clk: Add support for rate table based dividers

Some divider clks do not have any obvious relationship
between the divider and the value programmed in the
register. For instance, say a value of 1 could signify divide
by 6 and a value of 2 could signify divide by 4 etc.
Also there are dividers where not all values possible
based on the bitfield width are valid. For instance
a 3 bit wide bitfield can be used to program a value
from 0 to 7. However its possible that only 0 to 4
are valid values.

All these cases need the platform code to pass a simple
table of divider/value tuple, so the framework knows
the exact value to be written based on the divider
calculation and can also do better error checking.

This patch adds support for such rate table based
dividers and as part of the support adds a new
registration function 'clk_register_divider_table()'
and a new macro for static definition
'DEFINE_CLK_DIVIDER_TABLE'.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 18 insertions, 2 deletions

diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index eb3f84bc532..cc9972d1429 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -103,9 +103,9 @@ struct clk {
         DEFINE_CLK(_name, clk_gate_ops, _flags,                 \
                         _name##_parent_names, _name##_parents);
 
-#define DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,    \
+#define _DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,   \
                                 _flags, _reg, _shift, _width,   \
-                                _divider_flags, _lock)          \
+                                _divider_flags, _table, _lock)  \
         static struct clk _name;                                \
         static const char *_name##_parent_names[] = {           \
                 _parent_name,                                   \
@@ -121,11 +121,27 @@ struct clk {
                 .shift = _shift,                                \
                 .width = _width,                                \
                 .flags = _divider_flags,                        \
+                .table = _table,                                \
                 .lock = _lock,                                  \
         };                                                      \
         DEFINE_CLK(_name, clk_divider_ops, _flags,              \
                         _name##_parent_names, _name##_parents);
 
+#define DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,    \
+                                _flags, _reg, _shift, _width,   \
+                                _divider_flags, _lock)          \
+        _DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,   \
+                                _flags, _reg, _shift, _width,   \
+                                _divider_flags, NULL, _lock)
+
+#define DEFINE_CLK_DIVIDER_TABLE(_name, _parent_name,           \
+                                _parent_ptr, _flags, _reg,      \
+                                _shift, _width, _divider_flags, \
+                                _table, _lock)                  \
+        _DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,   \
+                                _flags, _reg, _shift, _width,   \
+                                _divider_flags, _table, _lock)  \
+
 #define DEFINE_CLK_MUX(_name, _parent_names, _parents, _flags,  \
                                 _reg, _shift, _width,           \
                                 _mux_flags, _lock)              \