fix --pins usage and filtering of boards in same pins file

[linux-gpio-pinout] / README.md

diff --git a/README.md b/README.md
index 6d6a29f..fe50d98 100644 (file)
--- a/README.md
+++ b/README.md
@@ -2,4 +2,33 @@
 
 lookup kernel's view of pinouts on different boards (useful for device tree and gpio debugging)
 
+
+It supports simple one or two row pin headers with 2.54mm pin spacing which are specified in
+simple text form at end of file based on model derived from device tree.
+
+This tool also creates svg pinouts which you can print out with correct 2.54mm spacing and put
+on your board to make wiring easier.
+
+
+For device tree information, best source right now is this presentation:
 https://elinux.org/images/d/dc/Elce_2017_dt_bof.pdf
+
+
+device-tree/ directory contains examples
+
+to use device trees, do something like:
+
+       vi device-tree/gpio-leds.dts
+       armbian-add-overlay device-tree/gpio-led.dts
+       dmesg -w &
+       ./overlay-load.sh /boot/overlay-user/gpio-led.dtbo
+
+
+To load kernel module for i2c sensors without writing device tree
+echo module_name address into i2c bus:
+
+echo lm75 0x49 > /sys/bus/i2c/devices/i2c-1/new_device
+
+
+
+i2c-usersapce/ contains random i2c userspace device drivers