> Subject: Re: [PATCH 5/5] Clocksource: Flextimer: Use Macro for clock source > selection. > > On Tue, 26 Aug 2014, Xiubo Li wrote: > > FTM source clock is selectable: > > Source clock can be the system clock, the fixed frequency clock, > > or an external clock. > > Fixed frequency clock is an additional clock input to allow the > > selection of an on chip clock source other than the system clock. > > Selecting external clock connects FTM clock to a chip level input > > pin therefore allowing to synchronize the FTM counter with an off > > chip clock source > > > > Clock Source Selection: > > Selects one of the three FTM counter clock sources. > > > > 00 No clock selected. This in effect disables the FTM counter. > > 01 System clock > > --- > > 10 Fixed frequency clock > > 11 External clock > > > > These two will be useful for the alarm on LS1 platform in late future, > > the system clock's frequency is too high to get a long delay timer when > > go to sleep, so the fixed or external clock could be used instead. > > And how is that relevant to changing the mask from a hardcoded value > to a constant? It's still hardcoded at compile time and I don't see > how that helps chosing the clock at runtime for a particular use case. > > > #define FTM_SC 0x00 > > +#define FTM_SC_CLKS_NON 0 > > +#define FTM_SC_CLKS_SYS 1 > > #define FTM_SC_CLK_SHIFT 3 > > #define FTM_SC_CLK_MASK (0x3 << FTM_SC_CLK_SHIFT) > > #define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_SHIFT) > > @@ -67,7 +69,7 @@ static inline void ftm_counter_enable(void __iomem *base) > > /* select and enable counter clock source */ > > val = ftm_readl(base + FTM_SC); > > val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); > > - val |= priv->ps | FTM_SC_CLK(1); > > + val |= priv->ps | FTM_SC_CLK(FTM_SC_CLKS_SYS); > > ftm_writel(val, base + FTM_SC); > > } > > > > @@ -77,7 +79,8 @@ static inline void ftm_counter_disable(void __iomem *base) > > > > /* disable counter clock source */ > > val = ftm_readl(base + FTM_SC); > > - val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); > > + val &= ~(FTM_SC_CLK_MASK); > > So you remove the FTM_SC_PS_MASK without mentioning it in the > changelog. Either this is by mistake or it wants to be documented WHY > it is not needed in the first place. >
This is just prepare for the other new features in the future. And delay this changes maybe better. Thanks, BRs Xiubo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
