Better Styled: http://blog.modest-destiny.com/posts/linux-device-tree-pinctrl-tutorial/

When porting drivers on a specific board for a comparatively new linux kernel, it is common to edit the linux device tree files to put together all the device configurations with register values, working modes and pin control offsets set to expected values.

Here in this post we focus on the exact steps one needs to find the correct pin control offset for specific devices. Here we'd take TI's AM4379 (AM437x) chip as an example for this tutorial.

link: http://modest-destiny.net/wp/?p=77

GCC Build With Strange Errors

I have been fighting with these strange errors for some days, and finally I got it.

Problem

The core problem is that my C_INCLUDE_PATH and CPLUS_INCLUDE_PATHends with a colon. Path ending with a colon will include current path, aka./ which caused the error.

Solution

We need to remove the trailing colon, so I write a bash function for it.

# usage: removeTrailingColon str
# example:
#    C_INCLUDE_PATH=$(removeTrailingColon $C_INCLUDE_PATH)
removeTrailingColon() {
    if [[ $1 == *: ]]
    then
        local strColonRemoved=$1;
        local strColonRemoved=${strColonRemoved:0:(-1)};
        echo $strColonRemoved;
    else
        echo $1
    fi
}

Usage is like this:

export C_INCLUDE_PATH=$(removeTrailingColon $C_INCLUDE_PATH)
export CPLUS_INCLUDE_PATH=$(removeTrailingColon $CPLUS_INCLUDE_PATH)
export LD_LIBRARY_PATH=$(removeTrailingColon $LD_LIBRARY_PATH)
export LIBRARY_PATH=$(removeTrailingColon $LIBRARY_PATH)

Elaborate on problem

I’ll list the error I encountered building gcc-4.7.3, so that people will be able to access it through a search engine:

In file included from ../.././gcc/c-lang.c:24:
../.././gcc/system.h:499: error: conflicting types for ‘strsignal’
/usr/include/string.h:566: note: previous declaration of ‘strsignal’ was here
In file included from ./tm.h:19,
                 from ../.././gcc/c-lang.c:26:
./options.h:3750:2: error: #error too many masks for ix86_isa_flags
In file included from ../.././gcc/input.h:25,
                 from ../.././gcc/tree.h:27,
                 from ../.././gcc/c-lang.c:27:
../.././gcc/../libcpp/include/line-map.h:208: error: ‘CHAR_BIT’ undeclared here (not in a function)
../.././gcc/../libcpp/include/line-map.h:208: error: bit-field ‘reason’ width not an integer constant
../.././gcc/../libcpp/include/line-map.h:208: warning: ‘reason’ is narrower than values of its type
In file included from ../.././gcc/tree.h:32,
                 from ../.././gcc/c-lang.c:27:
../.././gcc/real.h:87:5: error: division by zero in #if
../.././gcc/real.h:87:5: error: division by zero in #if
../.././gcc/real.h:90:6: error: division by zero in #if
../.././gcc/real.h:90:6: error: division by zero in #if
../.././gcc/real.h:93:7: error: division by zero in #if
../.././gcc/real.h:93:7: error: division by zero in #if
../.././gcc/real.h:96:8: error: division by zero in #if
../.././gcc/real.h:96:8: error: division by zero in #if
../.././gcc/real.h:99:9: error: division by zero in #if
../.././gcc/real.h:99:9: error: division by zero in #if
../.././gcc/real.h:102:10: error: division by zero in #if
../.././gcc/real.h:102:10: error: division by zero in #if
../.././gcc/real.h:105:9: error: #error "REAL_WIDTH > 6 not supported"
In file included from ../.././gcc/c-family/c-common.h:26,
                 from ../.././gcc/c-tree.h:25,
                 from ../.././gcc/c-lang.c:28:
../.././gcc/../libcpp/include/cpplib.h:225: error: bit-field ‘type’ width not an integer constant
../.././gcc/../libcpp/include/cpplib.h:225: warning: ‘type’ is narrower than values of its type
In file included from ../.././gcc/c-family/c-common.h:26,
                 from ../.././gcc/c-tree.h:25,
                 from ../.././gcc/c-lang.c:28:
../.././gcc/../libcpp/include/cpplib.h:267:3: error: #error "Cannot find a least-32-bit signed integer type"
../.././gcc/../libcpp/include/cpplib.h:269: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘cppchar_t’
../.././gcc/../libcpp/include/cpplib.h:270: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘cppchar_signed_t’
../.././gcc/../libcpp/include/cpplib.h:768: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘cpp_interpret_charconst’
../.././gcc/../libcpp/include/cpplib.h:779: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘cpp_host_to_exec_charset’
../.././gcc/../libcpp/include/cpplib.h:954: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘cpp_parse_escape’
make[2]: *** [c-lang.o] Error 1

Add Apache2 Perl Support in Ubuntu 12.04

• sudo apt-get install libapache2-mod-perl2 (if Ubuntu Server use aptitude install)
• ( if the perl-mod is not enabled, you may use: sudo a2enmod perl )
• mkdir ~/www/cgi-bin (it could be anywhere, just take it as an example)
• Add the following code to /etc/apache2/sites-enabled/000-default file before </VirtualHost> line.

# Use 'ModPerl' module to process '.pl' and '.cgi' file
<Files ~ "\.(pl|cgi)$">
    SetHandler perl-script
    PerlResponseHandler ModPerl::PerlRun
    Options +ExecCGI
    PerlSendHeader On
</Files>

# Use '/home/www/cgi-bin/' as a CGI Directory
ScriptAlias /cgi-bin/ /home/www/cgi-bin/
<Directory "/home/www/cgi-bin/">
    Options ExecCGI
    AddHandler cgi-script cgi pl
</Directory>

• Restart the apache2 service: sudo service apache2 restart
• Test the perl environment:

• Create file test.pl in /home/www/cgi-bin/:

#!/usr/bin/perl -w
print "Content-type: text/html\r\n\r\n";
print "Hello there!<br />\nJust testing .<br />\n";

for ($i=0; $i<10; $i++)
{
print $i."<br />";
}

• Note 1: #!/usr/bin/perl -w is used to locate the perl parser which could be located by which perl.
• Note 2: code print "Content-type: text/html\r\n\r\n"; is required to make it a valid CGI program.

如果你在zsh中鍵入的命令中有誤，它會提示你是否要correct。

比如：

如果你在zsh中鍵入ks，它會提示你是否要換成ls，如下：

% ks
zsh: correct ‘ks’ to ‘ls’ [nyae]?

如果你覺得特別麻煩，你可以整體禁用所有的autocorrect。

在~/.zshrc中添加如下代碼：

unsetopt correct_all

注：更新版的ZSH，使用的option是這樣的

unsetopt correct

即可達到你的要求。

如果你只是想某些情況下不使用autocorrect，那麼你可以試試使用alias，比如：

alias vim = 'nocorrect vim '