* 'next-i2c' of git://git.fluff.org/bjdooks/linux: (25 commits)
i2c-pnx: Map I2C adapter number to platform ID number
i2c-omap: OMAP3: PM: (re)init for every transfer to support off-mode
i2c-designware: i2c_dw_handle_tx_abort: Use dev_dbg() for NOACK cases
i2c-designware: Cosmetic cleanups
i2c-designware: Tx abort cleanups
i2c-designware: Skip RX_FULL and TX_EMPTY bits on tx abort errors
i2c-designware: i2c_dw_xfer_msg: Fix error handling procedures
i2c-designware: Disable TX_EMPTY when all i2c_msg msgs has been processed
i2c-designware: Process all i2c_msg messages in the interrupt handler
i2c-designware: i2c_dw_read: Remove redundant target address checker
i2c-designware: i2c_dw_func: Set I2C_FUNC_SMBUS_foo bits
i2c-designware: Initialize byte count variables just prior to being used
i2c-designware: i2c_dw_xfer_msg: Introduce a local "buf" pointer
i2c-designware: Divide i2c_dw_xfer_msg into two functions
i2c-designware: Enable RX_FULL interrupt
i2c-designware: Set Tx/Rx FIFO threshold levels
i2c-designware: Process i2c_msg messages in the interrupt handler
i2c-designware: i2c_dw_xfer_msg: Fix i2c_msg search bug
i2c-designware: Improved _HCNT/_LCNT calculation
i2c-designware: Remove an useless local variable "num"
...
* 's3c24xx-updates' of git://git.fluff.org/bjdooks/linux:
ARM: S3C24XX: DMA: Use valid index when accessing array
ARM: S3C: move s3c_pwm_remove to .devexit.text
ARM: S3C24XX: Export s3c24xx_set_fiq for modules.
ARM: S3C: move s3c_adc_remove to .devexit.text
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-next-2.6:
sl82c105: remove no longer needed debugging code
sis5513: remove stale TODO
pdc202xx_old: remove no longer needed debugging code
cy82c693: remove no longer needed debugging code
cmd64x: remove no longer needed debugging code
alim15x3: remove obsolete and dangerous wdc_udma parameter
ide: Increase WAIT_DRQ to accomodate some CF cards and SSD drives.
cs5535: add pci id for AMD based CS5535 controllers
slc90e66: fix UDMA handling
drivers/ide/tx4938ide.c: use resource_size()
drivers/ide/ide_platform.c: use resource_size()
drivers/ide/au1xxx-ide.c: use resource_size()
hpt366: remove dead old timing tables
ide: update Kconfig text to mark as deprecated
ide-tape: remove the BKL
hpt366: kill unused #define's
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
HID: add multi-input quirk for NextWindow Touchscreen.
HID: add support for Acan FG-8100 barcode reader
HID: make Media key on Logitech DiNovo Mini work
HID: support Logitech/3DConnexion SpaceTraveler and SpaceNavigator
HID: remove BKL from hiddev_ioctl_usage()
HID: fixup quirk for NCR devices
HID: pidff - fix unnecessary loop iterations on reset
HID: add NOGET quirk for another device from CH Products
HID: remove useless DRIVER_VERSION macro
HID: fix MODULE_AUTHOR usage in HID modules
HID: blacklist Acer Ferrari 4005 optical mouse
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (222 commits)
[SCSI] zfcp: Remove flag ZFCP_STATUS_FSFREQ_TMFUNCNOTSUPP
[SCSI] zfcp: Activate fc4s attributes for zfcp in FC transport class
[SCSI] zfcp: Block scsi_eh thread for rport state BLOCKED
[SCSI] zfcp: Update FSF error reporting
[SCSI] zfcp: Improve ELS ADISC handling
[SCSI] zfcp: Simplify handling of ct and els requests
[SCSI] zfcp: Remove ZFCP_DID_MASK
[SCSI] zfcp: Move WKA port to zfcp FC code
[SCSI] zfcp: Use common code definitions for FC CT structs
[SCSI] zfcp: Use common code definitions for FC ELS structs
[SCSI] zfcp: Update FCP protocol related code
[SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport
[SCSI] zfcp: Assign scheduled work to driver queue
[SCSI] zfcp: Remove STATUS_COMMON_REMOVE flag as it is not required anymore
[SCSI] zfcp: Implement module unloading
[SCSI] zfcp: Merge trace code for fsf requests in one function
[SCSI] zfcp: Access ports and units with container_of in sysfs code
[SCSI] zfcp: Remove suspend callback
[SCSI] zfcp: Remove global config_mutex
[SCSI] zfcp: Replace local reference counting with common kref
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
m68knommu: export clk_* symbols in clk.c
m68knommu: Split the .init section into INIT_TEXT_SECTION and INIT_DATA_SECTION.
