From d04ad245d67a3991dfea5e108e4c452c2ab39bac Mon Sep 17 00:00:00 2001
From: Prasad Kumpatla <quic_pkumpatl@quicinc.com>
Date: Thu, 17 Feb 2022 14:20:07 +0530
Subject: [PATCH] regmap-irq: Update interrupt clear register for proper reset
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Git-commit: d04ad245d67a3991dfea5e108e4c452c2ab39bac
Patch-mainline: v5.17-rc6
References: git-fixes

With the existing logic where clear_ack is true (HW doesn’t support
auto clear for ICR), interrupt clear register reset is not handled
properly. Due to this only the first interrupts get processed properly
and further interrupts are blocked due to not resetting interrupt
clear register.

Example for issue case where Invert_ack is false and clear_ack is true:

    Say Default ISR=0x00 & ICR=0x00 and ISR is triggered with 2
    interrupts making ISR = 0x11.

    Step 1: Say ISR is set 0x11 (store status_buff = ISR). ISR needs to
            be cleared with the help of ICR once the Interrupt is processed.

    Step 2: Write ICR = 0x11 (status_buff), this will clear the ISR to 0x00.

    Step 3: Issue - In the existing code, ICR is written with ICR =
            ~(status_buff) i.e ICR = 0xEE -> This will block all the interrupts
            from raising except for interrupts 0 and 4. So expectation here is to
            reset ICR, which will unblock all the interrupts.

            if (chip->clear_ack) {
                 if (chip->ack_invert && !ret)
                  ........
                 else if (!ret)
                     ret = regmap_write(map, reg,
                            ~data->status_buf[i]);

So writing 0 and 0xff (when ack_invert is true) should have no effect, other
than clearing the ACKs just set.

Fixes: 3a6f0fb7b8eb ("regmap: irq: Add support to clear ack registers")
Signed-off-by: Prasad Kumpatla <quic_pkumpatl@quicinc.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220217085007.30218-1-quic_pkumpatl@quicinc.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/base/regmap/regmap-irq.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index d2656581a608..4a446259a184 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -189,11 +189,9 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 				ret = regmap_write(map, reg, d->mask_buf[i]);
 			if (d->chip->clear_ack) {
 				if (d->chip->ack_invert && !ret)
-					ret = regmap_write(map, reg,
-							   d->mask_buf[i]);
+					ret = regmap_write(map, reg, UINT_MAX);
 				else if (!ret)
-					ret = regmap_write(map, reg,
-							   ~d->mask_buf[i]);
+					ret = regmap_write(map, reg, 0);
 			}
 			if (ret != 0)
 				dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
@@ -556,11 +554,9 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 						data->status_buf[i]);
 			if (chip->clear_ack) {
 				if (chip->ack_invert && !ret)
-					ret = regmap_write(map, reg,
-							data->status_buf[i]);
+					ret = regmap_write(map, reg, UINT_MAX);
 				else if (!ret)
-					ret = regmap_write(map, reg,
-							~data->status_buf[i]);
+					ret = regmap_write(map, reg, 0);
 			}
 			if (ret != 0)
 				dev_err(map->dev, "Failed to ack 0x%x: %d\n",
@@ -817,13 +813,9 @@ int regmap_add_irq_chip_fwnode(struct fwnode_handle *fwnode,
 					d->status_buf[i] & d->mask_buf[i]);
 			if (chip->clear_ack) {
 				if (chip->ack_invert && !ret)
-					ret = regmap_write(map, reg,
-						(d->status_buf[i] &
-						 d->mask_buf[i]));
+					ret = regmap_write(map, reg, UINT_MAX);
 				else if (!ret)
-					ret = regmap_write(map, reg,
-						~(d->status_buf[i] &
-						  d->mask_buf[i]));
+					ret = regmap_write(map, reg, 0);
 			}
 			if (ret != 0) {
 				dev_err(map->dev, "Failed to ack 0x%x: %d\n",
-- 
2.31.1