On Thu, Apr 11, 2019 at 09:39:06AM +0000, S.j. Wang wrote:
+/*
- Select the pre-processing and post-processing options
By aligning with other function comments: /** * Select the pre-processing and post-processing options
- Fsin: input sample rate
- Fsout: output sample rate
I would suggest to use inrate and outrate to keep naming consistent.
- pre_proc: return value for pre-processing option
- post_proc: return value for post-processing option
- */
+static int fsl_asrc_sel_proc(int Fsin, int Fsout, int *pre_proc, int *post_proc) +{
- bool det_out_op2_cond;
- bool det_out_op0_cond;
By looking at the comments below. Probably better to rename them bool post_proc_cond2, post_proc_cond0;
- /* Codition for selection of post-processing */
"Codition" -> "Conditions"
- det_out_op2_cond = (((Fsin * 15 > Fsout * 16) & (Fsout < 56000)) |
((Fsin > 56000) & (Fsout < 56000)));
Combining Daniel's comments + indentation alignment: det_out_op2_cond = (Fsin * 15 > Fsout * 16 && Fsout < 56000) || (Fsin > 56000 && Fsout < 56000);
- det_out_op0_cond = (Fsin * 23 < Fsout * 8);
- /*
* unsupported case: Tsout>16.125*Tsin, and Tsout>8.125*Tsin.
Funny thing is that there'd be no point in checking the 16.125, if Tsout is bigger than 8.125 times of Tsin, i.e. only one condition: Tsout > 8.125 * Tsin
* Tsout>16.125*Tsin -> Fsin * 8 > 129 * Fsout* Tsout>8.125*Tsin -> Fsin * 8 > 65 * Fsout* Tsout>4.125*Tsin -> Fsin * 8 > 33 * Fsout* Tsout>1.875*Tsin -> Fsin * 8 > 15 * Fsout
Took me a while to understand what it is saying....
Better to write like this: /* Does not support cases: Tsout > 8.125 * Tsin */ if (Fsin * 8 > 65 * Fsout) { pair_err("Does not support %d > 8.125 * %d\n", Fsout, Fsin); return -EINVAL; }
/* Otherwise, select pre_proc between [0, 2] */ if (Fsin * 8 > 33 * Fsout)
*pre_proc = 2;- else if (Fsin * 8 > 15 * Fsout) {
if (Fsin > 152000)*pre_proc = 2;else*pre_proc = 1;- } else if (Fsin < 76000)
*pre_proc = 0;- else if (Fsin > 152000)
*pre_proc = 2;- else
*pre_proc = 1;
<== Would look better by moving post_cond calculations here.
- if (det_out_op2_cond)
*post_proc = 2;- else if (det_out_op0_cond)
*post_proc = 0;- else
*post_proc = 1;
And we could remove this check below:
- /* unsupported options */
- if (*pre_proc == 4 || *pre_proc == 5)
return -EINVAL;
So basically we are doing: 1) Error out unsupported cases 2) Select pre_proc 3) Calculate conditions for post_proc 4) Select post_proc
Thanks