From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org [140.211.169.13]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "smtp.linux-foundation.org", Issuer "CA Cert Signing Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id EEF7CB6F94 for ; Thu, 26 May 2011 09:56:59 +1000 (EST) Date: Wed, 25 May 2011 16:56:20 -0700 From: Andrew Morton To: Jain Priyanka-B32167 Subject: Re: [rtc-linux] [PATCH] RTC driver(Linux) for PT7C4338 chip. Message-Id: <20110525165620.eeaa11ff.akpm@linux-foundation.org> In-Reply-To: <470DB7CE2CD0944E9436E7ADEFC02FE313B36C@039-SN1MPN1-003.039d.mgd.msft.net> References: <1299124299-26991-1-git-send-email-Priyanka.Jain@freescale.com> <20110303092239.GB3649@pengutronix.de> <470DB7CE2CD0944E9436E7ADEFC02FE313B1C2@039-SN1MPN1-003.039d.mgd.msft.net> <20110310085414.GA4460@pengutronix.de> <470DB7CE2CD0944E9436E7ADEFC02FE313B36C@039-SN1MPN1-003.039d.mgd.msft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: "a.zummo@towertech.it" , "linuxppc-dev@lists.ozlabs.org" , "rtc-linux@googlegroups.com" , "p_gortmaker@yahoo.com" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 10 Mar 2011 11:06:27 +0000 Jain Priyanka-B32167 wrote: > Hi Wolfram, > > > > -----Original Message----- > > From: Wolfram Sang [mailto:w.sang@pengutronix.de] > > Sent: Thursday, March 10, 2011 2:24 PM > > To: Jain Priyanka-B32167 > > Cc: rtc-linux@googlegroups.com; linuxppc-dev@lists.ozlabs.org; > > a.zummo@towertech.it; p_gortmaker@yahoo.com; akpm@linux-foundation.org > > Subject: Re: [rtc-linux] [PATCH] RTC driver(Linux) for PT7C4338 chip. > > > > Hi Priyanka, > > > > > Though register-set looks identical but features were different. > > > > Can you tell what exactly is different? > I will check both the devices data sheets again in detail and will get back on this. > > > > > And also manufacturer is different. > > > > That does not matter. If you look at ds_type, there are already different > > manufacturers. They will be correctly distinguished by i2c_device_id. The > > name of the driver itself is, well, just a name. > > > > > But still it might be possible that we can reuse ds1307.c with some > > > modification. > > > > I agree. The driver already supports some variants. Adding one more > > should not hurt. See 97f902b7be4dd6ba03c6aa8d3400783ed687ebd1 for an > > example which added ds3231 support. > > > > > But if I look at the drivers present in drivers/rtc folder. Most of > > > them looks similar but still there are different drivers for different > > > chips. > > > > Yes, it probably could be cleaned up if somebody had the time/hardware. > > > > > Please suggest which way is more preferred: modifying existing > > > drivers(of different manufacturer) or writing new driver. > > > > Ususally avoiding code duplication is good, it reduces maintenance > > burden. However, if adding the support turns out to make the original > > code unreadable or hard to follow, a new driver might be justified. This > > is why it is important to understand the differences of the chip as a > > first step. (I have the feeling, that modifying is the way to go here, > > though). > > > > I will explore possibility of using ds1307 driver for this. > Has there been any movement here?