: tLOW = 5.56 us, tHIGH = 4.44 us
Fast-mode: tLOW = 1.39 us, tHIGH = 1.11 us
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
- For a repeated START condition, this controller starts data transfer
immediately after the slave address is written to the TX-FIFO.
- Once the TX-FIFO empty interrupt is asserted, the controller makes
a pause even if additional data are written to the TX-FIFO.
Given those circumstances, the data after a repeated START may not be
transferred if the interrupt is asserted while the TX-FIFO is being
filled up. A more reliable way is to append TX data only in the
interrupt handler.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
I was totally screwed up in commit eaba68785c ("i2c: uniphier-f:
fix race condition when IRQ is cleared"). Since that commit, if the
number of read bytes is multiple of the FIFO size (8, 16, 24... bytes),
the STOP condition could be issued twice, depending on the timing.
If this happens, the controller will go wrong, resulting in the timeout
error.
It was more than 3 years ago when I wrote this driver, so my memory
about this hardware was vague. Please let me correct the description
in the commit log of eaba68785c.
Clearing the IRQ status on exiting the IRQ handler is absolutely
fine. This controller makes a pause while any IRQ status is asserted.
If the IRQ status is cleared first, the hardware may start the next
transaction before the IRQ handler finishes what it supposed to do.
This partially reverts the bad commit with clear comments so that I
will never repeat this mistake.
I also investigated what is happening at the last moment of the read
mode. The UNIPHIER_FI2C_INT_RF interrupt is asserted a bit earlier
(by half a period of the clock cycle) than UNIPHIER_FI2C_INT_RB.
I consulted a hardware engineer, and I got the following information:
UNIPHIER_FI2C_INT_RF
asserted at the falling edge of SCL at the 8th bit.
UNIPHIER_FI2C_INT_RB
asserted at the rising edge of SCL at the 9th (ACK) bit.
In order to avoid calling uniphier_fi2c_stop() twice, check the latter
interrupt. I also commented this because it is obscure hardware internal.
Fixes: eaba68785c ("i2c: uniphier-f: fix race condition when IRQ is cleared")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Some AMD based HP laptops have a SMB0001 ACPI device node which does not
define any methods.
This leads to the following error in dmesg:
[ 5.222731] cmi: probe of SMB0001:00 failed with error -5
This commit makes acpi_smbus_cmi_add() return -ENODEV instead in this case
silencing the error. In case of a failure of the i2c_add_adapter() call
this commit now propagates the error from that call instead of -EIO.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
According to Intel (R) Axxia TM Lionfish Communication Processor
Peripheral Subsystem Hardware Reference Manual, the AXXIA I2C module
have a programmable Master Wait Timer, which among others, checks the
time between commands send in manual mode. When a timeout (25ms) passes,
TSS bit is set in Master Interrupt Status register and a Stop command is
issued by the hardware.
The axxia_i2c_xfer(), does not properly handle this situation, however.
For each message a separate axxia_i2c_xfer_msg() is called and this
function incorrectly assumes that any interrupt might happen only when
waiting for completion. This is mostly correct but there is one
exception - a master timeout can trigger if enough time has passed
between individual transfers. It will, by definition, happen between
transfers when the interrupts are disabled by the code. If that happens,
the hardware issues Stop command.
The interrupt indicating timeout will not be triggered as soon as we
enable them since the Master Interrupt Status is cleared when master
mode is entered again (which happens before enabling irqs) meaning this
error is lost and the transfer is continued even though the Stop was
issued on the bus. The subsequent operations completes without error but
a bogus value (0xFF in case of read) is read as the client device is
confused because aborted transfer. No error is returned from
master_xfer() making caller believe that a valid value was read.
To fix the problem, the TSS bit (indicating timeout) in Master Interrupt
Status register is checked before each transfer. If it is set, there was
a timeout before this transfer and (as described above) the hardware
already issued Stop command so the transaction should be aborted thus
-ETIMEOUT is returned from the master_xfer() callback. In order to be
sure no timeout was issued we can't just read the status just before
starting new transaction as there will always be a small window of time
(few CPU cycles at best) where this might still happen. For this reason
we have to temporally disable the timer before checking for TSS bit.
Disabling it will, however, clear the TSS bit so in order to preserve
that information, we have to read it in ISR so we have to ensure that
the TSS interrupt is not masked between transfers of one transaction.
There is no need to call bus recovery or controller reinitialization if
that happens so it's skipped.
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use PM Runtime API to enable/disable clock
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We should check the bus state before reinitializing the IP core.
Otherwise, the internal bus busy state which also tracks multi-master
activity is lost.
Credits go to the Renesas BSP team for suggesting this change.
Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Fixes: ae481cc139 ("i2c: rcar: fix resume by always initializing registers before transfer")
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
If the controller can only do 4 byte reads, this needs to be applied for
the read-part of combined messages, too.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: c71bcdcb42 ("i2c: add i2c bus driver for NVIDIA GPU")
Acked-by: Ajay Gupta <ajayg@nvidia.com>
Tested-by: Ajay Gupta <ajayg@nvidia.com>
As described in Documentation/i2c/fault-codes.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: c71bcdcb42 ("i2c: add i2c bus driver for NVIDIA GPU")
Acked-by: Ajay Gupta <ajayg@nvidia.com>
Tested-by: Ajay Gupta <ajayg@nvidia.com>
Add support for the IIC code for the r8a77990 (R-Car E3).
