From: William Breathitt Gray <wbg@kernel.org>
To: Julien Panis <jpanis@baylibre.com>
Cc: william.gray@linaro.org, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
mranostay@ti.com
Subject: Re: [PATCH v9 0/4] ECAP support on TI AM62x SoC
Date: Tue, 27 Sep 2022 17:49:09 -0400 [thread overview]
Message-ID: <YzNv1c1NyUv7xKVT@ishi> (raw)
In-Reply-To: <20220923142437.271328-1-jpanis@baylibre.com>
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On Fri, Sep 23, 2022 at 04:24:33PM +0200, Julien Panis wrote:
> The Enhanced Capture (ECAP) module can be used to timestamp events
> detected on signal input pin. It can be used for time measurements
> of pulse train signals.
>
> ECAP module includes 4 timestamp capture registers. For all 4 sequenced
> timestamp capture events (0->1->2->3->0->...), edge polarity (falling/rising
> edge) can be selected.
>
> This driver leverages counter subsystem to :
> - select edge polarity for all 4 capture events (event mode)
> - log timestamps for each capture event
> Event polarity, and CAP0/1/2/3 timestamps give all the information
> about the input pulse train. Further information can easily be computed :
> period and/or duty cycle if frequency is constant, elapsed time between
> pulses, etc...
>
> This patchset must be applied on top of the following counter subsystem patchset :
> https://lore.kernel.org/all/cover.1663693757.git.william.gray@linaro.org/
>
> Modifications since v8 :
> - Add documentation to private driver structure
> - Add mutex to prevent IO race conditions
> - Stop counter before disabling interrupts in ecap_cnt_capture_disable() function
> - Remove returning of status in ecap_cnt_count_get/set_val() functions
> - Remove unnecessary 'return -EBUSY' in all callbacks
> - Remove unnecessary '.id = 0' in ecap_cnt_counts[]
> - Modify driver info in MAINTAINER file
>
> Userspace commands :
> ### CLOCK SIGNAL ###
> cd /sys/bus/counter/devices/counter0/signal0
>
> # Get frequency
> cat frequency
>
> ### INPUT SIGNAL ###
> cd /sys/bus/counter/devices/counter0/signal1
>
> # Get polarity for each capture event
> cat polarity0
> cat polarity1
> cat polarity2
> cat polarity3
>
> # Set polarity for each capture event
> echo positive > polarity0
> echo negative > polarity1
> echo positive > polarity2
> echo negative > polarity3
>
> ### COUNT ###
> cd /sys/bus/counter/devices/counter0/count0
>
> # Get ceiling (counter max value)
> cat ceiling
>
> # Reset number of overflows & current timebase counter value
> echo 0 > num_overflows
> echo 0 > count
>
> # Run ECAP
> echo 1 > enable
>
> # Get number of overflows & current timebase counter value
> cat num_overflows
> cat count
>
> # Get captured timestamps
> cat capture0
> cat capture1
> cat capture2
> cat capture3
>
> # Note that counter watches can also be used to get
> # data from userspace application
> # -> see tools/counter/counter_example.c
>
> # Pause ECAP
> echo 0 > enable
>
> Julien Panis (4):
> dt-bindings: counter: add ti,am62-ecap-capture.yaml
> Documentation: ABI: sysfs-bus-counter: add frequency & num_overflows
> items
> counter: ti-ecap-capture: capture driver support for ECAP
> MAINTAINERS: add TI ECAP driver info
>
> Documentation/ABI/testing/sysfs-bus-counter | 14 +
> .../counter/ti,am62-ecap-capture.yaml | 61 ++
> MAINTAINERS | 9 +
> drivers/counter/Kconfig | 15 +
> drivers/counter/Makefile | 1 +
> drivers/counter/ti-ecap-capture.c | 614 ++++++++++++++++++
> 6 files changed, 714 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml
> create mode 100644 drivers/counter/ti-ecap-capture.c
>
> --
> 2.37.3
Queued for counter-next with a minor context adjustment for
sysfs-bus-counter changes.
Thanks,
William Breathitt Gray
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prev parent reply other threads:[~2022-09-27 21:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 14:24 [PATCH v9 0/4] ECAP support on TI AM62x SoC Julien Panis
2022-09-23 14:24 ` [PATCH v9 1/4] dt-bindings: counter: add ti,am62-ecap-capture.yaml Julien Panis
2022-09-23 14:24 ` [PATCH v9 2/4] Documentation: ABI: sysfs-bus-counter: add frequency & num_overflows items Julien Panis
2022-09-23 14:24 ` [PATCH v9 3/4] counter: ti-ecap-capture: capture driver support for ECAP Julien Panis
2022-09-23 14:24 ` [PATCH v9 4/4] MAINTAINERS: add TI ECAP driver info Julien Panis
2022-09-23 14:55 ` [PATCH v9 0/4] ECAP support on TI AM62x SoC William Breathitt Gray
2022-09-27 21:49 ` William Breathitt Gray [this message]
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