From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jernej Skrabec Subject: [PATCH v5 02/12] clk: sunxi-ng: Use u64 for calculation of nkmp rate Date: Wed, 14 Feb 2018 21:08:56 +0100 Message-ID: <20180214200906.31509-3-jernej.skrabec@siol.net> References: <20180214200906.31509-1-jernej.skrabec@siol.net> Reply-To: jernej.skrabec-gGgVlfcn5nU@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20180214200906.31509-1-jernej.skrabec-gGgVlfcn5nU@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, airlied-cv59FeDIM0c@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, a.hajda-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, Laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, narmstrong-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, Jose.Abreu-HKixBCOQz3hWk0Htik3J/w@public.gmane.org Cc: jernej.skrabec-gGgVlfcn5nU@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org When parent rate is 24MHz and multiplier N >= 180, intermediate clock rate doesn't fit in 32 bit variable anymore. Because of that, introduce function for calculating clock rate which uses 64 bit variable for intermediate result. Acked-by: Maxime Ripard Signed-off-by: Jernej Skrabec --- drivers/clk/sunxi-ng/ccu_nkmp.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.c b/drivers/clk/sunxi-ng/ccu_nkmp.c index a99068a08315..c3f6fe7be565 100644 --- a/drivers/clk/sunxi-ng/ccu_nkmp.c +++ b/drivers/clk/sunxi-ng/ccu_nkmp.c @@ -20,6 +20,18 @@ struct _ccu_nkmp { unsigned long p, min_p, max_p; }; +static unsigned long ccu_nkmp_calc_rate(unsigned long parent, + unsigned long n, unsigned long k, + unsigned long m, unsigned long p) +{ + u64 rate = parent; + + rate *= n * k; + do_div(rate, m * p); + + return rate; +} + static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate, struct _ccu_nkmp *nkmp) { @@ -33,7 +45,9 @@ static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate, for (_p = nkmp->min_p; _p <= nkmp->max_p; _p <<= 1) { unsigned long tmp_rate; - tmp_rate = parent * _n * _k / (_m * _p); + tmp_rate = ccu_nkmp_calc_rate(parent, + _n, _k, + _m, _p); if (tmp_rate > rate) continue; @@ -107,7 +121,7 @@ static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw, p = reg >> nkmp->p.shift; p &= (1 << nkmp->p.width) - 1; - return (parent_rate * n * k >> p) / m; + return ccu_nkmp_calc_rate(parent_rate, n, k, m, 1 << p); } static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate, @@ -127,7 +141,8 @@ static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate, ccu_nkmp_find_best(*parent_rate, rate, &_nkmp); - return *parent_rate * _nkmp.n * _nkmp.k / (_nkmp.m * _nkmp.p); + return ccu_nkmp_calc_rate(*parent_rate, _nkmp.n, _nkmp.k, + _nkmp.m, _nkmp.p); } static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate, -- 2.16.1