From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailrelay005.isp.belgacom.be (mailrelay005.isp.belgacom.be [195.238.6.171]) by ozlabs.org (Postfix) with ESMTP id AC647DDF6C for ; Wed, 29 Oct 2008 02:10:18 +1100 (EST) From: Laurent Pinchart To: "Leon Woestenberg" Subject: Re: Floating inputs on unused GPIO pins Date: Tue, 28 Oct 2008 16:10:09 +0100 References: <200810131156.59477.laurentp@cse-semaphore.com> <48F34922.503@billgatliff.com> In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1996234.hrPGy7VxOM"; protocol="application/pgp-signature"; micalg=pgp-sha1 Message-Id: <200810281610.12445.laurentp@cse-semaphore.com> Cc: linuxppc-dev@ozlabs.org, Bill Gatliff List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --nextPart1996234.hrPGy7VxOM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi Leon, sorry for the late reply. On Monday 13 October 2008, Leon Woestenberg wrote: > Hello Laurent, >=20 > On Mon, Oct 13, 2008 at 3:12 PM, Bill Gatliff wrot= e: > > At least until someone plugs in that expansion module! > > > Bill's remark made a neuron connection in my head: >=20 > Can you detect if the module is inserted or not? (By reading a known > state of some pin)? I can, although it's a bit more complex than that. The module is connected = to the main board I2C bus so I can detect its presence by checking if chips= connected to the bus are detected. Using a GPIO would have been much easie= r, but that's life :-) > You could then configure the pins dynamically in your driver. That's what I'm doing. As dynamic pin configuration requires board-specific= knowledge in the device driver I would have liked to avoid that if possibl= e. Best regards, and thanks for your help. =2D-=20 Laurent Pinchart CSE Semaphore Belgium Chaussee de Bruxelles, 732A B-1410 Waterloo Belgium T +32 (2) 387 42 59 =46 +32 (2) 387 42 75 --nextPart1996234.hrPGy7VxOM Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEABECAAYFAkkHK1QACgkQlyYWY4YEWhX3xQCfe++SHcE/YFnnNKJQOHaHIMhk 4tUAn2bsvcEDC7ejqz/FUiCK3wWFloGE =Yuyz -----END PGP SIGNATURE----- --nextPart1996234.hrPGy7VxOM--