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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Heiko Stuebner <heiko@sntech.de>
Cc: gregkh@linuxfoundation.org, jslaby@suse.com,
	matwey.kornilov@gmail.com, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org, lukas@wunner.de,
	christoph.muellner@theobroma-systems.com,
	giulio.benetti@micronovasrl.com,
	Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Subject: Re: [PATCH v2 4/7] serial: 8250: Handle implementations not having TEMT interrupt using em485
Date: Mon, 30 Mar 2020 17:52:39 +0300	[thread overview]
Message-ID: <20200330145239.GV1922688@smile.fi.intel.com> (raw)
In-Reply-To: <20200325231422.1502366-5-heiko@sntech.de>

On Thu, Mar 26, 2020 at 12:14:19AM +0100, Heiko Stuebner wrote:
> From: Giulio Benetti <giulio.benetti@micronovasrl.com>
> 
> Some 8250 ports have a TEMT interrupt but it's not a part of the 8250
> standard, instead only available on some implementations.
> 
> The current em485 implementation does not work on ports without it.
> The only chance to make it work is to loop-read on LSR register.
> 
> So add UART_CAP_TEMT to mark 8250 uarts having this interrupt,
> update all current em485 users with that capability and make
> the stop_tx function loop-read on uarts not having it.

> +		if (p->capabilities & UART_CAP_TEMT) {
> +			if ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
> +				return;
> +		} else {
> +			int lsr;
> +

> +			if (readx_poll_timeout(__get_lsr, p, lsr,
> +					(lsr & BOTH_EMPTY) == BOTH_EMPTY,
> +					0, 10000) < 0)

			ret = readx_poll_timeout(...);
			if (ret)
				...

will look better.

> +				pr_warn("%s: timeout waiting for fifos to empty\n",
> +					p->port.name);
> +		}

-- 
With Best Regards,
Andy Shevchenko



  parent reply	other threads:[~2020-03-30 14:52 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 23:14 [PATCH RFC v2 0/7] serial: 8250: Add rs485 emulation to 8250_dw Heiko Stuebner
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 1/7] serial: Allow uart_get_rs485_mode() to return errno Heiko Stuebner
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 2/7] dt-bindings: serial: Add binding for rs485 bus termination GPIO Heiko Stuebner
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 3/7] serial: 8250: Support " Heiko Stuebner
2020-03-30 14:51   ` Andy Shevchenko
2020-03-25 23:14 ` [PATCH v2 4/7] serial: 8250: Handle implementations not having TEMT interrupt using em485 Heiko Stuebner
2020-03-25 23:47   ` Giulio Benetti
2020-03-26  0:05     ` Heiko Stübner
2020-03-26  2:02       ` Giulio Benetti
2020-05-17 15:04         ` Heiko Stübner
2020-05-17 17:28           ` Giulio Benetti
2020-03-30 14:52   ` Andy Shevchenko [this message]
2020-05-02 13:49   ` Lukas Wunner
2020-05-05 16:38     ` Maarten Brock
2020-05-17 22:01     ` Heiko Stübner
2020-03-25 23:14 ` [PATCH v2 5/7] dt-bindings: serial: Add binding for rs485 receiver enable GPIO Heiko Stuebner
2020-03-30 14:54   ` Andy Shevchenko
2020-05-02 13:51   ` Lukas Wunner
2020-03-25 23:14 ` [PATCH v2 6/7] serial: 8250: Support separate rs485 rx-enable GPIO Heiko Stuebner
2020-03-30 14:56   ` Andy Shevchenko
2020-05-16 20:14   ` Lukas Wunner
2020-03-25 23:14 ` [PATCH v2 7/7] serial: 8250_dw: add em485 support Heiko Stuebner
2020-05-06 15:25   ` Andy Shevchenko

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