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.
Thanks,
tglx
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