From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Stigge Subject: Re: [PATCH] serial/of-serial: Add 16654 chip to compatible string list Date: Mon, 28 May 2012 19:48:57 +0200 Message-ID: <4FC3BA89.4060804@antcom.de> References: <1338199134-23885-1-git-send-email-stigge@antcom.de> <20120528100338.GI24149@n2100.arm.linux.org.uk> <4FC35F97.2030400@antcom.de> <20120528150311.GA28290@n2100.arm.linux.org.uk> <4FC3A768.3060208@antcom.de> <20120528163151.GB28290@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from antcom.de ([188.40.178.216]:44772 "EHLO chuck.antcom.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753396Ab2E1RtA (ORCPT ); Mon, 28 May 2012 13:49:00 -0400 In-Reply-To: <20120528163151.GB28290@n2100.arm.linux.org.uk> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Russell King - ARM Linux Cc: alan@linux.intel.com, gregkh@linuxfoundation.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, kevin.wells@nxp.com, srinivas.bakki@nxp.com, linux-arm-kernel@lists.infradead.org, arnd@arndb.de On 28/05/12 18:31, Russell King - ARM Linux wrote: >>>> So maybe 16750 is the better choice for me, anyway. Already supported in >>>> of-serial. Works for now, but need more testing. Another hint is that >>>> 16750 is advertised as "IP core for Soc" which matches the case of LPC32xx. >>> >>> 16750 also has automatic hardware flow control support, selectable through >>> bit 5 in the MCR register. If your UART has that, then it's probably a >>> 16750 derivative rather than a 16550 or 16650 derivative. >>> >>> 16650s have an EFR register at offset 2, selectable by writing 0xBF into >>> the LCR register, which the 16750 doesn't have. 16650 also has automatic >>> hardware flow control, bit this is selected through a couple of bits in >>> the EFR. >> >> The 4 LPC32xx's "Standard" UARTs have neither of those. >> >> Is it ok to use "ns16650", i.e. PORT_16650, or do I need to introduce a >> FIFO depth configuration? > > I think you need a new type, because as I said above, 16650s have that > additional EFR, and we will attempt to access that register which > isn't present in yours. I actually meant 16750 instead of 16650, sorry, but this basically means the same - I would refer to extensions that are actually not there... Now, introducing a new type, can I add to 8250.c's uart_config[] by introducing a new type (no. 22) after PORT_XR17D15X? Unfortunately, there are the "ARM specific type numbers" after current PORT_MAX_8250 (21), but those are not listed in 8250.c's uart_config[]. Or how am I supposed to add a new type? Thanks in advance, Roland From mboxrd@z Thu Jan 1 00:00:00 1970 From: stigge@antcom.de (Roland Stigge) Date: Mon, 28 May 2012 19:48:57 +0200 Subject: [PATCH] serial/of-serial: Add 16654 chip to compatible string list In-Reply-To: <20120528163151.GB28290@n2100.arm.linux.org.uk> References: <1338199134-23885-1-git-send-email-stigge@antcom.de> <20120528100338.GI24149@n2100.arm.linux.org.uk> <4FC35F97.2030400@antcom.de> <20120528150311.GA28290@n2100.arm.linux.org.uk> <4FC3A768.3060208@antcom.de> <20120528163151.GB28290@n2100.arm.linux.org.uk> Message-ID: <4FC3BA89.4060804@antcom.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 28/05/12 18:31, Russell King - ARM Linux wrote: >>>> So maybe 16750 is the better choice for me, anyway. Already supported in >>>> of-serial. Works for now, but need more testing. Another hint is that >>>> 16750 is advertised as "IP core for Soc" which matches the case of LPC32xx. >>> >>> 16750 also has automatic hardware flow control support, selectable through >>> bit 5 in the MCR register. If your UART has that, then it's probably a >>> 16750 derivative rather than a 16550 or 16650 derivative. >>> >>> 16650s have an EFR register at offset 2, selectable by writing 0xBF into >>> the LCR register, which the 16750 doesn't have. 16650 also has automatic >>> hardware flow control, bit this is selected through a couple of bits in >>> the EFR. >> >> The 4 LPC32xx's "Standard" UARTs have neither of those. >> >> Is it ok to use "ns16650", i.e. PORT_16650, or do I need to introduce a >> FIFO depth configuration? > > I think you need a new type, because as I said above, 16650s have that > additional EFR, and we will attempt to access that register which > isn't present in yours. I actually meant 16750 instead of 16650, sorry, but this basically means the same - I would refer to extensions that are actually not there... Now, introducing a new type, can I add to 8250.c's uart_config[] by introducing a new type (no. 22) after PORT_XR17D15X? Unfortunately, there are the "ARM specific type numbers" after current PORT_MAX_8250 (21), but those are not listed in 8250.c's uart_config[]. Or how am I supposed to add a new type? Thanks in advance, Roland