Commit Graph

24 Commits

Author SHA1 Message Date
Linus Torvalds
c2a96b7f18 Driver core changes for 6.11-rc1
Here is the big set of driver core changes for 6.11-rc1.
 
 Lots of stuff in here, with not a huge diffstat, but apis are evolving
 which required lots of files to be touched.  Highlights of the changes
 in here are:
   - platform remove callback api final fixups (Uwe took many releases to
     get here, finally!)
   - Rust bindings for basic firmware apis and initial driver-core
     interactions.  It's not all that useful for a "write a whole driver
     in rust" type of thing, but the firmware bindings do help out the
     phy rust drivers, and the driver core bindings give a solid base on
     which others can start their work.  There is still a long way to go
     here before we have a multitude of rust drivers being added, but
     it's a great first step.
   - driver core const api changes.  This reached across all bus types,
     and there are some fix-ups for some not-common bus types that
     linux-next and 0-day testing shook out.  This work is being done to
     help make the rust bindings more safe, as well as the C code, moving
     toward the end-goal of allowing us to put driver structures into
     read-only memory.  We aren't there yet, but are getting closer.
   - minor devres cleanups and fixes found by code inspection
   - arch_topology minor changes
   - other minor driver core cleanups
 
 All of these have been in linux-next for a very long time with no
 reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the big set of driver core changes for 6.11-rc1.

  Lots of stuff in here, with not a huge diffstat, but apis are evolving
  which required lots of files to be touched. Highlights of the changes
  in here are:

   - platform remove callback api final fixups (Uwe took many releases
     to get here, finally!)

   - Rust bindings for basic firmware apis and initial driver-core
     interactions.

     It's not all that useful for a "write a whole driver in rust" type
     of thing, but the firmware bindings do help out the phy rust
     drivers, and the driver core bindings give a solid base on which
     others can start their work.

     There is still a long way to go here before we have a multitude of
     rust drivers being added, but it's a great first step.

   - driver core const api changes.

     This reached across all bus types, and there are some fix-ups for
     some not-common bus types that linux-next and 0-day testing shook
     out.

     This work is being done to help make the rust bindings more safe,
     as well as the C code, moving toward the end-goal of allowing us to
     put driver structures into read-only memory. We aren't there yet,
     but are getting closer.

   - minor devres cleanups and fixes found by code inspection

   - arch_topology minor changes

   - other minor driver core cleanups

  All of these have been in linux-next for a very long time with no
  reported problems"

* tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
  ARM: sa1100: make match function take a const pointer
  sysfs/cpu: Make crash_hotplug attribute world-readable
  dio: Have dio_bus_match() callback take a const *
  zorro: make match function take a const pointer
  driver core: module: make module_[add|remove]_driver take a const *
  driver core: make driver_find_device() take a const *
  driver core: make driver_[create|remove]_file take a const *
  firmware_loader: fix soundness issue in `request_internal`
  firmware_loader: annotate doctests as `no_run`
  devres: Correct code style for functions that return a pointer type
  devres: Initialize an uninitialized struct member
  devres: Fix memory leakage caused by driver API devm_free_percpu()
  devres: Fix devm_krealloc() wasting memory
  driver core: platform: Switch to use kmemdup_array()
  driver core: have match() callback in struct bus_type take a const *
  MAINTAINERS: add Rust device abstractions to DRIVER CORE
  device: rust: improve safety comments
  MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer
  MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER
  firmware: rust: improve safety comments
  ...
2024-07-25 10:42:22 -07:00
Greg Kroah-Hartman
d69d804845 driver core: have match() callback in struct bus_type take a const *
In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *.  This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.

Because the match() callback is in all busses, all busses are modified
to handle this properly.  This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.

For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-03 15:16:54 +02:00
Jeff Johnson
c41cc3c287 siox: bus-gpio: add missing MODULE_DESCRIPTION()
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/siox/siox-bus-gpio.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/20240530-md-siox-bus-gpio-v1-1-6a2f943ac8ad@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-04 17:41:53 +02:00
Linus Torvalds
0045341957 SIOX changes for 6.9-rc1
These patches rework how siox device registration works yielding a saner
 API. This allows to simplify the gpio bus driver using two new devm
 functions.
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Merge tag 'siox/for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux

Pull siox updates from Uwe Kleine-König:
 "This reworks how siox device registration works yielding a saner API.

  This allows us to simplify the gpio bus driver using two new devm
  functions"

* tag 'siox/for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux:
  siox: bus-gpio: Simplify using devm_siox_* functions
  siox: Provide a devm variant of siox_master_register()
  siox: Provide a devm variant of siox_master_alloc()
  siox: Don't pass the reference on a master in siox_master_register()
2024-03-21 15:18:18 -07:00
Uwe Kleine-König
db418d5f1c siox: bus-gpio: Simplify using devm_siox_* functions
With the devm variant of siox_master_allocate() and
siox_master_register() the remove callback can be dropped. This also
simplifies the error paths in the probe function.

Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/e3c598de536deadc7efef9c21ccb49d31eb240a9.1708328466.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-03-08 22:01:10 +01:00
Uwe Kleine-König
91d5bb579c siox: Provide a devm variant of siox_master_register()
This allows to simplify siox master drivers in the next step.

Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/e961dfb3e94f106b16f5eacff2110fc7fa0cab13.1708328466.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-03-08 22:01:10 +01:00
Uwe Kleine-König
9ecfbf7053 siox: Provide a devm variant of siox_master_alloc()
This allows to simplify siox master drivers in the next step.

Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/ad141dd22c7d95ad0bd347f257ce586e1afb22a4.1708328466.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-03-08 22:01:09 +01:00
Uwe Kleine-König
2c12932b8e siox: Don't pass the reference on a master in siox_master_register()
While it's technically fine to pass the ownership of the reference on
a struct siox_master from the caller of siox_master_register() to the
framework this is hard to use. Instead let the framework take its own
reference (that is freed in siox_master_unregister()) and drop the bus
driver's reference in its remove callback.

Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/1e8d09d17848e58e8fc6a46278b5e8fb0cf4618a.1708328466.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-03-08 22:01:09 +01:00
Ricardo B. Marliere
664c89c56e siox: make siox_bus_type const
Since commit d492cc2573 ("driver core: device.h: make struct bus_type
a const *"), the driver core can properly handle constant struct
bus_type. Move the siox_bus_type variable to be a constant structure as
well, placing it into read-only memory which can not be modified at
runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/20240204-bus_cleanup-siox-v2-1-3813a6a55dcc@marliere.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-07 20:40:36 +00:00
Ricardo B. Marliere
6501ac11b9 siox: constify the struct device_type usage
Since commit aed65af1cc ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
siox_device_type and siox_master_type variables to be constant structures
as well, placing it into read-only memory which can not be modified at
runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: "Ricardo B. Marliere" <ricardo@marliere.net>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/20240219-device_cleanup-siox-v1-1-eb32ca2b0113@marliere.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-07 20:37:04 +00:00
Yang Yingliang
6e63153db5 siox: fix possible memory leak in siox_device_add()
If device_register() returns error in siox_device_add(),
the name allocated by dev_set_name() need be freed. As
comment of device_register() says, it should use put_device()
to give up the reference in the error path. So fix this
by calling put_device(), then the name can be freed in
kobject_cleanup(), and sdevice is freed in siox_device_release(),
set it to null in error path.

Fixes: bbecb07fa0 ("siox: new driver framework for eckelmann SIOX")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20221104021334.618189-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-09 15:40:14 +01:00
Uwe Kleine-König
fc7a6209d5 bus: Make remove callback return void
The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix <trix@redhat.com> (For fpga)
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> (For ARM, Amba and related parts)
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Chen-Yu Tsai <wens@csie.org> (for sunxi-rsb)
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org> (for media)
Acked-by: Hans de Goede <hdegoede@redhat.com> (For drivers/platform)
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Juergen Gross <jgross@suse.com> (For xen)
Acked-by: Lee Jones <lee.jones@linaro.org> (For mfd)
Acked-by: Johannes Thumshirn <jth@kernel.org> (For mcb)
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> (For slimbus)
Acked-by: Kirti Wankhede <kwankhede@nvidia.com> (For vfio)
Acked-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com> (For ipack)
Acked-by: Geoff Levand <geoff@infradead.org> (For ps3)
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com> (For thunderbolt)
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> (For intel_th)
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> (For pcmcia)
Acked-by: Rafael J. Wysocki <rafael@kernel.org> (For ACPI)
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> (For intel-ish-hid)
Acked-by: Dan Williams <dan.j.williams@intel.com> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> (For isa)
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (For firewire)
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> (For hid)
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de> (For siox)
Acked-by: Sven Van Asbroeck <TheSven73@gmail.com> (For anybuss)
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> (For MMC)
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Finn Thain <fthain@linux-m68k.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210713193522.1770306-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-21 11:53:42 +02:00
Thorsten Scherer
75020f2df6 siox: Simplify error handling via dev_err_probe()
commit a787e5400a ("driver core: add device probe log helper")
introduced a helper for a common error checking pattern.  Use it.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thorsten Scherer <t.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/20210616061736.3786173-2-t.scherer@eckelmann.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-24 15:46:34 +02:00
Uwe Kleine-König
1c12c27086 siox: Make remove callback return void
The driver core ignores the return value of the remove callback, so
don't give siox drivers the chance to provide a value.

All siox drivers only allocate devm-managed resources in
.probe, so there is no .remove callback to fix.

