Pull i2c updates from Wolfram Sang:
"Highlights:
- new drivers for Intel ismt & Broadcom bcm2835
- a number of drivers got support for more variants and mostly got
cleaned up on the way (sis630, i801, at91, tegra, designware)
- i2c got rid of all *_set_drvdata(..., NULL) on remove/probe failure
- removed the i2c_smbus_process_call from the core since there are no
users
- mxs can now switch between PIO and DMA depending on the message
size and the bus speed can now be arbitrary
In addition, there is the usual bunch of fixes, cleanups, devm_*
conversions, etc"
Fixed conflict (and buggy devm_* conversion) in i2c-s3c2410.c
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (39 commits)
i2c: Remove unneeded xxx_set_drvdata(..., NULL) calls
i2c: pxa: remove incorrect __exit annotations
i2c: ocores: Fix pointer to integer cast warning
i2c: tegra: remove warning dump if timeout happen in transfer
i2c: fix i2c-ismt.c printk format warning
i2c: i801: Add Device IDs for Intel Wellsburg PCH
i2c: add bcm2835 driver
i2c: ismt: Add Seth and Myself as maintainers
i2c: sis630: checkpatch cleanup
i2c: sis630: display unsigned hex
i2c: sis630: use hex to constants for SMBus commands
i2c: sis630: fix behavior after collision
i2c: sis630: clear sticky bits
i2c: sis630: Add SIS964 support
i2c: isch: Add module parameter for backbone clock rate if divider is unset
i2c: at91: fix unsed variable warning when building with !CONFIG_OF
i2c: Adding support for Intel iSMT SMBus 2.0 host controller
i2c: sh_mobile: don't send a stop condition by default inside transfers
i2c: sh_mobile: eliminate an open-coded "goto" loop
i2c: sh_mobile: fix timeout error handling
...
err_cpufreq label is now used only once. It can be removed and related
code can be moved to the caller location.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
In i2c-s3c2410 driver probe, only s3c24xx_i2c_init() needs the I2C clock
to be enabled. Moving clk_prepare_enable() and clk_disable_unprepare()
calls to around this function simplifies the return path of probe call.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
i2c-s3c2410 driver is modified to use devm_clk_get()
and devm_request_irq(). This also simplifies the
return path in driver's probe.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
err_noclk label redirects to a simple return statement. Move the
return statement to the caller location and remove the label.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Convert all uses of devm_request_and_ioremap() to the newly introduced
devm_ioremap_resource() which provides more consistent error handling.
devm_ioremap_resource() provides its own error messages so all explicit
error messages can be removed from the failure code paths.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull i2c-embedded changes from Wolfram Sang:
- CBUS driver (an I2C variant)
- continued rework of the omap driver
- s3c2410 gets lots of fixes and gains pinctrl support
- at91 gains DMA support
- the GPIO muxer gains devicetree probing
- typical fixes and additions all over
* 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux: (45 commits)
i2c: omap: Remove the OMAP_I2C_FLAG_RESET_REGS_POSTIDLE flag
i2c: at91: add dma support
i2c: at91: change struct members indentation
i2c: at91: fix compilation warning
i2c: mxs: Do not disable the I2C SMBus quick mode
i2c: mxs: Handle i2c DMA failure properly
i2c: s3c2410: Remove recently introduced performance overheads
i2c: ocores: Move grlib set/get functions into #ifdef CONFIG_OF block
i2c: s3c2410: Add fix for i2c suspend/resume
i2c: s3c2410: Fix code to free gpios
i2c: i2c-cbus-gpio: introduce driver
i2c: ocores: Add support for the GRLIB port of the controller and use function pointers for getreg and setreg functions
i2c: ocores: Add irq support for sparc
i2c: omap: Move the remove constraint
ARM: dts: cfa10049: Add the i2c muxer buses to the CFA-10049
i2c: s3c2410: do not special case HDMIPHY stuck bus detection
i2c: s3c2410: use exponential back off while polling for bus idle
i2c: s3c2410: do not generate STOP for QUIRK_HDMIPHY
i2c: s3c2410: grab adapter lock while changing i2c clock
i2c: s3c2410: Add support for pinctrl
...
