Re: [PATCH 06/17] soundwire: cadence_master: use firmware defaults for frame shape

Cezary Rojewski
2019-08-06T15:27:39Z

On 2019-08-06 02:55, Pierre-Louis Bossart wrote:
> diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
> index 5d9729b4d634..89c55e4bb72c 100644
> --- a/drivers/soundwire/cadence_master.c
> +++ b/drivers/soundwire/cadence_master.c
> @@ -48,6 +48,8 @@
> #define CDNS_MCP_SSPSTAT 0xC
> #define CDNS_MCP_FRAME_SHAPE 0x10
> #define CDNS_MCP_FRAME_SHAPE_INIT 0x14
> +#define CDNS_MCP_FRAME_SHAPE_COL_MASK GENMASK(2, 0)
> +#define CDNS_MCP_FRAME_SHAPE_ROW_OFFSET 3
>
> #define CDNS_MCP_CONFIG_UPDATE 0x18
> #define CDNS_MCP_CONFIG_UPDATE_BIT BIT(0)
> @@ -175,7 +177,6 @@
> /* Driver defaults */
>
> #define CDNS_DEFAULT_CLK_DIVIDER 0
> -#define CDNS_DEFAULT_FRAME_SHAPE 0x30
> #define CDNS_DEFAULT_SSP_INTERVAL 0x18
> #define CDNS_TX_TIMEOUT 2000
>
> @@ -901,6 +902,20 @@ int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
> }
> EXPORT_SYMBOL(sdw_cdns_pdi_init);
>
> +static u32 cdns_set_initial_frame_shape(int n_rows, int n_cols)
> +{
> + u32 val;
> + int c;
> + int r;
> +
> + r = sdw_find_row_index(n_rows);
> + c = sdw_find_col_index(n_cols) & CDNS_MCP_FRAME_SHAPE_COL_MASK;
> +
> + val = (r << CDNS_MCP_FRAME_SHAPE_ROW_OFFSET) | c;
> +
> + return val;
> +}
> +

Guess this have been said already, but this function could be simplified
- unless you really want to keep explicit variable declaration. Both "c"
and "r" declarations could be merged into single line while "val" is not
needed at all.

One more thing - is AND bitwise op really needed for cols explicitly? We
know all col values upfront - these are static and declared in global
table nearby. Static declaration takes care of "initial range-check". Is
another one necessary?

Moreover, this is a _get_ and certainly not a _set_ type of function.
I'd even consider renaming it to: "cdns_get_frame_shape" as this is
neither a _set_ nor an explicit initial frame shape setter.

It might be even helpful to split two usages:

#define sdw_frame_shape(col_idx, row_idx) \
((row_idx << CDNS_MCP_FRAME_SHAPE_ROW_OFFSET) | col_idx)

u32 cdns_get_frame_shape(u16 rows, u16 cols)
{
u16 c, r;

r = sdw_find_row_index(rows);
c = sdw_find_col_index(cols);

return sdw_frame_shape(c, r);
}

The above may even be simplified into one-liner.