[PATCH v5 06/14] ARM: OMAP2+: gpmc: CS configuration helper

On 06/12/2012 07:58 AM, Mohammed, Afzal wrote:

Hi Jon,

On Tue, Jun 12, 2012 at 14:10:08, Mohammed, Afzal wrote:

quoted

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+	l |= conf & GPMC_CONFIG1_DEVICETYPE_NAND;
+	l |= conf & GPMC_CONFIG1_DEVICESIZE_16;

I can see that it works to use the above definitions as masks because of
the possible values that can be programmed into these fields. However,
from a read-ability standpoint this is unclear and requires people to
review the documentation to understand what you are doing here.
Furthermore, if any new device-types or sizes were added in the future
this could lead to bugs. Hence, it would be better to define a mask for
these fields.

I had thought about it initially, but then it was felt it will
lead to a less simple code, that path was not taken, let me
revisit this.

Thinking again over it, I am feeling above is sufficient, reason same as
said earlier, to keep code simple & currently this is sufficient to
handle GPMC bit patterns for IPs presently available. What you are
suggesting is to take care of the imaginary case when new GPMC IP happens
with new device type or size, I think that should be handled when such a
scenario happens. Probably, it is better here to add a comment to make
intention clear.

That is one possibility but I think that more important reasons are ...

1. Readability, at first it appears that we are always configuring the
CS for NAND. However, this is not the case. Maybe a comment here can
help as you mentioned.

2. A bad setting in the configuration passed. Hopefully, people will
stick to the flags but we know that we expect the device type to be a 0
or 2 and so should we check?

Cheers
Jon