From: arno@natisbad.org (Arnaud Ebalard) Date: Mon, 17 Nov 2014 09:25:15 +0100 Subject: [PATCHv1 2/3] arm: mvebu: add .dts file for Synology DS213j In-Reply-To: <546931E1.5070909@killerwolves.net> (Ben Peddell's message of "Mon, 17 Nov 2014 09:23:13 +1000") References: <1eb26f8c1946622910a7e2318c895a7082fea7e5.1416095841.git.arno@natisbad.org> <20141116020024.GC15870@lunn.ch> <87d28nb83u.fsf@natisbad.org> <546931E1.5070909@killerwolves.net> Message-ID: <878ujas07o.fsf@natisbad.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Ben Peddell writes: > On 16/11/2014 11:14 PM, Arnaud Ebalard wrote: >>>> + gpio-fan-100-32-35 { >>> There is some logic to this naming, but i don't remember what it is. >>> Did you check this is appropriate? >> The 32-35 is for the MPP i.e. fan uses mpp32 to mpp35 (3 MPP for speed, >> one for alarm). I don't know what the 100 part means. What I did is I >> googled to see which fan supported kirkwood models have and noticed >> that the DS212j uses the exact same fan, i.e. Y.S.Tech FD129225LL-N so >> I opted for the same naming. >> >> On that aspect, you may be able to explain why the speed-map for this >> fan goes up to 5000 RPM. This fan is supposed to operate at 1900RPM. >> Note that it does not matter in practice. > > On the Kirkwood Diskstations, the first number (100, 120 or 150) refers > to the middle of the three fan speed resistors, Would not have found that alone ;-) Thanks for clarifying. > the second number (15 or > 32) refers to the first fan control pin, and the third number (18 or 35) > refers to the first fan alarm pin. > > i.e. the 100-32-35 uses fan speed resistors of 33, 100 and 150 ohms, > uses pins 32-34 for fan control, and uses pin 35 for the fan alarm. > > The 5000RPM was interpolated from my measured RPM pulse rate (4200PPM) > of the 80mm fan in my DS211j (which uses the 150-32-35 fan config) at > maximum RPM. Then, I think I need to change the speed map to have 1900 RPM as max speed. Out of curiosity, how did you measured the RPM pulse rate exactly? Cheers, a+