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| author | Steven A. Falco <sfalco@harris.com> | 2013-04-22 09:34:39 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-07 19:57:24 -0700 |
| commit | 9702319c6eb4ebedc334ea5825ccce3b210c4a32 (patch) | |
| tree | 341bda190d1bd216221827bf9586cc597e7b145e | |
| parent | 08181f491cd016e610d072dd42e8d0e7bda4a789 (diff) | |
| download | lwn-9702319c6eb4ebedc334ea5825ccce3b210c4a32.tar.gz lwn-9702319c6eb4ebedc334ea5825ccce3b210c4a32.zip | |
i2c: xiic: must always write 16-bit words to TX_FIFO
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@harris.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/i2c/busses/i2c-xiic.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c index 4bb68f35caf2..64e7065e8b86 100644 --- 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 xiic_i2c *i2c) /* 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); } } |