[U-Boot,2/3] ARM: uniphier: compute SSCPLL values more precisely

Message ID 1512537394-9608-2-git-send-email-yamada.masahiro@socionext.com
State Accepted
Delegated to: Masahiro Yamada
Headers show
Series
  • [U-Boot,1/3] ARM: uniphier: fix SSCPLL init code for LD11 SoC
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Commit Message

Masahiro Yamada Dec. 6, 2017, 5:16 a.m.
Use DIV_ROUND_CLOSEST().  To make the JK value even more precise,
I used a bigger coefficient, then divide it by 512.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 arch/arm/mach-uniphier/clk/pll-base-ld20.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/arch/arm/mach-uniphier/clk/pll-base-ld20.c b/arch/arm/mach-uniphier/clk/pll-base-ld20.c
index 45fdf0a..c9b78b9 100644
--- a/arch/arm/mach-uniphier/clk/pll-base-ld20.c
+++ b/arch/arm/mach-uniphier/clk/pll-base-ld20.c
@@ -7,6 +7,7 @@ 
 
 #include <linux/bitops.h>
 #include <linux/delay.h>
+#include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/sizes.h>
@@ -41,13 +42,14 @@  int uniphier_ld20_sscpll_init(unsigned long reg_base, unsigned int freq,
 	if (freq != UNIPHIER_PLL_FREQ_DEFAULT) {
 		tmp = readl(base);	/* SSCPLLCTRL */
 		tmp &= ~SC_PLLCTRL_SSC_DK_MASK;
-		tmp |= (487 * freq * ssc_rate / divn / 512) &
+		tmp |= DIV_ROUND_CLOSEST(487UL * freq * ssc_rate, divn * 512) &
 							SC_PLLCTRL_SSC_DK_MASK;
 		writel(tmp, base);
 
 		tmp = readl(base + 4);
 		tmp &= ~SC_PLLCTRL2_SSC_JK_MASK;
-		tmp |= (41859 * freq / divn) & SC_PLLCTRL2_SSC_JK_MASK;
+		tmp |= DIV_ROUND_CLOSEST(21431887UL * freq, divn * 512) &
+							SC_PLLCTRL2_SSC_JK_MASK;
 		writel(tmp, base + 4);
 
 		udelay(50);