m68knommu: Move __init_end out of the .init section.
m68knommu: Move __init_begin out of the .init section.
m68knommu: Use more macros inside the .init section.
m68knommu: Use INIT_TASK_DATA and CACHELINE_ALIGNED_DATA.
m68knommu: Make THREAD_SIZE available to assembly files.
m68knommu: Don't hardcode the value of PAGE_SIZE in the linker script.
m68knommu: rename BSS define in linker script
m68knommu: add a task_pt_regs() macro
m68knommu: define arch_has_single_step() and friends
m68knommu: add uboot commandline argument passing support
m68knommu: Coldfire GPIO corrections
m68knommu: move mcf_remove to .devexit.text
Fixed up (?) conflict in arch/m68k/include/asm/ptrace.h
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (137 commits)
sh: include empty zero page in romImage
sh: Make associative cache writes fatal on all SH-4A parts.
sh: Drop associative writes for SH-4 cache flushes.
sh: Partial revert of copy/clear_user_highpage() optimizations.
sh: Add default uImage rule for se7724, ap325rxa, and migor.
sh: allow runtime pm without suspend/resume callbacks
sh: mach-ecovec24: Remove un-defined settings for VPU
sh: mach-ecovec24: LCDC drive ability become high
sh: fix sh7724 VEU3F resource size
serial: sh-sci: Fix too early port disabling.
sh: pfc: pr_info() -> pr_debug() cleanups.
sh: pfc: Convert from ctrl_xxx() to __raw_xxx() I/O routines.
sh: Improve kfr2r09 serial port setup code
sh: Break out SuperH PFC code
sh: Move KEYSC header file
sh: convert /proc/cpu/aligmnent, /proc/cpu/kernel_alignment to seq_file
sh: Add CPG save/restore code for sh7724 R-standby
sh: Add SDHI power control support to Ecovec
mfd: Add power control platform data to SDHI driver
sh: mach-ecovec24: modify address map
...
* 'davinci-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci: (69 commits)
davinci: Initial support for Neuros OSD2 platform.
davinci: remove unused variable in arch/arm/mach-davinci/board-sffsdr.c
davinci: fix section mismatch warning in arch/arm/mach-davinci/board-dm646x-evm.c
DaVinci: DM365: Enable DaVinci RTC support for DM365 EVM
DA8xx/OMAP-L1xx: Add high speed SD/MMC capabilities
davinci: DA8XX/OMAP-L1XX: enable cpuidle and regulator in defconfig
davinci: DA850/OMAP-L138: avoid using separate initcall for initializing regulator
davinci: DA850/OMAP-L138 EVM: register for cpuidle support
davinci: DA8XX/OMAP-L1XX: add support for cpuidle driver register
davinci: add CPU idle driver
davinci: DA8XX/OMAP-L1XX: fix compiler warning
davinci: DA850/OMAP-L138: eliminate static function declaration
davinci: DA850/OMAP-L138 EVM: simplify configuration of emac in MII/RMII mode
davinci: DA850/OMAP-L138 EVM: get rid of DA850_UI_EXP config option
davinci: DA850/OMAP-L138 EVM: implement autodetect of RMII PHY
davinci: DA830/OMAP-L137 EVM: do not configure NAND on UI card when MMC/SD is selected
davinci: DA830/OMAP-L137 EVM: use runtime detection for UI card
davinci: DA830/OMAP-L137 EVM: remove ifdefs inside da830_evm_init()
davinci: DA830/OMAP-L137 EVM: fix warning with default config
davinci: Add NAND support for DA830/OMAP-L137 EVM platform
...
