From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: PCF8563 doesn't pass validation check Date: Wed, 2 Jul 2008 13:17:48 +0200 Message-ID: <200807021317.50944.laurentp@cse-semaphore.com> References: <200807021134.59668.laurentp@cse-semaphore.com> <20080702131020.28e1979a@hyperion.delvare> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5965440441399414032==" Return-path: In-Reply-To: <20080702131020.28e1979a-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: Jean Delvare Cc: a.zummo-BfzFCNDTiLLj+vYz1yj4TQ@public.gmane.org, i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org, rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Rod Whitby List-Id: linux-i2c@vger.kernel.org --===============5965440441399414032== Content-Type: multipart/signed; boundary="nextPart2503923.We6ivNc4W0"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart2503923.We6ivNc4W0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Wednesday 02 July 2008, Jean Delvare wrote: > Hi Laurent, >=20 > On Wed, 2 Jul 2008 11:34:55 +0200, Laurent Pinchart wrote: > > I'm having issues with the PCF8563 RTC chip. > >=20 > > The Linux driver tries to validate the chip by checking if the > > BCD-coded time and date registers contain valid values. > >=20 > > When a low voltage condition is detected, the registers are not > > guaranteed to contain valid values. Experimentation showed that > > while the seconds, minutes, hours and day of the week registers > > didn't cause any issue, the months register could get out of the > > 01-12 range. > >=20 > > Has anyone experienced the same issue ? >=20 > This issue sounds familiar, I think Alessandro mentioned it to me a few > weeks ago in private already. >=20 > > Would it be acceptable to remove the months register check ? >=20 > I think you should convert rtc-pcf8563 to a new-style i2c driver. Then > the whole validation function becomes pointless and you can delete it. > I guess that the PCF8563 chip is used in embedded designs with platform > code to instantiate the I2C devices as needed, so it should work fine. > Apparently some IXP4xx platforms already expect rtc-pcf8563 to be a > new-style i2c driver... I'm curious if some ARM people have already > converted the driver. Rod? Isn't rtc-pcf8563 a new-style i2c driver already ? > > I've contacted NXP to get more information about what the chip > > guarantees and what it doesn't. I haven't had any answer yet but > > I expect them to tell me there is no guarantee at all. =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 --nextPart2503923.We6ivNc4W0 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) iEYEABECAAYFAkhrY94ACgkQ8y9gWxC9vpdHmgCffQKiyPmUff+1C+tShSiSsoOf XSAAn0TBYwjwTurQJDN9zrs2uFkNyTwY =PbOZ -----END PGP SIGNATURE----- --nextPart2503923.We6ivNc4W0-- --===============5965440441399414032== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c --===============5965440441399414032==--