This includes the device tree binding and I2C core changes to support
the i2c-bus subnode that I2C masters can use to describe their slaves
in a separate namespace and therefore avoid clashing with potentially
other subnodes.
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Merge tag 'tegra-for-4.8-i2c' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into i2c/for-next
[wsa: fell through the cracks, applied to 4.9 now]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: 'i2c-bus' node support for v4.8-rc1
This includes the device tree binding and I2C core changes to support
the i2c-bus subnode that I2C masters can use to describe their slaves
in a separate namespace and therefore avoid clashing with potentially
other subnodes.
Pull i2c updates from Wolfram Sang:
"Here is the 4.9 pull request from I2C including:
- centralized error messages when registering to the core
- improved lockdep annotations to prevent false positives
- DT support for muxes, gates, and arbitrators
- bus speeds can now be obtained from ACPI
- i2c-octeon got refactored and now supports ThunderX SoCs, too
- i2c-tegra and i2c-designware got a bigger bunch of updates
- a couple of standard driver fixes and improvements"
* 'i2c/for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (71 commits)
i2c: axxia: disable clks in case of failure in probe
i2c: octeon: thunderx: Limit register access retries
i2c: uniphier-f: fix misdetection of incomplete STOP condition
gpio: pca953x: variable 'id' was used twice
i2c: i801: Add support for Kaby Lake PCH-H
gpio: pca953x: fix an incorrect lockdep warning
i2c: add a warning to i2c_adapter_depth()
lockdep: make MAX_LOCKDEP_SUBCLASSES unconditionally visible
i2c: export i2c_adapter_depth()
i2c: rk3x: Fix variable 'min_total_ns' unused warning
i2c: rk3x: Fix sparse warning
i2c / ACPI: Do not touch an I2C device if it belongs to another adapter
i2c: octeon: Fix high-level controller status check
i2c: octeon: Avoid sending STOP during recovery
i2c: octeon: Fix set SCL recovery function
i2c: rcar: add support for r8a7796 (R-Car M3-W)
i2c: imx: make bus recovery through pinctrl optional
i2c: meson: add gxbb compatible string
i2c: uniphier-f: set the adapter to master mode when probing
i2c: uniphier-f: avoid WARN_ON() of clk_disable() in failure path
...
* acpi-wdat:
watchdog: wdat_wdt: Fix warning for using 0 as NULL
watchdog: wdat_wdt: fix return value check in wdat_wdt_probe()
platform/x86: intel_pmc_ipc: Do not create iTCO watchdog when WDAT table exists
i2c: i801: Do not create iTCO watchdog when WDAT table exists
mfd: lpc_ich: Do not create iTCO watchdog when WDAT table exists
ACPI / watchdog: Add support for WDAT hardware watchdog
* acpi-ec:
ACPI / EC: Fix issues related to boot_ec
ACPI / EC: Fix a gap that ECDT EC cannot handle EC events
ACPI / EC: Fix a memory leakage issue in acpi_ec_add()
ACPI / EC: Cleanup first_ec/boot_ec code
ACPI / EC: Enable event freeze mode to improve event handling for suspend process
ACPI / EC: Add PM operations to improve event handling for suspend process
ACPI / EC: Add PM operations to improve event handling for resume process
ACPI / EC: Fix an issue that SCI_EVT cannot be detected after event is enabled
ACPI / EC: Add EC_FLAGS_QUERY_ENABLED to reveal a hidden logic
ACPI / EC: Add PM operations for suspend/resume noirq stage
ACPI WDAT table is the preferred way to use hardware watchdog over the
native iTCO_wdt. Windows only uses this table for its hardware watchdog
implementation so we should be relatively safe to trust it has been
validated by OEMs
Prevent iTCO watchdog creation if we detect that there is ACPI WDAT table.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
axxia_i2c_probe() does not disable clock in case of failure
in i2c_add_adapter(). Also it ignores returned value from
clk_prepare_enable().
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Do not infinitely retry register readq and writeq operations
in order to not lock up the CPU in case the TWSI gets stuck.
Return -ETIMEDOUT in case of a failed data read. For all other
cases just return so subsequent operations will fail.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently, the status register FI2C_SR is checked immediately after
a STOP condition is issued in case of the deferred STOP condition.
It takes typically 5-10 usec until the corresponding bits in the
register are set, so the error check for "stop condition was not
completed" is very likely to be false positive.
Add wait code to relax the status register check.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Intel Kaby Lake PCH-H has the same legacy SMBus host controller than Intel
Sunrisepoint PCH. It also has same iTCO watchdog on the bus.
Add Kaby Lake PCH-H PCI ID to the list of supported devices.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This routine is only used together with lockdep for nested locking.
