From: Tony Lindgren tony@atomide.com
[ Upstream commit 14639a22de657eabbb776f503a816594393cc935 ]
With commit 3a6f0fb7b8eb ("regmap: irq: Add support to clear ack registers"), the cpcap interrupts are no longer getting acked properly leading to a very unresponsive device with CPUs fully loaded spinning in the threaded IRQ handlers.
To me it looks like the clear_ack commit above actually fixed a long standing bug in regmap_irq_thread() where we unconditionally acked the interrupts earlier without considering ack_invert. And the issue with cpcap started happening as we now also consider ack_invert.
Tim Harvey tharvey@gateworks.com tried to fix this issue earlier with "[PATCH v2] regmap: irq: fix ack-invert", but the reading of the ack register was considered unnecessary for just ack_invert, and we did not have clear_ack available yet. As the cpcap irqs worked both with and without ack_invert earlier because of the unconditional ack, the problem remained hidden until now.
Also, looks like the earlier v3.0.8 based Motorola Android Linux kernel does clear_ack style read-clear-write with "ireg_val & ~mreg_val" instead of just ack_invert style write. So let's switch cpcap to use clear_ack to fix the issue.
Fixes: 3a6f0fb7b8eb ("regmap: irq: Add support to clear ack registers") Cc: Carl Philipp Klemm philipp@uvos.xyz Cc: Laxminath Kasam lkasam@codeaurora.org Cc: Merlijn Wajer merlijn@wizzup.org Cc: Mark Brown broonie@kernel.org Cc: Pavel Machek pavel@ucw.cz Cc: Sebastian Reichel sre@kernel.org Cc: Tim Harvey tharvey@gateworks.com Signed-off-by: Tony Lindgren tony@atomide.com Tested-by: Pavel Machek pavel@ucw.cz Reviewed-By: Tim Harvey tharvey@gateworks.com Signed-off-by: Lee Jones lee.jones@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mfd/motorola-cpcap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/mfd/motorola-cpcap.c b/drivers/mfd/motorola-cpcap.c index 2283d88adcc25..30d82bfe5b02f 100644 --- a/drivers/mfd/motorola-cpcap.c +++ b/drivers/mfd/motorola-cpcap.c @@ -97,7 +97,7 @@ static struct regmap_irq_chip cpcap_irq_chip[CPCAP_NR_IRQ_CHIPS] = { .ack_base = CPCAP_REG_MI1, .mask_base = CPCAP_REG_MIM1, .use_ack = true, - .ack_invert = true, + .clear_ack = true, }, { .name = "cpcap-m2", @@ -106,7 +106,7 @@ static struct regmap_irq_chip cpcap_irq_chip[CPCAP_NR_IRQ_CHIPS] = { .ack_base = CPCAP_REG_MI2, .mask_base = CPCAP_REG_MIM2, .use_ack = true, - .ack_invert = true, + .clear_ack = true, }, { .name = "cpcap1-4", @@ -115,7 +115,7 @@ static struct regmap_irq_chip cpcap_irq_chip[CPCAP_NR_IRQ_CHIPS] = { .ack_base = CPCAP_REG_INT1, .mask_base = CPCAP_REG_INTM1, .use_ack = true, - .ack_invert = true, + .clear_ack = true, }, };