From dc73483a122960d094486fc58df953209bdb1edd Mon Sep 17 00:00:00 2001 From: David Lechner Date: Wed, 14 Mar 2018 20:36:30 -0500 Subject: [PATCH] davinci: omapl138_lcdk: fix PLL0 frequency commit 1601dd97edc6 ("davinci: omapl138_lcdk: increase PLL0 frequency") changed the PLL0 frequency to 456MHz, which is needed for the LCDC IP block. However, in doing so, it caused the PLLOUT clock to be outside of the allowable specifications given in the OMAP-L138 data sheet. (It says PLLOUT must be 600MHz max). It also uses a PLLM value outside of the range given in the TRM (it says PLLM must in the range 0 to 0x1f). So here is what we have currently: PLLOUT = 24 / (0 + 1) * (37 + 1) = 912MHz (out of spec) ^ ^ ^ CLKIN PREDIV PLLM (out of spec) input to PLLDIVn = 912 / (1 + 1) = 456MHz (desired result) ^ ^ PLLOUT POSTDIV This changes the PLLM value to 18 and the POSTDIV value to 0 so that PLLOUT is now within specification but we still get the desired result. PLLOUT = 24 / (0 + 1) * (18 + 1) = 456MHz (within spec) ^ ^ ^ CLKIN PREDIV PLLM input to PLLDIVn = 456 / (0 + 1) = 456MHz (desired result) ^ ^ PLLOUT POSTDIV Fixes: 1601dd97edc6 ("davinci: omapl138_lcdk: increase PLL0 frequency") Signed-off-by: David Lechner Reported-by: Sekhar Nori Tested-by: Sekhar Nori --- configs/omapl138_lcdk_defconfig | 1 + include/configs/omapl138_lcdk.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/configs/omapl138_lcdk_defconfig b/configs/omapl138_lcdk_defconfig index ccb308bf01..0a2af1170e 100644 --- a/configs/omapl138_lcdk_defconfig +++ b/configs/omapl138_lcdk_defconfig @@ -2,6 +2,7 @@ CONFIG_ARM=y CONFIG_ARCH_DAVINCI=y CONFIG_SYS_TEXT_BASE=0xc1080000 CONFIG_TARGET_OMAPL138_LCDK=y +CONFIG_SYS_DA850_PLL0_POSTDIV=0 CONFIG_SYS_DA850_PLL1_PLLDIV3=0x8003 CONFIG_TI_COMMON_CMD_OPTIONS=y CONFIG_SPL_LIBCOMMON_SUPPORT=y diff --git a/include/configs/omapl138_lcdk.h b/include/configs/omapl138_lcdk.h index 12b266e515..2a390bfcea 100644 --- a/include/configs/omapl138_lcdk.h +++ b/include/configs/omapl138_lcdk.h @@ -57,7 +57,8 @@ * PLL configuration */ -#define CONFIG_SYS_DA850_PLL0_PLLM 37 +/* Requires CONFIG_SYS_DA850_PLL0_POSTDIV=0, set in Kconfig */ +#define CONFIG_SYS_DA850_PLL0_PLLM 18 #define CONFIG_SYS_DA850_PLL1_PLLM 21 /* -- 2.25.1