Cleanup the weird function-level comments and remove obvious
documentation for probe/remove.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
If during probe() the s3c24xx_i2c_init() failed, the clock was left in
disabled but prepared state.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS to simplify the code.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
RuntimePM of the adapter device is now taken care of by the core. So, we
can remove these calls.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The core may register clients attached to this master which may use
funtionality from the master. So, RuntimePM must be enabled before, otherwise
this will fail. While here, move drvdata, too.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Pull i2c updates from Wolfram Sang:
"Highlights:
- new drivers for Mediatek I2C, APM X-Gene, Broadcom Settop
- major updates to at91, davinci
- bugfixes to the mux infrastructure when dealing with the new quirk
mechanism
- more users for the bus recovery feature
- further improvements to the slave framework
Plus the usual bunch of smaller driver and core improvements and
fixes.
There is one patch removing old code from an ARM platform. This has
been acked by the sh_mobile maintainer Simon Horman"
* 'i2c/for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (48 commits)
i2c: busses: i2c-bcm2835: limits cdiv to allowed values
i2c: sh_mobile: use proper type for timeout
i2c: sh_mobile: use adapter default for timeout
i2c: rcar: use proper type for timeout
i2c: rcar: use adapter default for timeout
i2c: designware: Make sure the device is suspended before disabling runtime PM
i2c: tegra: apply size limit quirk
i2c: tegra: don't advertise SMBUS_QUICK
i2c: octeon: remove unused signal handling
i2c: davinci: Optimize SCL generation
i2c: mux: pca954x: Use __i2c_transfer because of quirks
i2c: mux: Use __i2c_transfer() instead of calling parent's master_xfer()
i2c: use parent adapter quirks in mux
i2c: bcm2835: clear reserved bits in S-Register
ARM: shmobile: r8a7740: remove I2C errata handling
i2c: sh_mobile: add errata workaround
i2c: at91: fix code checker warnings
i2c: busses: xgene-slimpro: fix incorrect __init declation for probe
i2c: davinci: Avoid sending to own address
i2c: davinci: Refactor i2c_davinci_wait_bus_not_busy()
...
The platform_device_id is not modified by these drivers and core uses it
as const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Initialize sysreg by default, otherwise driver will crash in suspend
callback when not using DT.
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Fixes: a7750c3ef0 ("i2c: s3c2410: Handle i2c sys_cfg register in i2c driver")
This patch solves deadlock between clock prepare mutex and regmap mutex reported
by Tomasz Figa in [1] by implementing solution from [2]: "always leave the clock
of the i2c controller in a prepared state".
[1] https://lkml.org/lkml/2014/7/2/171
[2] https://lkml.org/lkml/2014/7/2/207
On each i2c transfer handled by s3c24xx_i2c_xfer(), clk_prepare_enable() was
called, which calls clk_prepare() then clk_enable(). clk_prepare() takes
prepare_lock mutex before proceeding. Note that i2c transfer functions are
invoked from many places in kernel, typically with some other additional lock
held.
It may happen that function on CPU1 (e.g. regmap_update_bits()) has taken a
mutex (i.e. regmap lock mutex) then it attempts i2c communication in order to
proceed (so it needs to obtain clock related prepare_lock mutex during transfer
preparation stage due to clk_prepare() call). At the same time other task on
CPU0 wants to operate on clock (e.g. to (un)prepare clock for some other reason)
so it has taken prepare_lock mutex.
CPU0: CPU1:
clk_disable_unused() regulator_disable()
clk_prepare_lock() map->lock(map->lock_arg)
regmap_read() s3c24xx_i2c_xfer()
map->lock(map->lock_arg) clk_prepare_lock()
Implemented solution from [2] leaves i2c clock prepared. Preparation is done in
s3c24xx_i2c_probe() function. Without this patch, it is immediately unprepared
by clk_disable_unprepare() call. I've replaced this call with clk_disable() and
I've added clk_unprepare() call in s3c24xx_i2c_remove().
The s3c24xx_i2c_xfer() function now uses clk_enable() instead of
clk_prepare_enable() (and clk_disable() instead of clk_unprepare_disable()).
Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Here's the set of driver core patches for 3.19-rc1.
They are dominated by the removal of the .owner field in platform
drivers. They touch a lot of files, but they are "simple" changes, just
removing a line in a structure.
Other than that, a few minor driver core and debugfs changes. There are
some ath9k patches coming in through this tree that have been acked by
the wireless maintainers as they relied on the debugfs changes.
Everything has been in linux-next for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iEYEABECAAYFAlSOD20ACgkQMUfUDdst+ylLPACg2QrW1oHhdTMT9WI8jihlHVRM
53kAoLeteByQ3iVwWurwwseRPiWa8+MI
=OVRS
-----END PGP SIGNATURE-----
Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core update from Greg KH:
"Here's the set of driver core patches for 3.19-rc1.
They are dominated by the removal of the .owner field in platform
drivers. They touch a lot of files, but they are "simple" changes,
just removing a line in a structure.
Other than that, a few minor driver core and debugfs changes. There
are some ath9k patches coming in through this tree that have been
acked by the wireless maintainers as they relied on the debugfs
changes.
Everything has been in linux-next for a while"
* tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
fs: debugfs: add forward declaration for struct device type
firmware class: Deletion of an unnecessary check before the function call "vunmap"
firmware loader: fix hung task warning dump
devcoredump: provide a one-way disable function
device: Add dev_<level>_once variants
ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
ath: use seq_file api for ath9k debugfs files
debugfs: add helper function to create device related seq_file
drivers/base: cacheinfo: remove noisy error boot message
Revert "core: platform: add warning if driver has no owner"
drivers: base: support cpu cache information interface to userspace via sysfs
drivers: base: add cpu_device_create to support per-cpu devices
topology: replace custom attribute macros with standard DEVICE_ATTR*
cpumask: factor out show_cpumap into separate helper function
driver core: Fix unbalanced device reference in drivers_probe
driver core: fix race with userland in device_add()
sysfs/kernfs: make read requests on pre-alloc files use the buffer.
sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
fs: sysfs: return EGBIG on write if offset is larger than file size
...
Let's handle i2c interrupt re-configuration in i2c driver. This will
help us in removing some soc specific checks from machine files and
will help in removing static iomapping of SYS register in exynos.c
Also handle saving and restoring of SYS_I2C_CFG register during
suspend and resume of i2c driver.
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch fix spelling typo in printk within vairous
part of the code.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
When the wake-up is triggered by the PMIC RTC, the RTC driver is trying
to read the PMIC interrupt status over I2C and fails because the I2C
controller is not resumed yet.
Let's resume the I2C controller earlier in the _noirq phase
(as other hardwares are doing), so we can properly get the wake-up
condition.
[tomasz: Also fixes certain issues on Exynos4-based boards.]
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This driver has been flagged to drop class based instantiation. The removal
improves boot-up time and is unneeded for embedded controllers. Users have been
warned to switch for some time now, so we can actually do the removal. Keep the
DEPRECATED flag, so the core can inform users that the behaviour finally
changed now. After another transition period, this flag can go, too.
While we are here, remove the indentation for the array setup because
such things always break after some time.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Sachin Kamat <sachin.kamat@samsung.com>
The site-specific OOM messages are unnecessary, because they
duplicate the MM subsystem generic OOM message. For example,
k.alloc and v.alloc failures use dump_stack().
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Don't unmark the device as suspended until after it's been re-setup.
The main race would be w.r.t. an i2c driver that gets resumed at the same
time (asyncronously), that is allowed to do a transfer since suspended
is set to 0 before reinit, but really should have seen the -EIO return
instead.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
There is a rather odd feature of the exynos i2c controller that if it
is left enabled, it can lock itself up with the clk line held low.
This makes the bus unusable.
Unfortunately, the s3c24xx_i2c_set_master() function does not notice
this, and reports a timeout. From then on the bus cannot be used until
the AP is rebooted.
The problem happens when any sort of interrupt occurs (e.g. due to a
bus transition) when we are not in the middle of a transaction. We
have seen many instances of this when U-Boot leaves the bus apparently
happy, but Linux cannot access it.
The current code is therefore pretty fragile.
