[rtc-linux] [PATCH] RTC driver(Linux) for PT7C4338 chip.

Andrew Morton akpm at linux-foundation.org
Thu May 26 09:56:20 EST 2011


On Thu, 10 Mar 2011 11:06:27 +0000
Jain Priyanka-B32167 <B32167 at freescale.com> wrote:

> Hi Wolfram, 
> 
> 
> > -----Original Message-----
> > From: Wolfram Sang [mailto:w.sang at pengutronix.de]
> > Sent: Thursday, March 10, 2011 2:24 PM
> > To: Jain Priyanka-B32167
> > Cc: rtc-linux at googlegroups.com; linuxppc-dev at lists.ozlabs.org;
> > a.zummo at towertech.it; p_gortmaker at yahoo.com; akpm at 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?


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