On Mon, Jul 15, 2013 at 11:08:55AM +0800, Huang Shijie wrote:
> The originall DMA support works only when the rts/cts is enabled.
s/originall/original/. I'd drop "the" and capitalize RTS/CTS.
> But after several patchs, the DMA support has lost this limit.
s/patchs/patches/, s/the //.
do you want to say that the driver fails to only enable DMA when RTS/CTS
are available; or that today the driver can handle DMA just fine even
without RTS/CTS? I interpret your commit log as the latter, your patch
implements the former however.
> This patch adds an optional property for the uart DT node
> which indicates the uart has rts and cts.
which indicates that the UART has RTS and CTS lines.
> This patch also adds the check for rts/cts before we enable the DMA
> for the uart.
>
> Signed-off-by: Huang Shijie <b32955@xxxxxxxxxxxxx>
> ---
> .../bindings/tty/serial/fsl-mxs-auart.txt | 3 +++
> drivers/tty/serial/mxs-auart.c | 5 ++++-
> 2 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> index 2c00ec6..ef82002 100644
> --- a/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> +++ b/Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
> @@ -10,6 +10,9 @@ Required properties:
> Refer to dma.txt and fsl-mxs-dma.txt for details.
> - dma-names: "rx" for RX channel, "tx" for TX channel.
>
> +Optional properties:
> +- fsl,uart-has-rtscts : Indicate the uart has rts and cts
> +
> Example:
> auart0: serial@8006a000 {
> compatible = "fsl,imx28-auart", "fsl,imx23-auart";
> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
> index 465ef0b..27532fd 100644
> --- a/drivers/tty/serial/mxs-auart.c
> +++ b/drivers/tty/serial/mxs-auart.c
> @@ -134,6 +134,7 @@ enum mxs_auart_type {
> struct mxs_auart_port {
> struct uart_port port;
>
> +#define MXS_AUART_RTSCTS 1
> #define MXS_AUART_DMA_ENABLED 0x2
> #define MXS_AUART_DMA_TX_SYNC 2 /* bit 2 */
> #define MXS_AUART_DMA_RX_READY 3 /* bit 3 */
> @@ -639,7 +640,7 @@ static void mxs_auart_settermios(struct uart_port *u,
> * we can only implement the DMA support for auart
> * in mx28.
> */
> - if (is_imx28_auart(s)) {
> + if (is_imx28_auart(s) && (s->flags & MXS_AUART_RTSCTS)) {
> if (!mxs_auart_dma_init(s))
> /* enable DMA tranfer */
> ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE
> @@ -1001,6 +1002,8 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
> }
> s->port.line = ret;
>
> + if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
> + s->flags |= MXS_AUART_RTSCTS;
> return 0;
> }
>
> --
> 1.7.1
>
>
>
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--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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