[PATCH] regmap-irq: do not write mask register if mask_base is zero

[Linus Walleij <linus.walleij@linaro.org>]

From: Mark Zhang <markz@nvidia.com>

commit 7151449fe7fa5962c6153355f9779d6be99e8e97 upstream.

If client have not provided the mask base register then do not
write into the mask register.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Jinyoung Park <jinyoungp@nvidia.com>
Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
Signed-off-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
This commit was found in an nVidia product tree based on
v4.19, and looks like definitive stable material to me.
It should go into v4.19 only as far as I can tell.
---
 drivers/base/regmap/regmap-irq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index 429ca8ed7e51..982c7ac311b8 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -91,6 +91,9 @@ 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)
+			continue;
+
 		reg = d->chip->mask_base +
 			(i * map->reg_stride * d->irq_reg_stride);
 		if (d->chip->mask_invert) {
@@ -526,6 +529,9 @@ 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)
-- 
2.20.1