From: heiko@sntech.de (Heiko Stuebner)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/8] clk: rockchip: Make calculations use rounding
Date: Mon, 31 Aug 2015 20:24:00 +0200 [thread overview]
Message-ID: <1441045446-30858-3-git-send-email-heiko@sntech.de> (raw)
In-Reply-To: <1441045446-30858-1-git-send-email-heiko@sntech.de>
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
next prev parent reply other threads:[~2015-08-31 18:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-31 18:23 [PATCH 0/8] mmc: dw_mmc: allow tuning using the clk-phase api Heiko Stuebner
2015-08-31 18:23 ` [PATCH 1/8] clk: rockchip: Allow more precision for some mmc clock phases Heiko Stuebner
2015-08-31 18:24 ` Heiko Stuebner [this message]
2015-08-31 18:24 ` [PATCH 3/8] mmc: core: Add mmc_regulator_set_vqmmc() Heiko Stuebner
2015-09-02 11:38 ` Ulf Hansson
2015-09-02 16:20 ` Doug Anderson
2015-09-10 12:40 ` Ulf Hansson
2015-08-31 18:24 ` [PATCH 4/8] mmc: dw_mmc: Use mmc_regulator_set_vqmmc in start_signal_voltage_switch Heiko Stuebner
2015-08-31 18:24 ` [PATCH 5/8] mmc: dw_mmc: dt-binding: Add tuning related things Heiko Stuebner
2015-09-02 5:01 ` Jaehoon Chung
2015-09-02 7:41 ` Heiko Stuebner
2015-08-31 18:24 ` [PATCH 6/8] mmc: dw_mmc: Generic MMC tuning with the clock phase framework Heiko Stuebner
2015-09-15 8:25 ` Jaehoon Chung
2015-09-15 22:09 ` Heiko Stübner
2015-09-16 2:30 ` Jaehoon Chung
2015-09-16 14:52 ` Heiko Stübner
2015-09-17 2:03 ` Jaehoon Chung
2015-08-31 18:24 ` [PATCH 7/8] ARM: dts: rockchip: Add drive/sample clocks for rk3288 dw_mmc devices Heiko Stuebner
2015-08-31 18:24 ` [PATCH 8/8] ARM: dts: rockchip: add tuning related settings to veyron devices Heiko Stuebner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1441045446-30858-3-git-send-email-heiko@sntech.de \
--to=heiko@sntech.de \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).