This is a note to let you know that I've just added the patch titled
i2c: omap: fix i207 errata handling
to the 3.14-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-i207-errata-handling.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ccfc866356674cb3a61829d239c685af6e85f197 Mon Sep 17 00:00:00 2001
From: Alexander Kochetkov <al.kochet@xxxxxxxxx>
Date: Fri, 21 Nov 2014 04:16:51 +0400
Subject: i2c: omap: fix i207 errata handling
From: Alexander Kochetkov <al.kochet@xxxxxxxxx>
commit ccfc866356674cb3a61829d239c685af6e85f197 upstream.
commit 6d9939f651419a63e091105663821f9c7d3fec37 (i2c: omap: split out [XR]DR
and [XR]RDY) changed the way how errata i207 (I2C: RDR Flag May Be Incorrectly
Set) get handled. 6d9939f6514 code doesn't correspond to workaround provided by
errata.
According to errata ISR must filter out spurious RDR before data read not after.
ISR must read RXSTAT to get number of bytes available to read. Because RDR
could be set while there could no data in the receive FIFO.
Restored pre 6d9939f6514 way of handling errata.
Found by code review. Real impact haven't seen.
Tested on Beagleboard XM C.
Signed-off-by: Alexander Kochetkov <al.kochet@xxxxxxxxx>
Fixes: 6d9939f651419a63e09110 i2c: omap: split out [XR]DR and [XR]RDY
Tested-by: Felipe Balbi <balbi@xxxxxx>
Reviewed-by: Felipe Balbi <balbi@xxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -956,11 +956,13 @@ omap_i2c_isr_thread(int this_irq, void *
if (dev->fifo_size)
num_bytes = dev->buf_len;
- omap_i2c_receive_data(dev, num_bytes, true);
-
- if (dev->errata & I2C_OMAP_ERRATA_I207)
+ if (dev->errata & I2C_OMAP_ERRATA_I207) {
i2c_omap_errata_i207(dev, stat);
+ num_bytes = (omap_i2c_read_reg(dev,
+ OMAP_I2C_BUFSTAT_REG) >> 8) & 0x3F;
+ }
+ omap_i2c_receive_data(dev, num_bytes, true);
omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
continue;
}
Patches currently in stable-queue which might be from al.kochet@xxxxxxxxx are
queue-3.14/i2c-omap-fix-nack-and-arbitration-lost-irq-handling.patch
queue-3.14/i2c-omap-fix-i207-errata-handling.patch
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