[PATCH 2/4] mfd: rk8xx-core: keep the PMIC interrupt disabled during system suspend

[Jakob Unterwurzacher]

From: Jakob Unterwurzacher <jakob.unterwurzacher at cherry.de>

When the system is woken up by the PMIC (e.g. by the power key), the
PMIC interrupt is handled as soon as interrupts are re-enabled on
resume. At that point, the bus to the PMIC may not have resumed yet, so
reading and acking the interrupt status fails. On RK3588 with an RK806
on SPI:

  spi_master spi2: noqueue transfer failed
  rk8xx-spi spi2.0: Failed to ack 0x79: -13

Disable the interrupt at the end of rk8xx_suspend() and re-enable it at
the start of rk8xx_resume(). Both run in the regular suspend/resume
phase, while the parent bus controller is active. If the interrupt is a
wakeup source, it stays armed while disabled, and the pending event is
replayed by enable_irq() on resume.

Store the interrupt number in struct rk808 for this.
---
 drivers/mfd/rk8xx-core.c  | 19 ++++++++++++++++++-
 include/linux/mfd/rk808.h |  1 +
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/rk8xx-core.c b/drivers/mfd/rk8xx-core.c
index 21182df45d1b6..2ae9107fc5161 100644
--- a/drivers/mfd/rk8xx-core.c
+++ b/drivers/mfd/rk8xx-core.c
@@ -851,6 +851,8 @@ int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap
 	if (!irq)
 		return dev_err_probe(dev, -EINVAL, "No interrupt support, no core IRQ\n");
 
+	rk808->irq = irq;
+
 	ret = devm_regmap_add_irq_chip(dev, rk808->regmap, irq,
 				       IRQF_ONESHOT | dual_support, -1,
 				       rk808->regmap_irq_chip, &rk808->irq_data);
@@ -929,7 +931,20 @@ int rk8xx_suspend(struct device *dev)
 		break;
 	}
 
-	return ret;
+	if (ret)
+		return ret;
+
+	/*
+	 * Keep the interrupt disabled while the bus to the PMIC may be
+	 * suspended: otherwise a wakeup event (e.g. the power key) is handled
+	 * as soon as interrupts are re-enabled on resume, before the bus has
+	 * resumed, and reading/acking the interrupt status fails. If the
+	 * interrupt is a wakeup source, it stays armed, and the pending event
+	 * is replayed by enable_irq() on resume.
+	 */
+	disable_irq(rk808->irq);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(rk8xx_suspend);
 
@@ -938,6 +953,8 @@ int rk8xx_resume(struct device *dev)
 	struct rk808 *rk808 = dev_get_drvdata(dev);
 	int ret = 0;
 
+	enable_irq(rk808->irq);
+
 	switch (rk808->variant) {
 	case RK809_ID:
 	case RK817_ID:
diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index 7ffc904c864c9..1255de484ab51 100644
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -1461,6 +1461,7 @@ enum {
 
 struct rk808 {
 	struct device			*dev;
+	unsigned int			irq;
 	struct regmap_irq_chip_data	*irq_data;
 	struct regmap			*regmap;
 	long				variant;

-- 
2.47.3