We have a directory for misc drivers documentation, let's use it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
the description in Documentation/filesystems/proc.txt of the
procs_running entry in /proc/stat is confusing (according to that
description, it looks as if procs_running could only be a number
between 0 and the number of CPUs).
Changed it to a more accurate description in the patch attached.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since signal_pending() takes a task_struct pointer as an argument, update
the example to pass in 'current'.
Signed-off-by: Shawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use DMA_BIT_MASK(24) instead of 0x00ffffff in DMA-mapping.txt
Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The bkl has been removed from nvram_llseek() and smp_lock.h was removed
because another patch in the same tree zapped the remaining usage of bkl
in the same file. But this patch must have been excluded later, then we
still need the smp_lock.h headers for the bkl use in nvram_open().
This fixes the following build error:
drivers/char/nvram.c: In function ‘nvram_open’:
drivers/char/nvram.c:332: erreur: implicit declaration of function ‘lock_kernel’
drivers/char/nvram.c:339: erreur: implicit declaration of function ‘unlock_kernel’
make[2]: *** [drivers/char/nvram.o] Erreur 1
make[1]: *** [drivers/char] Erreur 2
make: *** [drivers] Erreur 2
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'bkl-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
mn10300: Remove the BKL from sys_execve
m68knommu: Remove the BKL from sys_execve
m68k: Remove the BKL from sys_execve
h83000: Remove BKL from sys_execve
frv: Remove the BKL from sys_execve
blackfin: Remove the BKL from sys_execve
um: Remove BKL from mmapper
um: Remove BKL from random
s390: Remove BKL from prng
* 'bkl-drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
agp: Remove the BKL from agp_open
inifiband: Remove BKL from ipath_open()
mips: Remove BKL from tb0219
drivers: Remove BKL from scx200_gpio
drivers: Remove BKL from pc8736x_gpio
parisc: Remove BKL from eisa_eeprom
rtc: Remove BKL from efirtc
input: Remove BKL from hp_sdc_rtc
hw_random: Remove BKL from core
macintosh: Remove BKL from ans-lcd
nvram: Drop the bkl from non-generic nvram_llseek()
nvram: Drop the bkl from nvram_llseek()
mem_class: Drop the bkl from memory_open()
spi: Remove BKL from spidev_open
drivers: Remove BKL from cs5535_gpio
drivers: Remove BKL from misc_open
* 'bkl-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sys: Remove BKL from sys_reboot
pm_qos: clean up racy global "name" variable
pm_qos: remove BKL
* 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing: (31 commits)
kill-the-bkl/reiserfs: turn GFP_ATOMIC flag to GFP_NOFS in reiserfs_get_block()
kill-the-bkl/reiserfs: drop the fs race watchdog from _get_block_create_0()
kill-the-bkl/reiserfs: definitely drop the bkl from reiserfs_ioctl()
kill-the-bkl/reiserfs: always lock the ioctl path
kill-the-bkl/reiserfs: fix reiserfs lock to cpu_add_remove_lock dependency
kill-the-bkl/reiserfs: Fix induced mm->mmap_sem to sysfs_mutex dependency
kill-the-bkl/reiserfs: panic in case of lock imbalance
kill-the-bkl/reiserfs: fix recursive reiserfs write lock in reiserfs_commit_write()
kill-the-bkl/reiserfs: fix recursive reiserfs lock in reiserfs_mkdir()
kill-the-bkl/reiserfs: fix "reiserfs lock" / "inode mutex" lock inversion dependency
kill-the-bkl/reiserfs: move the concurrent tree accesses checks per superblock
kill-the-bkl/reiserfs: acquire the inode mutex safely
kill-the-bkl/reiserfs: unlock only when needed in search_by_key
kill-the-bkl/reiserfs: use mutex_lock in reiserfs_mutex_lock_safe
kill-the-bkl/reiserfs: factorize the locking in reiserfs_write_end()
kill-the-bkl/reiserfs: reduce number of contentions in search_by_key()
kill-the-bkl/reiserfs: don't hold the write recursively in reiserfs_lookup()
kill-the-bkl/reiserfs: lock only once on reiserfs_get_block()
kill-the-bkl/reiserfs: conditionaly release the write lock on fs_changed()
kill-the-BKL/reiserfs: add reiserfs_cond_resched()
...
