| Message ID | 1408203002-26403-1-git-send-email-broonie@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 38ec10f60d9ca3a7eb3a5b52500a67479296b86f |
| Headers | show |
Mark, On Sat, Aug 16, 2014 at 8:30 AM, Mark Brown <broonie@kernel.org> wrote: > From: Mark Brown <broonie@linaro.org> > > Client drivers such as the ChomeOS EC driver sometimes use transfers with > no buffers and only a delay specified in order to allow a delay after the > assertion of /CS. Rather than require controller drivers handle this noop > case gracefully put checks in the core to ensure that we don't call into > the controller for such transfers. > > Reported-by: Addy Ke <addy.ke@rock-chips.com> > Signed-off-by: Mark Brown <broonie@linaro.org> > --- > > Completely untested at this point. > > drivers/spi/spi.c | 44 ++++++++++++++++++++++++++------------------ > 1 file changed, 26 insertions(+), 18 deletions(-) Thank you for writing this patch. It looks great and works for me. Tested-by: Doug Anderson <dianders@chromium.org> Reviewed-by: Doug Anderson <dianders@chromium.org> -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index ca935df..95cfe3b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -789,27 +789,35 @@ static int spi_transfer_one_message(struct spi_master *master, list_for_each_entry(xfer, &msg->transfers, transfer_list) { trace_spi_transfer_start(msg, xfer); - reinit_completion(&master->xfer_completion); - - ret = master->transfer_one(master, msg->spi, xfer); - if (ret < 0) { - dev_err(&msg->spi->dev, - "SPI transfer failed: %d\n", ret); - goto out; - } + if (xfer->tx_buf || xfer->rx_buf) { + reinit_completion(&master->xfer_completion); + + ret = master->transfer_one(master, msg->spi, xfer); + if (ret < 0) { + dev_err(&msg->spi->dev, + "SPI transfer failed: %d\n", ret); + goto out; + } - if (ret > 0) { - ret = 0; - ms = xfer->len * 8 * 1000 / xfer->speed_hz; - ms += ms + 100; /* some tolerance */ + if (ret > 0) { + ret = 0; + ms = xfer->len * 8 * 1000 / xfer->speed_hz; + ms += ms + 100; /* some tolerance */ - ms = wait_for_completion_timeout(&master->xfer_completion, - msecs_to_jiffies(ms)); - } + ms = wait_for_completion_timeout(&master->xfer_completion, + msecs_to_jiffies(ms)); + } - if (ms == 0) { - dev_err(&msg->spi->dev, "SPI transfer timed out\n"); - msg->status = -ETIMEDOUT; + if (ms == 0) { + dev_err(&msg->spi->dev, + "SPI transfer timed out\n"); + msg->status = -ETIMEDOUT; + } + } else { + if (xfer->len) + dev_err(&msg->spi->dev, + "Bufferless transfer has length %u\n", + xfer->len); } trace_spi_transfer_stop(msg, xfer);