According to the chip manual, the I2C register access type of
Loongson-2K2000/LS7A is "B", so we can only access registers in byte
form (readb()/writeb()).
Although Loongson-2K0500/Loongson-2K1000 do not have similar
constraints, register accesses in byte form also behave correctly.
Also, in hardware, the frequency division registers are defined as two
separate registers (high 8-bit and low 8-bit), so we just access them
directly as bytes.
Fixes: 015e61f0bf ("i2c: ls2x: Add driver for Loongson-2K/LS7A I2C controller")
Co-developed-by: Hongliang Wang <wanghongliang@loongson.cn>
Signed-off-by: Hongliang Wang <wanghongliang@loongson.cn>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Cc: stable@vger.kernel.org # v6.3+
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250220125612.1910990-1-zhoubinbin@loongson.cn
drivers/i2c/i2c-core-base.c: In function ‘i2c_detect.isra’:
drivers/i2c/i2c-core-base.c:2544:1: warning: the frame size of 1312 bytes is larger than 1024 bytes [-Wframe-larger-than=]
2544 | }
| ^
Fix this by allocating the temporary client structure dynamically, as it
is a rather large structure (1216 bytes, depending on kernel config).
This is basically a revert of the to-be-fixed commit with some
checkpatch improvements.
Fixes: 735668f8e5 ("i2c: core: Allocate temp client on the stack in i2c_detect")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
[wsa: updated commit message, merged tags from similar patch]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Pull i2c fixes from Wolfram Sang:
- add a missing Kconfig dependency for imx-lpi2c
- in the core, handle the new per-client debugfs directory during
probe/remove, not during {un}register
* tag 'i2c-for-6.14-rc1-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: Fix core-managed per-client debugfs handling
i2c: imx-lpi2c: select CONFIG_I2C_SLAVE
Pull driver core and debugfs updates from Greg KH:
"Here is the big set of driver core and debugfs updates for 6.14-rc1.
Included in here is a bunch of driver core, PCI, OF, and platform rust
bindings (all acked by the different subsystem maintainers), hence the
merge conflict with the rust tree, and some driver core api updates to
mark things as const, which will also require some fixups due to new
stuff coming in through other trees in this merge window.
There are also a bunch of debugfs updates from Al, and there is at
least one user that does have a regression with these, but Al is
working on tracking down the fix for it. In my use (and everyone
else's linux-next use), it does not seem like a big issue at the
moment.
Here's a short list of the things in here:
- driver core rust bindings for PCI, platform, OF, and some i/o
functions.
We are almost at the "write a real driver in rust" stage now,
depending on what you want to do.
- misc device rust bindings and a sample driver to show how to use
them
- debugfs cleanups in the fs as well as the users of the fs api for
places where drivers got it wrong or were unnecessarily doing
things in complex ways.
- driver core const work, making more of the api take const * for
different parameters to make the rust bindings easier overall.
- other small fixes and updates
All of these have been in linux-next with all of the aforementioned
merge conflicts, and the one debugfs issue, which looks to be resolved
"soon""
* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
rust: device: Use as_char_ptr() to avoid explicit cast
rust: device: Replace CString with CStr in property_present()
devcoredump: Constify 'struct bin_attribute'
devcoredump: Define 'struct bin_attribute' through macro
rust: device: Add property_present()
saner replacement for debugfs_rename()
orangefs-debugfs: don't mess with ->d_name
octeontx2: don't mess with ->d_parent or ->d_parent->d_name
arm_scmi: don't mess with ->d_parent->d_name
slub: don't mess with ->d_name
sof-client-ipc-flood-test: don't mess with ->d_name
qat: don't mess with ->d_name
xhci: don't mess with ->d_iname
mtu3: don't mess wiht ->d_iname
greybus/camera - stop messing with ->d_iname
mediatek: stop messing with ->d_iname
netdevsim: don't embed file_operations into your structs
b43legacy: make use of debugfs_get_aux()
b43: stop embedding struct file_operations into their objects
carl9170: stop embedding file_operations into their objects
...
The debugfs directory should be created when a device
is probed, not when it is registered. It should be removed
when the device is removed, not when it is unregistered.
