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From:   Fenglin Wu <quic_fenglinw@quicinc.com>
To:     <linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <sboyd@kernel.org>
CC:     <collinsd@codeaurora.org>, <subbaram@codeaurora.org>,
        <quic_fenglinw@quicinc.com>
Subject: [PATCH V1 2/9] spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup_irq
Date:   Thu, 29 Jul 2021 09:12:40 +0800
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From: Subbaraman Narayanamurthy <subbaram@codeaurora.org>

Currently, cleanup_irq() is invoked when a peripheral's interrupt
fires and there is no mapping present in the interrupt domain of
spmi interrupt controller.

The cleanup_irq clears the arbiter bit, clears the pmic interrupt
and disables it at the pmic in that order. The last disable in
cleanup_irq races with request_irq() in that it stomps over the
enable issued by request_irq. Fix this by not writing to the pmic
in cleanup_irq. The latched bit will be left set in the pmic,
which will not send us more interrupts even if the enable bit
stays enabled.

When a client wants to request an interrupt, use the activate
callback on the irq_domain to clear latched bit. This ensures
that the latched, if set due to the above changes in cleanup_irq
or when the bootloader leaves it set, gets cleaned up, paving way
for upcoming interrupts to trigger.

With this, there is a possibility of unwanted triggering of
interrupt right after the latched bit is cleared - the interrupt
may be left enabled too. To avoid that, clear the enable first
followed by clearing the latched bit in the activate callback.

Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>
[collinsd@codeaurora.org: fix merge conflict]
Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
---
 drivers/spmi/spmi-pmic-arb.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
index 295e19f..4d7ad004 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -492,16 +492,6 @@ static void cleanup_irq(struct spmi_pmic_arb *pmic_arb, u16 apid, int id)
 	dev_err_ratelimited(&pmic_arb->spmic->dev, "%s apid=%d sid=0x%x per=0x%x irq=%d\n",
 			__func__, apid, sid, per, id);
 	writel_relaxed(irq_mask, pmic_arb->ver_ops->irq_clear(pmic_arb, apid));
-
-	if (pmic_arb_write_cmd(pmic_arb->spmic, SPMI_CMD_EXT_WRITEL, sid,
-			(per << 8) + QPNPINT_REG_LATCHED_CLR, &irq_mask, 1))
-		dev_err_ratelimited(&pmic_arb->spmic->dev, "failed to ack irq_mask = 0x%x for ppid = %x\n",
-				irq_mask, ppid);
-
-	if (pmic_arb_write_cmd(pmic_arb->spmic, SPMI_CMD_EXT_WRITEL, sid,
-			       (per << 8) + QPNPINT_REG_EN_CLR, &irq_mask, 1))
-		dev_err_ratelimited(&pmic_arb->spmic->dev, "failed to ack irq_mask = 0x%x for ppid = %x\n",
-				irq_mask, ppid);
 }
 
 static void periph_interrupt(struct spmi_pmic_arb *pmic_arb, u16 apid)
@@ -667,6 +657,7 @@ static int qpnpint_irq_domain_activate(struct irq_domain *domain,
 	u16 apid = hwirq_to_apid(d->hwirq);
 	u16 sid = hwirq_to_sid(d->hwirq);
 	u16 irq = hwirq_to_irq(d->hwirq);
+	u8 buf;
 
 	if (pmic_arb->apid_data[apid].irq_ee != pmic_arb->ee) {
 		dev_err(&pmic_arb->spmic->dev, "failed to xlate sid = %#x, periph = %#x, irq = %u: ee=%u but owner=%u\n",
@@ -675,6 +666,10 @@ static int qpnpint_irq_domain_activate(struct irq_domain *domain,
 		return -ENODEV;
 	}
 
+	buf = BIT(irq);
+	qpnpint_spmi_write(d, QPNPINT_REG_EN_CLR, &buf, 1);
+	qpnpint_spmi_write(d, QPNPINT_REG_LATCHED_CLR, &buf, 1);
+
 	return 0;
 }
 
-- 
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