Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932319AbbFRQgs (ORCPT ); Thu, 18 Jun 2015 12:36:48 -0400 Received: from down.free-electrons.com ([37.187.137.238]:44714 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751961AbbFRQgk (ORCPT ); Thu, 18 Jun 2015 12:36:40 -0400 Date: Thu, 18 Jun 2015 18:36:36 +0200 From: Alexandre Belloni To: Cyrille Pitchen Cc: nicolas.ferre@atmel.com, gregkh@linuxfoundation.org, wenyou.yang@atmel.com, ludovic.desroches@atmel.com, leilei.zhao@atmel.com, josh.wu@atmel.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, galak@codeaurora.org, ijc+devicetree@hellion.org.uk, mark.rutland@arm.com, pawel.moll@arm.com, robh+dt@kernel.org Subject: Re: [PATCH linux-next v2 3/4] tty/serial: at91: add support to FIFOs Message-ID: <20150618163636.GP27492@piout.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1254 Lines: 36 Hi, On 11/06/2015 at 18:20:16 +0200, Cyrille Pitchen wrote : > > Signed-off-by: Cyrille Pitchen Seems good to me, a few comments: > + if (port->fifo_size < 8 || port->fifo_size > 32) { I'm not sure why you limit the size to 32. At some point, a new SoC may be release with a bigger FIFO then we'll have to change the code instead of just putting the appropriate value in the device tree. > + port->fifo_size = 0; > + dev_err(&pdev->dev, "Invalid FIFO size\n"); > + return; > + } > + > + /* > + * 0 <= rts_low <= rts_high <= fifo_size > + * Once their CTS line asserted by the remote peer, some x86 UARTs tend > + * to flush their internal TX FIFO, commonly up to 8 data, before > + * actually stopping to send new data. So we try to set the RTS High > + * Threshold to a raisonable high value respecting this 8 data empirical reasonably --^ -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/