Re: [RFC PATCH v2 3/4] clk: renesas: Add family-specific clock driver for RZ/V2H(P)

Lad, Prabhakar
2024-06-27T13:25:47Z

Hi Geert,

On Thu, Jun 27, 2024 at 8:01 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Wed, Jun 26, 2024 at 7:36 PM Lad, Prabhakar
> <prabhakar.csengg@gmail.com> wrote:
> > On Wed, Jun 26, 2024 at 11:07 AM Geert Uytterhoeven
> > <geert@linux-m68k.org> wrote:
> > > On Tue, Jun 11, 2024 at 1:32 AM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > Add family-specific clock driver for RZ/V2H(P) SoCs.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> > > > +/**
> > > > + * struct mod_clock - Module clock
> > > > + *
> > > > + * @hw: handle between common and hardware-specific interfaces
> > > > + * @off: register offset
> > > > + * @bit: ON/MON bit
> > > > + * @monoff: monitor register offset
> > > > + * @monbit: montor bit
> > > > + * @priv: CPG private data
> > > > + */
> > > > +struct mod_clock {
> > > > + struct clk_hw hw;
> > > > + u8 on_index;
> > > > + u8 on_bit;
> > > > + u16 mon_index;
>
> BTW, why is this u16? The corresponding member in rzv2h_mod_clk is u8.
>
Oops, I will fix this.

> > > > + u8 mon_bit;
>
> > > > +static int rzv2h_mod_clock_endisable(struct clk_hw *hw, bool enable)
> > > > +{
> > > > + struct mod_clock *clock = to_mod_clock(hw);
> > > > + unsigned int reg = GET_CLK_ON_OFFSET(clock->on_index);
> > > > + struct rzv2h_cpg_priv *priv = clock->priv;
> > > > + u32 bitmask = BIT(clock->on_bit);
> > > > + struct device *dev = priv->dev;
> > > > + u32 value;
> > > > + int error;
> > > > +
> > > > + dev_dbg(dev, "CLK_ON 0x%x/%pC %s\n", reg, hw->clk,
> > > > + enable ? "ON" : "OFF");
> > > > +
> > > > + value = bitmask << 16;
> > > > + if (enable)
> > > > + value |= bitmask;
> > > > +
> > > > + writel(value, priv->base + reg);
> > > > +
> > > > + if (!enable)
> > > > + return 0;
> > > > +
> > > > + reg = GET_CLK_MON_OFFSET(clock->mon_index);
> > >
> > > What if a clock does not have a clock monitor bit?
> > > Clock bits in registers CPG_CLKON_22 and later do not have corresponding
> > > clock monitor bits.
> > >
> > Oops I had missed this case.
> >
> > I'll introduce a macro (NO_MON_REG_INDEX) for clocks which do not have
> > monitor support and add a check above to skip clk monitor operation if
> > clock->mon_index == NO_MON_REG_INDEX.
> >
> > /* monitor index for clocks which do not have CLKMON support */
> > #define NO_MON_REG_INDEX 0xff
> >
> > Does this sound OK?
>
> Either that, or make mon_index signed (which would reduce its
> effective range by one bit).
>
Ok I'll make it to s8 instead and add a negative check monitor index.

Cheers,
Prabhakar