This is a reimplementation of the Generic Counter driver interface.
There are no modifications to the Counter subsystem userspace interface,
so existing userspace applications should continue to run seamlessly.
The purpose of this patch is to internalize the sysfs interface code
among the various counter drivers into a shared module. Counter drivers
pass and take data natively (i.e. u8, u64, etc.) and the shared counter
module handles the translation between the sysfs interface and the
device drivers. This guarantees a standard userspace interface for all
counter drivers, and helps generalize the Generic Counter driver ABI in
order to support the Generic Counter chrdev interface (introduced in a
subsequent patch) without significant changes to the existing counter
drivers.
Note, Counter device registration is the same as before: drivers
populate a struct counter_device with components and callbacks, then
pass the structure to the devm_counter_register function. However,
what's different now is how the Counter subsystem code handles this
registration internally.
Whereas before callbacks would interact directly with sysfs data, this
interaction is now abstracted and instead callbacks interact with native
C data types. The counter_comp structure forms the basis for Counter
extensions.
The counter-sysfs.c file contains the code to parse through the
counter_device structure and register the requested components and
extensions. Attributes are created and populated based on type, with
respective translation functions to handle the mapping between sysfs and
the counter driver callbacks.
The translation performed for each attribute is straightforward: the
attribute type and data is parsed from the counter_attribute structure,
the respective counter driver read/write callback is called, and sysfs
I/O is handled before or after the driver read/write function is called.
Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> # for stm32
Link: https://lore.kernel.org/r/c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Currently, the STM32 LP Timer counter driver registers into both IIO and
counter subsystems, which is redundant.
Remove the IIO counter ABI and IIO registration from the STM32 LP Timer
counter driver since it's been superseded by the Counter subsystem
as discussed in [1].
Keep only the counter subsystem related part.
Move a part of the ABI documentation into a driver comment.
This also removes a duplicate ABI warning
$ scripts/get_abi.pl validate
...
/sys/bus/iio/devices/iio:deviceX/in_count0_preset is defined 2 times:
./Documentation/ABI/testing/sysfs-bus-iio-timer-stm32:100
./Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32:0
[1] https://lkml.org/lkml/2021/1/19/347
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/1611926542-2490-1-git-send-email-fabrice.gasnier@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This patch applies the semantic patch:
@@
expression I, P, SP;
@@
I = devm_iio_device_alloc(P, SP);
...
- I->dev.parent = P;
It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'
But this is is only done in case where the block is left empty.
The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.
However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
The count_read and count_write callbacks are simplified to pass val as
unsigned long rather than as an opaque data structure. The opaque
counter_count_read_value and counter_count_write_value structures,
counter_count_value_type enum, and relevant counter_count_read_value_set
and counter_count_write_value_get functions, are removed as they are no
longer used.
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
