Re: [PATCH] ASoC: wm_hubs: Fix DC Servo readback

From: Charles Keepax
Date: Wed Aug 13 2014 - 07:08:51 EST


On Wed, Aug 13, 2014 at 11:47:20AM +0100, Nikesh Oswal wrote:
> wm_hubs is a common driver code shared by WM8958, WM1811, WM8944
> and WM8993 all these codecs have the DC Servo Values either in register
> 57h or 59h. Current code was reading register 58h for WM8958 and WM8994
> revisions 2 and 3 but looking at the data sheet the DC Servo Values are
> stored in register 57h for these codecs. This patch fixes it by reading
> the correct register for DC Servo
>
> Signed-off-by: Nikesh Oswal <nikesh@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> sound/soc/codecs/wm_hubs.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/sound/soc/codecs/wm_hubs.c b/sound/soc/codecs/wm_hubs.c
> index 916817f..95c5d71 100644
> --- a/sound/soc/codecs/wm_hubs.c
> +++ b/sound/soc/codecs/wm_hubs.c
> @@ -210,9 +210,6 @@ static int wm_hubs_read_dc_servo(struct snd_soc_codec *codec,
> case 2:
> dcs_reg = WM8994_DC_SERVO_4E;
> break;
> - case 1:
> - dcs_reg = WM8994_DC_SERVO_READBACK;
> - break;
> default:
> dcs_reg = WM8993_DC_SERVO_3;
> break;
> --

This doesn't look right, firstly if it is the same register for
all versions then surely we should change the code that sets
dcs_readback_mode rather than setting that to different values
but treating them the same. Although obviously if nothing still
uses this case we could remove it as well.

Also I think the situation is more complex for example on version
4.4 of the datasheet for wm8994 the WR_VAL fields appear to be in
register 59h. Which is not consistent with this.

Thanks,
Charles
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