[alsa-devel] [PATCH v2] ASoC: fsl_sai: Add isr to deal with error flag

Mark Brown broonie at kernel.org
Thu Mar 27 14:26:27 CET 2014

On Thu, Mar 27, 2014 at 07:06:59PM +0800, Nicolin Chen wrote:
> It's quite cricial to clear error flags because SAI might hang if getting
> FIFO underrun during playback (I haven't confirmed the same issue on Rx
> overflow though).
> So this patch enables those irq and adds isr() to clear the flags so as to
> keep playback entirely safe.

So, I've applied this since we're (hopefully!) very near the merge
window opening and it seems like it should be an improvement overall.
However a few things below:

> +	/* Only handle those what we enabled */

The shifting here could use a comment.

> +	regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
> +			   FSL_SAI_CSR_xF_W_MASK | FSL_SAI_CSR_FR, xcsr);

Using update_bits() is going to do an extra read, better to do this as:

	if (xcsr)
		regmap_write(sai->regmap, FSL_SAI_RCSR, xcsr);

otherwise we might be ignoring any of the bits that are actually clear
on read (it seems like there are some?).

> +	return IRQ_HANDLED;

I'd expect to see IRQ_NONE if we didn't actually see an interrupt
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