From 4d6857993ea9f39ff4113809fd7b2272ff83647f Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Sun, 30 Jul 2023 16:08:45 +0200 Subject: Finish the Framework EC page --- src/srp/fw-ec/index.html | 155 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 155 insertions(+) (limited to 'src/srp/fw-ec/index.html') diff --git a/src/srp/fw-ec/index.html b/src/srp/fw-ec/index.html index d8a48ba..cdfc8b5 100644 --- a/src/srp/fw-ec/index.html +++ b/src/srp/fw-ec/index.html @@ -87,6 +87,161 @@ tuples which is awesome, because it opens the door to custom RGB effects in the future!

+ +

There’s More Than One LED!?

+ +

+ That’s right! The Framework laptop I own (13″; the 16″ releases + soon though!) has 3 more LED lights. + One on the left of the chassis, one on right of the chassis, and + one on the capslock key. The capslock + LED acts as an indicator of whether or + not you’ve got capslock enabled. This is useless to me though, + because my custom keyboard layout doesn’t even support capslock + (see the next section) — so I patched it to be a function-lock + indicator instead! +

+ +

+ Here’s the diff — but do take care if you want to apply similar + patches to your laptop! The files I’m editing are under + board/hx20 since I’m on an 11th Gen Intel + CPU. If you have a different + CPU, you will probably need to fuck with + different code: +

+ +
+
+ ~/board/hx20/board.h +
+ 
m4_include(fn-lock-1.diff.html)
+
+ +
+
+ ~/board/hx20/keyboard-customization.c +
+ 
m4_include(fn-lock-2.diff.html)
+
+ +

+ As you can see, toggling the capslock + LED is as simple as + invoking gpio_set_level(). Not only that, but + disabling its functionality with the capslock key is as easy as + undefining the CONFIG_CAPSLOCK_SUPPORT macro. + Figuring out if the function key is locked is also really easy. + The Fn_key global variable is a bit-field containing + information pertaining to the function key, and we also + conveniently already have the FN_LOCKED constant + defined that we can bitwise-AND with Fn_key to check + the locked state! +

+ +

+ We also setup some hooks with the DECLARE_HOOK() + macro. These just ensure that we are behaving properly on system + resume and -suspend. +

+ +

The Hybrid Key

+ +

+ Wouldn’t it be cool if a physical key could represent two keys at + the same time? I thought so too. Like all Emacs users, I suffer + from a distinct lack of easily-accessible modifier keys. I need + escape because I use Vim bindings; I need left-control because + all the Emacs bindings use it; I need super for my + window-managers’ bindings; I need left-alt so I can type + characters that don’t come on a standard American keyboard (such + as ß, €, and é), and now I have a + problem. All my modifiers are taken, but Emacs still needs a + meta key to work! +

+
+
+ Workflow by Randall Munroe +
+ XKCD Comic 1172 +
+ +

+ What will I ever do!? Well thanks to Framework making + the EC open-source, and conveniently + giving me a file called keyboard_customization.c, + I’m going to take two keys and stick them in one! The basic + premise is this: the capslock key is arguably the easiest + modifier key to hit, and it’s currently bound to the escape key + on my system. This is inefficient though, because nobody makes + key-bindings that chord the escape-key with another key; chords + are always done with a modifier like control, and Emacs is no + different. So my plan was to make it so that the capslock key + when used on its own mimics an escape-key, while instead + mimicking the left-control-key when used in a chord with another + key. +

+ +

+ It took me a little longer this time to figure out how to + implement what I wanted since the code isn’t as clear, but it was + still a surprisingly easy feature to patch into the + EC! I basically just updated the + scancode table, swapping out the capslock scancode for my own + random one that I called SCANCODE_CTRL_ESC. I then + created a new function called try_ctrl_esc() which + is called in the on-keyup and -down callback function. The + try_ctrl_esc() function handles all of the logic as + you can see in the following diff; it’s basically just a state + machine: +

+ + + +
+
~/board/hx20/keyboard_customization.c
+ 
m4_include(hybrid.diff.html)
+
+ +

+ One thing that’s good to take note of is what I return from + try_ctrl_esc(). The general pattern for handling a + keyup or -down event is to stick the following code into + keyboard_scancode_callback(): +

+ +
+
+ keyboard_scancode_callback() in + ~/board/hx20/keyboard_customization.c +
+ 
m4_include(kbd-sc-cb.c.html)
+
+ +

+ In my_handler_function() (or whatever you decide to + name it), you attempt to handle the event. If you don’t want to + handle a particular event and instead want to pass it on to the + next handler, you need to return EC_SUCCESS. If you + managed to successfully handle the event though, then you need to + return an error such as EC_ERROR_UNIMPLEMENTED. + It’s pretty stupid and makes very little sense from a naming + perspective, but oh well… +

+ +

What’s Next?

+ +

+ RGB + LEDs + maybe. +

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