最近の Raspberry Pi で I2C を有効化

Raspberry Pi で I2C を有効化する方法を紹介します．

はじめに
設定手順
参考文献

はじめに

2014年までの Raspbian では，/etc/modprobe.d/raspi-blacklist.conf を使って I2C の有効/無効を切り替えるようになっていました．

しかし，2015-01-31 リリースからは，より汎用的な Device Tree という仕組みが導入されたのに伴い，I2C のペリフェラル機能の有効化方法が変わりました．

なお，この方法は Raspberry Pi2 でも有効です．

設定手順

以降では，Device Tree を使う Raspberry Pi 環境で I2C を有効化する方法を，次の 3 パターン紹介します．

raspi-config を使う方法
手動で行う方法
Fabric を使ってリモートから自動的に行う方法

raspi-config を使う方法

raspi-config を root で実行します．

$ sudo raspi-config

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$ sudo raspi-config
「8 Advanced Options」を選択．
「A7 I2C」を選択．
「はい」を選択．
「はい」を選択．
再起動．

$ sudo reboot

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$ sudo reboot

手動で行う方法

「/boot/config.txt」の末尾に以下を追加．

dtparam=i2c_arm=on

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dtparam=i2c_arm=on
「/etc/modules」の末尾に以下を追加．

i2c-dev

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i2c-dev
再起動．

$ sudo reboot

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$ sudo reboot

Fabric で自動的に行う方法

次のエントリーで紹介した Fabric のレシピを使う方法について紹介します．

Fabric とCuisine による Raspberry Pi の自動セットアップ
https://rabbit-note.com/2014/12/31/fabric-cuisine-raspberry-pi-automated-setup/

以下の内容を fabfile.py というファイルに保存し，fab -H pi@raspberrypi setup を実行すれば OK です．

# -*- coding: utf-8 -*-

import imp
import os

from fabric.api import run, sudo, settings
from fabric.decorators import task
from fabric.context_managers import hide
from fabric.utils import puts

import fabric.colors
import cuisine

@task
def setup():
    with settings(
        # hide('warnings', 'stdout', 'stderr')
    ):
        # raspi-config の自動起動を無効化
        if cuisine.file_exists('/etc/profile.d/raspi-config.sh'):
            # NOTE: sudo() だと，raspi-config が起動してしまうので run()
            run('sudo rm -f /etc/profile.d/raspi-config.sh')

        if os.environ.has_key('RASP_HOSTNAME'):
            setup_hostname(os.environ['RASP_HOSTNAME'])

        setup_locale()
        setup_ssh()
        setup_package()
        setup_i2c()
        setup_wlan()

        # rootfs サイズを拡張
        sudo('raspi-config --expand-rootfs')

        # 再起動
        sudo('reboot')


# タイムゾーンとロケールの設定        
def setup_locale():
    puts(fabric.colors.green('[Setting Locale]', True))
    sudo('echo "Asia/Tokyo" > /etc/timezone')
    sudo('dpkg-reconfigure -f noninteractive tzdata')
    sudo('sed -i -e \'s/^en_GB.UTF-8 UTF-8/# en_GB.UTF-8 UTF-8/\' /etc/locale.gen')
    sudo('sed -i -e \'s/^# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/\' /etc/locale.gen')
    sudo('sed -i -e \'s/^# ja_JP.UTF-8 UTF-8/ja_JP.UTF-8 UTF-8/\' /etc/locale.gen')
    sudo('dpkg-reconfigure --frontend=noninteractive locales')

# タイムゾーンとロケールの設定        
def setup_hostname(hostname):
    puts(fabric.colors.green('[Setting Hostname]', True))
    sudo('sed -i -e \'s/^.*/%s/\' /etc/hostname' % (hostname))
    sudo('sed -i -e \'s/^127.0.1.1\t.*/127.0.1.1\t%s/\' /etc/hosts' % (hostname))

# 公開鍵のコピー
def setup_ssh():
    puts(fabric.colors.green('[Install SSH Publickey]', True))

    with cuisine.mode_sudo():
        cuisine.ssh_authorize("pi", cuisine.file_local_read('~/.ssh/id_rsa.pub'))

# パッケージのインストール
def setup_package():
    puts(fabric.colors.green('[Install Packages]', True))

    with cuisine.mode_sudo():
        cuisine.package_update()
        cuisine.package_upgrade()
        cuisine.package_ensure([
                'gcc',
                'make',
                'automake',
                'emacs23-nox',
                'tmux',
                'ruby',
                'git',
                'zsh',
                'i2c-tools',
                'lsb-release',
                'mlocate',
                ])

