Re: [PATCH v4 03/22] ASoC: sun4i-i2s: Change get_sr() and get_wss() to be more explicit

[Maxime Ripard]

On Mon, Sep 21, 2020 at 12:27:12PM +0200, Clément Péron wrote:
> We are actually using a complex formula to just return a bunch of
> simple values. Also this formula is wrong for sun4i.

Just like the previous patch, this could use a bit more explanation,
like why it's a good thing, or how it's wrong on sun4i

> Replace this with a simpler switch case.
> 
> Also drop the i2s params not used.
> 
> Signed-off-by: Clément Péron <peron.clem@xxxxxxxxx>
> ---
>  sound/soc/sunxi/sun4i-i2s.c | 69 +++++++++++++++++++++++--------------
>  1 file changed, 44 insertions(+), 25 deletions(-)
> 
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index 0633b9fba3d7..11bbcbe24d6b 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c
> @@ -175,8 +175,8 @@ struct sun4i_i2s_quirks {
>  	unsigned int			num_mclk_dividers;
>  
>  	unsigned long (*get_bclk_parent_rate)(const struct sun4i_i2s *);
> -	s8	(*get_sr)(const struct sun4i_i2s *, int);
> -	s8	(*get_wss)(const struct sun4i_i2s *, int);
> +	int	(*get_sr)(unsigned int width);
> +	int	(*get_wss)(unsigned int width);
>  	int	(*set_chan_cfg)(const struct sun4i_i2s *i2s,
>  				unsigned int channels,	unsigned int slots,
>  				unsigned int slot_width);
> @@ -381,37 +381,56 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
>  	return 0;
>  }
>  
> -static s8 sun4i_i2s_get_sr(const struct sun4i_i2s *i2s, int width)
> +static int sun4i_i2s_get_sr(unsigned int width)
>  {
> -	if (width < 16 || width > 24)
> -		return -EINVAL;
> -
> -	if (width % 4)
> -		return -EINVAL;
> +	switch (width) {
> +	case 16:
> +		return 0x0;
> +	case 20:
> +		return 0x1;
> +	case 24:
> +		return 0x2;
> +	}

Why do we need an hex number here?

Also, why is the return type change needed?

Maxime