From f5982261f7f9bfe1a39b8d739a3e6c2693e373ac Mon Sep 17 00:00:00 2001
From: Walter Fetter Lages <w.fetter@ieee.org>
Date: Thu, 31 May 2018 17:14:59 -0300
Subject: [PATCH] Add udev rule to configure /dev/i2c-*.

---
 .gitignore                    |  1 +
 README                        | 18 ++++++++++++++++++
 udev/rules.d/99-i2c-dev.rules |  2 ++
 3 files changed, 21 insertions(+)
 create mode 100644 README
 create mode 100644 udev/rules.d/99-i2c-dev.rules

diff --git a/.gitignore b/.gitignore
index c02f83a..982c590 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@
 # C++
 # Prerequisites
 *.d
+!udev/rules.d
 
 # Compiled Object files
 *.slo
diff --git a/README b/README
new file mode 100644
index 0000000..d6a3902
--- /dev/null
+++ b/README
@@ -0,0 +1,18 @@
+The user should have read and write access to /dev/i2c-0 (or the
+corresponding device if there is more than on I2C bus).
+
+The recomended way to grand the required premissions is to incude the user
+in the i2c group:
+
+groupadd -r i2c
+groupmems -g i2c -a <login>
+
+and set the /dev/i2c-0 read and write permissions to this group by
+installing the file 99-i2c-dev.rules in the /etc/udev/rules.d directory and
+reloading the udev rules and the i2c-dev module with the commands:
+
+udvadm control -R
+rmmod i2c-dev
+modprobe i2c-dev
+
+
diff --git a/udev/rules.d/99-i2c-dev.rules b/udev/rules.d/99-i2c-dev.rules
new file mode 100644
index 0000000..b854019
--- /dev/null
+++ b/udev/rules.d/99-i2c-dev.rules
@@ -0,0 +1,2 @@
+KERNEL=="i2c-[0-9]*", GROUP="i2c", MODE="0660"
+
-- 
2.12.0