[PATCH] i2c: designware: Don't mask TX_EMPTY if write is in progress
jarkko.nikula at linux.intel.com
Fri Oct 30 05:03:53 PDT 2015
On 10/30/2015 09:37 AM, Jisheng Zhang wrote:
> Currently when i2c_msg index search is completed, TX_EMPTY interrupt
> will be masked. But if the size of i2c_msg data is longer than the size
> of the tx buffer, we still need TX_EMPTY interrupt, otherwise we will
> get "controller timed out" error.
> This patch fixes this issue by only masking TX_EMPTY if i2c_msg index
> search is completed and write is not in progress.
> Signed-off-by: Jisheng Zhang <jszhang at marvell.com>
> drivers/i2c/busses/i2c-designware-core.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> index 7441cdc..a2eb212 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -542,10 +542,11 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
> - * If i2c_msg index search is completed, we don't need TX_EMPTY
> - * interrupt any more.
> + * If i2c_msg index search is completed and writing is not in progress,
> + * we don't need TX_EMPTY interrupt any more.
> - if (dev->msg_write_idx == dev->msgs_num)
> + if (dev->msg_write_idx == dev->msgs_num &&
> + !(dev->status & STATUS_WRITE_IN_PROGRESS))
> intr_mask &= ~DW_IC_INTR_TX_EMPTY;
This looks a possible scenario here. What I'm wondering how is the
transfer ending and what condition in i2c_dw_isr() causes the complete()
Assuming we break the for loop in i2c_dw_xfer_msg() with buf_len > 0 and
dev->msg_write_idx == dev->msgs_num how we get back inside the for loop
for writing the remaining bytes and stop command?
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