Fixes: d06905d686 ("i2c: add core-managed per-client directory in debugfs")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
The addition of target mode causes a build failure when CONFIG_I2C_SLAVE
is turned off:
drivers/i2c/busses/i2c-imx-lpi2c.c:1273:10: error: 'const struct i2c_algorithm' has no member named 'reg_target'
1273 | .reg_target = lpi2c_imx_register_target,
| ^~~~~~~~~~
drivers/i2c/busses/i2c-imx-lpi2c.c:1274:10: error: 'const struct i2c_algorithm' has no member named 'unreg_target'
1274 | .unreg_target = lpi2c_imx_unregister_target,
| ^~~~~~~~~~~~
Select the Kconfig symbol like we do for other similar drivers.
Fixes: 1ee867e465 ("i2c: imx-lpi2c: add target mode support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Pull x86 platform driver updates from Ilpo Järvinen:
"acer-wmi:
- Add support for PH14-51, PH16-72, and Nitro AN515-58
- Add proper hwmon support
- Improve error handling when reading "gaming system info"
- Replace direct EC reads for the current platform profile with WMI
calls to handle EC address variations
- Replace custom platform_profile cycling with the generic one
ACPI:
- platform_profile: Major refactoring and improvements
- Support registering multiple platform_profile handlers concurrently
to avoid the need to quirk which handler takes precedence
- Support reporting "custom" profile for cases where the current
profile is ambiguous or when settings tweaks are done outside the
pre-defined profile
- Abstract and layer platform_profile API better using the class_dev
and drvdata
- Various minor improvements
- Add Documentation and kerneldoc
amd/hsmp:
- Add support for HSMP protocol v7
amd/pmc:
- Support AMD 1Ah family 70h
- Support STB with Ryzen desktop SoCs
amd/pmf:
- Support Custom BIOS inputs for PMF TA
- Support passing SRA sensor data from AMD SFH (HID) to PMF TA
dell-smo8800:
- Move SMO88xx quirk away from the generic i2c-i801 driver
- Add accelerometer support for Dell Latitude E6330/E6430 and XPS
9550
- Support probing accelerometer for models yet to be listed in the
DMI mapping table because ACPI lacks i2c-address for the
accelerometer (behind a module parameter because probing might be
dangerous)
HID:
- amd_sfh: Add support for exporting SRA sensor data
hp-wmi:
- Add fan and thermal support for Victus 16-s1000
input:
- Add key for phone linking
- i8042: Add context for the i8042 filter to enable cleaning up the
filter related global variables from pdx86 drivers
lenovo-wmi-camera:
- Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA_ACCESS
mellanox mlxbf-pmc:
- Add support for monitoring cycle count
- Add Documentation
thinkpad_acpi:
- Add support for phone link key
tools/power/x86/intel-speed-select:
- Fix Turbo Ratio Limit restore
x86-android-tables:
- Add support for Vexia EDU ATLA 10 Bluetooth and EC battery driver
And miscellaneous cleanups / refactoring / improvements"
* tag 'platform-drivers-x86-v6.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (133 commits)
platform/x86: acer-wmi: Fix initialization of last_non_turbo_profile
platform/x86: acer-wmi: Ignore AC events
platform/mellanox: mlxreg-io: use sysfs_emit() instead of sprintf()
platform/mellanox: mlxreg-hotplug: use sysfs_emit() instead of sprintf()
platform/mellanox: mlxbf-bootctl: use sysfs_emit() instead of sprintf()
platform/x86: hp-wmi: Add fan and thermal profile support for Victus 16-s1000
ACPI: platform_profile: Add a prefix to log messages
ACPI: platform_profile: Add documentation
ACPI: platform_profile: Clean platform_profile_handler
ACPI: platform_profile: Move platform_profile_handler
ACPI: platform_profile: Remove platform_profile_handler from exported symbols
platform/x86: thinkpad_acpi: Use devm_platform_profile_register()
platform/x86: inspur_platform_profile: Use devm_platform_profile_register()
platform/x86: hp-wmi: Use devm_platform_profile_register()
platform/x86: ideapad-laptop: Use devm_platform_profile_register()
platform/x86: dell-pc: Use devm_platform_profile_register()
platform/x86: asus-wmi: Use devm_platform_profile_register()
platform/x86: amd: pmf: sps: Use devm_platform_profile_register()
platform/x86: acer-wmi: Use devm_platform_profile_register()
platform/surface: surface_platform_profile: Use devm_platform_profile_register()
...
Pull i2c updates from Wolfram Sang:
"Core:
- list-based mechanisms for handling auto-detected and userspace
created clients are replaced with a flag-based approach. The
resulting code is much simpler as well as the locking.
- i2c clients now get a default debugfs dir managed by the I2C core.
Drivers don't have to maintain their own directory anymore.
