[PATCH 2/2] regmap: irq: do not write mask register if it is not supported

[Laxman Dewangan <ldewangan@nvidia.com>]

Ignore the mask register write if mask_base is not provided by
regmap irq client. This is useful when regmap irq framework is
used for the MFD's gpio interrupt support. Typically, gpio has
two registers related to interrupt, one is for setting interrupt
edge type like rising and falling which indirectly work as mask
interrupt register and second as interrupt status register. In
this case mask_base is set as 0.

Now when interrupt enabled/disabled, the mask_buf get set/reset as
it keeps the interrupt enable/disable state but need not to be write
into register. When interrupt occurs, it is masked with interrupt mask
to check interrupt is valid or not and accordingly the isr handler
get called.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 drivers/base/regmap/regmap-irq.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index e7a1a26..dbdd407 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -80,6 +80,9 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 	 * suppress pointless writes.
 	 */
 	for (i = 0; i < d->chip->num_regs; i++) {
+		if (!d->chip->mask_base)
+			goto skip_mask_reg_update;
+
 		reg = d->chip->mask_base +
 			(i * map->reg_stride * d->irq_reg_stride);
 		if (d->chip->mask_invert)
@@ -92,6 +95,7 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 			dev_err(d->map->dev, "Failed to sync masks in %x\n",
 				reg);
 
+skip_mask_reg_update:
 		reg = d->chip->wake_base +
 			(i * map->reg_stride * d->irq_reg_stride);
 		if (d->wake_buf) {
@@ -470,6 +474,9 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
 	/* Mask all the interrupts by default */
 	for (i = 0; i < chip->num_regs; i++) {
 		d->mask_buf[i] = d->mask_buf_def[i];
+		if (!chip->mask_base)
+			continue;
+
 		reg = chip->mask_base +
 			(i * map->reg_stride * d->irq_reg_stride);
 		if (chip->mask_invert)
-- 
1.7.1.1