Re: [PATCH 1/2] ASoC: rt5677: allow multiple interrupt sources

From: Mark Brown
Date: Tue Apr 02 2019 - 01:03:17 EST


On Mon, Apr 01, 2019 at 02:55:18PM -0600, Fletcher Woodruff wrote:
> From: Ben Zhang <benzh@xxxxxxxxxxxx>
>
> This patch allows headphone plug detect and mic present
> detect to be enabled at the same time. This patch implements
> an irq_chip with irq_domain directly instead of using
> regmap_irq, so that interrupt source line polarities can
> be flipped to support irq sharing.

regmap-irq should support active high/low, and if it doesn't it can't be
a unique thing that only this device wants to implement so the common
code should be improved.

> + mutex_lock(&rt5677->irq_lock);
> + /*
> + * Loop to handle interrupts until the last i2c read shows no pending
> + * irqs. The interrupt line is shared by multiple interrupt sources.
> + * After the regmap_read() below, a new interrupt source line may
> + * become high before the regmap_write() finishes, so there isn't a
> + * rising edge on the shared interrupt line for the new interrupt. Thus,
> + * the loop is needed to avoid missing irqs.
> + *
> + * A safeguard of 20 loops is used to avoid hanging in the irq handler
> + * if there is something wrong with the interrupt status update. The
> + * interrupt sources here are audio jack plug/unplug events which
> + * shouldn't happen at a high frequency for a long period of time.
> + * Empirically, more than 3 loops have never been seen.
> + */
> + for (loop = 0; loop < 20; loop++) {

This looks unrelated to the polarity of the interupt?

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