On Monday 24 November 2008 07:32:31 David Brownell wrote: > On Sunday 23 November 2008, Trilok Soni wrote: > > > 2) Please use the media/v4l2-i2c-drv.h or > > > media/v4l2-i2c-drv-legacy.h header to hide some of the i2c > > > complexity (again, see e.g. saa7115.c). The i2c API tends to > > > change a lot (and some changes are upcoming) so > > What "changes" do you mean? Since this is not a legacy-style > driver (yay!), the upcoming changes won't affect it at all. Oops, sorry. I thought it was a legacy driver, but it isn't. There are changes upcoming for legacy drivers, but not for new-style drivers. > > > using this header will mean that i2c driver changes will be > > > minimal in the future. In addition it will ensure that this > > > driver can be compiled with older kernels as well once it is part > > > of the v4l-dvb repository. > > > > I don't agree with having support to compile with older kernels. > > Right. Folk wanting legacy tvp5146 and tvp5140 support could > try to use the legacy drivers from the DaVinci tree. The v4l-dvb mercurial tree at www.linuxtv.org/hg which is the main v4l-dvb repository can support kernels >= 2.6.16. Before new stuff is merged with the git kernel all the compatibility stuff for old kernels is stripped out, so you don't see it in the actual kernel code. Using the media/v4l2-i2c-drv.h header makes it much easier to support these older kernels and it actually reduces the code size as well. Most v4l i2c drivers are already converted or will be converted soon. It's a v4l thing. > > Even though I2C APIs change as lot it is for good, and creating > > abstractions doesn't help as saa7xxx is family of chips where I > > don't see the case here. Once this driver is mainlined if someone > > does i2c subsystem change which breaks this driver from building > > then he/she has to make changes to all the code affecting it. > > And AFAIK no such change is anticipated. The conversion from > legacy style I2C drivers to "new style" driver-model friendly > drivers is progressing fairly well, so that legacy support can > be completely removed. > > > I am not in favour of adding support to compile with older kernels. > > My two cents: I'm not in favor either. In fact that's the > general policy for mainline drivers, and I'm surprised to hear > any maintainer suggest it be added. Again, it's specific to v4l drivers. You don't have to do it, but it makes it consistent with the other v4l i2c drivers and when the driver is in the v4l-dvb repository you get support for older kernels for free. Whether it is good or bad that the v4l-dvb repo works this way is a completely different discussion. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
