Hello All,
I am new to the Linux Kernel programming, and still learning the OS concepts. (but project deadlines don’t consider it u know ;-)
Can anyone explain why do we write driver code like this :
static void s3c24a0_ac97_write(struct ac97_codec *codec, u8 reg, u16 val)
{
down(&CAR_mutex);
init_completion(&CAR_completion);
AC_CODEC_CMD = AC_CMD_ADDR(reg) | AC_CMD_DATA(val);
wait_for_completion(&CAR_completion);
up(&CAR_mutex);
}
why it cant be written as
static void s3c24a0_ac97_write(struct ac97_codec *codec, u8 reg, u16 val)
{
AC_CODEC_CMD = AC_CMD_ADDR(reg) | AC_CMD_DATA(val);
}
what is the meaning of down,up,completion etc.
Shiv Kumar Garg
Senior Software Engineer
System LSI Division
Samsung India Software Operation
3/1 Millers Road, Bangalore
Phone: +91-80-51197777 ext 2018
email: shivg@xxxxxxxxxxx
_________________________________
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