The number of lock subclasses is limited to 8 as defined in lockdep.h
Emit a warning if the adapter depth exceeds the maximum number of
lockdep subclasses.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Peter Rosin <peda@axentia.se>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
For crazy setups in which an i2c gpio expander is behind an i2c gpio
multiplexer controlled by a gpio provided a second expander using the
same device driver we need to explicitly tell lockdep how to handle
nested locking.
Export i2c_adapter_depth() as public API to be reused outside of i2c
core code.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Peter Rosin <peda@axentia.se>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
If the i2c device is already runtime suspended, if qup_i2c_suspend is
executed during suspend-to-idle or suspend-to-ram it will result in the
following splat:
WARNING: CPU: 3 PID: 1593 at drivers/clk/clk.c:476 clk_core_unprepare+0x80/0x90
Modules linked in:
CPU: 3 PID: 1593 Comm: bash Tainted: G W 4.8.0-rc3 #14
Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
PC is at clk_core_unprepare+0x80/0x90
LR is at clk_unprepare+0x28/0x40
pc : [<ffff0000086eecf0>] lr : [<ffff0000086f0c58>] pstate: 60000145
Call trace:
clk_core_unprepare+0x80/0x90
qup_i2c_disable_clocks+0x2c/0x68
qup_i2c_suspend+0x10/0x20
platform_pm_suspend+0x24/0x68
...
This patch fixes the issue by executing qup_i2c_pm_suspend_runtime
conditionally in qup_i2c_suspend.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
This patch fixs the following warning:
drivers/i2c/busses/i2c-rk3x.c: In function 'rk3x_i2c_v1_calc_timings':
drivers/i2c/busses/i2c-rk3x.c:745:41: warning: variable 'min_total_ns' set but not used [-Wunused-but-set-variable]
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: David Wu <david.wu@rock-chips.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch fixes the following sparse warning:
drivers/i2c/busses/i2c-rk3x.c:888:17: warning: cast truncates bits from constant value (ffffffffff00 becomes ffffff00)
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: David Wu <david.wu@rock-chips.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When enumerating I2C devices connected to an I2C adapter we scan the whole
namespace (as it is possible to have devices anywhere in that namespace,
not just below the I2C adapter device) and add each found device to the I2C
bus in question.
Now after commit 525e6fabea ("i2c / ACPI: add support for ACPI
reconfigure notifications") checking of the adapter handle to the one found
in the I2cSerialBus() resource was moved to happen after resources of the
I2C device has been parsed. This means that if the I2cSerialBus() resource
points to an adapter that does not exists in the system we still parse
those resources. This is problematic in particular because
acpi_dev_resource_interrupt() tries to configure GSI if the device also has
an Interrupt() resource. Failing to do that results errrors like this to be
printed on the console:
[ 10.409490] ERROR: Unable to locate IOAPIC for GSI 37
To fix this we pass the I2C adapter to i2c_acpi_get_info() and make sure
the handle matches the one in the I2cSerialBus() resource before doing
anything else to the device.
Reported-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The cached value of the last selected channel prevents retries on the
next call, even on failure to update the selected channel. Fix that.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
In case the high-level controller (HLC) is used the status code is
reported at a different location. Check that location after HLC
write operations if the ready bit is not set and return an appropriate
error code instead of always returning -EAGAIN.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Due to a bug in the ThunderX I2C hardware sending STOP during
a recovery attempt could lock up the hardware. To work around
this problem do not send STOP at the beginning of the recovery
but use the override registers to bring the TWSI including
the high-level controller out of the bad state.
Signed-off-by: Dmitry Bazhenov <dmitry.bazhenov@auriga.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[Changed commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The set SCL recovery function unconditionally pulls the SCL line low.
Only pull SCL line low according to val parameter.
Signed-off-by: Dmitry Bazhenov <dmitry.bazhenov@auriga.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[Changed commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
the eg20t driver call request_irq() function before the pch_base_address,
base address of i2c controller's register, is assigned an effective value.
there is one possible scenario that an interrupt which isn't inside eg20t
arrives immediately after request_irq() is executed when i2c controller
shares an interrupt number with others. since the interrupt handler
pch_i2c_handler() has already active as shared action, it will be called
and read its own register to determine if this interrupt is from itself.
At that moment, since base address of i2c registers is not remapped
in kernel space yet,so the INT handler will access an illegal address
and then a error occurs.
