Hi Paul, On Thu, 4 Jun 2015 23:02:25 +0000 (UTC) Paul Walmsley <paul@xxxxxxxxx> wrote: > 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); > > long (*determine_rate)(struct clk_hw *hw, > > unsigned long 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. Yep, that was something I was considering too. If Stephen agrees I'll change that in the next version. BTW, you're referring to the second version of this patch, but things have changed a bit: Stephen recommended to only modify the ->determine_rate() prototype and pass a structure instead of a list of arguments. Here is the last version of this series [1]. Best Regards, Boris [1]http://patchwork.linux-mips.org/patch/10092/ -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