Driver updates:
- xiic: atomic_transfer support
- imx-lpi2c: DMA and target mode support
- riic cleanups
- npcm: better timeout handling and more precise frequency setups
- davinci: remove unused platform_data
- at24: add new compatibles for variants from Giantec and Puya
Semiconductor (together with a new vendor prefix)"
* tag 'i2c-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (52 commits)
i2c: add kdoc for the new debugfs entry of clients
i2c: designware: Actually make use of the I2C_DW_COMMON and I2C_DW symbol namespaces
i2c: add core-managed per-client directory in debugfs
i2c: Force ELAN06FA touchpad I2C bus freq to 100KHz
i2c: riic: Add `riic_bus_barrier()` to check bus availability
i2c: riic: Use predefined macro and simplify clock tick calculation
i2c: riic: Mark riic_irqs array as const
i2c: riic: Make use of devres helper to request deasserted reset line
i2c: riic: Use GENMASK() macro for bitmask definitions
i2c: riic: Use BIT macro consistently
i2c: riic: Use local `dev` pointer in `dev_err_probe()`
i2c: riic: Use dev_err_probe in probe and riic_init_hw functions
i2c: riic: Introduce a separate variable for IRQ
i2c: amd756: Remove superfluous TODO
Revert "i2c: amd756: Fix endianness handling for word data"
i2c: i801: Add lis3lv02d for Dell Precision M6800
i2c: i801: Remove unnecessary PCI function call
i2c: core: Allocate temp client on the stack in i2c_detect
i2c: slave-eeprom: Constify 'struct bin_attribute'
i2c: imx-lpi2c: make controller available until the system enters suspend_noirq() and from resume_noirq().
...
This backend requests a NACK from the controller driver when it detects
an error. If that request gets ignored from some reason, subsequent
accesses will wrongly be handled OK. To fix this, an error now changes
the state machine, so the backend will report NACK until a STOP
condition has been detected. This make the driver more robust against
controllers which will sadly apply the NACK not to the current byte but
the next one.
Fixes: a8335c64c5 ("i2c: add slave testunit driver")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
When this controller is a target, the NACK handling had two issues.
First, the return value from the backend was not checked on the initial
WRITE_REQUESTED. So, the driver missed to send a NACK in this case.
Also, the NACK always arrives one byte late on the bus, even in the
WRITE_RECEIVED case. This seems to be a HW issue. We should then not
rely on the backend to correctly NACK the superfluous byte as well. Fix
both issues by introducing a flag which gets set whenever the backend
requests a NACK and keep sending it until we get a STOP condition.
Fixes: de20d1857d ("i2c: rcar: add slave support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
When misconfigured, the initial setup of the current mux channel can
fail, too. It must be checked as well.
Fixes: 50a5ba8769 ("i2c: mux: demux-pinctrl: add driver")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
More and more I2C client drivers use debugfs entries and currently they
need to manage a subdir for their files on their own. This means
inconsistent naming for these subdirs and they are scattered all over
the debugfs-tree as well. Not to mention the duplicated code.
Let the I2C core provide and maintain a proper directory per client.
Note: It was considered to save the additional pointer in 'struct
i2c_client' and only provide a subdir when requested via a helper
function. When sketching this approach, more and more corner cases
appeared, though, so the current solution with its simple and unabiguous
code was chosen.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
When a 400KHz freq is used on this model of ELAN touchpad in Linux,
excessive smoothing (similar to when the touchpad's firmware detects
a noisy signal) is sometimes applied. As some devices' (e.g, Lenovo
V15 G4) ACPI tables specify a 400KHz frequency for this device and
some I2C busses (e.g, Designware I2C) default to a 400KHz freq,
force the speed to 100KHz as a workaround.
For future investigation: This problem may be related to the default
HCNT/LCNT values given by some busses' drivers, because they are not
specified in the aforementioned devices' ACPI tables, and because
the device works without issues on Windows at what is expected to be
a 400KHz frequency. The root cause of the issue is not known.
Signed-off-by: Randolph Ha <rha051117@gmail.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Introduce a new `riic_bus_barrier()` function to verify bus availability
before initiating an I2C transfer. This function enhances the bus
arbitration check by ensuring that the SDA and SCL lines are not held low,
in addition to checking the BBSY flag using `readb_poll_timeout()`.
Previously, only the BBSY flag was checked to determine bus availability.
However, it is possible for the SDA line to remain low even when BBSY = 0.
This new implementation performs an additional check on the SDA and SCL
lines to avoid potential bus contention issues.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Refactor error handling in the riic_i2c_probe() and riic_init_hw()
functions by replacing multiple dev_err() calls with dev_err_probe().