Pull trivial branch from Jiri Kosina:
"Usual stuff -- comment/printk typo fixes, documentation updates, dead
code elimination."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
HOWTO: fix double words typo
x86 mtrr: fix comment typo in mtrr_bp_init
propagate name change to comments in kernel source
doc: Update the name of profiling based on sysfs
treewide: Fix typos in various drivers
treewide: Fix typos in various Kconfig
wireless: mwifiex: Fix typo in wireless/mwifiex driver
messages: i2o: Fix typo in messages/i2o
scripts/kernel-doc: check that non-void fcts describe their return value
Kernel-doc: Convention: Use a "Return" section to describe return values
radeon: Fix typo and copy/paste error in comments
doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c
various: Fix spelling of "asynchronous" in comments.
Fix misspellings of "whether" in comments.
eisa: Fix spelling of "asynchronous".
various: Fix spelling of "registered" in comments.
doc: fix quite a few typos within Documentation
target: iscsi: fix comment typos in target/iscsi drivers
treewide: fix typo of "suport" in various comments and Kconfig
treewide: fix typo of "suppport" in various comments
...
The changes in "i2c-s3c2410: use exponential back off while polling for
bus idle" remove the initial busy wait for I2C transfers to complete and
replace it with usleep_range() calls which will schedule.
Since for older SoCs I2C transfers would usually complete within an
extremely small number of CPU cycles there is a win from not having to
schedule. This happens because on the older SoCs the cores run at a
smaller multiple of the speeds that the I2C bus is operating at; on more
modern SoCs the busy wait is less likely to be effective.
Fix the issue by restoring the busy wait, reducing the number of spins
from 20 to 3 which covers the overwhelming majority of I2C transfers on
the SoCs where the busy wait is effective.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Olof Johansson <olof@lixom.net>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Store the requested gpios so that they can be freed on error/removal.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
The I2C driver makes a gpio_request during initialization. This request
happens again on resume and fails due to the earlier successful request.
Re-factor the code to only initialize the gpios during probe.
Errors on resume without this:
[ 16.020000] s3c-i2c s3c2440-i2c.0: gpio [42] request failed
[ 16.020000] s3c-i2c s3c2440-i2c.1: gpio [44] request failed
[ 16.020000] s3c-i2c s3c2440-i2c.2: gpio [6] request failed
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Store the requested gpios so that they can be freed on error/removal.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Commit "i2c-s3c2410: Add HDMIPHY quirk for S3C2440" added support for
HDMIPHY with some special handling in s3c24xx_i2c_set_master:
"due to unknown reason (probably HW bug in HDMIPHY and/or the controller)
a transfer fails to finish. The controller hangs after sending the last
byte, the workaround for this bug is resetting the controller after each
transfer"
The "unknown reason" was that the proper sequence for generating a STOP
condition wasn't being followed as per the datasheet. Since this is fixed
by "PATCH: i2c-s3c2410: do not generate STOP for QUIRK_HDMIPHY buses",
remove the special handling.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Usually, the i2c controller has finished emitting the i2c STOP before the
driver reaches the bus idle polling loop. Optimize for this most common
case by reading IICSTAT first and potentially skipping the loop.
If the cpu is faster than the hardware, we wait for bus idle in a polling
loop. However, since the duration of one iteration of the loop is
dependent on cpu freq, and this i2c IP is used on many different systems,
use a time based loop timeout (5 ms).
We would like very low latencies to detect bus idle for the normal
'fast' case. However, if a device is slow to release the bus for some
reason, it could hold off the STOP generation for up to several
milliseconds. Rapidly polling for bus idle would seriously load the CPU
while waiting for it to release the bus. So, use a partial exponential
backoff as a compromise between idle detection latency and cpu load.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
The datasheet says that the STOP sequence should be:
1) I2CSTAT.5 = 0 - Clear BUSY (or 'generate STOP')
2) I2CCON.4 = 0 - Clear IRQPEND
3) Wait until the stop condition takes effect.
4*) I2CSTAT.4 = 0 - Clear TXRXEN
Where, step "4*" is only for buses with the "HDMIPHY" quirk.
However, after much experimentation, it appears that:
a) normal buses automatically clear BUSY and transition from
Master->Slave when they complete generating a STOP condition.
Therefore, step (3) can be done in doxfer() by polling I2CCON.4
after starting the STOP generation here.
b) HDMIPHY bus does neither, so there is no way to do step 3.
There is no indication when this bus has finished generating STOP.
In fact, we have found that as soon as the IRQPEND bit is cleared in
step 2, the HDMIPHY bus generates the STOP condition, and then immediately
starts transferring another data byte, even though the bus is supposedly
stopped. This is presumably because the bus is still in "Master" mode,
and its BUSY bit is still set.
