This is a note to let you know that I've just added the patch titled
i2c: omap: Fix standard mode false ACK readings
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-omap-fix-standard-mode-false-ack-readings.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c770657bd2611b077ec1e7b1fe6aa92f249399bd Mon Sep 17 00:00:00 2001
From: Reid Tonking <reidt@xxxxxx>
Date: Wed, 26 Apr 2023 14:49:56 -0500
Subject: i2c: omap: Fix standard mode false ACK readings
From: Reid Tonking <reidt@xxxxxx>
commit c770657bd2611b077ec1e7b1fe6aa92f249399bd upstream.
Using standard mode, rare false ACK responses were appearing with
i2cdetect tool. This was happening due to NACK interrupt triggering
ISR thread before register access interrupt was ready. Removing the
NACK interrupt's ability to trigger ISR thread lets register access
ready interrupt do this instead.
Cc: <stable@xxxxxxxxxxxxxxx> # v3.7+
Fixes: 3b2f8f82dad7 ("i2c: omap: switch to threaded IRQ support")
Signed-off-by: Reid Tonking <reidt@xxxxxx>
Acked-by: Vignesh Raghavendra <vigneshr@xxxxxx>
Reviewed-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1058,7 +1058,7 @@ omap_i2c_isr(int irq, void *dev_id)
u16 stat;
stat = omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG);
- mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG);
+ mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG) & ~OMAP_I2C_STAT_NACK;
if (stat & mask)
ret = IRQ_WAKE_THREAD;
Patches currently in stable-queue which might be from reidt@xxxxxx are
queue-5.15/i2c-omap-fix-standard-mode-false-ack-readings.patch