# I2C の有効化
def setup_i2c():
    if cuisine.file_exists('/etc/modprobe.d/raspi-blacklist.conf'):
        sudo('sed -i -e \'s/^blacklist i2c-bcm2708/# blacklist i2c-bcm2708/g\' ' +
             '/etc/modprobe.d/raspi-blacklist.conf')
    else:
        # RASPBIAN Release 2015-01-31 or later
        boot_conf = cuisine.text_ensure_line(
            cuisine.file_read('/boot/config.txt'),
            'dtparam=i2c_arm=on'
            )
        cuisine.file_write(
            location = '/boot/config.txt',
            content  = boot_conf,
            mode='755',
            sudo=True
            )
        modules_conf = cuisine.text_ensure_line(
            cuisine.file_read('/etc/modules'),
            'i2c-dev'
            )
        cuisine.file_write(
            location = '/etc/modules',
            content  = modules_conf,
            mode='644',
            sudo=True
            )

# WiFi の有効化
def setup_wlan():
    if not cuisine.file_exists('/sys/class/net/wlan0'):
        return

    puts(fabric.colors.green('[Setting Wireless LAN]', True))
    wifi_config = None
    try:
        (file, pathname, description) = imp.find_module('wifi_config', ['.'])
        wifi_config = imp.load_module("wifi_config", file, pathname, description)
    except ImportError:
        puts(fabric.colors.red('SKIP WiFi Configuration. (FAILED to load wifi_config.py)', True))
        return 

    cuisine.file_write(
        location = '/etc/wpa_supplicant/wpa_supplicant.conf',
        content  = 'ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev\n'
                 + 'update_config=1\n'
                 + 'network={\n'
                 + ('    ssid=\"%s\"\n' % (wifi_config.WIFI_SSID))
                 + ('    psk=%s\n' % (wifi_config.WIFI_PSK))
                 + '    key_mgmt=WPA-PSK\n'
                 + '    proto=WPA2\n'
                 + '    pairwise=CCMP\n'
                 + '    group=CCMP\n'
                 + '}\n',
        mode='600',
        sudo=True
        )

    sudo('sed -i -e \'s/^wpa-roam \/etc\/wpa_supplicant\/wpa_supplicant.conf/'
         + 'wpa-conf \/etc\/wpa_supplicant\/wpa_supplicant.conf/\' /etc/network/interfaces') 
    sudo('sed -i -e \'s/^iface wlan0 inet manual/iface wlan0 inet dhcp/\' /etc/network/interfaces')

    # NOTE: Wifi の場合は「ホスト名-wifi」でアクセスできるようにする
    dhclient_conf = cuisine.text_ensure_line(
        cuisine.file_read('/etc/dhcp/dhclient.conf'),
        'interface "wlan0" { send host-name = concat (gethostname(), "-wifi"); }'
        )

    cuisine.file_write(
        location = '/etc/dhcp/dhclient.conf',
        content  = dhclient_conf,
        mode='644',
        sudo=True
        )

# Local Variables:
# coding: utf-8-unix
# mode: python
# c-basic-offset: 4
# tab-width: 4
# indent-tabs-mode: nil
# End:

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# -*- coding: utf-8 -*-

import imp

import os

from fabric.api import run, sudo, settings

from fabric.decorators import task

from fabric.context_managers import hide

from fabric.utils import puts

import fabric.colors

import cuisine

@task

def setup():

with settings(

# hide('warnings', 'stdout', 'stderr')

# raspi-config の自動起動を無効化

if cuisine.file_exists('/etc/profile.d/raspi-config.sh'):

# NOTE: sudo() だと，raspi-config が起動してしまうので run()

run('sudo rm -f /etc/profile.d/raspi-config.sh')

if os.environ.has_key('RASP_HOSTNAME'):

setup_hostname(os.environ['RASP_HOSTNAME'])

setup_locale()

setup_ssh()

setup_package()

setup_i2c()

setup_wlan()

# rootfs サイズを拡張

sudo('raspi-config --expand-rootfs')

# 再起動

sudo('reboot')

# タイムゾーンとロケールの設定

def setup_locale():

puts(fabric.colors.green('[Setting Locale]', True))

sudo('echo "Asia/Tokyo" > /etc/timezone')

sudo('dpkg-reconfigure -f noninteractive tzdata')

sudo('sed -i -e \'s/^en_GB.UTF-8 UTF-8/# en_GB.UTF-8 UTF-8/\' /etc/locale.gen')

sudo('sed -i -e \'s/^# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/\' /etc/locale.gen')

sudo('sed -i -e \'s/^# ja_JP.UTF-8 UTF-8/ja_JP.UTF-8 UTF-8/\' /etc/locale.gen')

sudo('dpkg-reconfigure --frontend=noninteractive locales')

