[linux-sunxi] Re: [PATCH 2/4] clk: sunxi-ng: Add sun7i-a20 CCU driver
Maxime Ripard
maxime.ripard at free-electrons.com
Thu Mar 2 06:21:40 PST 2017
Hi Priit,
On Wed, Mar 01, 2017 at 11:38:14PM +0200, Priit Laes wrote:
> > > +/* PLL2 - Audio clock */
> > > +static struct ccu_nm pll_audio_base_clk = {
> > > > > > > + .enable = BIT(31),
> > > > > > > + .n = _SUNXI_CCU_MULT_OFFSET(8, 7, 0),
> > > > > > > + .m = _SUNXI_CCU_DIV_OFFSET(0, 5, 0),
> > > > > > > + .common = {
> > > > > > > + .reg = 0x008,
> > > > > > > + .hw.init = CLK_HW_INIT("pll-audio-base",
> > > > > + "hosc",
> > > > > + &ccu_nm_ops,
> > > > > + 0),
> > > > > + },
> > > +
> > > +};
> >
> > You're forgetting the post-divider here
>
> It's hardcoded to 4 during ccu initialization, similar to what is done
> on the other SoCs (A13, A31..).
Right, sorry, I only saw it later. Please move that define you've been
using here, and it will be fine :)
> > > +/* TODO: pll8 gpu 0x040 */
> >
> > Please add all the clocks.
>
> I'm not really comfortable adding clocks for blocks that currently lack
> drivers.
Yet, you did it for quite a significant amount already (VE, NAND,
AC97, DE MP, etc.). Don't get me wrong, this is definitely not a
criticism. One of the point of the switch to sunxi-ng was that we
would get out of the previous situation where every time you wanted to
do something, you needed to add some clocks.
We have some generic code that, if fed the right data, will
(hopefully) just work. So it's pretty safe to add (and this is better
to be consistent, and that's the policy we had for all the other CCU
drivers).
> > > +/* BIT(21 .. 31) - reserved */
> >
> > I'm not sure we need those comments either.
> >
> > > +/*
> > > + * TODO: SATA clock also supports external clock as parent.
> > > + * Currently we default to using PLL6 SATA gate.
> > > + */
> >
> > Which external clock? It should be modelled anyway. If we have a
> > dependency on some other clock, it should be in our DT binding, and
> > listed in the mux there.
> >
> > Otherwise, the clock framework will not be able to deal with that mux
> > being already set by the bootloader, and if we need to support that
> > clock in the future, our binding will be ready for it.
>
> I wish I knew which clock they're talking about..
>
> User manuals (A10/A20) only specify following in the clock register
> description:
>
> BIT(24) - CLK_SRC_GATING, default 0x0
> Clock Source Select:
> 0: PLL6 for SATA(100MHz)
> 1: External Clock
>
> There's no section for SATA (called NC) in A10 manual, and in A20
> manual only contains list of SATA/AHCI features.
Hmmmm, ok :/
> > > +/* Some AHB gates are exported */
> > > > > +#define CLK_AHB_BIST 31
> > > > > +#define CLK_AHB_MS 36
> > > > > +#define CLK_AHB_SDRAM 38
> > > > > +#define CLK_AHB_ACE 39
> > > > > +#define CLK_AHB_TS 41
> > > > > +#define CLK_AHB_VE 48
> > > > > +#define CLK_AHB_TVD 49
> > > > > +#define CLK_AHB_TVE1 51
> > > > > +#define CLK_AHB_LCD1 53
> > > > > +#define CLK_AHB_CSI0 54
> > > > > +#define CLK_AHB_CSI1 55
> > > > > +#define CLK_AHB_HDMI0 56
> > > > > +#define CLK_AHB_DE_BE1 59
> > > > > +#define CLK_AHB_DE_FE0 60
> > > > > +#define CLK_AHB_DE_FE1 61
> > > > > +#define CLK_AHB_MP 63
> > > > > +#define CLK_AHB_GPU 64
> > > +
> > > +/* Some APB0 gates are exported */
> > > > > +#define CLK_APB0_AC97 67
> > > > > +#define CLK_APB0_KEYPAD 74
> > > +
> > > +/* Some APB1 gates are exported */
> > > > > +#define CLK_APB1_CAN 79
> > > > > +#define CLK_APB1_SCR 80
> > > +
> > > +/* Some IP module clocks are exported */
> > > > > +#define CLK_MS 93
> > > > > +#define CLK_TS 106
> > > > > +#define CLK_PATA 111
> > > > > +#define CLK_AC97 115
> > > > > +#define CLK_KEYPAD 117
> > > > > +#define CLK_SATA 118
> > > +
> > > +/* Some DRAM gates are exported */
> > > > > +#define CLK_DRAM_VE 125
> > > > > +#define CLK_DRAM_CSI0 126
> > > > > +#define CLK_DRAM_CSI1 127
> > > > > +#define CLK_DRAM_TS 128
> > > > > +#define CLK_DRAM_TVD 129
> > > > > +#define CLK_DRAM_TVE1 131
> > > > > +#define CLK_DRAM_OUT 132
> > > > > +#define CLK_DRAM_DE_FE1 133
> > > > > +#define CLK_DRAM_DE_FE0 134
> > > > > +#define CLK_DRAM_DE_BE1 136
> > > > > +#define CLK_DRAM_MP 137
> > > > > +#define CLK_DRAM_ACE 138
> > > +
> > > > > +#define CLK_DE_BE1 140
> > > > > +#define CLK_DE_FE0 141
> > > > > +#define CLK_DE_FE1 142
> > > > > +#define CLK_DE_MP 143
> > > > > +#define CLK_TCON1_CH0 145
> > > > > +#define CLK_CSI_SPECIAL 146
> > > > > +#define CLK_TVD 147
> > > > > +#define CLK_TCON0_CH1_SCLK2 148
> > > > > +#define CLK_TCON1_CH1_SCLK2 150
> > > > > +#define CLK_TCON1_CH1 151
> > > > > +#define CLK_CSI0 152
> > > > > +#define CLK_CSI1 153
> > > > > +#define CLK_VE 154
> > > > > +#define CLK_AVS 156
> > > > > +#define CLK_ACE 157
> > > > > +#define CLK_HDMI 158
> > > > > +#define CLK_GPU 159
> > > > > +#define CLK_MBUS 160
> > > > > +#define CLK_HDMI1_SLOW 161
> > > > > +#define CLK_HDMI1_REPEAT 162
> > > > > +#define CLK_OUT_A 163
> > > +#define CLK_OUT_B 164
> >
> > Is there a reason not to expose these clocks?
>
> I exposed them on need to have basis. And basically did one-to-one
> conversion from devicetree.
I guess we can still make some pretty good assumptions on what's going
to be needed at some point.
All the mod clocks will be, the bus gates too, the CPU too. All the
internal ones (PLL, AXI, APB, etc) can remain hidden though.
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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