To avoid these extra post-STOP transactions on HDMI phy devices, we just
disable Serial Output on the bus (I2CSTAT.4 = 0) directly, instead of
first generating a proper STOP condition. This should float SDA & SCK
terminating the transfer. Subsequent transfers start with a proper START
condition, and proceed normally.
The HDMIPHY bus is an internal bus that always has exactly two devices,
the host as Master and the HDMIPHY device as the slave. Skipping the STOP
condition has been tested on this bus and works.
Also, since we disable the bus directly from the isr, we can skip the bus
idle polling loop at the end of doxfer().
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
We probably don't want to change I2C frequency while a transfer is in
progress. The current implementation grabs a spinlock, but that only
protected the writes to IICCON when starting a message, it didn't protect
against clock changes in the middle of a transaction.
Note: The i2c-core already grabs the adapter lock before calling
s3c24xx_i2c_doxfer(), which ensures that only one caller is issuing a
xfer at a time. This means it is not necessary to disable interrupts
(spin_lock_irqsave) when changing frequencies, since there won't be
any i2c interrupts if there is no on-going xfer.
Lastly, i2c_lock_adapter() may cause the cpufreq_transition to sleep if
if a xfer is in progress, but this is ok since cpufreq notifiers are
called in a kernel thread, and there are already cases where it could
sleep, such as when using i2c to update the output of a voltage
regulator.
Note: the cpufreq part of this change has no functional affect on
exynos, where the i2c clock is independent of the cpufreq.
But, there is a slight perfomance boost since we no longer need to
lock/unlock an additional spinlock.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This patch adds support for pin configuration using pinctrl subsystem
to the i2c-s3c2410 driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
A small code saving and less error handling to worry about.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Use the PM_SLEEP ifdef for system suspend and resume. This is partly
in preparation for adding runtime operations and partly because a user
may in theory choose to enable runtime suspend but not system suspend.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Pull i2c-embedded changes from Wolfram Sang:
"The changes for i2c-embedded include:
- massive rework of the omap driver
- massive rework of the at91 driver. In fact, the old driver gets
removed; I am okay with this approach since the old driver was
depending on BROKEN and its limitations made it practically
unusable, so people used bitbanging instead. But even if there are
users, there is no platform_data or module parameter which would
need to be converted. It is just another driver doing I2C
transfers, just way better. Modifications of arch/arm/at91 related
files have proper acks from the maintainer.
- new driver for R-Car I2C
- devicetree and generic_clock conversions and fixes
- usual driver fixes and changes.
The rework patches have come a long way and lots of people have been
involved in creating/testing them. Most patches have been in
linux-next at least since 3.6-rc5. A few have been added in the last
week, I have to admit.
An unexpected (but welcome :)) peak in private life is the cause for
that. The "late" patches shouldn't cause any merge conflicts and I
will have a special eye on them during the stabilization phase. This
is an exception and I want to have the patches in place properly in
time again for the next kernels."
* 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux: (44 commits)
MXS: Implement DMA support into mxs-i2c
i2c: add Renesas R-Car I2C driver
i2c: s3c2410: use clk_prepare_enable and clk_disable_unprepare
ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints
i2c: nomadik: Add Device Tree support to the Nomadik I2C driver
i2c: algo: pca: Fix chip reset function for PCA9665
i2c: mpc: Wait for STOP to hit the bus
i2c: davinci: preparation for switch to common clock framework
omap-i2c: fix incorrect log message when using a device tree
i2c: omap: sanitize exit path
i2c: omap: switch over to autosuspend API
i2c: omap: remove unnecessary pm_runtime_suspended check
i2c: omap: switch to threaded IRQ support
i2c: omap: remove redundant status read
i2c: omap: get rid of the "complete" label
i2c: omap: resize fifos before each message
i2c: omap: simplify IRQ exit path
i2c: omap: always return IRQ_HANDLED
i2c: omap: simplify errata check
i2c: omap: bus: add a receiver flag
...
Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
calls as required by common clock framework.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Platform data for device drivers should be defined in
include/linux/platform_data/*.h, not in the architecture
and platform specific directories.
