From: Russell King <rmk@arm.linux.org.uk>
To: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
Cc: gregkh@suse.de, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] amba-pl011: do not disable RTS during shutdown
Date: Tue, 17 Jan 2012 18:40:48 +0000 [thread overview]
Message-ID: <20120117184047.GE22472@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1326796189-21722-1-git-send-email-shreshthakumar.sahu@stericsson.com>
On Tue, Jan 17, 2012 at 03:59:49PM +0530, Shreshtha Kumar SAHU wrote:
> From: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
>
> In present driver, shutdown clears RTS in CR register. But the
> documentation "Documentation/serial/driver" suggests not to
> disable RTS in shutdown(). Also RTS is preserved between shutdown
> and startup calls, i.e. it is restored in startup if it was enabled
> during shutdown. So that if autorts is set and RTS is set using
> pl011_set_mctrl then it should continue even after shutdown->startup
> sequence. And hence during set_termios it will enable RTS only if RTS
> bit is set in UARTx_CR register. For throttling/unthrottling user
> should call pl011_set_mctrl.
>
> Change-Id: I743f33fb10e7e655657cd5dae1ec585e914a65bc
Please get rid of this line.
> Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> drivers/tty/serial/amba-pl011.c | 17 ++++++++++++++++-
> 1 files changed, 16 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 6958594..46a4690 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -160,6 +160,7 @@ struct uart_amba_port {
> unsigned int lcrh_tx; /* vendor-specific */
> unsigned int lcrh_rx; /* vendor-specific */
> bool autorts;
> + bool rts_state; /* state during shutdown */
Do we really need a variable to track this?
> char type[12];
> bool interrupt_may_hang; /* vendor-specific */
> #ifdef CONFIG_DMA_ENGINE
> @@ -1412,6 +1413,8 @@ static int pl011_startup(struct uart_port *port)
> barrier();
>
> cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
> + if (uap->rts_state)
> + cr |= UART011_CR_RTS;
> writew(cr, uap->port.membase + UART011_CR);
Note that this should preserve DTR as well.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
next prev parent reply other threads:[~2012-01-17 18:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-17 10:29 [PATCH] amba-pl011: do not disable RTS during shutdown Shreshtha Kumar SAHU
2012-01-17 15:41 ` Greg KH
2012-01-17 18:40 ` Russell King [this message]
2012-01-18 9:36 ` Shreshtha Kumar SAHU
2012-01-18 9:45 ` Shreshtha Kumar SAHU
2012-01-18 10:10 ` Russell King
2012-01-18 10:23 ` Shreshtha Kumar SAHU
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=20120117184047.GE22472@flint.arm.linux.org.uk \
--to=rmk@arm.linux.org.uk \
--cc=gregkh@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=shreshthakumar.sahu@stericsson.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).