[PATCH] i2c: designware: Don't mask TX_EMPTY if write is in progress
From: Jarkko Nikula <hidden>
Date: 2015-10-30 12:03:58
Also in:
linux-i2c, lkml
Hi On 10/30/2015 09:37 AM, Jisheng Zhang wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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() call? 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? -- Jarkko