On Thu, Nov 10, 2011 at 09:23:18AM +0000, Dong Aisheng-B29396 wrote:
+static const struct mxs_saif_platform_data
mx28evk_mxs_saif_pdata __initconst = {- .init = mx28evk_mxs_saif_pinit,
- .get_master_id = mxs_get_saif_clk_master_id,
This looks *very* suspicious. .init sets the mux register and .get_master_id reads the very same information back. Why not simply put a bool is_master into platform data?
Originally it's used to avoid introduce a global variable to save clkmux Since we can directly read it from register.
If put a bool is_master into pdata, we are assuming there are only two saif Instances. As I was suggested by Wolfram before that how about if there are more than two saifs in the future SoCs?
I don't understand. A is_master variable in platform_data does not make any assumption about the number of interfaces in the system.
So the original saif driver design is following this rule that it only needs to know its master id.
If that's the design then put the master id into platform_data. This information is purely static and the board knows it. No need to put a function in platform_data. Something like this:
struct saif_pdata { bool master_mode; /* if true use master mode */ int master_id; /* id of the master if in slave mode */ };
If we decide to change here, I may also have a lot to change in saif driver.
Some lines in the probe code, not more.
Sascha