This is a note to let you know that I've just added the patch titled
i2c: xiic: must always write 16-bit words to TX_FIFO
to the 3.4-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-xiic-must-always-write-16-bit-words-to-tx_fifo.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c39e8e4354ce4daf23336de5daa28a3b01f00aa6 Mon Sep 17 00:00:00 2001
From: "Steven A. Falco" <sfalco@xxxxxxxxxx>
Date: Mon, 22 Apr 2013 09:34:39 +0000
Subject: i2c: xiic: must always write 16-bit words to TX_FIFO
From: "Steven A. Falco" <sfalco@xxxxxxxxxx>
commit c39e8e4354ce4daf23336de5daa28a3b01f00aa6 upstream.
The TX_FIFO register is 10 bits wide. The lower 8 bits are the data to be
written, while the upper two bits are flags to indicate stop/start.
The driver apparently attempted to optimize write access, by only writing a
byte in those cases where the stop/start bits are zero. However, we have
seen cases where the lower byte is duplicated onto the upper byte by the
hardware, which causes inadvertent stop/starts.
This patch changes the write access to the transmit FIFO to always be 16 bits
wide.
Signed off by: Steven A. Falco <sfalco@xxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-xiic.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c
@@ -311,10 +311,8 @@ static void xiic_fill_tx_fifo(struct xii
/* last message in transfer -> STOP */
data |= XIIC_TX_DYN_STOP_MASK;
dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__);
-
- xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
- } else
- xiic_setreg8(i2c, XIIC_DTR_REG_OFFSET, data);
+ }
+ xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
}
}
Patches currently in stable-queue which might be from sfalco@xxxxxxxxxx are
queue-3.4/i2c-xiic-must-always-write-16-bit-words-to-tx_fifo.patch
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