This fixes things by leaving the bus disabled unless we are actually
in a transaction. We enable the bus at the start of the transaction and
disable it at the end. That way we won't get interrupts and will not
lock up the bus.
It might be possible to clear pending interrupts on start-up, but this
seems to be a more robust solution. We can't service interrupts when
we are not in a transaction, and anyway would rather not lock up the
bus while we try.
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Warn users that class based instantiation is going away soon in favour
of more robust probing and faster bootup times.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
If used 64 bit compiler GCC warns that:
drivers/i2c/busses/i2c-s3c2410.c: In function ‘s3c24xx_get_device_quirks’:
drivers/i2c/busses/i2c-s3c2410.c:168:10: warning: cast from pointer to integer
of different size [-Wpointer-to-int-cast]
This patch fixes this by converting "unsigned int" to "kernel_ulong_t".
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
For Exynos4 and Exynos5 SoCs from Samsung the i2c clock is based
on a fixed 66 MHz peripheral clock, and therefore is completely
independent of the cpu frequency.
Thus, registering for a CPU freq notifier is very wasteful.
This patch modifes the code such that, i2c bus registers to
cpu_freq_transition only if CONFIG_CPU_FREQ_S3C24XX is enabled.
This change should save a bunch of cpufreq transitions calls
which does not apply to exynos SoCs.
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds polling mode support for i2c-s3c2410 driver.The
SATA PHY controller's CMU and TRSV block's are of I2C register
map in exynos5250.These blocks can be configured using i2c.
But i2c controller instance on which these block's sits lacks an
interrupt line.Also the current i2c-s3c2410 driver is only interrupt
driven, thus a polling mode support is required in the driver for
supporting this controller. This patch adds this support to the driver.
Signed-off-by: Vasanth Ananthan <vasanth.a@samsung.com>
Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
'of_match_ptr' is defined in linux/of.h. Include it explicitly to
avoid build breakage in the future.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
commit d16933b339 "i2c: s3c2410: Move
location of clk_prepare_enable() call in probe function" refactored
clk_enable and clk_disable calls yet neglected to remove the
clk_disable_unprepare call in the module's remove().
It helps remove warnings on an arndale during unbind:
echo 12c90000.i2c > /sys/bus/platform/devices/12c90000.i2c/driver/unbind
------------[ cut here ]------------
WARNING: CPU: 0 PID: 2548 at drivers/clk/clk.c:842 clk_disable+0x18/0x24()
Modules linked in:
CPU: 0 PID: 2548 Comm: bash Not tainted 3.11.0-next-20130916-00003-gf4bddbc #6
[<c0014d48>] (unwind_backtrace+0x0/0xf8) from [<c00117d0>] (show_stack+0x10/0x14)
[<c00117d0>] (show_stack+0x10/0x14) from [<c0361be8>] (dump_stack+0x6c/0xac)
[<c0361be8>] (dump_stack+0x6c/0xac) from [<c001d864>] (warn_slowpath_common+0x64/0x88)
[<c001d864>] (warn_slowpath_common+0x64/0x88) from [<c001d8a4>] (warn_slowpath_null+0x1c/0x24)
[<c001d8a4>] (warn_slowpath_null+0x1c/0x24) from [<c02c4a64>] (clk_disable+0x18/0x24)
[<c02c4a64>] (clk_disable+0x18/0x24) from [<c028d0b0>] (s3c24xx_i2c_remove+0x28/0x70)
[<c028d0b0>] (s3c24xx_i2c_remove+0x28/0x70) from [<c0217a10>] (platform_drv_remove+0x18/0x1c)
[<c0217a10>] (platform_drv_remove+0x18/0x1c) from [<c0216358>] (__device_release_driver+0x58/0xb4)
[<c0216358>] (__device_release_driver+0x58/0xb4) from [<c02163d0>] (device_release_driver+0x1c/0x28)
