Hello Mike, On 07/01/2014 07:26 PM, Mike Turquette wrote: > Quoting Yadwinder Singh Brar (2014-06-29 21:01:36) >> Hi Javier, >> >> On Thu, Jun 26, 2014 at 11:45 PM, Javier Martinez Canillas >> <javier.martinez@xxxxxxxxxxxxxxx> wrote: >> > Maxim Integrated Power Management ICs are very similar with >> > regard to their clock outputs. Most of the clock drivers for >> > these chips are duplicating code and are simpler enough that >> > can be converted to use a generic driver to consolidate code >> > and avoid duplication. >> > >> > Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> >> > Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> >> > --- >> > >> > Changes since v4: >> > - Return recalc 0 if clock isn't enabled in Suggested by Yadwinder Singh Brar. >> > >> >> It seems you didn't implement or posted same patch again :) . >> >> > Changes since v3: >> > - Add current copyright information. Suggested by Krzysztof Kozlowski >> > - Do a single allocation for struct max_gen_clk. Suggested by Krzysztof Kozlowski >> > - Add EXPORT_SYMBOL() for exported symbols. Suggested by Krzysztof Kozlowski >> > >> > drivers/clk/Kconfig | 3 + >> > drivers/clk/Makefile | 1 + >> > drivers/clk/clk-max-gen.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++ >> > drivers/clk/clk-max-gen.h | 32 ++++++++ >> > 4 files changed, 231 insertions(+) >> > create mode 100644 drivers/clk/clk-max-gen.c >> > create mode 100644 drivers/clk/clk-max-gen.h >> > >> >> [ .. ] >> >> > + >> > +static unsigned long max_gen_recalc_rate(struct clk_hw *hw, >> > + unsigned long parent_rate) >> > +{ >> > + return 32768; >> > +} >> >> Its still same here. > > Changing this would be a new behavior. I do not know of any other clock > drivers that conditionally returns a rate of 0 based on whether or not > the clock is gated. > After Yadwinder feedback I searched for clock drivers that returned 0 when the clock was not enabled/prepared and found for example drivers/clk/clk-s2mps11.c: static unsigned long s2mps11_clk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct s2mps11_clk *s2mps11 = to_s2mps11_clk(hw); if (s2mps11->enabled) return 32768; else return 0; } > It is also buggy since calls to clk_enable and clk_disable do not invoke > .recalc_rate, so the rate of your clock would not be updated from the > framework's perspective until some later point where you call > clk_set_rate or something. > s2ps11->enabled is set in the driver's clk_ops .prepare and .unprepare function handlers and calls to clk_prepare and clk_unprepare also don't seems to invoke .recalc_rate so I guess that driver is wrong as well and should just return the clock rate unconditionally? > If your driver needs to know whether or not the clock is enabled then we > could introduce a new bool clk_is_enabled(struct clk *clk); to clk.h, > but I'd rather not do that. Instead if a driver needs a clock then it > calls clk_enable on it without any knowledge about the internal state of > the clock enable_count. > > Regards, > Mike > Thanks a lot for the explanation, I'll revert that change then and return the clock rate unconditionally on the next version of the patch-set. Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html