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Groups > linux.kernel > #1216359
| From | Heiko Stuebner <heiko@sntech.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 2/8] clk: rockchip: Make calculations use rounding |
| Date | 2015-08-31 20:30 +0200 |
| Message-ID | <q3C0a-7l6-21@gated-at.bofh.it> (permalink) |
| References | <q3C09-7l6-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Douglas Anderson <dianders@chromium.org> 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> --- drivers/clk/rockchip/clk-mmc-phase.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/clk/rockchip/clk-mmc-phase.c b/drivers/clk/rockchip/clk-mmc-phase.c index a797d86..bc24e5a 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; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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[PATCH 0/8] mmc: dw_mmc: allow tuning using the clk-phase api Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
[PATCH 3/8] mmc: core: Add mmc_regulator_set_vqmmc() Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
Re: [PATCH 3/8] mmc: core: Add mmc_regulator_set_vqmmc() Ulf Hansson <ulf.hansson@linaro.org> - 2015-09-02 13:40 +0200
Re: [PATCH 3/8] mmc: core: Add mmc_regulator_set_vqmmc() Doug Anderson <dianders@chromium.org> - 2015-09-02 18:30 +0200
[PATCH 6/8] mmc: dw_mmc: Generic MMC tuning with the clock phase framework Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
[PATCH 2/8] clk: rockchip: Make calculations use rounding Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
[PATCH 4/8] mmc: dw_mmc: Use mmc_regulator_set_vqmmc in start_signal_voltage_switch Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
[PATCH 1/8] clk: rockchip: Allow more precision for some mmc clock phases Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
[PATCH 7/8] ARM: dts: rockchip: Add drive/sample clocks for rk3288 dw_mmc devices Heiko Stuebner <heiko@sntech.de> - 2015-08-31 20:30 +0200
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