SMBus Host Notify allows a slave device to act as a master on a bus to
notify the host of an interrupt. On Intel chipsets, the functionality
is directly implemented in the firmware. We just need to export a
function to call .alert() on the proper device driver.
i2c_handle_smbus_host_notify() behaves like i2c_handle_smbus_alert().
When called, it schedules a task that will be able to sleep to go through
the list of devices attached to the adapter.
The current implementation allows one Host Notification to be scheduled
while an other is running.
Tested-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.
So, declare the i2c gate mux-locked, and zap the regmap overrides
that makes the i2c accesses unlocked and use plain old regmap
accesses. This also removes the need for the regmap wrappers used by
rtl2832_sdr, so deconvolute the code further and provide the regmap
handle directly instead of the wrapper functions.
Tested-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.
So, declare the i2c gate mux-locked, and zap the code that makes the
i2c accesses unlocked. But add a mutex so that firmware commands are
still serialized.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The root i2c adapter lock is then no longer held by the i2c mux during
accesses behind the i2c gate, and such accesses need to take that lock
just like any other ordinary i2c accesses do.
So, declare the i2c gate mux-locked, and zap the code that makes the
unlocked i2c accesses and just use ordinary regmap_write accesses.
This also happens to fix the deadlock described in
http://patchwork.ozlabs.org/patch/584776/ authored by
Adriana Reus <adriana.reus@intel.com> and submitted by
Daniel Baluta <daniel.baluta@intel.com>
----------8<----------
iio: imu: inv_mpu6050: Fix deadlock between i2c adapter lock and mpu lock
This deadlock occurs if the accel/gyro and the sensor on the auxiliary
I2C (in my setup it's an ak8975) are working at the same time.
Scenario:
T1 T2
==== ====
inv_mpu6050_read_fifo aux sensor op (eg. ak8975_read_raw)
| |
mutex_lock(&indio_dev->mlock) i2c_transfer
| |
i2c transaction i2c adapter lock
| |
i2c adapter lock i2c_mux_master_xfer
|
inv_mpu6050_select_bypass
|
mutex_lock(&indio_dev->mlock)
When we operate on an mpu sensor the order of locking is mpu lock
followed by the i2c adapter lock. However, when we operate the auxiliary
sensor the order of locking is the other way around.
...
----------8<----------
The reason this patch fixes the deadlock is that T2 does not grab the
i2c adapter lock until the very end (and grabs the newfangled i2c mux
lock where it previously grabbed the i2c adapter lock).
Acked-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Tested-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This path fix spelling typos found in Documentation/i2c.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add missing entries into i2c-i801 documentation and Kconfig about recently
added Intel DNV and Broxton.
Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
We now have seperate address spaces for 10 bit and we-are-slave clients.
Update the sysfs device instantiation method to support these types by
accepting the address offsets that are assigned to the extra address
spaces. Update the documentation, too.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add support for VCT-jig parallel port I2C adapter to i2c-parport.
The adapter schematic can be found here (in the RAR file):
http://remont-aud.net/shop/22/desc/vct-jig-komplekt-dlja-samostojatelnoj-sborki
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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()
...
I copied the wrong shell code into the documentation. Sorry to all who
tried to get sense out of this current example :/ Slight rewording while
we are here.
Reported-by: Tim Bakker <bakkert@mymail.vcu.edu>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
There was some confusion what was needed to utilize the slave support,
so let's be more precise about this. Add an introductory paragraph to
the development section while we are here.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Since commit 607ca46e97 ('UAPI: (Scripted) Disintegrate include/linux') the
list of functionality constants moved to include/uapi/linux/i2c.h. Update the
reference accordingly.
Fixes: 607ca46e97 ('UAPI: (Scripted) Disintegrate include/linux')
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
New drivers should use PM ops instead of the legacy suspend/resume
callbacks. Update the I2C device driver guides to reflect this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds the I2C/SMBus Device IDs for the Intel Sunrise Point PCH.
Signed-off-by: James Ralston <james.d.ralston@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The example code provided with the i2c device interface documentation
won't compile since it uses the reserved word "register" to name a
variable.
