forked from Minki/linux
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>
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@ -69,7 +69,7 @@ static int rockchip_mmc_get_phase(struct clk_hw *hw)
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delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK);
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delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET;
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degrees += delay_num * factor / 10000;
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degrees += DIV_ROUND_CLOSEST(delay_num * factor, 10000);
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}
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return degrees % 360;
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@ -82,7 +82,7 @@ static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees)
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u8 nineties, remainder;
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u8 delay_num;
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u32 raw_value;
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u64 delay;
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u32 delay;
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nineties = degrees / 90;
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remainder = (degrees % 90);
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@ -110,12 +110,13 @@ static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees)
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* Convert to delay; do a little extra work to make sure we
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* don't overflow 32-bit / 64-bit numbers.
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*/
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delay = PSECS_PER_SEC;
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delay = 10000000; /* PSECS_PER_SEC / 10000 / 10 */
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delay *= remainder;
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do_div(delay, 10000);
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do_div(delay, (rate / 1000) * 36 * ROCKCHIP_MMC_DELAY_ELEMENT_PSEC);
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delay = DIV_ROUND_CLOSEST(delay,
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(rate / 1000) * 36 *
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(ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10));
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delay_num = (u8) min(delay, 255ULL);
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delay_num = (u8) min_t(u32, delay, 255);
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raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0;
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raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET;
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