From mboxrd@z Thu Jan 1 00:00:00 1970 From: alexandre.belloni@free-electrons.com (Alexandre Belloni) Date: Thu, 18 Jun 2015 18:36:36 +0200 Subject: [PATCH linux-next v2 3/4] tty/serial: at91: add support to FIFOs In-Reply-To: References: Message-ID: <20150618163636.GP27492@piout.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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