The compiler fails with this error message:
error: expected identifier or '(' before '=' token
__u8 register = 0x20; /* Device register to access */
^
Rename the variable "register" to simply "reg" in the example code.
Another couple of typos has been fixed as well.
[Change "! =" to "!=".]
Signed-off-by: Jose Alarcon Roldan <jose.alarcon.roldan@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some chips implement banked register ranges. This allows implementing
more registers than the limited 8-bit address space originally allows.
In order to access a register on these chips, you must first select
the proper bank. Add support for this mechanism to the i2c-stub driver
so that such chips can be emulated. All the bank settings are passed
as module parameters.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
SMBus block commands are different to I2C block commands since
the returned data is not normally accessible with byte or word
commands on other command offsets. Add linked list of 'block'
commands to support those commands.
Access mechanism is quite simple: Block commands must be written
before they can be read. Subsequent writes can be partial. Block
read commands always return the number of bytes associated with
the longest previous write.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Sort the entries alphabetically. Make the introductory paragraph more
precise. Skip useless 'Flag' introduction from the entries. Remove
trailing white spaces from the file. Add missing I2C_M_STOP entry.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add Device ID of Intel BayTrail SMBus Controller.
Signed-off-by: Chew, Kean ho <kean.ho.chew@intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull more i2c updates from Wolfram Sang:
"Mostly bugfixes, small but wanted cleanups, and Paul's init.h removal
applied"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: rcar: fix NACK error code
i2c: update i2c_algorithm documentation
i2c: rcar: use devm_clk_get to ensure clock is properly ref-counted
i2c: rcar: do not print error if device nacks transfer
i2c: rely on driver core when sanitizing devices
i2c: delete non-required instances of include <linux/init.h>
i2c: acorn: is tristate and should use module.h
i2c: piix4: Standardize log messages
i2c: piix4: Use different message for AMD Auxiliary SMBus Controller
i2c: piix4: Add support for AMD ML and CZ SMBus changes
Pull hwmon updates from Jean Delvare:
"This include it87 driver improvements, and a tree-wide change of my
e-mail address"
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
Update Jean Delvare's e-mail address
hwmon: (it87) Print proper names for the IT8771E and IT8772E
hwmon: (it87) Add support for the ITE IT8603E
The locations of SMBus register base address and enablement bit are changed
from AMD ML, which need this patch to be supported.
Signed-off-by: Shane Huang <shane.huang@amd.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org
Documentation/i2c/fault-codes illustrates EINVAL error code
as follows:
"One example would be a driver trying an SMBus Block Write
with block size outside the range of 1-32 bytes."
However, the actual implementation of i2c subsystem truncates
data length to be 32 bytes.
Hence this example cannot happen anymore, and since it's obsolete,
let's simply remove it from Documentation/i2c/fault-codes.
Signed-off-by: Helia Correia <helia.correia@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds the SMBus Device IDs for the Intel Wildcat Point-LP PCH.
Signed-off-by: James Ralston <james.d.ralston@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull trivial tree from Jiri Kosina:
"The usual trivial updates all over the tree -- mostly typo fixes and
documentation updates"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (52 commits)
doc: Documentation/cputopology.txt fix typo
treewide: Convert retrun typos to return
Fix comment typo for init_cma_reserved_pageblock
Documentation/trace: Correcting and extending tracepoint documentation
mm/hotplug: fix a typo in Documentation/memory-hotplug.txt
power: Documentation: Update s2ram link
doc: fix a typo in Documentation/00-INDEX
Documentation/printk-formats.txt: No casts needed for u64/s64
doc: Fix typo "is is" in Documentations
treewide: Fix printks with 0x%#
zram: doc fixes
Documentation/kmemcheck: update kmemcheck documentation
doc: documentation/hwspinlock.txt fix typo
PM / Hibernate: add section for resume options
doc: filesystems : Fix typo in Documentations/filesystems
scsi/megaraid fixed several typos in comments
ppc: init_32: Fix error typo "CONFIG_START_KERNEL"
treewide: Add __GFP_NOWARN to k.alloc calls with v.alloc fallbacks
page_isolation: Fix a comment typo in test_pages_isolated()
doc: fix a typo about irq affinity
...
