From: Stefan Agner stefan@agner.ch
Enable the SCSC (Slow Clock Source Controller) and select the external 32KHz oscillator. This improves the accuracy of the RTC.
Signed-off-by: Sanchayan Maity maitysanchayan@gmail.com --- arch/arm/include/asm/arch-vf610/crm_regs.h | 1 + arch/arm/include/asm/arch-vf610/imx-regs.h | 11 ++++++++++- board/freescale/vf610twr/vf610twr.c | 13 ++++++++++++- 3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/arch-vf610/crm_regs.h b/arch/arm/include/asm/arch-vf610/crm_regs.h index 724682c..78708e2 100644 --- a/arch/arm/include/asm/arch-vf610/crm_regs.h +++ b/arch/arm/include/asm/arch-vf610/crm_regs.h @@ -199,6 +199,7 @@ struct anadig_reg { #define CCM_CCGR2_PORTD_CTRL_MASK (0x3 << 24) #define CCM_CCGR2_PORTE_CTRL_MASK (0x3 << 26) #define CCM_CCGR3_ANADIG_CTRL_MASK 0x3 +#define CCM_CCGR3_SCSC_CTRL_MASK (0x3 << 4) #define CCM_CCGR4_WKUP_CTRL_MASK (0x3 << 20) #define CCM_CCGR4_CCM_CTRL_MASK (0x3 << 22) #define CCM_CCGR4_GPC_CTRL_MASK (0x3 << 24) diff --git a/arch/arm/include/asm/arch-vf610/imx-regs.h b/arch/arm/include/asm/arch-vf610/imx-regs.h index 866b303..aa60031 100644 --- a/arch/arm/include/asm/arch-vf610/imx-regs.h +++ b/arch/arm/include/asm/arch-vf610/imx-regs.h @@ -65,7 +65,7 @@ #define QSPI0_BASE_ADDR (AIPS0_BASE_ADDR + 0x00044000) #define IOMUXC_BASE_ADDR (AIPS0_BASE_ADDR + 0x00048000) #define ANADIG_BASE_ADDR (AIPS0_BASE_ADDR + 0x00050000) -#define SCSCM_BASE_ADDR (AIPS0_BASE_ADDR + 0x00052000) +#define SCSC_BASE_ADDR (AIPS0_BASE_ADDR + 0x00052000) #define ASRC_BASE_ADDR (AIPS0_BASE_ADDR + 0x00060000) #define SPDIF_BASE_ADDR (AIPS0_BASE_ADDR + 0x00061000) #define ESAI_BASE_ADDR (AIPS0_BASE_ADDR + 0x00062000) @@ -264,6 +264,9 @@ #define SRC_SRSR_WDOG_A5 (0x1 << 3) #define SRC_SRSR_POR_RST (0x1 << 0)
+/* Slow Clock Source Controller Module (SCSC) */ +#define SCSC_SOSC_CTR_SOSC_EN 0x1 + #if !(defined(__KERNEL_STRICT_NAMES) || defined(__ASSEMBLY__)) #include <asm/types.h>
@@ -448,6 +451,12 @@ struct mscm_ir { u16 rsvd3[848]; };
+/* SCSC */ +struct scsc_reg { + u32 sirc_ctr; + u32 sosc_ctr; +}; + #endif /* __ASSEMBLER__*/
#endif /* __ASM_ARCH_IMX_REGS_H__ */ diff --git a/board/freescale/vf610twr/vf610twr.c b/board/freescale/vf610twr/vf610twr.c index eb27542..4160acd 100644 --- a/board/freescale/vf610twr/vf610twr.c +++ b/board/freescale/vf610twr/vf610twr.c @@ -227,7 +227,7 @@ static void clock_init(void) CCM_CCGR2_PORTD_CTRL_MASK | CCM_CCGR2_PORTE_CTRL_MASK | CCM_CCGR2_QSPI0_CTRL_MASK); clrsetbits_le32(&ccm->ccgr3, CCM_REG_CTRL_MASK, - CCM_CCGR3_ANADIG_CTRL_MASK); + CCM_CCGR3_ANADIG_CTRL_MASK | CCM_CCGR3_SCSC_CTRL_MASK); clrsetbits_le32(&ccm->ccgr4, CCM_REG_CTRL_MASK, CCM_CCGR4_WKUP_CTRL_MASK | CCM_CCGR4_CCM_CTRL_MASK | CCM_CCGR4_GPC_CTRL_MASK | CCM_CCGR4_I2C0_CTRL_MASK); @@ -308,9 +308,20 @@ int board_early_init_f(void)
int board_init(void) { + struct scsc_reg *scsc = (struct scsc_reg *)SCSC_BASE_ADDR; + /* address of boot parameters */ gd->bd->bi_boot_params = PHYS_SDRAM + 0x100;
+ /* + * Enable external 32K Oscillator + * + * The internal clock experiences significant drift + * so we must use the external oscillator in order + * to maintain correct time in the hwclock + */ + setbits_le32(&scsc->sosc_ctr, SCSC_SOSC_CTR_SOSC_EN); + return 0; }