Tested-by: Thorsten Scherer <t.scherer@eckelmann.de>
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201125093106.240643-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-10 16:17:15 +01:00
Uwe Kleine-König
07d9a767ae siox: Use bus_type functions for probe, remove and shutdown
The eventual goal is to get rid of the callbacks in struct
device_driver.

Tested-by: Thorsten Scherer <t.scherer@eckelmann.de>
Acked-by: Thorsten Scherer <t.scherer@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201125093106.240643-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-10 16:17:15 +01:00
Nishad Kamdar
5a158981aa siox: Use the correct style for SPDX License Identifier
This patch corrects the SPDX License Identifier style in
header file related to Eckelmann SIOX driver.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Thorsten Scherer <thorsten.scherer@eckelmann.de>
Link: https://lore.kernel.org/r/20200101131418.GA3110@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14 21:46:53 +01:00
Thomas Gleixner
ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Randy Dunlap
ac3167257b headers: separate linux/mod_devicetable.h from linux/platform_device.h
At over 4000 #includes, <linux/platform_device.h> is the 9th most
#included header file in the Linux kernel.  It does not need
<linux/mod_devicetable.h>, so drop that header and explicitly add
<linux/mod_devicetable.h> to source files that need it.

   4146 #include <linux/platform_device.h>

After this patch, there are 225 files that use <linux/mod_devicetable.h>,
for a reduction of around 3900 times that <linux/mod_devicetable.h>
does not have to be read & parsed.

    225 #include <linux/mod_devicetable.h>

This patch was build-tested on 20 different arch-es.

It also makes these drivers SubmitChecklist#1 compliant.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com> # drivers/media/platform/vimc/
Reported-by: kbuild test robot <lkp@intel.com> # drivers/pinctrl/pinctrl-u300.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:52:26 +02:00
Uwe Kleine-König
e890591413 siox: don't create a thread without starting it
When a siox master device is registered a kthread is created that is
only started when triggered by userspace. So this thread might be in
TASK_UNINTERRUPTIBLE state for long and trigger a warning

	[  241.130465] INFO: task siox-0:626 blocked for more than 120 seconds.

with the respective debug settings enabled. It might be right to put an
unstarted thread to TASK_IDLE (in kernel/kthread.c:kthread()) instead,
but independant of this discussion it is cleaner for
siox_master_register() to start the thread immediately. The effect is
that it enters its own waiting state and then stays in state TASK_IDLE
which doesn't trigger the above warning.

As siox_poll_thread() uses some variables of the device the
initialisation of these is moved before thread creation.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:38:57 +02:00
Uwe Kleine-König
7e6f7d2453 siox: treat type errors as status errors
The type bits are part of the per-device status word. So it's natural to
consider an error in the type bits as a status error instead of only
resulting in an unsynced state.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-07 17:38:57 +02:00
Gavin Schenk
f87deada80 siox: fix possible buffer overflow in device_add_store
Width 20 given in format string is larger than destination
buffer 'type[20]', use %19s to prevent overflowing it.

Fixes: bbecb07fa0 ("siox: new driver framework for eckelmann SIOX")
Cc: stable <stable@vger.kernel.org>
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Gavin Schenk <g.schenk@eckelmann.de>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-15 18:07:46 +01:00
Uwe Kleine-König
fd639726bf siox: add gpio bus driver
This bus driver uses GPIOs to control the four SIOX bus lines.

Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 10:56:53 +01:00
Uwe Kleine-König
297a344d52 siox: add support for tracing
Implement tracing for SIOX. There are events for the data that is
written to the bus and for data being read from it.

Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 10:56:24 +01:00
Uwe Kleine-König
bbecb07fa0 siox: new driver framework for eckelmann SIOX
SIOX is a bus system invented at Eckelmann AG to control their building
management and refrigeration systems. Traditionally the bus was
implemented on custom microcontrollers, today Linux based machines are
in use, too.

The topology on a SIOX bus looks as follows:

      ,------->--DCLK-->---------------+----------------------.
      ^                                v                      v
 ,--------.                ,----------------------.       ,------
 |        |                |   ,--------------.   |       |
 |        |--->--DOUT-->---|->-|shift register|->-|--->---|
 |        |                |   `--------------'   |       |
 | master |                |        device        |       |  device
 |        |                |   ,--------------.   |       |
 |        |---<--DIN---<---|-<-|shift register|-<-|---<---|
 |        |                |   `--------------'   |       |
 `--------'                `----------------------'       `------
      v                                ^                      ^
      `----------DLD-------------------+----------------------'

There are two control lines (DCLK and DLD) driven from the bus master to
all devices in parallel and two daisy chained data lines, one for input
and one for output. DCLK is the clock to shift both chains by a single
bit. On an edge of DLD the devices latch both their input and output
shift registers.

This patch adds a framework for this bus type.

Acked-by: Gavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 09:26:00 +01:00