From: Lukas Wunner <lukas@wunner.de>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: linux-serial <linux-serial@vger.kernel.org>,
"Greg KH" <gregkh@linuxfoundation.org>,
"Jiri Slaby" <jirislaby@kernel.org>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Vicente Bergas" <vicencb@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Johan Hovold" <johan@kernel.org>,
heiko@sntech.de, giulio.benetti@micronovasrl.com,
"Heikki Krogerus" <heikki.krogerus@linux.intel.com>,
"Raymond Tan" <raymond.tan@intel.com>
Subject: Re: [PATCH v4 04/13] serial: 8250_dwlib: RS485 HW half & full duplex support
Date: Tue, 20 Sep 2022 14:10:33 +0200 [thread overview]
Message-ID: <20220920121033.GA12065@wunner.de> (raw)
In-Reply-To: <64fb5487-76c6-f6ed-d110-c98bde2f7917@linux.intel.com>
On Tue, Sep 20, 2022 at 03:01:52PM +0300, Ilpo Järvinen wrote:
> I don't think you can just move from one to another like that because DE
> and RTS are not the same signal on these UARTs. So it's not going to be
> compatible w/o additional effort anyway.
>
> Initially, I tried to add a flag for selecting between the HW one and
> emulation but got overruled (you were among the opposing people ;-)).
> ...IIRC, I tried to explain back then that those signals are not the
> same with this HW.
Right, I remember that discussion. :)
I guess we can always retrofit that selection option if anyone needs it.
Generally if hardware RS485 support is available, one doesn't want to
use software emulation.
stm32-usart.c originally only had hardware-driven Driver Enable and
software emulation was added afterwards because the RTS pin is
sometimes pinmuxed to some other function. But such use cases are
probably rare.
Thanks,
Lukas
next prev parent reply other threads:[~2022-09-20 12:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-25 14:33 [PATCH v4 00/13] Add RS485 support to DW UART Ilpo Järvinen
2022-04-25 14:33 ` [PATCH v4 01/13] serial: Store character timing information to uart_port Ilpo Järvinen
2022-04-25 14:33 ` [PATCH v4 02/13] serial: 8250: use THRE & __stop_tx also with DMA Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 03/13] serial: 8250: Handle UART without interrupt on TEMT Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 04/13] serial: 8250_dwlib: RS485 HW half & full duplex support Ilpo Järvinen
2022-04-26 11:29 ` Greg KH
2022-09-20 11:37 ` Lukas Wunner
2022-09-20 12:01 ` Ilpo Järvinen
2022-09-20 12:10 ` Lukas Wunner [this message]
2022-04-25 14:34 ` [PATCH v4 05/13] serial: 8250_dwlib: Implement SW half " Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 06/13] dt_bindings: rs485: Add receiver enable polarity Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 07/13] ACPI / property: Document RS485 _DSD properties Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 08/13] serial: termbits: ADDRB to indicate 9th bit addressing mode Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 09/13] serial: General support for multipoint addresses Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 10/13] serial: 8250: make saved LSR larger Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 11/13] serial: 8250: create lsr_save_mask Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 12/13] serial: 8250_lpss: Use 32-bit reads Ilpo Järvinen
2022-04-25 14:34 ` [PATCH v4 13/13] serial: 8250_dwlib: Support for 9th bit multipoint addressing Ilpo Järvinen
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