| Message ID | 1421291488-24249-1-git-send-email-Peng.Fan@freescale.com |
|---|---|
| State | Rejected |
| Delegated to: | Stefano Babic |
| Headers | show |
Hi, Please ignore this patch. Wrong patch version. On 1/15/2015 11:11 AM, Peng Fan wrote: > The self-bias circuit is used by the bandgap during startup. > Once the bandgap has stabilized, the self-bias circuit should > be disabled for best noise performance of analog blocks. > Also this bit should be disabled before the chip enters STOP mode or > when ever the regular bandgap is disabled. > > Signed-off-by: Peng Fan <Peng.Fan@freescale.com> > Signed-off-by: Ranjani Vaidyanathan <Ranjani.Vaidyanathan@freescale.com> > --- > arch/arm/cpu/armv7/mx6/soc.c | 24 ++++++++++++++++++++++++ > arch/arm/include/asm/arch-mx6/crm_regs.h | 2 ++ > 2 files changed, 26 insertions(+) > > diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c > index 5f5f497..36572c6 100644 > --- a/arch/arm/cpu/armv7/mx6/soc.c > +++ b/arch/arm/cpu/armv7/mx6/soc.c > @@ -255,6 +255,23 @@ static void clear_mmdc_ch_mask(void) > writel(0, &mxc_ccm->ccdr); > } > > +static void init_bandgap(void) > +{ > + struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR; > + /* > + * Ensure the bandgap has stabilized. > + */ > + while (!(readl(&mxc_ccm->ana_misc0) & 0x80)) > + ; > + /* > + * For best noise performance of the analog blocks using the > + * outputs of the bandgap, the reftop_selfbiasoff bit should > + * be set. > + */ > + writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &mxc_ccm->ana_misc0_set); > +} > + > + > #ifdef CONFIG_MX6SL > static void set_preclk_from_osc(void) > { > @@ -275,6 +292,13 @@ int arch_cpu_init(void) > clear_mmdc_ch_mask(); > > /* > + * Disable self-bias circuit in the analog bandap. > + * The self-bias circuit is used by the bandgap during startup. > + * This bit should be set after the bandgap has initialized. > + */ > + init_bandgap(); > + > + /* > * When low freq boot is enabled, ROM will not set AHB > * freq, so we need to ensure AHB freq is 132MHz in such > * scenario. > diff --git a/arch/arm/include/asm/arch-mx6/crm_regs.h b/arch/arm/include/asm/arch-mx6/crm_regs.h > index 39f3c07..0592ce0 100644 > --- a/arch/arm/include/asm/arch-mx6/crm_regs.h > +++ b/arch/arm/include/asm/arch-mx6/crm_regs.h > @@ -1063,4 +1063,6 @@ struct mxc_ccm_reg { > #define BF_ANADIG_PFD_528_PFD0_FRAC(v) \ > (((v) << 0) & BM_ANADIG_PFD_528_PFD0_FRAC) > > +#define BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF 0x00000008 > + > #endif /*__ARCH_ARM_MACH_MX6_CCM_REGS_H__ */ Regards, Peng.
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c index 5f5f497..36572c6 100644 --- a/arch/arm/cpu/armv7/mx6/soc.c +++ b/arch/arm/cpu/armv7/mx6/soc.c @@ -255,6 +255,23 @@ static void clear_mmdc_ch_mask(void) writel(0, &mxc_ccm->ccdr); } +static void init_bandgap(void) +{ + struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR; + /* + * Ensure the bandgap has stabilized. + */ + while (!(readl(&mxc_ccm->ana_misc0) & 0x80)) + ; + /* + * For best noise performance of the analog blocks using the + * outputs of the bandgap, the reftop_selfbiasoff bit should + * be set. + */ + writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &mxc_ccm->ana_misc0_set); +} + + #ifdef CONFIG_MX6SL static void set_preclk_from_osc(void) { @@ -275,6 +292,13 @@ int arch_cpu_init(void) clear_mmdc_ch_mask(); /* + * Disable self-bias circuit in the analog bandap. + * The self-bias circuit is used by the bandgap during startup. + * This bit should be set after the bandgap has initialized. + */ + init_bandgap(); + + /* * When low freq boot is enabled, ROM will not set AHB * freq, so we need to ensure AHB freq is 132MHz in such * scenario. diff --git a/arch/arm/include/asm/arch-mx6/crm_regs.h b/arch/arm/include/asm/arch-mx6/crm_regs.h index 39f3c07..0592ce0 100644 --- a/arch/arm/include/asm/arch-mx6/crm_regs.h +++ b/arch/arm/include/asm/arch-mx6/crm_regs.h @@ -1063,4 +1063,6 @@ struct mxc_ccm_reg { #define BF_ANADIG_PFD_528_PFD0_FRAC(v) \ (((v) << 0) & BM_ANADIG_PFD_528_PFD0_FRAC) +#define BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF 0x00000008 + #endif /*__ARCH_ARM_MACH_MX6_CCM_REGS_H__ */