From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Tue, 20 Oct 2015 09:34:50 +0200 Subject: [PATCH v5 1/5] clk: Add a basic multiplier clock In-Reply-To: References: <1445242139-20965-1-git-send-email-maxime.ripard@free-electrons.com> <1445242139-20965-2-git-send-email-maxime.ripard@free-electrons.com> Message-ID: <20151020073450.GA2711@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Oct 19, 2015 at 04:22:15PM +0800, Chen-Yu Tsai wrote: > On Mon, Oct 19, 2015 at 4:08 PM, Maxime Ripard > wrote: > > Some clocks are using a multiplier component, however, unlike their mux, > > gate or divider counterpart, these factors don't have a basic clock > > implementation. > > > > This leads to code duplication across platforms that want to use that kind > > of clocks, and the impossibility to use the composite clocks with such a > > clock without defining your own rate operations. > > > > Create such a driver in order to remove these issues, and hopefully factor > > the implementations, reducing code size across platforms and consolidating > > the various implementations. > > > > Signed-off-by: Maxime Ripard > > --- > > drivers/clk/Makefile | 1 + > > drivers/clk/clk-multiplier.c | 181 +++++++++++++++++++++++++++++++++++++++++++ > > include/linux/clk-provider.h | 42 ++++++++++ > > 3 files changed, 224 insertions(+) > > create mode 100644 drivers/clk/clk-multiplier.c > > > > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > > index d08b3e5985be..0b2101039508 100644 > > --- a/drivers/clk/Makefile > > +++ b/drivers/clk/Makefile > > @@ -6,6 +6,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-divider.o > > obj-$(CONFIG_COMMON_CLK) += clk-fixed-factor.o > > obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o > > obj-$(CONFIG_COMMON_CLK) += clk-gate.o > > +obj-$(CONFIG_COMMON_CLK) += clk-multiplier.o > > obj-$(CONFIG_COMMON_CLK) += clk-mux.o > > obj-$(CONFIG_COMMON_CLK) += clk-composite.o > > obj-$(CONFIG_COMMON_CLK) += clk-fractional-divider.o > > diff --git a/drivers/clk/clk-multiplier.c b/drivers/clk/clk-multiplier.c > > new file mode 100644 > > index 000000000000..fed71de801ca > > --- /dev/null > > +++ b/drivers/clk/clk-multiplier.c > > > > > +static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate, > > + unsigned long *best_parent_rate, > > + u8 width, unsigned long flags) > > +{ > > + unsigned long orig_parent_rate = *best_parent_rate; > > + unsigned long parent_rate, current_rate, best_rate = ~0; > > + unsigned int i, bestmult = 0; > > + > > + if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) > > + return rate / *best_parent_rate; > > + > > + for (i = 1; i < ((1 << width) - 1); i++) { > > + if (rate * i == orig_parent_rate) { > > The tested multiplier "i" is on the wrong side of the equation when > compared to the statement "current_rate = parent_rate * i" > > Since this should be a clock multiplier, that test can only be true > when i == 1, given that rate >= parent_rate. In all other cases it'll > fallback to the clk_hw_round_rate() call below. > > Am I missing something? You're totally right, I just completely forgot this comment before sending the new version :/ I'll send a new version. > Otherwise, this is > > Reviewed-by: Chen-Yu Tsai Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: