regmap: irq: Enable devices for runtime PM while handling interrupts

Some devices need to have a runtime PM reference while handling interrupts
to ensure that the register I/O is available. Support this with a flag in
the chip.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap-irq.c

@@ -16,6 +16,7 @@
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/irqdomain.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #include "internal.h"
@@ -62,6 +63,13 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 	int i, ret;
 	u32 reg;
 
+	if (d->chip->runtime_pm) {
+		ret = pm_runtime_get_sync(map->dev);
+		if (ret < 0)
+			dev_err(map->dev, "IRQ sync failed to resume: %d\n",
+				ret);
+	}
+
 	/*
 	 * If there's been a change in the mask write it back to the
 	 * hardware.  We rely on the use of the regmap core cache to
@@ -77,6 +85,9 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 				reg);
 	}
 
+	if (d->chip->runtime_pm)
+		pm_runtime_put(map->dev);
+
 	/* If we've changed our wakeup count propagate it to the parent */
 	if (d->wake_count < 0)
 		for (i = d->wake_count; i < 0; i++)
@@ -147,6 +158,15 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 	bool handled = false;
 	u32 reg;
 
+	if (chip->runtime_pm) {
+		ret = pm_runtime_get_sync(map->dev);
+		if (ret < 0) {
+			dev_err(map->dev, "IRQ thread failed to resume: %d\n",
+				ret);
+			return IRQ_NONE;
+		}
+	}
+
 	/*
 	 * Ignore masked IRQs and ack if we need to; we ack early so
 	 * there is no race between handling and acknowleding the
@@ -162,6 +182,8 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 		if (ret != 0) {
 			dev_err(map->dev, "Failed to read IRQ status: %d\n",
 					ret);
+			if (chip->runtime_pm)
+				pm_runtime_put(map->dev);
 			return IRQ_NONE;
 		}
 
@@ -185,6 +207,9 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 		}
 	}
 
+	if (chip->runtime_pm)
+		pm_runtime_put(map->dev);
+
 	if (handled)
 		return IRQ_HANDLED;
 	else

include/linux/regmap.h

@@ -285,6 +285,7 @@ struct regmap_irq {
  * @ack_base:    Base ack address.  If zero then the chip is clear on read.
  * @wake_base:   Base address for wake enables.  If zero unsupported.
  * @irq_reg_stride:  Stride to use for chips where registers are not contiguous.
+ * @runtime_pm:  Hold a runtime PM lock on the device when accessing it.
  *
  * @num_regs:    Number of registers in each control bank.
  * @irqs:        Descriptors for individual IRQs.  Interrupt numbers are
@@ -299,6 +300,7 @@ struct regmap_irq_chip {
 	unsigned int ack_base;
 	unsigned int wake_base;
 	unsigned int irq_reg_stride;
+	bool runtime_pm;
 
 	int num_regs;