Mark, I got it. Once we set those volume update bits in wm8990_init(), those bits in the wm8985 register cache array, wm8985_reg[], will then be set too. So, whenever we write a new value to a volume register, wm8985_write() will then write the new value to the volume register and update the corresponding volume update bit also. This is the trick. A Great Idea! Thank you so much! Chitat On Mon, May 25, 2009 at 08:47:31PM +0800, Leung Chi Tat wrote: > I'm right now studying the driver code for wm8980 codec (from the main > trunk of linux-2.6-asoc) as it seems to be more close to wm8985. I > can't find any code for triggering those volume update bits after > modified those volume registers. But, the wm8980 datasheet states > that we have to do so to make those volume updates properly. Is there > some black magic in the code? The normal approach for volume update bits is to set them when initialising the CODEC at startup - this is what the wm8990 driver is doing when it writes to the volume registers in wm8990_init(). This means that any further register writes which only change the volume field in the registers will also have the volume update bit set. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