Signed-off-by: Yadi.hu <yadi.hu@windriver.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Since commit 1c4b6c3bcf ("i2c: imx: implement bus recovery") the
driver starts to use gpio/pinctrl to support optional bus recovery
feature. But pinctrl is not always usable. There are platforms such
as ls1021a and ls1043a that don't support pinctrl, and it could just
be broken due to old/broken device tree. The patch makes it really
optional that the probe function won't bailout on pinctrl problems
instead it just disables bus recovery and prints out notification when
there is problem with pinctrl. Since pinctrl is only used by bus
recovery in this driver, move pinctrl initialization into bus recovery
init function to prevent confusion.
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Depending on a number of factors including:
- Which exact Rockchip SoC we're working with
- How deep we suspend
- Which i2c port we're on
We might lose the state of the i2c registers at suspend time.
Specifically we've found that on rk3399 the i2c ports that are not in
the PMU power domain lose their state with the current suspend depth
configured by ARM Tursted Firmware.
Note that there are very few actual i2c registers that aren't configured
per transfer anyway so all we actually need to re-configure are the
clock config registers. We'll just add a call to rk3x_i2c_adapt_div()
at resume time and be done with it.
NOTE: On rk3399 on ports whose power was lost, I put printouts in at
resume time. I saw things like:
before: con=0x00010300, div=0x00060006
after: con=0x00010200, div=0x00180025
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: David Wu <david.wu@rock-chips.com>
Tested-by: David Wu <david.wu@rock-chips.com>
[wsa: removed duplicate const]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently, the adapter is set to the master mode at the first use.
Since then, it is kept in the slave mode, so unexpected glitch
signals on the I2C lines may cause the adapter into insane state.
Setting it to the master mode along with initialization solves the
problem.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reported-by: Akio Noda <noda.akio@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
If clk_prepare_enable() fails, clk_disable_unprepare() is called in
the failure path, where the enable_count is still zero, so it hits
WARN_ON(core->enable_count == 0) in the clk_core_disable().
To fix this, make the clock setting more linear in the probe function
so that it can exploit "goto err" in case of error.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
If clk_prepare_enable() fails, clk_disable_unprepare() is called in
the failure path, where the enable_count is still zero, so it hits
WARN_ON(core->enable_count == 0) in the clk_core_disable().
To fix this, make the clock setting more linear in the probe function
so that it can exploit "goto err" in case of error.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fix the following warnings reported by coccinelle for the Tegra I2C
driver.
drivers/i2c/busses/i2c-tegra.c:513:2-23: WARNING: Assignment of bool to 0/1
drivers/i2c/busses/i2c-tegra.c:539:3-24: WARNING: Assignment of bool to 0/1
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
To summarize the issue observed in error cases:
SW Flow: For i2c message transfer, packet header and data payload is
posted and then required error/packet completion interrupts are enabled
later.
HW flow: HW process the packet just after packet header is posted, if
ARB lost/NACK error occurs (SW will not handle immediately when error
happens as error interrupts are not enabled at this point). HW assumes
error is acknowledged and clears current data in FIFO, But SW here posts
the remaining data payload which still stays in FIFO as stale data
(data without packet header).
Now once the interrupts are enabled, SW handles ARB lost/NACK error by
clearing the ARB lost/NACK interrupt. Now HW assumes that SW attended
the error and will parse/process stale data (data without packet header)
present in FIFO which causes invalid NACK errors.
Fix: Enable the error interrupts before posting the packet into FIFO
which make sure HW to not clear the fifo. Also disable the packet mode
before acknowledging errors (ARB lost/NACK error) to not process any
stale data. As error interrupts are enabled before posting the packet
header use spinlock to avoid preempting.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use readl_poll_timeout_atomic() function as *wait_for_config_load()
function can be called from interrupt context.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Define separate function for configuration load register handling
to make it use by different functions later.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
During i2c controller initialization, when fifo flush fails return error
instead of returning the error during exit.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
After CONFIG_LOAD register is programmed instead of explicitly waiting
for timeout, use readl_poll_timeout() to check for register value to get
updated or wait till timeout.
Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
"i2c-sh_mobile" is used on sh7343, sh7366, sh7722, sh7723, and sh7724
only. As all of the above select ARCH_SHMOBILE, restrict its driver
dependencies from SUPERH to ARCH_SHMOBILE.
Signed-off-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>
There are several ways to set the SDA hold time for i2c controller,
including: Device Tree, built-in device properties and ACPI. However,
if the SDA hold time is not specified by above method, we should
read the value, where it is preset by firmware, and save it to
sda_hold_time. This is needed because when i2c controller enters
runtime suspend, the DW_IC_SDA_HOLD value will be reset to chipset
default value. And during runtime resume, i2c_dw_init will be called
to reconfigure i2c controller. If sda_hold_time is zero, the chipset
default hold time will be used, that will be too short for some
platforms. Therefore, to have a better tolerance, the DW_IC_SDA_HOLD
value should be kept by sda_hold_time.
Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We can't use a static property for all the changesets, so we now create
dynamic ones for each changeset.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Fixes: 50a5ba8769 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
It's better to have strings in the code like they appeared in the output.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This makes it trivial to constify them, so do that.
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
On Tegra124/132 the pins for I2C6 are shared with the Display Port AUX
(DPAUX) channel and on Tegra210 the pins for I2C4 and I2C6 are shared
with DPAUX1 and DPAUX0, respectively. The multiplexing of the pins is
handled by a register in the DPAUX and so the Tegra DPAUX driver has
been updated to register a pinctrl device for managing these pins.
The pins for these particular I2C devices are bound to the I2C device
prior to probing. However, these I2C devices are in a different power
partition to the DPAUX devices that own the pins. Hence, it is desirable
to place the pins in the 'idle' state and allow the DPAUX power
partition to switch off, when these I2C devices is not in use.
Therefore, add calls to place the I2C pins in the 'default' and 'idle'
states when the I2C device is runtime resumed and suspended,
respectively.
Please note that the pinctrl functions that set the state of the pins
check to see if the devices has pins associated and will return zero
if they do not. Therefore, it is safe to call these pinctrl functions
even for I2C devices that do not have any pins associated.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Update the Tegra I2C driver to use runtime PM and move the code in the
tegra_i2c_clock_enable/disable() functions to the PM runtime resume and
suspend callbacks, respectively.
Note that given that CONFIG_PM is not mandatory for Tegra, if CONFIG_PM
is not enabled and so runtime PM is not enabled, ensure that the I2C
clocks are turned on during probe and kept on by calling the resume
callback directly.
In the function tegra_i2c_init(), the variable 'err' does not need to be
initialised to zero in tegra_i2c_init() because it is initialised when
pm_runtime_get_sync() is called. Furthermore, to ensure we only return 0
from tegra_i2c_init(), it is necessary to re-initialise 'err' to 0 after
a successful call to pm_runtime_get_sync() because it can return a
positive value on success. However, alternatively re-initialise 'err' by
using the return value of the function tegra_i2c_flush_fifos() because
it can only be 0 or -ETIMEDOUT.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The I2C adapter is unlocked regardless of whether the tegra_i2c_init()
called during the resume is successful or not. However, if the
tegra_i2c_init() is not successful, then ->is_suspended is not set to
false. Simplify the resume code by only setting ->is_suspended to false
if tegra_i2c_init() is successful and return the error code from
tegra_i2c_init().
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
All Tegra I2C devices have the name "Tegra I2C adapter" which is not
very useful when viewing the I2C adapter names via the sysfs. Therefore,
use the device name, which is unique for each I2C device, instead.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tegra has only supported device-tree for platform/board configuration
for quite some time now and so simplify the Tegra I2C driver by dropping
code for non device-tree platforms/boards.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add missing new line characters for the various error messages.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Checkpatch warns about missing blank lines after declarations in the
Tegra I2C driver and so fix these.
Note that the initialisation of 'val' to zero in tegra_dvc_init() is
unnecessary and so remove this.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Checkpatch warns about spacing around the '<<' operator in the Tegra I2C
driver and so fix these by converting the bit definitions that are using
this operator to use the BIT macro.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Checkpatch warns about some lines over 80 characters in the Tegra I2C
driver and so fix these.
While we are at it, prefix the second instance of "STOP condition" in
the comment with a "the".
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Disabling the adapter after each transfer adds additional delays
for each I2C transfer. Even if we don't wait for it to be disabled
anymore, on next transfer we will need to if we have several transfers
in a row.
Now during the transfer init we check if IC_TAR can be changed
dynamically, the status register for no activity and TX buffer being
empty. In this case we don't need to disable it
When a transfer fails the adapter will still be disabled - this is a
conservative approach. When transfers succeed, the adapter is left
enabled and it's configured so to disable interrupts.
Alternating register reads on 2 slaves:
perf stat -r4 chrt -f 10 ./i2c-test /dev/i2c-1 25000 0x40 0x6 0x1e 0x00
Before:
8.638705161 seconds time elapsed ( +- 5.90% )
After:
7.516821591 seconds time elapsed ( +- 0.11% )
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Christian Ruppert <christian.ruppert@alitech.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This adapter can be synthesized with dynamic tar update enabled or disabled.
When enabled it is not necessary to disable the adapter to change the slave
address in some situations, which saves some time per transaction.
There is no direct register to know if this feature is enabled but we can do it
indirectly by writing to the 10BIT_ADDR field in IC_CON: this field is
read only when dynamic tar update is enabled.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Christian Ruppert <christian.ruppert@alitech.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
