regmap: irq: add an option to clear status registers on unmask

Some interrupt controllers whose interrupts are acked on read will set
the status bits for masked interrupts without changing the state of
the IRQ line.

Some chips have an additional "feature" where if those set bits are
not cleared before unmasking their respective interrupts, the IRQ
line will change the state and we'll interpret this as an interrupt
although it actually fired when it was masked.

Add a new field to the irq chip struct that tells the regmap irq chip
code to always clear the status registers before actually changing the
irq mask values.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index 31d23c9a5ae7..1bd1145ad8b5 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -44,6 +44,8 @@ struct regmap_irq_chip_data {
 
 	unsigned int irq_reg_stride;
 	unsigned int type_reg_stride;
+
+	bool clear_status:1;
 };
 
 static inline const
@@ -77,6 +79,7 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 	int i, ret;
 	u32 reg;
 	u32 unmask_offset;
+	u32 val;
 
 	if (d->chip->runtime_pm) {
 		ret = pm_runtime_get_sync(map->dev);
@@ -85,6 +88,20 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 				ret);
 	}
 
+	if (d->clear_status) {
+		for (i = 0; i < d->chip->num_regs; i++) {
+			reg = d->chip->status_base +
+				(i * map->reg_stride * d->irq_reg_stride);
+
+			ret = regmap_read(map, reg, &val);
+			if (ret)
+				dev_err(d->map->dev,
+					"Failed to clear the interrupt status bits\n");
+		}
+
+		d->clear_status = false;
+	}
+
 	/*
 	 * 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
@@ -217,6 +234,9 @@ static void regmap_irq_enable(struct irq_data *data)
 	else
 		mask = irq_data->mask;
 
+	if (d->chip->clear_on_unmask)
+		d->clear_status = true;
+
 	d->mask_buf[irq_data->reg_offset / map->reg_stride] &= ~mask;
 }
 
@@ -474,6 +494,9 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
 	if (chip->num_regs <= 0)
 		return -EINVAL;
 
+	if (chip->clear_on_unmask && (chip->ack_base || chip->use_ack))
+		return -EINVAL;
+
 	for (i = 0; i < chip->num_irqs; i++) {
 		if (chip->irqs[i].reg_offset % map->reg_stride)
 			return -EINVAL;