Hi Simon,
On Wed, Jan 3, 2018 at 1:18 PM, Simon Horman <horms+renesas@xxxxxxxxxxxx> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@xxxxxxxxxxx>
>
> This patch adds Z2 clock divider support for R-Car Gen3 SoC.
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@xxxxxxxxxxx>
> Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> ---
> v4 [Simon Horman]
> * Rebase
> * Use __ffs as FIELD_{GET,PREP} don't not work with non-constant masks
> * Use correct mask in cpg_z_clk_recalc_rate()
Thanks for the update!
> --- a/drivers/clk/renesas/rcar-gen3-cpg.c
> +++ b/drivers/clk/renesas/rcar-gen3-cpg.c
> @@ -63,7 +63,7 @@ static void cpg_simple_notifier_register(struct raw_notifier_head *notifiers,
> }
>
> /*
> - * Z Clock
> + * Z Clock & Z2 Clock
> *
> * Traits of this clock:
> * prepare - clk_prepare only ensures that parents are prepared
> @@ -75,11 +75,13 @@ static void cpg_simple_notifier_register(struct raw_notifier_head *notifiers,
> #define CPG_FRQCRB_KICK BIT(31)
> #define CPG_FRQCRC 0x000000e0
> #define CPG_FRQCRC_ZFC_MASK GENMASK(12, 8)
> +#define CPG_FRQCRC_Z2FC_MASK GENMASK(4, 0)
>
> struct cpg_z_clk {
> struct clk_hw hw;
> void __iomem *reg;
> void __iomem *kick_reg;
> + unsigned long mask;
> };
>
> #define to_z_clk(_hw) container_of(_hw, struct cpg_z_clk, hw)
> @@ -89,8 +91,10 @@ static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw,
> {
> struct cpg_z_clk *zclk = to_z_clk(hw);
> unsigned int mult;
> + u32 val;
>
> - mult = 32 - FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg));
> + val = clk_readl(zclk->reg) & zclk->mask;
> + mult = 32 - (val >> (__ffs(zclk->mask) - 1));
Shouldn't that be
mult = 32 - (val >> __ffs(zclk->mask));
(same below)?
__ffs() returns 0..31, so you will shift right by 7 (Z) or -1 (Z2)?
As the CPG/MSSR driver now has suspend/resume support, do we need
a notifier to restore the Z or Z2 registers? Or is that handled automatically
by cpufreq during system resume, for both the primary and the secondary
CPU cores?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
