From: zhangqiumiao <zhangqiumiao1@huawei.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: "jirislaby@kernel.org" <jirislaby@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
"Chenxiang (EulerOS)" <rose.chen@huawei.com>,
"Yanan (Euler)" <yanan@huawei.com>
Subject: Re: [PATCH v3] tty: make pl011 serial port driver support 485 mode
Date: Fri, 15 Jan 2021 02:32:39 +0000 [thread overview]
Message-ID: <BEEC2888CE24964AA5C6EAB9EA9DA122272F78@dggemi529-mbs.china.huawei.com> (raw)
On Thu, Jan 14, 2021 at 08:28:30PM +0800, zhangqiumiao1@huawei.com wrote:
> From: Qiumiao Zhang <zhangqiumiao1@huawei.com>
>
> make pl011 serial port support 485 mode full duplex communication
>
> Signed-off-by: Qiumiao Zhang <zhangqiumiao1@huawei.com>
> ---
> Changes in v3:
> -Fix busy loop forever in pl011_tx_empty
> -Move the definition of cr into uart_amba_port
> -run checkpatch with no error or warning
>
> Changes in v2:
> -Fix two compilation errors
>
> drivers/tty/serial/amba-pl011.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/tty/serial/amba-pl011.c
> b/drivers/tty/serial/amba-pl011.c index c255476..9da10a4 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -44,6 +44,7 @@
>
> #include "amba-pl011.h"
>
> +#define ISEMPTY 1
> #define UART_NR 14
>
> #define SERIAL_AMBA_MAJOR 204
> @@ -264,6 +265,7 @@ struct uart_amba_port {
> unsigned int fifosize; /* vendor-specific */
> unsigned int old_cr; /* state during shutdown */
> unsigned int fixed_baud; /* vendor-set fixed baud rate */
> + unsigned int cr;
> char type[12];
> #ifdef CONFIG_DMA_ENGINE
> /* DMA stuff */
> @@ -1284,6 +1286,8 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
> #define pl011_dma_flush_buffer NULL
> #endif
>
> +static unsigned int pl011_tx_empty(struct uart_port *port);
> +
> static void pl011_stop_tx(struct uart_port *port) {
> struct uart_amba_port *uap =
> @@ -1292,6 +1296,17 @@ static void pl011_stop_tx(struct uart_port *port)
> uap->im &= ~UART011_TXIM;
> pl011_write(uap->im, uap, REG_IMSC);
> pl011_dma_tx_stop(uap);
> + if (port->rs485.flags & SER_RS485_ENABLED) {
> + while(pl011_tx_empty(port) != ISEMPTY) ;
I intend to change this to:
while(pl011_tx_empty(port) != ISEMPTY)
cpu_relax();
Is this ok?
> +
> + uap->cr = pl011_read(uap, REG_CR);
> + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) {
> + uap->cr |= UART011_CR_RTS;
> + } else {
> + uap->cr &= ~UART011_CR_RTS;
> + }
Checkpatch doesn't find the problem here. Please tell me what's wrong here?
thanks,
Qiumiao Zhang
next reply other threads:[~2021-01-15 2:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 2:32 zhangqiumiao [this message]
2021-01-15 6:29 ` [PATCH v3] tty: make pl011 serial port driver support 485 mode Greg KH
[not found] <1610627310-28889-1-git-send-email-zhangqiumiao1@huawei.com>
2021-01-14 12:33 ` Greg KH
[not found] <1610615253-18940-1-git-send-email-zhangqiumiao1@huawei.com>
2021-01-14 9:20 ` Greg KH
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BEEC2888CE24964AA5C6EAB9EA9DA122272F78@dggemi529-mbs.china.huawei.com \
--to=zhangqiumiao1@huawei.com \
--cc=gregkh@linuxfoundation.org \
--cc=jirislaby@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=rose.chen@huawei.com \
--cc=yanan@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).