From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Fri, 13 Jun 2014 13:24:12 +0000 Subject: Re: [PATCH v2] ARM: shmobile: koelsch: Add support HSCIF1 Message-Id: <1751840.oCdYe48VRu@avalon> List-Id: References: <1402367659-21117-1-git-send-email-nobuhiro.iwamatsu.yj@renesas.com> <9058795.dyXpcFtuGJ@avalon> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-arm-kernel@lists.infradead.org Hi Geert, On Friday 13 June 2014 13:16:34 Geert Uytterhoeven wrote: > On Fri, Jun 13, 2014 at 12:49 PM, Laurent Pinchart wrote: > > On Friday 13 June 2014 16:43:07 Simon Horman wrote: > >> On Fri, Jun 13, 2014 at 09:01:27AM +0200, Laurent Pinchart wrote: > >> > On Tuesday 10 June 2014 16:00:48 Simon Horman wrote: > >> > > On Tue, Jun 10, 2014 at 01:14:27PM +0900, Magnus Damm wrote: > >> > > > On Tue, Jun 10, 2014 at 11:34 AM, Nobuhiro Iwamatsu wrote: > >> > > > > Koelsch can use HSCIF1 insetead of SCIF1 as serial port. But if > >> > > > > we want to use, we will need to disable the GPIO key and > >> > > > > remodeling of the board. Therefore status of hscif1 does not s= et > >> > > > > the "okay". > >> > > > >=20 > >> > > > > Signed-off-by: Nobuhiro Iwamatsu > >> > > > > > >> > > > > --- > >> > > > >=20 > >> > > > > V2: Remove hscif1_clk from renesas,groups. This pin does not > >> > > > > use. > >> > > >=20 > >> > > > Thanks for updating the patch. This looks fine to me. > >> > > >=20 > >> > > > Acked-by: Magnus Damm > >> > >=20 > >> > > Thanks, I will queue this up. > >> >=20 > >> > Sorry for the late reply, but I have some doubts about this. The HRX0 > >> > and HTX0 signals are connected to push buttons and used as GPIOs. > >> > Beside, they're not routed to serial port transceiver. If we want to > >> > use HSCIF0 on those pins on Koelsch and extension board must be > >> > connected to the EXIO C connector, and two resistors and two capacit= ors > >> > should be unsoldered. I thus don't think the Koeslch DT should conta= in > >> > pinmux data for the HSCIF0 device. If an extension board is used and > >> > HSCIF0 needed, then the DT file for the extension board should define > >> > pinmuxing for the serial port. >=20 > You mean HRX1, HTX1, and HSCIF1? *sigh*... :-) > HTX1 and HRX1 can be connected to the DEBUG1 transceiver by stuffing > zero-Ohm resisters to R834 and R835. >=20 > About your comment about the resistors and capacitors, which applies to > both HSCIF0 and HSCIF1: probably the serial port will still work if > these are present. With a 4.7=B5F capacitive load on the transmission line, assuming a drive=20 strength of 40mA (which is pretty high), switching between 0V and 3.3V take= s=20 388=B5s, corresponding to 2579 Hz. You'll have to reduce the baud rate :-) > >> If you would like me to revert this patch I am happy to consider doing > >> so. > >=20 > > That's one option, but I'd like to get feedback on my point of view bef= ore > > reverting it. Who knows, I might be wrong ;-) >=20 > Nevertheless, I agree with Laurent. >=20 > HSCIF1 (and HSCIF0) cannot be used on the Koelsch board as-is, hence they > should not be present in the plain Koelsch DTS. They should be put in > an overlay DTS instead. --=20 Regards, Laurent Pinchart