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d2011be1 |
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27-Sep-2022 |
William Breathitt Gray <william.gray@linaro.org> |
counter: Introduce the COUNTER_COMP_ARRAY component type
The COUNTER_COMP_ARRAY Counter component type is introduced to enable
support for Counter array components. With Counter array components,
exposure for buffers on counter devices can be defined via new Counter
array component macros. This should simplify code for driver authors who
would otherwise need to define individual Counter components for each
array element.
Eight Counter array component macros are introduced::
DEFINE_COUNTER_ARRAY_U64(_name, _length)
DEFINE_COUNTER_ARRAY_CAPTURE(_name, _length)
DEFINE_COUNTER_ARRAY_POLARITY(_name, _enums, _length)
COUNTER_COMP_DEVICE_ARRAY_U64(_name, _read, _write, _array)
COUNTER_COMP_COUNT_ARRAY_U64(_name, _read, _write, _array)
COUNTER_COMP_SIGNAL_ARRAY_U64(_name, _read, _write, _array)
COUNTER_COMP_ARRAY_CAPTURE(_read, _write, _array)
COUNTER_COMP_ARRAY_POLARITY(_read, _write, _array)
Eight Counter array callbacks are introduced as well::
int (*signal_array_u32_read)(struct counter_device *counter,
struct counter_signal *signal,
size_t idx, u32 *val);
int (*signal_array_u32_write)(struct counter_device *counter,
struct counter_signal *signal,
size_t idx, u32 val);
int (*device_array_u64_read)(struct counter_device *counter,
size_t idx, u64 *val);
int (*count_array_u64_read)(struct counter_device *counter,
struct counter_count *count,
size_t idx, u64 *val);
int (*signal_array_u64_read)(struct counter_device *counter,
struct counter_signal *signal,
size_t idx, u64 *val);
int (*device_array_u64_write)(struct counter_device *counter,
size_t idx, u64 val);
int (*count_array_u64_write)(struct counter_device *counter,
struct counter_count *count,
size_t idx, u64 val);
int (*signal_array_u64_write)(struct counter_device *counter,
struct counter_signal *signal,
size_t idx, u64 val);
Driver authors can handle reads/writes for an array component by
receiving an element index via the `idx` parameter and processing the
respective value via the `val` parameter.
For example, suppose a driver wants to expose a Count's read-only
capture buffer of four elements using a callback
`foobar_capture_read()`::
DEFINE_COUNTER_ARRAY_CAPTURE(foobar_capture_array, 4);
COUNTER_COMP_ARRAY_CAPTURE(foobar_capture_read, NULL,
foobar_capture_array)
Respective sysfs attributes for each array element would appear for the
respective Count:
* /sys/bus/counter/devices/counterX/countY/capture0
* /sys/bus/counter/devices/counterX/countY/capture1
* /sys/bus/counter/devices/counterX/countY/capture2
* /sys/bus/counter/devices/counterX/countY/capture3
If a user tries to read _capture2_ for example, `idx` will be `2` when
passed to the `foobar_capture_read()` callback, and thus the driver
knows which array element to handle.
Counter arrays for polarity elements can be defined in a similar
manner as u64 elements::
const enum counter_signal_polarity foobar_polarity_states[] = {
COUNTER_SIGNAL_POLARITY_POSITIVE,
COUNTER_SIGNAL_POLARITY_NEGATIVE,
};
DEFINE_COUNTER_ARRAY_POLARITY(foobar_polarity_array,
foobar_polarity_states, 4);
COUNTER_COMP_ARRAY_POLARITY(foobar_polarity_read,
foobar_polarity_write,
foobar_polarity_array)
Tested-by: Julien Panis <jpanis@baylibre.com>
Link: https://lore.kernel.org/r/5310c22520aeae65b1b74952419f49ac4c8e1ec1.1664204990.git.william.gray@linaro.org/
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/a51fd608704bdfc5a0efa503fc5481df34241e0a.1664318353.git.william.gray@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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| #
aaec1a0f |
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26-Aug-2021 |
William Breathitt Gray <vilhelm.gray@gmail.com> |
counter: Internalize sysfs interface code
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>
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