__initdata should be placed between the variable name and equal
sign for the variable to be placed in the intended section.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add support for the secondary SMBus controller on the AMD SB800 and AMD FCH
chipsets.
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Tested-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull i2c updates from Wolfram Sang:
- new drivers: Kontron PLD, Wondermedia VT
- mv64xxx driver gained sun4i support and a bigger cleanup
- duplicate driver 'intel-mid' removed
- added generic device tree binding for sda holding time (and
designware driver already uses it)
- we tried to allow driver probing with only device tree and no i2c
ids, but I had to revert it because of side effects. Needs some
rethinking.
- driver bugfixes, cleanups...
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (34 commits)
i2c-designware: use div_u64 to fix link
i2c: Kontron PLD i2c bus driver
i2c: iop3xxx: fix build failure after waitqueue changes
i2c-designware: make SDA hold time configurable
i2c: mv64xxx: Set bus frequency to 100kHz if clock-frequency is not provided
i2c: imx: allow autoloading on dt ids
i2c: mv64xxx: Fix transfer error code
i2c: i801: SMBus patch for Intel Coleto Creek DeviceIDs
i2c: omap: correct usage of the interrupt enable register
i2c-pxa: prepare clock before use
Revert "i2c: core: make it possible to match a pure device tree driver"
i2c: nomadik: allocate adapter number dynamically
i2c: nomadik: support elder Nomadiks
i2c: mv64xxx: Add Allwinner sun4i compatible
i2c: mv64xxx: make the registers offset configurable
i2c: mv64xxx: Add macros to access parts of registers
i2c: vt8500: Add support for I2C bus on Wondermedia SoCs
i2c: designware: fix race between subsequent xfers
i2c: bfin-twi: Read and write the FIFO in loop
i2c: core: make it possible to match a pure device tree driver
...
This patch adds the i801 SMBus Controller DeviceIDs for the Intel Coleto Creek PCH.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds the SMBus Device IDs for the Intel Wellsburg PCH
Signed-off-by: James Ralston <james.d.ralston@intel.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>
The iSMT (Intel SMBus Message Transport) supports multi-master I2C/SMBus,
as well as IPMI. It's operation is DMA-based and utilizes descriptors to
initiate transactions on the bus.
The iSMT hardware can act as both a master and a target, although this
driver only supports being a master.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Bill Brown <bill.e.brown@intel.com>
Tested-by: Seth Heasley <seth.heasley@intel.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>
This patch adds the PCU SMBus DeviceID for the Intel Avoton SOC.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
i2c_smbus_process_call has no users in the kernel, so this can be
removed. Documentation for the same has been updated accordingly.
Fixes following sparse warning.
drivers/i2c/i2c-core.c:1871:5: warning: symbol 'i2c_smbus_process_call'
was not declared. Should it be static?
[wsa: updated the documentation]
Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
CONFIG_HOTPLUG is going away as an option. As a result, the __dev*
markings need to be removed.
This change removes the use of __devinit, __devexit_p, __devinitdata,
__devinitconst, and __devexit from the kernel documentation.
Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While the mapping between I2C adapter functionality flags and
i2c_smbus_*() helper functions is rather obvious, let's still document
it for clarity.
Also drop the reference to 2 command byte I2C block reads, there is no
support for that in the kernel at the moment.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
* Document the possibility to pass relative GPIO pin numbers.
* Document what platform device IDs to use, so that they do not
collide.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
The SMBus controller in the VIA VX900 appears to be compatible with
the VIA VX855, so just add the device ID.
This closes kernel bug #43096.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add the SMBus Device IDs for the Intel Lynx Point-LP PCH.
Signed-off-by: James Ralston <james.d.ralston@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add a new 'feature' to i2c-i801 to enable using PCI interrupts.
When the feature is enabled, then an isr is installed for the device's
PCI IRQ.
An I2C/SMBus transaction is always terminated by one of the following
interrupt sources: FAILED, BUS_ERR, DEV_ERR, or on success: INTR.
