On Thu, 2015-12-31 at 22:19 +0800, Daniel Kurtz wrote:

On Wed, Dec 30, 2015 at 8:36 PM, Henry Chen [off-list ref] wrote:

quoted

The STAUPD_TRIG will be enable when WDT_INT enable on probe function, if
doesn't enable STAUPD_PRD together, interrupt will be triggered because
STAUPD timeout. To avoid unexpected interrupt, enable periodic status
update which will be updated to PMIC every selected time period.

Sorry, I don't really understand this.

What exactly is triggering the unexpected watchdog interrupt (WDT_INT)?

How does setting STAUPD_PRD disable this "unexpected interrupt"?

Yes, WDT_INT was triggered because the bit[25] of WDT_SRC_EN was
enabled:

bit[25] STAUPD_TRIG: STAUPD trigger signal timeout monitor

Setting STAUPD_PRD will update the status of PMIC periodic to avoid this
watchdog timeout.

From the MT8173 Datasheet, I can see that the value written to
STAUPD_PRD is the "periodic status update timing (period)".

quoted

Signed-off-by: Henry Chen <redacted>
---
 drivers/soc/mediatek/mtk-pmic-wrap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c b/drivers/soc/mediatek/mtk-pmic-wrap.c
index a8cde17..6e5c20f 100644
--- a/drivers/soc/mediatek/mtk-pmic-wrap.c
+++ b/drivers/soc/mediatek/mtk-pmic-wrap.c

@@ -904,6 +904,11 @@ static int pwrap_probe(struct platform_device *pdev)
                return -ENODEV;
        }

+       /*
+        * Enable periodic status update which will be updated to PMIC
+        * every selected time period.
+        */
+       pwrap_writel(wrp, 0x5, PWRAP_STAUPD_PRD);

nit: Perhaps use a define for 5, and specify the real period value.
Something like this:

#define PWRAP_STAUPD_98_5US  5

ok.

quoted

        /* Initialize watchdog, may not be done by the bootloader */
        pwrap_writel(wrp, 0xf, PWRAP_WDT_UNIT);
        pwrap_writel(wrp, 0xffffffff, PWRAP_WDT_SRC_EN);
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/