diff options
| author | Jernej Skrabec <jernej.skrabec@siol.net> | 2018-02-14 21:08:56 +0100 |
|---|---|---|
| committer | Maxime Ripard <maxime.ripard@bootlin.com> | 2018-02-15 14:40:24 +0100 |
| commit | a5ebc3368ef7c77da5a03ad52834520a634a36ef (patch) | |
| tree | 0997c61268d7a241b2c3036257de6793d0e535d8 /drivers/clk/sunxi-ng | |
| parent | d897ef56faf9bdb36e931251d0b70b10ebb03a14 (diff) | |
| download | linux-a5ebc3368ef7c77da5a03ad52834520a634a36ef.tar.bz2 | |
clk: sunxi-ng: Use u64 for calculation of nkmp rate
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@bootlin.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Diffstat (limited to 'drivers/clk/sunxi-ng')
| -rw-r--r-- | drivers/clk/sunxi-ng/ccu_nkmp.c | 21 |
1 files 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, |