* 'timers-for-linus-ntp' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ntp: Provide compability defines (You say MOD_NANO, I say ADJ_NANO)
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
genirq: do not execute DEBUG_SHIRQ when irq setup failed
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers, init: Limit the number of per cpu calibration bootup messages
posix-cpu-timers: optimize and document timer_create callback
clockevents: Add missing include to pacify sparse
x86: vmiclock: Fix printk format
x86: Fix printk format due to variable type change
sparc: fix printk for change of variable type
clocksource/events: Fix fallout of generic code changes
nohz: Allow 32-bit machines to sleep for more than 2.15 seconds
nohz: Track last do_timer() cpu
nohz: Prevent clocksource wrapping during idle
nohz: Type cast printk argument
mips: Use generic mult/shift factor calculation for clocks
clocksource: Provide a generic mult/shift factor calculation
clockevents: Use u32 for mult and shift factors
nohz: Introduce arch_needs_cpu
nohz: Reuse ktime in sub-functions of tick_check_idle.
time: Remove xtime_cache
time: Implement logarithmic time accumulation
* 'timers-for-linus-hpet' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: hpet: Make WARN_ON understandable
x86: arch specific support for remapping HPET MSIs
intr-remap: generic support for remapping HPET MSIs
x86, hpet: Simplify the HPET code
x86, hpet: Disable per-cpu hpet timer if ARAT is supported
Because of OMAP off-mode, powerdomain can go off when I2C is idle.
Save enough state, and do a re-init for each transfer.
Additional save/restore state added by Jagadeesh Bhaskar Pakaravoor
(SYSC_REG) and Aaro Koskinen (wakeup sources.)
Also, The OMAP3430 TRM states:
"During active mode (I2Ci.I2C_CON[15] I2C_EN bit is set to 1), make no
changes to the I2Ci.I2C_SCLL and I2Ci.I2C_SCLH registers. Changes may
result in unpredictable behavior."
Hence, the I2C_EN bit should be clearer when modifying these
registers. Please note that clearing the entire I2C_CON register to
disable the I2C module is safe, because the I2C_CON register is
re-configured for each transfer.
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Cc: Jagadeesh Bhaskar Pakaravoor <j-pakaravoor@ti.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Jon Hunter <jon-hunter@ti.com>
Cc: Hu Tao <taohu@motorola.com>
Cc: Xiaolong Chen <A21785@motorola.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
In the case of no-ACKs, we don't want to see dev_err() messages in the
console, because some utilities like i2c-tools are capable of printing
decorated console output. This patch will ease such situations.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
* ABRT_MASTER_DIS: Fix a typo.
* i2c_dw_handle_tx_abort: Return an appropriate error number
depending on abort_source.
* i2c_dw_xfer: Add a missing abort_source initialization.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Suppose TX_ABRT occurs in the middle of processing i2c_msg msgs[], and
a STOP condition has already been generated on the bus. In this case,
subsequent i2c_dw_xfer_msg() might initiate a new and unnecessary I2C
transaction, which we'd have to avoid.
Furthermore, anytime TX_ABRT is set, the contents of tx/rx buffers are
flushed, so we don't have to process RX_FULL and TX_EMPTY.
Disable interrupts, and skip them.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Current error handling procedures are not good in two respects:
* Forgot to mark dev->cmd_complete as "completed" on errors
Once an I2C transaction is initiated, wait_for_completion_
interruptible_timeout() waits for dev->cmd_complete to be completed.
