Hi Addy, On Thu, Aug 14, 2014 at 08:52:24AM +0800, Addy Ke wrote: > To do so, spi communication can use an empty buf to pull up CS. > > This patch merged from ChromiumOS tree. > Cros_ec use this function to turn off CS and add a delay to ensure > the rising edge doesn't come too soon after the end of the data. > > Tested-by: Doug Anderson <dianders@xxxxxxxxxxxx> > Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx> > Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx> > --- > drivers/spi/spi-rockchip.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c > index 72fb287..1e3bcfa 100644 > --- a/drivers/spi/spi-rockchip.c > +++ b/drivers/spi/spi-rockchip.c > @@ -511,8 +511,8 @@ static int rockchip_spi_transfer_one(struct spi_master *master, > WARN_ON((readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY)); > > if (!xfer->tx_buf && !xfer->rx_buf) { > - dev_err(rs->dev, "No buffer for transfer\n"); > - return -EINVAL; > + dev_dbg(rs->dev, "No buffer for transfer\n"); > + return 0; > } Maybe we should only return 0 if xfer->len is also 0, otherwise keep complaining loudly? if (!xfer->tx_buf && !xfer->rx_buf) { if (xfer->len == 0) return 0; dev_err(rs->dev, "Missing transfer buffer\n"); return -EINVAL; } Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html