This moves such data out of the samsung include directories
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "Wolfram Sang (embedded platforms)" <w.sang@pengutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Bryan Wu <bryan.wu@canonical.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: Chris Ball <cjb@laptop.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sangbeom Kim <sbkim73@samsung.com>
Cc: Liam Girdwood <lrg@ti.com>
Cc: linux-samsung-soc@vger.kernel.org
There's no point in using _sync() as we don't really care if the suspend
has completed immediately.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit fixes warning introduced in 27452498a ("i2c-s3c2410: Rework
device type handling"):
drivers/i2c/busses/i2c-s3c2410.c: In function 's3c24xx_get_device_quirks':
drivers/i2c/busses/i2c-s3c2410.c:125: warning: passing argument 1 of 'of_match_node' from incompatible pointer type
include/linux/of.h:245: note: expected 'const struct of_device_id *' but argument is of type 'const struct of_device_id (*)[4]'
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Since there are uses for I2C_M_NOSTART which are much more sensible and
standard than most of the protocol mangling functionality (the main one
being gather writes to devices where something like a register address
needs to be inserted before a block of data) create a new I2C_FUNC_NOSTART
for this feature and update all the users to use it.
Also strengthen the disrecommendation of the protocol mangling while we're
at it.
In the case of regmap-i2c we remove the requirement for mangling as
I2C_M_NOSTART is the only mangling feature which is being used.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
and other I2C controllers on Exynos4. These differences are:
- no GPIOs, HDMIPHY is inside the SoC and the controller is connected
internally
- due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
transfer fails to finish. The controller hangs after sending the last byte,
the workaround for this bug is resetting the controller after each transfer
Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Reorganize driver a bit to better handle device tree-based systems:
- move machine type to driver's private structure instead of
quering platform device variants in runtime
- replace s3c24xx_i2c_type enum with unsigned int that holds
bitmask with revision-specific quirks
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Use standard of_match_ptr() to avoid defining variable unused
in non device tree builds.
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Add stub runtime_pm calls which go through the flow of enabling and
disabling but don't actually do anything with the device itself as
there's nothing useful we can do. This provides the core PM framework
with information about when the device is idle, enabling chip wide
power savings.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Saves remembering to call kfree(). There's some kfree()s used by the
resource still, these will be removed in 3.3 using the newly added
devm_request_and_ioremap().
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
s3c24xx_i2c_parse_dt_gpio is called when cfg_gpio is not defined
in the platform data of the i2c device. When DT is not enabled,
the above function always returns -EINVAL. Since there can be
some i2c devices which don't need to configure any gpio lines,
the probe of such devices would fail here. Changing the default
return value to success would fix this issue.
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add device tree probe support for Samsung's s3c2410 i2c driver.
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The platform data is copied into driver's private data and the copy is
used for all access to the platform data. This simpifies the addition
of device tree support for the i2c-s3c2410 driver.
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Since commit [c58543c8: genirq: Run irq handlers with interrupts disabled],
We run all interrupt handlers with interrupts disabled
and we even check and yell when an interrupt handler
returns with interrupts enabled (see commit [b738a50a:
genirq: Warn when handler enables interrupts]).
So now this flag is a NOOP and can be removed.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
These drivers don't use anything which is defined in <linux/i2c-id.h>.
This header file was never meant to be included directly anyway, and
will be deleted soon.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Dave Airlie <airlied@linux.ie>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
This patch modify the s3c2410 i2c driver behaviour to enable the
i2c clock only when needed. I'm not sure if this has a big impact
on power usage but at least it's fixing a bug with the uda1380
codec which needs to be hard reset'ed if the i2c clock is enabled
before it's powered on (at least on h1940).
Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
S3C2440 style I2C controller uses PCLK to calculate the SDA line delay.
The driver wrongly assumed that this delay is calculated from the
frequency that the controller is operating on. This patch fixes this
issue.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
As warned by checkpatch.pl, <linux/io.h> should be used instead of
<asm/io.h>.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The S3C I2C controller indicates completion of I2C transfers before
the bus has a stop condition on it. In order to ensure that we do not
attempt to start a new transfer before the bus is idle the driver
currently inserts a 1ms delay. This is vastly larger than is generally
required and has a visible effect on performance under load, such as
when bringing up audio CODECs or reading back status information with
non-bulk I2C reads.
Replace the sleep with a spin on the IIC status register for up to 1ms.
This will busy wait but testing on my SMDK6410 system indicates that
the overwhelming majority of transactions complete on the first spin,
with maximum latencies of less than 10 spins so the absolute overhead
of busy waiting should be at worst comprable to msleep(), and the
overall system performance is dramatically improved.
The main risk is poor interaction with multimaster systems where
we may miss the bus going idle before the next transaction. Defend
against this by falling back to the original 1ms delay after 20 spins.
The overall effect in my testing is an approximately 20% improvement
in kernel startup time.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
s3c24xx_i2c_init() was overwriting the IICLC value set just above in
s3c24xx_i2c_clockrate() with zero, effectively disabling the platform
line control setting.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
