From: Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org>
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
Subject: [PATCH v5 02/12] clk: sunxi-ng: Use u64 for calculation of nkmp rate
Date: Wed, 14 Feb 2018 21:08:56 +0100 [thread overview]
Message-ID: <20180214200906.31509-3-jernej.skrabec@siol.net> (raw)
In-Reply-To: <20180214200906.31509-1-jernej.skrabec-gGgVlfcn5nU@public.gmane.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 <maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org>
---
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
next prev parent reply other threads:[~2018-02-14 20:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-14 20:08 [PATCH v5 00/12] drm/sun4i: Add A83T HDMI support Jernej Skrabec
[not found] ` <20180214200906.31509-1-jernej.skrabec-gGgVlfcn5nU@public.gmane.org>
2018-02-14 20:08 ` [PATCH v5 01/12] clk: sunxi-ng: Mask nkmp factors when setting register Jernej Skrabec
2018-02-14 20:08 ` Jernej Skrabec [this message]
2018-02-14 20:08 ` [PATCH v5 03/12] drm/bridge/synopsys: dw-hdmi: Enable workaround for v1.32a Jernej Skrabec
2018-02-16 5:01 ` Archit Taneja
2018-02-14 20:08 ` [PATCH v5 04/12] drm/bridge/synopsys: dw-hdmi: Export some PHY related functions Jernej Skrabec
2018-02-16 5:01 ` Archit Taneja
2018-02-14 20:08 ` [PATCH v5 05/12] drm/bridge/synopsys: dw-hdmi: don't clobber drvdata Jernej Skrabec
[not found] ` <20180214200906.31509-6-jernej.skrabec-gGgVlfcn5nU@public.gmane.org>
2018-02-16 5:01 ` Archit Taneja
2018-02-16 7:03 ` Heiko Stuebner
2018-02-19 13:49 ` Philipp Zabel
2018-02-14 20:09 ` [PATCH v5 06/12] dt-bindings: display: sun4i-drm: Add A83T HDMI pipeline Jernej Skrabec
2018-02-14 20:09 ` [PATCH v5 07/12] drm/sun4i: Add has_channel_0 TCON quirk Jernej Skrabec
2018-02-14 20:09 ` [PATCH v5 08/12] drm/sun4i: Add support for A83T second TCON Jernej Skrabec
2018-02-14 20:09 ` [PATCH v5 09/12] drm/sun4i: Add support for A83T second DE2 mixer Jernej Skrabec
2018-02-14 20:09 ` [PATCH v5 10/12] drm/sun4i: Implement A83T HDMI driver Jernej Skrabec
2018-02-14 21:42 ` Philippe Ombredanne
2018-02-14 20:09 ` [PATCH v5 11/12] ARM: dts: sun8i: a83t: Add HDMI display pipeline Jernej Skrabec
2018-02-14 20:09 ` [PATCH v5 12/12] ARM: dts: sun8i: a83t: Enable HDMI on BananaPi M3 Jernej Skrabec
2018-02-15 13:52 ` [PATCH v5 00/12] drm/sun4i: Add A83T HDMI support Maxime Ripard
2018-02-16 9:09 ` Maxime Ripard
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