On Monday, September 29, 2014 at 02:30:04 AM, bpqw wrote: > >> For Micron spi norflash,you can enable Quad spi transfer by clear > >> EVCR(Enhanced Volatile Configuration Register) Quad I/O protocol bit. > > > >OK, this information is nice and all, but what does this patch do? I can't > >learn this information from the commit message as it is, can I ? And , > >the purpose of the commit message is exactly to summarize the change the > >patch implements. > > you don't understand what purpose of this patch!
Well, I dare to say, reacting to feedback like you just did won't make you many allies around here. > just as subject and commit > message described, it is for enable Micron Quad spi transfer mode. I understand the subject part. The commit message, on the other hand, just states that it is possible to frob with a certain register to achieve a certain effect ; the commit message does not state what this patch does or how is the patch useful. Does this patch enable the bit or does it disable the bit ? I cannot tell without looking into the code , I really have no clue just by reading the subject and the commit message. > do you > read the spi-nor.c file? No, I didn't even look at the code. > please pay attention to the set_quad_mode() > function. No, what set_quad_mode_function() are you talking about ... > by the way,I can add more commit message for it,but I think it is > redundant,don't need. The commit message shall state what the patch does in the first place, what the hardware can do is ortogonal to that. The commit message can be as short as: The hardware supports 4-bit I/O when bit FOO is set in register BAR. This patch adds function that sets bit FOO in register BAR to enable 4-bit I/O if condition BAZ and QUUX are met. Then I do not even have to look at the code if I want to just get the high-level overview of what the patch does. If I want to know the details, I will look into the code. Do you know what I'm getting at ? [...] Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