Additionally, update the riic_init_hw() function to use a local `dev`
pointer instead of `riic->adapter.dev` for dev_err_probe(), as the I2C
adapter is not initialized at this stage. Drop the cast to (unsigned long)
in the riic_init_hw() function when printing the bus frequency, and update
the error message to display the frequency in Hz, improving clarity.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This reverts commit 70f3d3669c. We
concluded that removing the comments is the right thing to do. This will
be done by an incremental patch.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
On the Dell Precision M6800/OXD1M5, BIOS A26 06/13/2029, Linux prints the
warning below.
i801_smbus 0000:00:1f.4: Accelerometer lis3lv02d is present on SMBus but its address is unknown, skipping registration
Following the same suggestions by Wolfram Sang as for the Dell Precision
3540 [1], the accelerometer can be successfully found on I2C bus 0 at
address 0x29.
$ echo lis3lv02d 0x29 | sudo tee /sys/bus/i2c/devices/i2c-0/new_device
lis3lv02d 0x29
$ dmesg | tail -5
[1185.385204] lis3lv02d_i2c 0-0029: supply Vdd not found, using dummy regulator
[1185.385235] lis3lv02d_i2c 0-0029: supply Vdd_IO not found, using dummy regulator
[1185.399689] lis3lv02d: 8 bits 3DC sensor found
[1185.449391] input: ST LIS3LV02DL Accelerometer as /devices/platform/lis3lv02d/input/input371
[1185.449577] i2c i2c-0: new_device: Instantiated device lis3lv02d at 0x29
So, the device has that accelerometer. Add the I2C address to the
mapping list, and test it successfully on the device.
[1]: https://lore.kernel.org/linux-i2c/97708c11-ac85-fb62-2c8e-d37739ca826f@molgen.mpg.de/
Signed-off-by: Patrick Höhn <hoehnp@gmx.de>
Acked-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20240312193132.26518-1-hoehnp@gmx.de
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Since the changes in
commit f748a07a0b ("PCI: Remove legacy pcim_release()")
all pcim_enable_device() does is set up a callback that disables the
device from being disabled from driver detach. The function
pcim_pin_device() prevents said disabling. pcim_enable_device(),
therefore, sets up an action that is removed immediately afterwards by
pcim_pin_device().
Replace pcim_enable_device() with pci_enable_device() and remove the
unnecessary call to pcim_pin_device().
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Link: https://lore.kernel.org/r/20241121195624.144839-2-pstanner@redhat.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
The temp client is used only in scope of this function, so there's no
benefit in dynamic allocation.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
i2c-atr catches the BUS_NOTIFY_DEL_DEVICE event on the bus and removes
the translation by calling i2c_atr_detach_client().
However, BUS_NOTIFY_DEL_DEVICE happens when the device is about to be
removed from this bus, i.e. before removal, and thus before calling
.remove() on the driver. If the driver happens to do any i2c
transactions in its remove(), they will fail.
Fix this by catching BUS_NOTIFY_REMOVED_DEVICE instead, thus removing
the translation only after the device is actually removed.
Fixes: a076a860ac ("media: i2c: add I2C Address Translator (ATR) support")
Cc: stable@vger.kernel.org
Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Romain Gantois <romain.gantois@bootlin.com>
Tested-by: Romain Gantois <romain.gantois@bootlin.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
The reference count of the device incremented in device_initialize() is
not decremented when device_add() fails. Add a put_device() call before
returning from the function.
This bug was found by an experimental static analysis tool that I am
developing.
Fixes: 60f6859702 ("i2c: core: Setup i2c_adapter runtime-pm before calling device_add()")
Signed-off-by: Joe Hattori <joe@pf.is.s.u-tokyo.ac.jp>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or malicious modifications.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This is a general i2c controller feature. Some I2C devices may need the
I2C controller to remain active during resume_noirq() or suspend_noirq().
If the controller is autosuspended, there is no way to wake it up once
runtime PM disabled (in suspend_late()). During system resume, the I2C
controller will be available only after runtime PM is re-enabled
(in resume_early()). However, this may be too late for some devices.
Wake up the controller in the suspend() callback while runtime PM is
still enabled. The I2C controller will remain available until the
suspend_noirq() callback (pm_runtime_force_suspend()) is called. During
resume, the I2C controller can be restored by the resume_noirq() callback
(pm_runtime_force_resume()). Finally, the resume() callback re-enables
autosuspend. As a result, the I2C controller can remain available until
the system enters suspend_noirq() and from resume_noirq().