# タイムゾーンとロケールの設定

def setup_hostname(hostname):

puts(fabric.colors.green('[Setting Hostname]', True))

sudo('sed -i -e \'s/^.*/%s/\' /etc/hostname' % (hostname))

sudo('sed -i -e \'s/^127.0.1.1\t.*/127.0.1.1\t%s/\' /etc/hosts' % (hostname))

# 公開鍵のコピー

def setup_ssh():

puts(fabric.colors.green('[Install SSH Publickey]', True))

with cuisine.mode_sudo():

cuisine.ssh_authorize("pi", cuisine.file_local_read('~/.ssh/id_rsa.pub'))

# パッケージのインストール

def setup_package():

puts(fabric.colors.green('[Install Packages]', True))

with cuisine.mode_sudo():

cuisine.package_update()

cuisine.package_upgrade()

cuisine.package_ensure([

'gcc',

'make',

'automake',

'emacs23-nox',

'tmux',

'ruby',

'git',

'zsh',

'i2c-tools',

'lsb-release',

'mlocate',

])

# I2C の有効化

def setup_i2c():

if cuisine.file_exists('/etc/modprobe.d/raspi-blacklist.conf'):

sudo('sed -i -e \'s/^blacklist i2c-bcm2708/# blacklist i2c-bcm2708/g\' ' +

'/etc/modprobe.d/raspi-blacklist.conf')

else:

# RASPBIAN Release 2015-01-31 or later

boot_conf = cuisine.text_ensure_line(

cuisine.file_read('/boot/config.txt'),

'dtparam=i2c_arm=on'

)

cuisine.file_write(

location = '/boot/config.txt',

content = boot_conf,

mode='755',

sudo=True

)

modules_conf = cuisine.text_ensure_line(

cuisine.file_read('/etc/modules'),

'i2c-dev'

)

cuisine.file_write(

location = '/etc/modules',

content = modules_conf,

mode='644',

sudo=True

)

# WiFi の有効化

def setup_wlan():

if not cuisine.file_exists('/sys/class/net/wlan0'):

return

puts(fabric.colors.green('[Setting Wireless LAN]', True))

wifi_config = None

try:

(file, pathname, description) = imp.find_module('wifi_config', ['.'])

wifi_config = imp.load_module("wifi_config", file, pathname, description)

except ImportError:

puts(fabric.colors.red('SKIP WiFi Configuration. (FAILED to load wifi_config.py)', True))

return

cuisine.file_write(

location = '/etc/wpa_supplicant/wpa_supplicant.conf',

content = 'ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev\n'

+ 'update_config=1\n'

+ 'network={\n'

+ (' ssid=\"%s\"\n' % (wifi_config.WIFI_SSID))

+ (' psk=%s\n' % (wifi_config.WIFI_PSK))

+ ' key_mgmt=WPA-PSK\n'

+ ' proto=WPA2\n'

+ ' pairwise=CCMP\n'

+ ' group=CCMP\n'

+ '}\n',

mode='600',

sudo=True

)

sudo('sed -i -e \'s/^wpa-roam \/etc\/wpa_supplicant\/wpa_supplicant.conf/'

+ 'wpa-conf \/etc\/wpa_supplicant\/wpa_supplicant.conf/\' /etc/network/interfaces')

sudo('sed -i -e \'s/^iface wlan0 inet manual/iface wlan0 inet dhcp/\' /etc/network/interfaces')

# NOTE: Wifi の場合は「ホスト名-wifi」でアクセスできるようにする

dhclient_conf = cuisine.text_ensure_line(

cuisine.file_read('/etc/dhcp/dhclient.conf'),

'interface "wlan0" { send host-name = concat (gethostname(), "-wifi"); }'

)

cuisine.file_write(

location = '/etc/dhcp/dhclient.conf',

content = dhclient_conf,

mode='644',

sudo=True

)

# Local Variables:

# coding: utf-8-unix

# mode: python

# c-basic-offset: 4

# tab-width: 4

# indent-tabs-mode: nil

# End:

参考文献

DEVICE TREES, OVERLAYS AND PARAMETERS: Raspberry Pi における Device Tree の設定方法について詳細に解説されています．