From: Julien Panis <jpanis@baylibre.com>
To: william.gray@linaro.org, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, mranostay@ti.com,
Julien Panis <jpanis@baylibre.com>
Subject: [PATCH v5 0/3] ECAP support on TI AM62x SoC
Date: Wed, 17 Aug 2022 16:16:17 +0200 [thread overview]
Message-ID: <20220817141620.256481-1-jpanis@baylibre.com> (raw)
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 (1->2->3->4->1->...), 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 CAP1/2/3/4 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...
Modifications since v4:
- Modify yaml commit message prefix (dt-bindings)
- Modify driver file name & Makefile (ti-ecap-capture)
- Modify compilation flag name in Kconfig (TI_ECAP_CAPTURE)
- Select REGMAP_MMIO in Kconfig
- Add capture items to sysfs-bus-counter ABI documentation
- Cleanup probe function (dev_err_probe & devm_clk_get_enabled & devm_add_action_or_reset for PM)
- Enable/Disable device clock in suspend/resume functions
- Add PM explanations
- Add ECAP clock signal & 'frequency' sysfs entry
- Replace elapsed_time & spinlock by nb_ovf (atomic_t) & 'count_cumul' sysfs entry
- Add counter overflow event
- Modify 'name' sysfs entry for signal0 & signal1 & count0
- Modify watch_validate function
- Add macros for callbacks related to cap1/2/3/4
Userspace commands :
### SIGNAL INPUT ###
cd /sys/bus/counter/devices/counter0/signal0
# Get available polarities for each capture event
cat polarity1_available
cat polarity2_available
cat polarity3_available
cat polarity4_available
# Get polarity for each capture event
cat polarity1
cat polarity2
cat polarity3
cat polarity4
# Set polarity for each capture event
echo rising edge > polarity1
echo falling edge > polarity2
echo rising edge > polarity3
echo falling edge > polarity4
### SIGNAL CLOCK ###
cd /sys/bus/counter/devices/counter0/signal1
# Get clock rate
cat frequency
### COUNT ###
cd /sys/bus/counter/devices/counter0/count0
# Run ECAP
echo 1 > enable
# Get current timebase counter value
cat count
# Get cumulated counter value
cat count_cumul
# Get captured timestamps
cat capture1
cat capture2
cat capture3
cat capture4
# Note that counter watches can also be used to get
# data from userspace application
# -> see tools/counter/counter_example.c
# Stop ECAP
echo 0 > enable
Julien Panis (3):
dt-bindings: counter: add ti,am62-ecap-capture.yaml
Documentation: ABI: sysfs-bus-counter: add capture items
counter: ti-ecap-capture: capture driver support for ECAP
Documentation/ABI/testing/sysfs-bus-counter | 49 ++
.../counter/ti,am62-ecap-capture.yaml | 61 ++
drivers/counter/Kconfig | 15 +
drivers/counter/Makefile | 1 +
drivers/counter/ti-ecap-capture.c | 624 ++++++++++++++++++
include/uapi/linux/counter.h | 2 +
6 files changed, 752 insertions(+)
create mode 100644 Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml
create mode 100644 drivers/counter/ti-ecap-capture.c
--
2.25.1
next reply other threads:[~2022-08-17 14:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-17 14:16 Julien Panis [this message]
2022-08-17 14:16 ` [PATCH v5 1/3] dt-bindings: counter: add ti,am62-ecap-capture.yaml Julien Panis
2022-08-17 14:16 ` [PATCH v5 2/3] Documentation: ABI: sysfs-bus-counter: add capture items Julien Panis
2022-08-21 22:43 ` William Breathitt Gray
2022-08-17 14:16 ` [PATCH v5 3/3] counter: ti-ecap-capture: capture driver support for ECAP Julien Panis
2022-08-22 1:16 ` William Breathitt Gray
2022-08-20 22:00 ` [PATCH v5 0/3] ECAP support on TI AM62x SoC William Breathitt Gray
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