Re: [alsa-devel] [PATCH] sound: soc: fsl: Do not set DAI sysclk when it is equal to system freq

On Sun, Sep 3, 2017 at 11:40 AM, Łukasz Majewski lukma@denx.de wrote:

This is the part of fsl_ssi_set_bclk() function which is called after fsl_ssi_set_dai_sysclk() (which sets ssi_private->bitclk_freq = freq;).

Before the aforementioned check we do have:

    if (ssi_private->bitclk_freq)
            freq = ssi_private->bitclk_freq;
    else
            freq = params_channels(hw_params) * 32 *

params_rate(hw_params);

Which assigns freq = bitclk_freq (66 MHz)

And then we break on this particular check:

66MHz * 5 > 66 MHz.

The culprit IMHO is the ssi_private->bitclk_freq = freq; in the fsl_ssi_set_dai_sysclk(), since we _should_ set SSI's IP block clock (ssi_private->clk), not the bit clock (BCLK).

This patch just quits early if it detects change, which don't need to be done.

Thanks for the clarification.

Reviewed-by: Fabio Estevam fabio.estevam@nxp.com