It is not considered compatible with existing fallback bindings
due to the documented absence of automatic transmission registers.
These registers are currently not used by the driver and
thus the provides the same behaviour for "renesas,iic-r8a77990" and
"renesas,rcar-gen3-iic". The point of declaring incompatibility is
to allow for automatic transmission register support to be added to
"renesas,iic-r8a77990" and "renesas,rcar-gen3-iic" in future.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Read SYSCFG bindings to set Fast Mode Plus bits if Fast Mode Plus
speed is selected.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This is already done for us internally by the signal machinery.
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Probe deferral is a normal operating condition in the probe function,
so don't spam the log with an error in this case.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Latest NVIDIA GPU card has USB Type-C interface. There is a
Type-C controller which can be accessed over I2C.
This driver adds I2C bus driver to communicate with Type-C controller.
I2C client driver will be part of USB Type-C UCSI driver.
Signed-off-by: Ajay Gupta <ajayg@nvidia.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[wsa: kept Makefile sorting]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We need to enable runtime PM on this i2c controller before populating
child devices with i2c_add_adapter(). Otherwise, if a child device uses
runtime PM and stays runtime PM enabled we'll get the following warning
at boot.
Enabling runtime PM for inactive device (a98000.i2c) with active children
[...]
Call trace:
pm_runtime_enable+0xd8/0xf8
geni_i2c_probe+0x440/0x460
platform_drv_probe+0x74/0xc8
[...]
Let's move the runtime PM enabling and setup to before we add the
adapter, so that this device can respond to runtime PM requests from
children.
Fixes: 37692de5d5 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Allow I2C_OMAP to be built for K3 platforms.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Rework the handling of the P-unit semaphore on Intel Baytrail and
Cherrytrail systems to avoid race conditions and excessive overhead
related to it (Hans de Goede).
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Merge tag 'acpi-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more ACPI updates from Rafael Wysocki:
"Rework the handling of the P-unit semaphore on Intel Baytrail and
Cherrytrail systems to avoid race conditions and excessive overhead
related to it (Hans de Goede)"
* tag 'acpi-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / PMIC: xpower: Add depends on IOSF_MBI to Kconfig entry
i2c: designware: Cleanup bus lock handling
ACPI / PMIC: xpower: Block P-Unit I2C access during read-modify-write
x86: baytrail/cherrytrail: Rework and move P-Unit PMIC bus semaphore code
Pull i2c updates from Wolfram Sang:
"I2C has not so much stuff this time. Mostly driver enablement for new
SoCs, some driver bugfixes, and some cleanups"
* 'i2c/for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (35 commits)
MAINTAINERS: add maintainer for Renesas RIIC driver
i2c: sh_mobile: Remove dummy runtime PM callbacks
i2c: uniphier-f: fix race condition when IRQ is cleared
i2c: uniphier-f: fix occasional timeout error
i2c: uniphier-f: make driver robust against concurrency
i2c: i2c-qcom-geni: Simplify irq handler
i2c: i2c-qcom-geni: Simplify tx/rx functions
i2c: designware: Set IRQF_NO_SUSPEND flag for all BYT and CHT controllers
i2c: mux: mlxcpld: simplify code to reach the adapter
i2c: mux: ltc4306: simplify code to reach the adapter
i2c: mux: pca954x: simplify code to reach the adapter
i2c: core: remove level of indentation in i2c_transfer
i2c: core: remove outdated DEBUG output
i2c: zx2967: use core to detect 'no zero length' quirk
i2c: tegra: use core to detect 'no zero length' quirk
i2c: qup: use core to detect 'no zero length' quirk
i2c: omap: use core to detect 'no zero length' quirk
i2c: Convert to using %pOFn instead of device_node.name
i2c: brcmstb: Allow enabling the driver on DSL SoCs
eeprom: at24: fix unexpected timeout under high load
...
Platform drivers don't need dummy runtime PM callbacks that just return
success and non-NULL pm pointer in their struct device_driver in order
to have runtime PM happening. This has changed since following commits:
05aa55dddb ("PM / Runtime: Lenient generic runtime pm callbacks")
543f2503a9 ("PM / platform_bus: Allow runtime PM by default")
8b313a38ec ("PM / Platform: Use generic runtime PM callbacks directly")
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The current IRQ handler clears all the IRQ status bits when it bails
out. This is dangerous because it might clear away the status bits
that have just been set while processing the current handler. If this
happens, the IRQ event for the latest transfer is lost forever.
The IRQ status bits must be cleared *before* the next transfer is
kicked.
Fixes: 6a62974b66 ("i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently, a timeout error could happen at a repeated START condition.
For a (non-repeated) START condition, the controller starts sending
data when the UNIPHIER_FI2C_CR_STA bit is set. However, for a repeated
START condition, the hardware starts running when the slave address is
written to the TX FIFO - the write to the UNIPHIER_FI2C_CR register is
actually unneeded.
