linux-kernel - [PATCH 15/49] regmap-irq: Change the behavior of mask

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Message-Id: <20220620200644.1961936-16-aidanmacdonald.0x0@gmail.com>
Date:   Mon, 20 Jun 2022 21:06:10 +0100
From:   Aidan MacDonald <aidanmacdonald.0x0@...il.com>
To:     broonie@...nel.org
Cc:     agross@...nel.org, bjorn.andersson@...aro.org,
        srinivas.kandagatla@...aro.org, bgoswami@...eaurora.org,
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Subject: [PATCH 15/49] regmap-irq: Change the behavior of mask_writeonly

No drivers currently use mask_writeonly, and in its current form
it seems a bit misleading. When set, mask registers will be
updated with regmap_write_bits() instead of regmap_update_bits(),
but regmap_write_bits() still does a read-modify-write under the
hood. It's not a write-only operation.

Performing a simple regmap_write() is probably more useful, since
it can be used for chips that have separate set & clear registers
for controlling mask bits. Such registers are normally volatile
and read as 0, so avoiding a register read minimizes bus traffic.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@...il.com>
---
 drivers/base/regmap/regmap-irq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index dd22d13c54c8..4c0d7f7aa544 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -84,7 +84,7 @@ static int regmap_irq_update_bits(struct regmap_irq_chip_data *d,
 				  unsigned int val)
 {
 	if (d->chip->mask_writeonly)
-		return regmap_write_bits(d->map, reg, mask, val);
+		return regmap_write(d->map, reg, val & mask);
 	else
 		return regmap_update_bits(d->map, reg, mask, val);
 }
-- 
2.35.1