When the isr fires for one of these cases, it sets the ->status variable
and wakes up the waitq. The waitq then saves off the status code, and
clears ->status (in preparation for some future transaction).
The SMBus controller generates an INTR irq at the end of each
transaction where INTREN was set in the HST_CNT register.
No locking is needed around accesses to priv->status since all writes to
it are serialized: it is only ever set once in the isr at the end of a
transaction, and cleared while no interrupts can occur. In addition, the
I2C adapter lock guarantees that entire I2C transactions for a single
adapter are always serialized.
For this patch, the INTREN bit is set only for SMBus block, byte and word
transactions, but not for I2C reads or writes. The use of the DS
(BYTE_DONE) interrupt with byte-by-byte I2C transactions is implemented in
a subsequent patch.
The interrupt feature has only been enabled for COUGARPOINT hardware.
In addition, it is disabled if SMBus is using the SMI# interrupt.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Based on a previous patch from Peter Meerwald.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Meerwald <p.meerwald@bct-electronic.com>
Some AMD chipsets, such as the SP5100, have an auxiliary SMBus
controller with a second set of registers. This patch adds
support for this auxiliary controller.
Tested on ASUS KCMA-D8 motherboard.
Signed-off-by: Andrew Armenia <andrew@asquaredlabs.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
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>
Update the MAINTAINERS entry and all other references accordingly.
Based on an original patch by Wolfram Sang.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
[wsa: fixed merge conflict due to rework in i2c_add_mux_adapter()]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Usage of /etc/modprobe.conf file was deprecated by module-init-tools and
is no longer parsed by new kmod tool. References to this file are
replaced in Documentation, comments and Kconfig according to the
context.
There are also some references to the old /etc/modules.conf from 2.4
kernels that are being removed.
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the SMBus controller device IDs for the Intel Lynx Point PCH.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Since this driver is compatible with several NXP devices, the driver was renamed
accordingly. This patch also changes the respective symbol names.
Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10-bit addresses overlap with traditional 7-bit addresses, leading in
device name collisions. Add an arbitrary offset to 10-bit addresses to
prevent this collision. The offset was chosen so that the address is
still easily recognizable.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Reimplemented at least 17 times discounting error mangling cases
where it could be used.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This patch adds the SMBus controller DeviceID for the Intel Panther Point PCH.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The i2c_device_id structure variable's name is not used in the
i2c_driver structure.
Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>
* 'for-linus/2639/i2c-2' of git://git.fluff.org/bjdooks/linux:
i2c-pxa2xx: Don't clear isr bits too early
i2c-pxa2xx: Fix register offsets
i2c-pxa2xx: pass of_node from platform driver to adapter and publish
i2c-pxa2xx: check timeout correctly
i2c-pxa2xx: add support for shared IRQ handler
i2c-pxa2xx: Add PCI support for PXA I2C controller
ARM: pxa2xx: reorganize I2C files
i2c-pxa2xx: use dynamic register layout
i2c-mxs: set controller to pio queue mode after reset
i2c-eg20t: support new device OKI SEMICONDUCTOR ML7213 IOH
i2c/busses: Add support for Diolan U2C-12 USB-I2C adapter
Add the SMBus Controller DeviceIDs for the Intel DH89xxCC PCH.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
* Typical legacy drivers implemented method .detach_client, not
.detach_adapter.
* Drop all references to __devexit, as i2c drivers shouldn't use it.
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The struct i2c_board_info member holding the name is "type", not
"name".
Signed-off-by: Roman Fietze <roman.fietze@telemotive.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org
This patch adds support for the Diolan U2C-12 USB-I2C adapter.
It also updates MAINTAINERS to list the author as maintainer.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add an i2c mux driver providing access to i2c bus segments using a
hardware MUX sitting on a master bus and controlled through gpio pins.
E.G. something like:
---------- ---------- Bus segment 1 - - - - -
| | SCL/SDA | |-------------- | |
| |------------| |
| | | | Bus segment 2 | |
| Linux | GPIO 1..N | MUX |--------------- Devices
| |------------| | | |
| | | | Bus segment M
| | | |---------------| |
---------- ---------- - - - - -
SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M
according to the settings of the GPIO pins 1..N.
Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
These are the extra 'Integrated Device Function' SMBus controllers found
on the Patsburg chipset. Mention the absence of slave mode support.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add support for the Intel Patsburg PCH SMBus Controller.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The probe method used by i2c_new_probed_device() may not be suitable
for all cases. Let the caller provide its own, optional probe
function.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Below you will find an updated version from the original series bunching all patches into one big patch
updating broken web addresses that are located in Documentation/*
Some of the addresses date as far far back as 1995 etc... so searching became a bit difficult,
the best way to deal with these is to use web.archive.org to locate these addresses that are outdated.
Now there are also some addresses pointing to .spec files some are located, but some(after searching
on the companies site)where still no where to be found. In this case I just changed the address
to the company site this way the users can contact the company and they can locate them for the users.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Thomas Weber <weber@corscience.de>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Cc: Paulo Marques <pmarques@grupopie.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Remove all trailing whitespace in Documentation/i2c.
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Let the user disable selected features normally supported by the
device. This makes it possible to work around possible driver or
hardware bugs if the feature in question doesn't work as intended
for whatever reason.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Felix Rubinstein <felixru@gmail.com>
After discovering that a lot of i2c-drivers leave the pointer to their
clientdata dangling, it was decided to let the core handle this issue.
It is assumed that the core may access the private data after remove()
as there are no guarantees for the lifetime of such pointers anyhow (see
thread starting at http://lkml.org/lkml/2010/3/21/68)
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
i2c_master_send & i2c_master_recv do not support more than 64 kb
transfer, since msg.len is u16.
Signed-off-by: Zhangfei Gao <zgao6@marvell.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add support for the SMBus alert mechanism to the i2c-parport-light
driver. The ADM1032 evaluation board at least is properly wired for
this.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Trent Piepho <tpiepho@freescale.com>
Add support for the SMBus alert mechanism to the i2c-parport driver.
The ADM1032 evaluation board at least is properly wired for this.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Trent Piepho <tpiepho@freescale.com>
SMBus alert support. The SMBus alert protocol allows several SMBus
slave devices to share a single interrupt pin on the SMBus master,
while still allowing the master to know which slave triggered the
interrupt.
This is based on preliminary work by David Brownell. The key
difference between David's implementation and mine is that his was
part of i2c-core, while mine is split into a separate, standalone
module named i2c-smbus. The i2c-smbus module is meant to include
support for all SMBus extensions to the I2C protocol in the future.
The benefit of this approach is a zero cost for I2C bus segments which
do not need SMBus alert support. Where David's implementation
increased the size of struct i2c_adapter by 7% (40 bytes on i386),
mine doesn't touch it. Where David's implementation added over 150
lines of code to i2c-core (+10%), mine doesn't touch it. The only
change that touches all the users of the i2c subsystem is a new
callback in struct i2c_driver (common to both implementations.) I seem
to remember Trent was worried about the footprint of David'd
implementation, hopefully mine addresses the issue.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Trent Piepho <tpiepho@freescale.com>
Struct i2c_client_address_data only contains one field at this point,
which makes its usefulness questionable. Get rid of it and pass simple
address lists around instead.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Add a module parameter to override the functionality bitfield. This
lets the user disable some commands. This can be used to force a chip
driver to take different code paths.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The legacy probe and force module parameters are obsolete now, the
same can be achieved using the new_device sysfs interface, which is
both more flexible and cheaper (it is implemented by i2c-core rather
than replicated in every driver module.)
The legacy ignore module parameters can be dropped as well. Ignoring
can be done by instantiating a "dummy" device at the problematic
address.
This is the first step of a huge cleanup to i2c-core's i2c_detect
function, i2c.h's I2C_CLIENT_INSMOD* macros, and all drivers that made
use of them.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Superseded by tdfxfb. I2C/DDC support used to live in a separate
driver but this caused driver conflicts.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Some times ago the eeprom and max6875 drivers moved to
drivers/misc/eeprom, but their documentation did not follow. It's
finally time to get rid of Documentation/i2c/chips.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Ben Gardner <gardner.ben@gmail.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
The pcf8574 driver in drivers/i2c/chips which just exports its register to
sysfs is superseded by drivers/gpio/pcf857x.c which properly uses the gpiolib.