Because the hardware is already running before the IRQ is enabled for
a repeated START, the driver may miss the IRQ event. In most cases,
this problem does not show up since modern CPUs are much faster than
the I2C transfer. However, it is still possible that a context switch
happens after the controller starts, but before the IRQ register is
set up.
To fix this,
- Do not write UNIPHIER_FI2C_CR for repeated START conditions.
- Enable IRQ *before* writing the slave address to the TX FIFO.
- Disable IRQ for the current CPU while queuing up the TX FIFO;
If the CPU is interrupted by some task, the interrupt handler
might be invoked due to the empty TX FIFO before completing the
setup.
Fixes: 6a62974b66 ("i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This is unlikely to happen, but it is possible for a CPU to enter
the interrupt handler just after wait_for_completion_timeout() has
expired. If this happens, the hardware is accessed from multiple
contexts concurrently.
Disable the IRQ after wait_for_completion_timeout(), and do nothing
from the handler when the IRQ is disabled.
Fixes: 6a62974b66 ("i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Now that most of the special Bay- / Cherry-Trail bus lock handling has
been moved to the iosf_mbi code we can simplify the remaining code a bit.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
On some BYT/CHT systems the SoC's P-Unit shares the I2C bus with the
kernel. The P-Unit has a semaphore for the PMIC bus which we can take to
block it from accessing the shared bus while the kernel wants to access it.
Currently we have the I2C-controller driver acquiring and releasing the
semaphore around each I2C transfer. There are 2 problems with this:
1) PMIC accesses often come in the form of a read-modify-write on one of
the PMIC registers, we currently release the P-Unit's PMIC bus semaphore
between the read and the write. If the P-Unit modifies the register during
this window?, then we end up overwriting the P-Unit's changes.
I believe that this is mostly an academic problem, but I'm not sure.
2) To safely access the shared I2C bus, we need to do 3 things:
a) Notify the GPU driver that we are starting a window in which it may not
access the P-Unit, since the P-Unit seems to ignore the semaphore for
explicit power-level requests made by the GPU driver
b) Make a pm_qos request to force all CPU cores out of C6/C7 since entering
C6/C7 while we hold the semaphore hangs the SoC
c) Finally take the P-Unit's PMIC bus semaphore
All 3 these steps together are somewhat expensive, so ideally if we have
a bunch of i2c transfers grouped together we only do this once for the
entire group.
Taking the read-modify-write on a PMIC register as example then ideally we
would only do all 3 steps once at the beginning and undo all 3 steps once
at the end.
For this we need to be able to take the semaphore from within e.g. the PMIC
opregion driver, yet we do not want to remove the taking of the semaphore
from the I2C-controller driver, as that is still necessary to protect many
other code-paths leading to accessing the shared I2C bus.
This means that we first have the PMIC driver acquire the semaphore and
then have the I2C controller driver trying to acquire it again.
To make this possible this commit does the following:
1) Move the semaphore code from being private to the I2C controller driver
into the generic iosf_mbi code, which already has other code to deal with
the shared bus so that it can be accessed outside of the I2C bus driver.
2) Rework the code so that it can be called multiple times nested, while
still blocking I2C accesses while e.g. the GPU driver has indicated the
P-Unit needs the bus through a iosf_mbi_punit_acquire() call.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
DMA needs to be cleaned up not only on timeout, but on all errors where
it has been setup before.
Fixes: 73e8b05283 ("i2c: rcar: add DMA support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We don't need to use goto here, we can just collapse the if statement
and goto chain into multiple branches and then combine some duplicate
completion calls into one big if statement. Let's do it to clean up code
some more.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We never really look at the 'ret' local variable in these functions, so
let's remove it to make way for shorter and simpler code. Furthermore,
we can shorten some lines by adding two local variables for the SE and
the message length so that everything fits in 80 columns and testing the
'dma_buf' local variable in lieu of the 'mode' local variable. And
kernel style is to leave the return statement by itself, detached from
the rest of the function.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Alok Chauhan <alokc@codeaurora.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
On some Cherry Trail systems the GPU ACPI fwnode has power-resources which
point to the PMIC, which is connected over a LPSS I2C controller. The GPU
is a PCI device and PCI devices are powered-on at the resume_noirq resume
phase.
Since the GPU power-resources need the I2C controller, recent acpi_lpss.c
changes now also power-up the LPSS I2C controllers on BYT and CHT devices
in the resume_noirq resume phase. But during this phase the IRQ of the
controller is disabled leading to these errors:
i2c_designware 808622C1:06: controller timed out
ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
ACPI Error: Method parse/execution failed \_SB.P18W._ON, AE_ERROR
video LNXVIDEO:00: Failed to change power state to D0
This commit makes the i2c-designware controller set the IRQF_NO_SUSPEND
flag when requesting the interrupt on BYT and CHT devices, so that the IRQ
is left enabled during the noirq phase, fixing this.
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
And don't reimplement in the driver.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
And don't reimplement in the driver.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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