diff mbox series

[v2] doc: document the pwm command

Message ID 20240731084809.30370-1-emil.kronborg@protonmail.com
State Changes Requested, archived
Delegated to: Heinrich Schuchardt
Headers show
Series [v2] doc: document the pwm command | expand

Commit Message

Emil Kronborg July 31, 2024, 8:48 a.m. UTC 
Signed-off-by: Emil Kronborg <emil.kronborg@protonmail.com>
---
Changes in v2:
- Fixed 'pwm enable' appearing twice in the examples section.
- Rebased on top of master.

 doc/usage/cmd/pwm.rst | 80 +++++++++++++++++++++++++++++++++++++++++++
 doc/usage/index.rst   |  1 +
 2 files changed, 81 insertions(+)
 create mode 100644 doc/usage/cmd/pwm.rst


base-commit: 8877bc51a8a4d921ba2f163208b8b1a57ba47c18

Comments

Emil Kronborg Aug. 1, 2024, 9:59 a.m. UTC | #1 
On Thu, Aug 01, 2024 at 11:16 GMT, Quentin Schulz wrote:
> 
>    Did you test this? It doesn't match the synopsis section, the help text
> 
>    of the command and the source code.
> 
>    Reading the code, pwm enable only expects two arguments, same for pwm
>    disable, so I would assume that the following should be used instead:
> 
>    pwm enable 0 0
>    pwm disable 0 0
> 
>    Did we forget to fix the help text and I misread the code maybe?
> 
>    Cheers,
>    Quentin
> 

Hi Quentin,

I did indeed test it, and you are correct that pwm enable and disable
only expect two arguments. The additional two arguments (20000 14000)
were a leftover from copy-pasting that I forgot to delete.

You did not misread anything, but I sent out a v2 patch to address
another issue before I got your email.

I will send a v3 patch, which:

- Changes the help text to be explicit about 20 us and 14 us for the
  period and duty cycle, respectively.
- Fixes pwm enable and disable to only expect 2 arguments.

Thanks again.
diff mbox series

Patch

diff --git a/doc/usage/cmd/pwm.rst b/doc/usage/cmd/pwm.rst
new file mode 100644
index 000000000000..3562e50280e6
--- /dev/null
+++ b/doc/usage/cmd/pwm.rst
@@ -0,0 +1,80 @@ 
+.. SPDX-License-Identifier: GPL-2.0+:
+
+.. index::
+   single: pwm (command)
+
+pwm command
+===========
+
+Synopsis
+--------
+
+::
+
+    pwm invert <pwm_dev_num> <channel> <polarity> - invert polarity
+    pwm config <pwm_dev_num> <channel> <period_ns> <duty_ns> - config PWM
+    pwm enable <pwm_dev_num> <channel> - enable PWM output
+    pwm disable <pwm_dev_num> <channel> - disable PWM output
+
+
+Description
+-----------
+
+The ``pwm`` command is used to access and configure PWM (Pulse Width Modulation)
+signals. For all subcommands, the following arguments are common:
+
+pwm_dev_num
+    device number
+
+channel
+    channel on chosen device
+
+pwm invert
+----------
+
+The signal's active and inactive states are swapped.
+
+pwm config
+----------
+
+Configure the period and duty cycle in nanoseconds.
+
+pwm enable
+----------
+
+Enable output on the configured device and channel.
+
+pwm disable
+-----------
+
+Disable output on the configured device and channel.
+
+Examples
+--------
+
+Configure device 0 channel 0 to 50 kHz period and 70% duty cycle::
+
+    => pwm config 0 0 20000 14000
+
+Enable output on the configured device and channel::
+
+    => pwm enable 0 0 20000 14000
+
+Disable output on the configured device and channel::
+
+    => pwm disable 0 0 20000 14000
+
+Invert the signal on the configured device and channel::
+
+    => pwm invert 0 0 1
+
+Configuration
+-------------
+
+The ``pwm`` command is only available if CONFIG_CMD_PWM=y.
+
+Return value
+------------
+
+If the command succeeds, the return value ``$?`` is set to 0. If an error occurs, the
+return value ``$?`` is set to 1.
diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index 49b354e6ffd2..1adab5283950 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -92,6 +92,7 @@  Shell commands
    cmd/pinmux
    cmd/printenv
    cmd/pstore
+   cmd/pwm
    cmd/qfw
    cmd/read
    cmd/reset