diff options
| author | Douglas Anderson <dianders@chromium.org> | 2015-09-30 16:07:38 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2015-10-26 16:00:07 +0100 |
| commit | 4351f19a337d48a780762d076408ebe9b0c1f945 (patch) | |
| tree | 903abc321be44907394e9d399066126c2f0db5de /drivers/clk | |
| parent | f0232063fb64fc79bfb7b6b35d611b2e4a79ffe6 (diff) | |
| download | linux-4351f19a337d48a780762d076408ebe9b0c1f945.tar.bz2 | |
clk: rockchip: Make calculations use rounding
Let's use DIV_ROUND_CLOSEST for rounding, not just truncating
division. This lets us get closer to the right rate.
Before this:
set_phase(86) delay_nums=26 reg[0xf000420c]=0x468 actual_degrees=83
set_phase(89) delay_nums=27 reg[0xf000420c]=0x46c actual_degrees=86
After this:
set_phase(86) delay_nums=27 reg[0xf000420c]=0x46c actual_degrees=86
set_phase(89) delay_nums=28 reg[0xf000420c]=0x470 actual_degrees=90
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/clk')
| -rw-r--r-- | drivers/clk/rockchip/clk-mmc-phase.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/clk/rockchip/clk-mmc-phase.c b/drivers/clk/rockchip/clk-mmc-phase.c index a797d8625f6d..bc24e5a002e7 100644 --- a/drivers/clk/rockchip/clk-mmc-phase.c +++ b/drivers/clk/rockchip/clk-mmc-phase.c @@ -69,7 +69,7 @@ static int rockchip_mmc_get_phase(struct clk_hw *hw) delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK); delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET; - degrees += delay_num * factor / 10000; + degrees += DIV_ROUND_CLOSEST(delay_num * factor, 10000); } return degrees % 360; @@ -82,7 +82,7 @@ static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees) u8 nineties, remainder; u8 delay_num; u32 raw_value; - u64 delay; + u32 delay; nineties = degrees / 90; remainder = (degrees % 90); @@ -110,12 +110,13 @@ static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees) * Convert to delay; do a little extra work to make sure we * don't overflow 32-bit / 64-bit numbers. */ - delay = PSECS_PER_SEC; + delay = 10000000; /* PSECS_PER_SEC / 10000 / 10 */ delay *= remainder; - do_div(delay, 10000); - do_div(delay, (rate / 1000) * 36 * ROCKCHIP_MMC_DELAY_ELEMENT_PSEC); + delay = DIV_ROUND_CLOSEST(delay, + (rate / 1000) * 36 * + (ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10)); - delay_num = (u8) min(delay, 255ULL); + delay_num = (u8) min_t(u32, delay, 255); raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0; raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET; |