We have to take care of it whenever an error is detected, otherwise
we will have a needless HZ timeout.
* Forgot to disable interrupts
In the previous patch, interrupt mask operations have been changed.
We don't disable interrupts at the end of the interrupt handler any
more, and try to keep RX_FULL (and TX_EMPTY if required) enabled
during the transaction so that we can send longer data than the size
of Tx/Rx FIFO.
If an error is detected, we need to disable interrupts before
quitting current transaction.
We can work around above points using dev->msg_err effectively.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Currently we disable TX_EMPTY interrupt when buf_len is zero, but this
is wrong. (buf_len == 0) means that all transmit data in the current
i2c_msg message has been sent out, but that doesn't necessarily mean
all i2c_msg messages have been processed.
TX_EMPTY interrupt is used as the driving force of DW I2C transactions,
so we need to keep it enabled as long as i2c_msg messages are available.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Currently we process the first i2c_dw_xfer_msg() in i2c_dw_xfer(),
but in this case there is a possibility to be interrupted by certain
interrupts. As described before in this patchset, we need to keep
providing new transmit data within a given time period, otherwise Tx
FIFO underrun takes place and STOP condition will be generated on the
bus, even if we have more bytes to be written.
In order to exclude all such possibilities, change TX_EMPTY interrupt
usage as below:
* DW_IC_INTR_DEFAULT_MASK: Define a default interrupt mask set, and
put TX_EMPTY there.
* i2c_dw_xfer_init: Enable DW_IC_INTR_DEFAULT_MASK prior to initiating
a new I2C transaction. The first TX_EMPTY will be triggered shortly.
With the help of it, we can make the first call to i2c_dw_xfer_msg()
in the interrupt handler.
* i2c_dw_xfer_msg: Fixup intr_mask operation accordingly. Make sure
that TX_EMPTY operations need to be reversed.
* request_irq: Set IRQF_DISABLED so that we could load transmit data
into Tx FIFO without being distracted by other interrupts.
* Remove i2c_dw_xfer_msg() in i2c_dw_xfer().
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
I2c_dw_xfer_msg() also has the same target address inconsistency check,
and furthermore it checks across all i2c_msg messages, while
i2c_dw_read() walks through i2c_msg messages only with_ I2C_M_RD flag.
That is, target address check in i2c_dw_read() is redundant and useless.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Set proper I2C_FUNC_SMBUS_* bits so that the driver could be used with
some utilities requiring SMBus functionalities, such as i2c-tools.
Note that DW I2C core doesn't support I2C_FUNC_SMBUS_QUICK, as it's not
capable of zero-length data transactions.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
As the driver and hardware always process the given data in parallel,
then it would be better to initialize tx_limit, rx_limit and rx_valid
variables just prior to being used.
This will help us to send / receive as much data as possible.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
While we have a local variable "buf_len" for dev->tx_buf_len, we don't
have such local variable for dev->tx_buf pointer. While "buf_len" is
restored at first then updated when we start processing a new i2c_msg
(determined by STATUS_WRITE_IN_PROGRESS flag), ->tx_buf is different.
Such inconsistency makes the code slightly hard to follow.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We have some steps at the top of i2c_dw_xfer_msg() to set up a slave
address and enable DW I2C core. And it's executed only when we don't
have STATUS_WRITE_IN_PROGRESS.
But we need to make sure that STATUS_WRITE_IN_PROGRESS only indicates
that we have a pending i2c_msg to process. In other words, even if
STATUS_WRITE_IN_PROGRESS is not set, that doesn't mean we're at initial
state in the I2C transaction.
Since i2c_dw_xfer_msg() will be invoked again and again during a
transaction, those init steps have a possibility to be re-processed
needlessly. For example, this issue easily takes place when processing
a combined transaction with a certain condition (the number of tx bytes
in the first i2c_msg, equals to the Tx FIFO depth).
Consequently we should not use STATUS_WRITE_IN_PROGRESS to determine
where we're at in an I2C transaction. It would be better to separate
those initialization steps from i2c_dw_xfer_msg().