As this driver has been deprecated for more than a year, finally remove it.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The pca9539 driver in drivers/i2c/chips which just exports its registers to
sysfs is superseded by drivers/gpio/pca953x.c which properly uses the gpiolib.
As this driver has been deprecated for more than a year, finally remove it.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Ben Gardner <gardner.ben@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The pcf8575 driver in drivers/i2c/chips which just exports its register to
sysfs is superseded by drivers/gpio/pcf857x.c which properly uses the gpiolib.
As this driver has been deprecated for more than a year, finally remove it.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Bart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add a sysfs interface to instantiate and delete I2C devices. This is
primarily a replacement of the force_* module parameters implemented
by some i2c drivers. These module parameters were implemented
internally by the I2C_CLIENT_INSMOD* macros, which don't scale well.
This can also be used when developing a driver on a self-soldered
board which doesn't yet have proper I2C device declaration at the
platform level, and presumably for various debugging situations.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
We converted all the legacy i2c drivers so we can finally get rid of
the legacy binding model. Hooray!
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
The south bridge of the VIA VX855 chipset has a different PCI Device ID
so i2c-viapro.c needs to be updated with this.
Signed-off-by: Harald Welte <HaraldWelte@viatech.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
There is sometimes a need for the ocores driver to add devices to the
bus when installed.
i2c_register_board_info can not always be used, because the I2C devices
are not known at an early state, they could for instance be connected
on a I2C bus on a PCI device which has the Open Cores IP.
i2c_new_device can not be used in all cases either since the resulting
bus nummer might be unknown.
The solution is the pass a list of I2C devices in the platform data to
the Open Cores driver. This is useful for MFD drivers.
Signed-off-by: Richard Röjfors <richard.rojfors.ext@mocean-labs.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Directory drivers/i2c/chips is going away, so drivers there must find
new homes. For the pcf8591 driver, the best choice seems to be the
hwmon subsystem. While the Philips PCF8591 device isn't a typical
hardware monitoring chip, its DAC interface is compatible with the
hwmon one, so it fits somewhat.
If a better subsystem is ever created for ADC/DAC chips, the driver
could be moved there.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Add support for the Broadcom HT1100 LD chipset (SMBus function.)
Signed-off-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The MCP78S and MCP79 appear to be compatible with the previous nForce
chips as far as the SMBus controller is concerned. The MCP67 and MCP73
were not tested yet but I'd be very surprised if they weren't
compatible too.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Oleg Ryjkov <olegr@olegr.ca>
Cc: Malcolm Lalkaka <mlalkaka@gmail.com>
Cc: Zbigniew Luszpinski <zbiggy@o2.pl>
On popular demand, here comes some documentation about how to
instantiate i2c devices in the new (standard) i2c device driver
binding model.
I have also clarified how the class bitfield lets driver authors
control which buses are probed in the auto-detect case, and warned
more loudly against the abuse of this method.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Michael Lawnick <nospam_lawnick@gmx.de>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
* Strip trailing white space.
* Remove out-of-date or irrelevant parts.
* Insist on the fact that command is deprecated.
* Fix spelling mistakes and typos.
* Reformat code examples and function prototypes to comply with the
kernel coding style.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The legacy i2c binding model is deprecated and will be removed soon,
so we no longer need to document it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
i2c_get_clientdata doesn't change the i2c_client it is passed as a
parameter, so it can be constified. Same for i2c_get_adapdata.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The document describing how to port i2c chip drivers from Linux 2.4 to
Linux 2.6 is outdated. As I suspect that most drivers that had to be
ported have already been by now, I do not want to spend time updating
it. Let's just delete it instead.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Restore the i2c_smbus_process_call() as one driver (for the
Micronas MAP5401) will need it soon.
[JD: Update documentation accordingly.]
Signed-off-by: Prakash Mortha <pmortha@escient.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
I wrote this explanation to answer a question on the i2c mailing list,
and thought it would be good to have in the kernel documentation.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
* Clarify some points.
* Point developers to i2c-tools instead of lm_sensors.
