Hi folks
just a brief comment on this one:
On Thu, 30 Apr 2015, Boris Brezillon wrote:
Clock rates are stored in an unsigned long field, but ->round_rate() (which returns a rounded rate from a requested one) returns a long value (errors are reported using negative error codes), which can lead to long overflow if the clock rate exceed 2Ghz.
Change ->round_rate() prototype to return 0 or an error code, and pass the requested rate as a pointer so that it can be adjusted depending on hardware capabilities.
...
diff --git a/Documentation/clk.txt b/Documentation/clk.txt index 0e4f90a..fca8b7a 100644 --- a/Documentation/clk.txt +++ b/Documentation/clk.txt @@ -68,8 +68,8 @@ the operations defined in clk.h: int (*is_enabled)(struct clk_hw *hw); unsigned long (*recalc_rate)(struct clk_hw *hw, unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw,unsigned long rate,
int (*round_rate)(struct clk_hw *hw,unsigned long *rate, unsigned long *parent_rate);
I'd suggest that we should probably go straight to 64-bit rates. There are already plenty of clock sources that can generate rates higher than 4GiHz.
- Paul