linux-kernel - [PATCH V1 14/15] spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup

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Date:   Tue, 30 May 2017 18:09:02 +0530
From:   Kiran Gunda <kgunda@...eaurora.org>
To:     Kiran Gunda <kgunda@...eaurora.org>,
        Abhijeet Dharmapurikar <adharmap@...eaurora.org>,
        David Collins <collinsd@...eaurora.org>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Subbaraman Narayanamurthy <subbaram@...eaurora.org>,
        linux-kernel@...r.kernel.org
Cc:     linux-arm-msm@...r.kernel.org, adharmap@...cinc.com,
        aghayal@....qualcomm.com, sboyd@...eaurora.org
Subject: [PATCH V1 14/15] spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup_irq

From: Subbaraman Narayanamurthy <subbaram@...eaurora.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@...eaurora.org>
Signed-off-by: Kiran Gunda <kgunda@...eaurora.org>
---
 drivers/spmi/spmi-pmic-arb.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
index b755c24..767bd2c 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -522,24 +522,9 @@ static void qpnpint_spmi_read(struct irq_data *d, u8 reg, void *buf, size_t len)
 
 static void cleanup_irq(struct spmi_pmic_arb *pa, u16 apid, int id)
 {
-	u16 ppid = pa->apid_data[apid].ppid;
-	u8 sid = ppid >> 8;
-	u8 per = ppid & 0xFF;
 	u8 irq_mask = BIT(id);
 
 	writel_relaxed(irq_mask, pa->intr + pa->ver_ops->irq_clear(apid));
-
-	if (pmic_arb_write_cmd(pa->spmic, SPMI_CMD_EXT_WRITEL, sid,
-			(per << 8) + QPNPINT_REG_LATCHED_CLR, &irq_mask, 1))
-		dev_err_ratelimited(&pa->spmic->dev,
-				"failed to ack irq_mask = 0x%x for ppid = %x\n",
-				irq_mask, ppid);
-
-	if (pmic_arb_write_cmd(pa->spmic, SPMI_CMD_EXT_WRITEL, sid,
-			       (per << 8) + QPNPINT_REG_EN_CLR, &irq_mask, 1))
-		dev_err_ratelimited(&pa->spmic->dev,
-				"failed to ack irq_mask = 0x%x for ppid = %x\n",
-				irq_mask, ppid);
 }
 
 static void periph_interrupt(struct spmi_pmic_arb *pa, u16 apid)
@@ -698,6 +683,17 @@ static int qpnpint_get_irqchip_state(struct irq_data *d,
 			| IRQCHIP_SKIP_SET_WAKE,
 };
 
+static void qpnpint_irq_domain_activate(struct irq_domain *domain,
+					struct irq_data *d)
+{
+	u8 irq = HWIRQ_IRQ(d->hwirq);
+	u8 buf;
+
+	buf = BIT(irq);
+	qpnpint_spmi_write(d, QPNPINT_REG_EN_CLR, &buf, 1);
+	qpnpint_spmi_write(d, QPNPINT_REG_LATCHED_CLR, &buf, 1);
+}
+
 static int qpnpint_irq_domain_dt_translate(struct irq_domain *d,
 					   struct device_node *controller,
 					   const u32 *intspec,
@@ -1164,6 +1160,7 @@ static u32 pmic_arb_channel_map_offset_v5(u16 n)
 static const struct irq_domain_ops pmic_arb_irq_domain_ops = {
 	.map	= qpnpint_irq_domain_map,
 	.xlate	= qpnpint_irq_domain_dt_translate,
+	.activate	= qpnpint_irq_domain_activate,
 };
 
 static int spmi_pmic_arb_probe(struct platform_device *pdev)
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
--