* Fix coding style in code examples.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Thanks to new datasheets published on http://linux.via.com.tw we can now add
support for VX800/VX820 chipsets.
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add a document describing how i2c clients on Linux 2.6 can be
moved from the old to the new driver model.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The new-style max6875 driver implements the optional detect() callback
to cover the use cases of the legacy driver. I'm curious if anyone
really needs this though, so it might be removed in the feature.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The new-style pca9539 driver implements the optional detect() callback
to cover the use cases of the legacy driver.
Warning: users will now have to use the force module parameter to get
the driver to attach to their device. That's not a bad thing as these
devices can't be detected anyway.
Note that this doesn't change the fact that this driver is deprecated
in favor of gpio/pca953x.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The new-style pcf8575 driver implements the optional detect() callback
to cover the use cases of the legacy driver.
Warning: users will now have to use the force module parameter to get
the driver to attach to their device. That's not a bad thing as these
devices can't be detected anyway.
Note that this doesn't change the fact that this driver is deprecated
in favor of gpio/pcf857x.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The new-style pcf8574 driver implements the optional detect() callback
to cover the use cases of the legacy driver.
Warning: users will now have to use the force module parameter to get
the driver to attach to their device. That's not a bad thing as these
devices can't be detected anyway.
Note that this doesn't change the fact that this driver is deprecated
in favor of gpio/pcf857x.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add a mechanism to let new-style i2c drivers optionally autodetect
devices they would support on selected buses and ask i2c-core to
instantiate them. This is a replacement for legacy i2c drivers, much
cleaner.
Where drivers had to implement both a legacy i2c_driver and a
new-style i2c_driver so far, this mechanism makes it possible to get
rid of the legacy i2c_driver and implement both enumerated and
detected device support with just one (new-style) i2c_driver.
Here is a quick conversion guide for these drivers, step by step:
* Delete the legacy driver definition, registration and removal.
Delete the attach_adapter and detach_client methods of the legacy
driver.
* Change the prototype of the legacy detect function from
static int foo_detect(struct i2c_adapter *adapter, int address, int kind);
to
static int foo_detect(struct i2c_client *client, int kind,
struct i2c_board_info *info);
* Set the new-style driver detect callback to this new function, and
set its address_data to &addr_data (addr_data is generally provided
by I2C_CLIENT_INSMOD.)
* Add the appropriate class to the new-style driver. This is
typically the class the legacy attach_adapter method was checking
for. Class checking is now mandatory (done by i2c-core.) See
<linux/i2c.h> for the list of available classes.
* Remove the i2c_client allocation and freeing from the detect
function. A pre-allocated client is now handed to you by i2c-core,
and is freed automatically.
* Make the detect function fill the type field of the i2c_board_info
structure it was passed as a parameter, and return 0, on success. If
the detection fails, return -ENODEV.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Function i2c_smbus_write_quick has no users left, so we can delete it.
Also update the list of these helper functions which are gone but
could be added back if needed.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
More updates to the I2C stack's fault reporting: make the core stop
returning "-1" (usually "-EPERM") for all faults. Instead, pass lower
level fault code up the stack, or return some appropriate errno.
This patch happens to touch almost exclusively SMBus calls.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Create Documentation/i2c/fault-codes to help standardize
fault/error code usage in the I2C stack. It turns out that
returning -1 (-EPERM) for everything was not at all helpful.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This patch contains the scheduled removal of i2c-i810, i2c-prosavage
and i2c-savage4.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The matching process described for new style clients in
Documentation/i2c/writing-clients is classed as out-of-date
as it requires the presence of an .id_table entry in the
driver's i2c_driver entry.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Improve the smbus-protocol documentation file somewhat:
- Use the names of the SMBus protocol operations (from the 2.0
specification), not made-up-for-Linux names.
- Add the name of the call used to execute each operation ... and
point out that there are mismatches, where functions execute
different protocol operations than their names specify.
The most confusing examples are that "Read Byte" isn't executed by
i2c_smbus_read_byte(), and that "Write Byte" isn't executed by
i2c_smbus_write_byte(). When coding, that's not as bad as it may
seem; but that case would seem to be worth fixing.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Based on earlier work by Jon Smirl and Jochen Friedrich.
