Hi Heinrich,

On 8/2/22 14:28, Heinrich Schuchardt wrote:
Provide a man-page for the gpio command.

Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
---
  doc/usage/cmd/gpio.rst | 90 ++++++++++++++++++++++++++++++++++++++++++
  doc/usage/index.rst    |  1 +
  2 files changed, 91 insertions(+)
  create mode 100644 doc/usage/cmd/gpio.rst

diff --git a/doc/usage/cmd/gpio.rst b/doc/usage/cmd/gpio.rst
new file mode 100644
index 0000000000..f6a5668388
--- /dev/null
+++ b/doc/usage/cmd/gpio.rst
@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+gpio command
+============
+
+Synopsis
+--------
+
+::
+
+    gpio <input|set|clear|toggle> <pin>
+    gpio read <name> <pin>
+    gpio status [-a] [<bank>|<pin>]
+
+The gpio command is used to access General Purpose Inputs/Outputs.
+
+gpio input
+----------
+
+Switch the GPIO *pin* to input mode.
+
+gpio set
+--------
+
+Switch the GPIO *pin* to output mode and set the signal to 1.
+

I think this is supposed to follow the GPIOD_ACTIVE_LOW/GPIOD_ACTIVE_HIGH flag. So I think it's better to say "set the state to active"? Maybe add a few words on this active high/low thing to explicit that using gpio set does not necessarily mean that the GPIO output will have some voltage.

+gpio clear
+----------
+
+Switch the GPIO *pin* to output mode and set the signal to 0.
+

Ditto.

+gpio toggle
+-----------
+
+Switch the GPIO *pin* to output mode and reverse the signal state.
+
+gpio read
+---------
+
+Read the signal state of the GPIO *pin* and save it in environment variable
+*name*.
+
+gpio status
+-----------
+
+Display the status of one or multiple GPIOs. By default only claimed GPIOs
+are displayed.
+
+-a
+    Display GPIOs irrespective of being claimed.
+
+bank
+    Name of a bank of GPIOs to be displayed.
+
+pin
+    Name of a single GPIO to be displayed or manipulated.
+
+Examples
+--------
+
+Switch the status of a GPIO::
+
+    => gpio set a5
+    gpio: pin a5 (gpio 133) value is 1

and I guess we should maybe patch the gpio cmd to say here "high" instead of "1"?

+    => gpio clear a5
+    gpio: pin a5 (gpio 133) value is 0

ditto

+    => gpio toggle a5
+    gpio: pin a5 (gpio 133) value is 1

ditto

+    => gpio read myvar a5
+    gpio: pin a5 (gpio 133) value is 1

ditto

+    => echo $myvar
+    1
+    => gpio toggle a5
+    gpio: pin a5 (gpio 133) value is 0

ditto

+    => gpio read myvar a5
+    gpio: pin a5 (gpio 133) value is 0

ditto

Cheers,
Quentin

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