From patchwork Thu Mar 22 23:05:01 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1/1] ARM iMX28: incorrect frac/div calculation Date: Thu, 22 Mar 2012 13:05:01 -0000 From: Matt Burtch X-Patchwork-Id: 148352 Message-Id: <1332457501-8153-1-git-send-email-matt@grid-net.com> To: Sascha Hauer , Shawn Guo , Russell King , linux-arm-kernel@lists.infradead.org Cc: Matt Burtch , stable@kernel.org The frac and div values in _CLK_SET_RATE are calculated incorrectly for some clock rates ie. CPU clk of 454.73MHz, 392.72MHz, 261.81Mhz, etc. Now the frac and div values which result in the closest actual clock rate to that requested is selected. Also there are no limitations on what frac values can be used, as long as they fall in the valid (18 < frac < 35) range. Tested on custom iMX28 board. Signed-off-by: Matt Burtch --- arch/arm/mach-mxs/clock-mx28.c | 8 ++------ 1 files changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/arm/mach-mxs/clock-mx28.c b/arch/arm/mach-mxs/clock-mx28.c index 5d68e41..a058b99 100644 --- a/arch/arm/mach-mxs/clock-mx28.c +++ b/arch/arm/mach-mxs/clock-mx28.c @@ -354,19 +354,15 @@ static int name##_set_rate(struct clk *clk, unsigned long rate) \ } \ for (d = 1; d <= div_max; d++) { \ f = parent_rate * 18 / d / rate; \ - if ((parent_rate * 18 / d) % rate) \ - f++; \ if (f < 18 || f > 35) \ continue; \ \ calc_rate = parent_rate * 18 / f / d; \ - if (calc_rate > rate) \ - continue; \ \ - if (rate - calc_rate < diff) { \ + if (abs(rate - calc_rate) < diff) { \ frac = f; \ div = d; \ - diff = rate - calc_rate; \ + diff = abs(rate - calc_rate); \ } \ \ if (diff == 0) \