This patch allows new-style i2c chip drivers to have alias names using
the official kernel aliasing system and MODULE_DEVICE_TABLE(). At this
point, the old i2c driver binding scheme (driver_name/type) is still
supported.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Jochen Friedrich <jochen@scram.de>
Cc: Jon Smirl <jonsmirl@gmail.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Add the Intel ICH10 SMBus Controller DeviceID's and updates
Tolapai support.
Signed-off-by: Jason Gaston <jason.d.gaston@intel.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
It's about time to reflect the move of the lm-sensors project to
lm-sensors.org.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Use drivers/gpio/pca9539.c instead.
Signed-off-by: eric miao <eric.miao@marvell.com>
Acked-by: Ben Gardner <bgardner@wabtec.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for another variant of the VT8237. I couldn't test
I2C block support but I assume it is present as well.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
I2C block read is supported since the ICH5. I couldn't get it to work
using the block buffer, so it's using the old-style byte-by-byte mode
for now.
Note: I'm also updating the driver author... The i2c-i801 driver was
really written by Mark Studebaker, even though he based his work on
the i2c-piix4 driver which was written by Philip Edelbrock.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
There's a new script named i2c-stub-from-dump that can be very helpful
when working with the i2c-stub driver.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Rename I2C_FUNC_SMBUS_HWPEC_CALC as I2C_FUNC_SMBUS_PEC, and list that
functionality as always available through the software implementation.
Update documentation accordingly (and list similar requirements).
The way it's currently packaged doesn't present the capability in a
useful way.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add support for multiple chips to i2c-stub. I've changed the memory
allocation scheme from static to dynamic, so that we don't waste too
much memory.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mark M. Hoffman <mhoffman@lightlink.com>
Do not initialize the PCF8574 with an arbitrary value. Users will have
to write the initial value to sysfs themselves.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Aurelien Jarno <aurelien@aurel32.net>
We find that SB700 and SB800 use the same SMBus device ID as SB600, which is
0x4385, instead of the already submitted 0x4395.
Besides removing the wrong SB700 device ID, add SB800 support to kernel, by
renaming the PCI_DEVICE_ID_ATI_IXP600_SMBUS into
PCI_DEVICE_ID_ATI_SBX00_SMBUS.
Signed-off-by: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This driver has been broken forever. It depends on i2c-algo-8xx which
has never been in the mainline kernel.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This is a new I2C bus driver for the TAOS evaluation modules. Developped
and tested on the TAOS TSL2550 EVM.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Add an ability to utilize the internal SRAM buffer on ICH4
and newer host controllers to speed up execution of block operations.
I've split the code so that it is more clear which block transaction is
performed.
First of all the host controller's type is identified. isich4 is set when
we think that the controller has the internal buffer. Then, before every
block transaction, if isich4 is set, we attempt to enable the E32B bit in
SMBAUXCTL register.
Signed-off-by: Oleg Ryjkov <olegr@google.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Let the drivers specify how many bytes they want to read with
i2c_smbus_read_i2c_block_data(). So far, the block count was
hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense.
Many driver authors complained about this before, and I believe it's
about time to fix it. Right now, authors have to do technically stupid
things, such as individual byte reads or full-fledged I2C messaging,
to work around the problem. We do not want to encourage that.
I even found that some bus drivers (e.g. i2c-amd8111) already
implemented I2C block read the "right" way, that is, they didn't
follow the old, broken standard. The fact that it was never noticed
before just shows how little i2c_smbus_read_i2c_block_data() was used,
which isn't that surprising given how broken its prototype was so far.
There are some obvious compatiblity considerations:
* This changes the i2c_smbus_read_i2c_block_data() prototype. Users
outside the kernel tree will notice at compilation time, and will
have to update their code.
* User-space has access to i2c_smbus_xfer() directly using i2c-dev, so
the changed expectations would affect tools such as i2cdump. In order
to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA
a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the
old numeric value. When i2c-dev receives a transaction with the
old value, it can convert it to the new format on the fly.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
