Messages in this thread | | | Date | Mon, 13 Jul 2015 12:01:05 +0300 | From | Tero Kristo <> | Subject | Re: [PATCH v5] clk: change clk_ops' ->determine_rate() prototype |
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On 07/08/2015 03:57 AM, Stephen Boyd wrote: > On 07/07, Boris Brezillon wrote: >> Clock rates are stored in an unsigned long field, but ->determine_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 ->determine_rate() prototype to return 0 or an error code, and pass >> a pointer to a clk_rate_request structure containing the expected target >> rate and the rate constraints imposed by clk users. >> >> The clk_rate_request structure might be extended in the future to contain >> other kind of constraints like the rounding policy, the maximum clock >> inaccuracy or other things that are not yet supported by the CCF >> (power consumption constraints ?). >> >> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> >> >> CC: Jonathan Corbet <corbet@lwn.net> >> CC: Tony Lindgren <tony@atomide.com> >> CC: Ralf Baechle <ralf@linux-mips.org> >> CC: "Emilio López" <emilio@elopez.com.ar> >> CC: Maxime Ripard <maxime.ripard@free-electrons.com> >> CC: Tero Kristo <t-kristo@ti.com> >> CC: Peter De Schrijver <pdeschrijver@nvidia.com> >> CC: Prashant Gaikwad <pgaikwad@nvidia.com> >> CC: Stephen Warren <swarren@wwwdotorg.org> >> CC: Thierry Reding <thierry.reding@gmail.com> >> CC: Alexandre Courbot <gnurou@gmail.com> >> CC: linux-doc@vger.kernel.org >> CC: linux-kernel@vger.kernel.org >> CC: linux-arm-kernel@lists.infradead.org >> CC: linux-omap@vger.kernel.org >> CC: linux-mips@linux-mips.org >> CC: linux-tegra@vger.kernel.org >> >> --- > > I'll throw this patch into -next now to see if any other problems > shake out. I'm hoping we get some more acks though, so it'll be > on it's own branch and become immutable in a week or so. One > question below.
Gave this patch a quick test on the boards I have access to, and didn't notice any obvious problems.
So, for the TI parts:
Acked-by: Tero Kristo <t-kristo@ti.com>
> >> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c >> index 616f5ae..9e69f34 100644 >> --- a/drivers/clk/clk-composite.c >> +++ b/drivers/clk/clk-composite.c >> @@ -99,33 +99,33 @@ static long clk_composite_determine_rate(struct clk_hw *hw, unsigned long rate, >> >> parent_rate = __clk_get_rate(parent); >> >> - tmp_rate = rate_ops->round_rate(rate_hw, rate, >> + tmp_rate = rate_ops->round_rate(rate_hw, req->rate, >> &parent_rate); >> if (tmp_rate < 0) >> continue; >> >> - rate_diff = abs(rate - tmp_rate); >> + rate_diff = abs(req->rate - tmp_rate); >> >> - if (!rate_diff || !*best_parent_p >> + if (!rate_diff || !req->best_parent_hw >> || best_rate_diff > rate_diff) { >> - *best_parent_p = __clk_get_hw(parent); >> - *best_parent_rate = parent_rate; >> + req->best_parent_hw = __clk_get_hw(parent); >> + req->best_parent_rate = parent_rate; >> best_rate_diff = rate_diff; >> best_rate = tmp_rate; >> } >> >> if (!rate_diff) >> - return rate; >> + return 0; >> } >> >> - return best_rate; >> + req->rate = best_rate; >> + return 0; >> } else if (mux_hw && mux_ops && mux_ops->determine_rate) { >> __clk_hw_set_clk(mux_hw, hw); >> - return mux_ops->determine_rate(mux_hw, rate, min_rate, >> - max_rate, best_parent_rate, >> - best_parent_p); >> + return mux_ops->determine_rate(mux_hw, req); >> } else { >> pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n"); >> + req->rate = 0; >> return 0; > > Shouldn't this return an error now? And then assigning req->rate > wouldn't be necessary. Sorry I must have missed this last round. >
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