On Tue, May 11, 2010 at 11:07:38AM +0800, Zhang JieJing wrote:
2010/5/10 Mark Brown broonie@opensource.wolfsonmicro.com
Hi, Our kernel version is 2.6.28, but port the wm8993 driver to this version's kernel.
Normally in these situations I would recommend backporting the entire ASoC subsystem - it's fairly well isolated from the rest of the kernel so this tends to be reasonably straightforward.
the amplifying pop is when system resume, the speaker will hear one short pop noise, also, this short pop noise will hear the first time driver is opened.
When exactly do you hear this noise? The WM8993 driver will not power up the speaker outputs unless they are in use and there are no audio paths configured to the speakers by default. Are you configuring an audio path in the CODEC at system startup? Which mode do you have the WM8993 speaker drivers in - class D or class A/B?
It might be helpful to capture all the register writes done when bringing up the WM8993. Also, if you are configuring an audio path from an analogue input you should check that there is no DC offset present in the input signal - if there is one then the WM8993 will reproduce it into the output path, which would result in an audible noise.
In 53242c68333570631a15a69842851b458eca3d99, there was a line:
ret = wm8993_set_fll(codec->dai, 0, wm8993->fll_src,fll_fref, fll_fout);
but in lastest version of wm8993 driver, wm8993_set_fll will do nothing we the second parameter(fll_id) is 0, so, I don't know what this function want to do, Cound you give me some idea ?
This parameter specifies which of the FLLs/PLLs in the device to configure. Since the WM8993 has only one FLL it just ignores this parameter, other devices with multiple FLLs such as the WM8994 need this to select between the FLLs.