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Link: https://lore.kernel.org/r/20241227084736.1323943-1-carlos.song@nxp.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
There are no more board file users of this driver. The platform data
structure is only used internally. Two of the four fields it stores are
not used at all anymore. Pull the remainder into the driver data struct
and shrink code by removing parts that are now dead code.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/r/20241211102337.37956-1-brgl@bgdev.pl
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Ensure correct handling of "endianness"
for word-sized data in amd756_access
- Convert word data into little-endian using cpu_to_le16
- Convert word data from little-endian
to cpu native format using le16_to_cpu
This fixes poteential issues on big-endian systems and
ensure proper byte ordering for SMBus word transacitions
Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
Link: https://lore.kernel.org/r/20250101103422.30523-1-evepolonium@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
LPI2C support master controller and target controller enabled
simultaneously. Both controllers share the same SDA/SCL lines
and interrupt source but has a separate control and status
registers. When target is enabled and an interrupt has been
triggered, target register status will be checked to determine
IRQ source. Then enter the corresponding interrupt handler
function of master or target to handle the interrupt event.
This patch supports basic target data read/write operations in
7-bit target address. LPI2C target mode can be enabled by using
I2C slave backend. I2C slave backend behaves like a standard I2C
client. For simple use and test, Linux I2C slave EEPROM backend
can be used.
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Link: https://lore.kernel.org/r/20241230033846.2302500-1-carlos.song@nxp.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Avoid repeating the error handling pattern:
geni_se_resources_off(&gi2c->se);
clk_disable_unprepare(gi2c->core_clk);
return;
Introduce a single 'goto' exit label for cleanup in case of
errors. While there are currently two distinct exit points, there
is no overlap in their handling, allowing both branches to
coexist cleanly.
Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Link: https://lore.kernel.org/r/20241227223230.462395-3-andi.shyti@kernel.org
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Add eDMA mode support for LPI2C.
There are some differences between TX DMA mode and RX DMA mode.
LPI2C MTDR register is Controller Transmit Data Register.
When lpi2c send data, it is tx cmd register and tx data fifo.
When lpi2c receive data, it is just a rx cmd register. LPI2C MRDR
register is Controller Receive Data Register, received data are
stored in this.
MTDR[8:10] is CMD field and MTDR[0:7] is DATA filed.
+-----------+-------------------------------+
| C M D | D A T A |
+---+---+---+---+---+---+---+---+---+---+---+
| 10| 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+---+---+---+---+---+---+---+---+---+---+---+
MRDR is Controller Receive Data Register.
MRDR[0:7] is DATA filed.
+-------------------------------+
| D A T A |
+---+---+---+---+---+---+---+---+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+---+---+---+---+---+---+---+---+
When the LPI2C controller needs to send data, tx cmd and 8-bit data
should be written into MTDR:
CMD: 000b: Transmit the value in DATA[7:0].
DATA: 8-bit data.
If lpi2c controller needs to send N 8-bit data, just write N times
(CMD(W) + DATA(u8)) to MTDR.
When the LPI2C controller needs to receive data, rx cmd should be
written into MTDR, the received data will be stored in the MRDR.
MTDR(CMD): 001b: Receive (DATA[7:0] + 1) 8-bit data.
MTDR(DATA): byte counter.
MRDR(DATA): 8-bit data.
So when lpi2c controller needs to receive N 8-bit data,
1. N <= 256:
Write 1 time (CMD(R) + BYTE COUNT(N-1)) into MTDR and receive data from
MRDR.
2. N > 256:
Write N/256 times (CMD(R) + BYTE COUNT(255)) + 1 time (CMD(R) + BYTE
COUNT(N%256)) into MTDR and receive data from MRDR.
Due to these differences, when lpi2c is in DMA TX mode, only enable TX
channel to send data. But when lpi2c is in DMA RX mode, TX and RX channel
are both enabled, TX channel is used to send RX cmd and RX channel is
used to receive data.
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Frank Li <frank.li@nxp.com>
Link: https://lore.kernel.org/r/20241125142909.1613245-1-carlos.song@nxp.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Replace comma between expressions with semicolons.
Using a ',' in place of a ';' can have unintended side effects.
Although that is not the case here, it is seems best to use ';'
unless ',' is intended.
Found by inspection.
No functional change intended.
Compile tested only.
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://lore.kernel.org/r/20241126023839.251922-1-nichen@iscas.ac.cn
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