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Enable RX_FULL interrupt mask by default, and hook it in the interrupt
handler. If requested amount of rx data (defined by IC_RX_TL) is not
available, we don't have to process i2c_dw_read().
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
As a hardware feature, DW I2C core generates a STOP condition whenever
the Tx FIFO becomes empty (strictly speaking, whenever the last byte in
the Tx FIFO is sent out), even if we have more bytes to be written.
In other words, we must never make "Tx FIFO underrun" happen during
a transaction, except for the last byte. For the safety's sake, we'd
make TX_EMPTY interrupt get triggered every time one byte is processed.
The Rx FIFO threshold needs to be set as well.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Symptom:
--------
When we're going to send/receive the longer size of data than the Tx
FIFO length, the I2C transaction will be divided into several separated
transactions, limited by the Tx FIFO length.
Details:
--------
As a hardware feature, DW I2C core generates a STOP condition whenever
the Tx FIFO becomes empty (strictly speaking, whenever the last byte in
the Tx FIFO is sent out), even if we have more bytes to be written.
Then, once a new transmit data is written to the Tx FIFO, DW I2C core
will initiate a new transaction, which leads to another START condition.
This explains how the transaction in question goes, and implies that
current tasklet-based dw_i2c_pump_msg() strategy couldn't meet the
timing constraint required for avoiding Tx FIFO underrun.
To avoid this scenario, we must keep providing new transmit data within
a given time period. In case of Fast-mode + 32-byte Tx FIFO, for
instance, it takes about 22.5[us] to process single byte, and 720[us] in
total.
This patch removes the existing tasklet-based "pump" system, and move
its jobs into the interrupt handler.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
In case a work-in-progress i2c_msg has more bytes to be written, we
need to set STATUS_WRITE_IN_PROGRESS and exit from the msg_write_idx-
searching loop. Otherwise, we will overtake the current msg_write_idx
without waiting for its transmission to be processed.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
* Calculate with accurate conditional expressions from DW manuals.
* Round ic_clk by adding 0.5 as it's important at high ic_clk rate.
* Take into account "tHD;STA" issue for _HCNT calculation.
* Take into account "tf" for _LCNT calculation.
* Add "cond" and "offset" fot further correction requirements.
For _HCNT calculation, there's one issue needs to be carefully
considered; DesignWare I2C core doesn't seem to have solid strategy
to meet the tHD;STA timing spec. If you configure _HCNT based on the
tHIGH timing spec, it easily results in violation of the tHD;STA spec.
After many trials, we came to the conclusion that the tHD;STA period
is proportional to (_HCNT + 3). For the safety's sake, this should be
selected by default.
As for _LCNT calculation, DW I2C core has one characteristic behavior;
he starts counting the SCL CNTs for the LOW period of the SCL clock
(tLOW) as soon as it pulls the SCL line. At that time, he doesn't take
into account the fall time of SCL signal (tf), IOW, he starts counting
CNTs without confirming the SCL input voltage has dropped to below VIL.
This characteristics becomes a problem on some platforms where tf is
considerably long, and results in violation of the tLOW timing spec.
To make the driver configurable as much as possible for various cases,
we'd have separated arguments "tf" and "offset", and for safety default
values should be 0.3 us and 0, respectively.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We couldn't know the original intent for this variable, but at this
point it's useless.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We don't have to use "struct i2c_adapter" pointer here.
Let's use a local "struct dw_i2c_dev" pointer, instead.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We don't have to use "struct i2c_adapter" pointer here.
Let's use a local "struct dw_i2c_dev" pointer, instead.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We're strongly discouraged from using the IC_CLR_INTR register because
it clears all software-clearable interrupts asserted at the moment.
stat = readl(IC_INTR_STAT);
:
: <=== Interrupts asserted during this period will be lost
:
readl(IC_CLR_INTR);
Instead, use the separately-prepared IC_CLR_* registers.
At the same time, this patch adds all remaining interrupt definitions
available in the DesignWare I2C hardware.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
