sh: SH7722 clock framework support.

[pandora-kernel.git] / Documentation / sh / clk.txt

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+Clock framework on SuperH architecture
+
+The framework on SH extends existing API by the function clk_set_rate_ex,
+which prototype is as follows:
+
+    clk_set_rate_ex (struct clk *clk, unsigned long rate, int algo_id)
+
+The algo_id parameter is used to specify algorithm used to recalculate clocks,
+adjanced to clock, specified as first argument. It is assumed that algo_id==0
+means no changes to adjanced clock
+
+Internally, the clk_set_rate_ex forwards request to clk->ops->set_rate method,
+if it is present in ops structure. The method should set the clock rate and adjust
+all needed clocks according to the passed algo_id.
+Exact values for algo_id are machine-dependend. For the sh7722, the following
+values are defined:
+
+       NO_CHANGE       = 0,
+       IUS_N1_N1,      /* I:U = N:1, U:Sh = N:1 */
+       IUS_322,        /* I:U:Sh = 3:2:2        */
+       IUS_522,        /* I:U:Sh = 5:2:2        */
+       IUS_N11,        /* I:U:Sh = N:1:1        */
+       SB_N1,          /* Sh:B = N:1            */
+       SB3_N1,         /* Sh:B3 = N:1           */
+       SB3_32,         /* Sh:B3 = 3:2           */
+       SB3_43,         /* Sh:B3 = 4:3           */
+       SB3_54,         /* Sh:B3 = 5:4           */
+       BP_N1,          /* B:P   = N:1           */
+       IP_N1           /* I:P   = N:1           */
+
+Each of these constants means relation between clocks that can be set via the FRQCR
+register