Hi Shengjiu, On Mon, Jun 29, 2020 at 11:10 AM Shengjiu Wang <shengjiu.wang@xxxxxxx> wrote: > +/** "/**" notation may confuse 'make htmldocs". Since this is a single line comment you could do: /* Select proper clock source for internal ratio mode */ > + * Select proper clock source for internal ratio mode > + */ > +static int fsl_asrc_select_clk(struct fsl_asrc_priv *asrc_priv, > + struct fsl_asrc_pair *pair, > + int in_rate, > + int out_rate) > +{ > + struct fsl_asrc_pair_priv *pair_priv = pair->private; > + struct asrc_config *config = pair_priv->config; > + int rate[2], select_clk[2]; /* Array size 2 means IN and OUT */ > + int clk_rate, clk_index; > + int i = 0, j = 0; > + bool clk_sel[2]; > + > + rate[0] = in_rate; > + rate[1] = out_rate; > + > + /* Select proper clock source for internal ratio mode */ > + for (j = 0; j < 2; j++) { > + for (i = 0; i < ASRC_CLK_MAP_LEN; i++) { > + clk_index = asrc_priv->clk_map[j][i]; > + clk_rate = clk_get_rate(asrc_priv->asrck_clk[clk_index]); > + if (clk_rate != 0 && (clk_rate / rate[j]) <= 1024 && > + (clk_rate % rate[j]) == 0) > + break; > + } > + > + if (i == ASRC_CLK_MAP_LEN) { > + select_clk[j] = OUTCLK_ASRCK1_CLK; > + clk_sel[j] = false; > + } else { > + select_clk[j] = i; > + clk_sel[j] = true; > + } > + } > + > + /* Switch to ideal ratio mode if there is no proper clock source */ > + if (!clk_sel[IN] || !clk_sel[OUT]) > + select_clk[IN] = INCLK_NONE; > + > + config->inclk = select_clk[IN]; > + config->outclk = select_clk[OUT]; > + > + return 0; This new function always returns 0. Should it be converted to 'void' type instead? > + ret = fsl_asrc_select_clk(asrc_priv, pair, > + config.input_sample_rate, > + config.output_sample_rate); > + if (ret) { > + dev_err(dai->dev, "fail to select clock\n"); fsl_asrc_select_clk() does not return error, so you could skip the error checking.