[<c02163d0>] (device_release_driver+0x1c/0x28) from [<c02153c0>] (unbind_store+0x58/0x90)
[<c02153c0>] (unbind_store+0x58/0x90) from [<c0214c90>] (drv_attr_store+0x20/0x2c)
[<c0214c90>] (drv_attr_store+0x20/0x2c) from [<c01032c0>] (sysfs_write_file+0x168/0x198)
[<c01032c0>] (sysfs_write_file+0x168/0x198) from [<c00ae1c0>] (vfs_write+0xb0/0x194)
[<c00ae1c0>] (vfs_write+0xb0/0x194) from [<c00ae594>] (SyS_write+0x3c/0x70)
[<c00ae594>] (SyS_write+0x3c/0x70) from [<c000e3e0>] (ret_fast_syscall+0x0/0x30)
---[ end trace 4c9f9403066f57a6 ]---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 2548 at drivers/clk/clk.c:751 clk_unprepare+0x14/0x1c()
Modules linked in:
CPU: 0 PID: 2548 Comm: bash Tainted: G W 3.11.0-next-20130916-00003-gf4bddbc #6
[<c0014d48>] (unwind_backtrace+0x0/0xf8) from [<c00117d0>] (show_stack+0x10/0x14)
[<c00117d0>] (show_stack+0x10/0x14) from [<c0361be8>] (dump_stack+0x6c/0xac)
[<c0361be8>] (dump_stack+0x6c/0xac) from [<c001d864>] (warn_slowpath_common+0x64/0x88)
[<c001d864>] (warn_slowpath_common+0x64/0x88) from [<c001d8a4>] (warn_slowpath_null+0x1c/0x24)
[<c001d8a4>] (warn_slowpath_null+0x1c/0x24) from [<c02c5834>] (clk_unprepare+0x14/0x1c)
[<c02c5834>] (clk_unprepare+0x14/0x1c) from [<c028d0b8>] (s3c24xx_i2c_remove+0x30/0x70)
[<c028d0b8>] (s3c24xx_i2c_remove+0x30/0x70) from [<c0217a10>] (platform_drv_remove+0x18/0x1c)
[<c0217a10>] (platform_drv_remove+0x18/0x1c) from [<c0216358>] (__device_release_driver+0x58/0xb4)
[<c0216358>] (__device_release_driver+0x58/0xb4) from [<c02163d0>] (device_release_driver+0x1c/0x28)
[<c02163d0>] (device_release_driver+0x1c/0x28) from [<c02153c0>] (unbind_store+0x58/0x90)
[<c02153c0>] (unbind_store+0x58/0x90) from [<c0214c90>] (drv_attr_store+0x20/0x2c)
[<c0214c90>] (drv_attr_store+0x20/0x2c) from [<c01032c0>] (sysfs_write_file+0x168/0x198)
[<c01032c0>] (sysfs_write_file+0x168/0x198) from [<c00ae1c0>] (vfs_write+0xb0/0x194)
[<c00ae1c0>] (vfs_write+0xb0/0x194) from [<c00ae594>] (SyS_write+0x3c/0x70)
[<c00ae594>] (SyS_write+0x3c/0x70) from [<c000e3e0>] (ret_fast_syscall+0x0/0x30)
---[ end trace 4c9f9403066f57a7 ]---
Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
devm_ioremap_resource does sanity checks on the given resource. No need to
duplicate this in the driver.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Barry Song <Baohua.Song@csr.com>
SMBus read and write are supported by the emulation layer of i2c
framework if the controller doesn't have SMBus features.
I2C_M_RECV_LEN flag is used to let i2c drivers know rx length is not
yet determined but will be read to the first byte in rx buffer.
s3c2410 doesn't handle this flag. So only one byte is read from slave.
There fore following two features are added to the driver code.
1. skip rx length check if I2C_M_RECV_LEN is set and the length is 1.
2. add actual bytes to the rx length after reading first bytes if
I2C_M_RECV_LEN.
I2C_M_RECV_LEN is only set for SMBus command. So this code does not
affect legacy codes which only use i2c command for s3c2410.
Signed-off-by: Jaemin Yoo <jmin.yoo@samsung.com>
Tested-by: Prasanna Kumar <prasanna.ps@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Make them conform more to established standards.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The register definitions are only used in the driver itself.
This also removes the last dependency on plat/ includes from the
i2c driver.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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>
Krzysztof Kozlowski