[alsa-devel] [PATCH] ASoC: nau8825: fix fake interruption when booting

[Cheng-yi Chiang]

On Mon, Jun 10, 2019 at 10:13 AM John Hsu <KCHSU0 at nuvoton.com> wrote:
>
> There is no pull-up resistor at IRQ line where it connects from
> the codec to SoC. When booting, the signal of IRQ pin will keep low
> which makes the SoC invoke the ISR repeatedly because the IRQ is
> registered trigger low. It will not stop until the codec sets up
> the interruption and pulls the signal high. In the patch,
> nau8825 will internally pull the signal to high at booting in case
> the fake interrupts happen.
>
> The patch help to fix the issue as follows:
> Google issue 133904101: Cave: excessive number of interrupts before Nau8825 codec is initialized
> Reported Issue
> Chrome OS Version  :  ChromeOS R76-12217.0.0
> Type of hardware   :
>
> What steps will reproduce the problem?
> Boot device
> What is the expected output?
> A lot of interrupts without any events
> What do you see instead?
> The fake interrupts are gone
>
> How frequently does this problem reproduce?
> Always
>
> What is the impact to the user, and is there a workaround?
> If so, what is it?
>
> BUG=b:133904101
> TEST=Boot device, and then check the interrupts are real.
>
> Signed-off-by: John Hsu <KCHSU0 at nuvoton.com>

Tested-by: Cheng-Yi Chiang <cychiang at chromium.org>

Thank you for the fix.
I think you can remove the description about issue 133904101 in the
commit messages and BUG and TEST fields.




>
> ---
>  sound/soc/codecs/nau8825.c | 4 ++++
>  sound/soc/codecs/nau8825.h | 2 ++
>  2 files changed, 6 insertions(+)
>
> diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c
> index 47e65cf99879..83ec841f7865 100644
> --- a/sound/soc/codecs/nau8825.c
> +++ b/sound/soc/codecs/nau8825.c
> @@ -1881,6 +1881,10 @@ static void nau8825_init_regs(struct nau8825 *nau8825)
>                 NAU8825_JACK_EJECT_DEBOUNCE_MASK,
>                 nau8825->jack_eject_debounce << NAU8825_JACK_EJECT_DEBOUNCE_SFT);
>
> +       /* Pull up IRQ pin */
> +       regmap_update_bits(regmap, NAU8825_REG_INTERRUPT_MASK,
> +               NAU8825_IRQ_PIN_PULLUP | NAU8825_IRQ_PIN_PULL_EN,
> +               NAU8825_IRQ_PIN_PULLUP | NAU8825_IRQ_PIN_PULL_EN);
>         /* Mask unneeded IRQs: 1 - disable, 0 - enable */
>         regmap_update_bits(regmap, NAU8825_REG_INTERRUPT_MASK, 0x7ff, 0x7ff);
>
> diff --git a/sound/soc/codecs/nau8825.h b/sound/soc/codecs/nau8825.h
> index f6074c618569..3f41897ed3f6 100644
> --- a/sound/soc/codecs/nau8825.h
> +++ b/sound/soc/codecs/nau8825.h
> @@ -171,6 +171,8 @@
>  #define NAU8825_JACK_POLARITY  (1 << 1) /* 0 - active low, 1 - active high */
>
>  /* INTERRUPT_MASK (0xf) */
> +#define NAU8825_IRQ_PIN_PULLUP (1 << 14)
> +#define NAU8825_IRQ_PIN_PULL_EN (1 << 13)
>  #define NAU8825_IRQ_OUTPUT_EN (1 << 11)
>  #define NAU8825_IRQ_HEADSET_COMPLETE_EN (1 << 10)
>  #define NAU8825_IRQ_RMS_EN (1 << 8)
> --
> 2.21.0
>