Re: [PATCH v6 5/6] reset: spacemit: define three more CCUs

[Alex Elder]

On 5/8/25 4:11 AM, Philipp Zabel wrote:
> On Di, 2025-05-06 at 16:06 -0500, Alex Elder wrote:
> > Three more CCUs on the SpacemiT K1 SoC implement only resets, not clocks.
> > Define these resets so they can be used.
> >
> > Signed-off-by: Alex Elder <elder@xxxxxxxxxxxx>
> > ---
> >   drivers/clk/spacemit/ccu-k1.c | 24 ++++++++++++++++
> >   drivers/reset/spacemit/k1.c   | 54 +++++++++++++++++++++++++++++++++++
> >   include/soc/spacemit/ccu_k1.h | 30 +++++++++++++++++++
> >   3 files changed, 108 insertions(+)
> >
> > diff --git a/drivers/clk/spacemit/ccu-k1.c b/drivers/clk/spacemit/ccu-k1.c
> > index 6b1845e899e5f..bddc83aff23cd 100644
> > --- a/drivers/clk/spacemit/ccu-k1.c
> > +++ b/drivers/clk/spacemit/ccu-k1.c
> > @@ -939,6 +939,18 @@ static const struct spacemit_ccu_data k1_ccu_apmu_data = {
> >   	.num		= ARRAY_SIZE(k1_ccu_apmu_hws),
> >   };
> >   
> > +static const struct spacemit_ccu_data k1_ccu_rcpu_data = {
>
> The /* No clocks in the RCPU CCU */ comment belongs here, instead of in
> the reset driver.
>
> I wonder though, if these units have no clocks, why are they called
> CCUs? It doesn't make much sense to me to add their compatibles to the
> ccu-k1 driver only to load the reset aux driver. Why not just add a
> platform driver next to the aux driver in reset-spacemit.ko for these
> three?

In fact, the particular registers involved *do* have fields
to control some clocks, but there is currently no use for
them, so support for them isn't implemented.  The reset
controls in those registers are needed now, however.

I actually first implemented this as a small, separate reset
driver, only to learn late in the process that these other
clocks might be needed someday.

> > +	.reset_name	= "rcpu-reset",
> > +};
> > +
> > +static const struct spacemit_ccu_data k1_ccu_rcpu2_data = {
> > +	.reset_name	= "rcpu2-reset",
> > +};
> > +
> > +static const struct spacemit_ccu_data k1_ccu_apbc2_data = {
> > +	.reset_name	= "apbc2-reset",
> > +};
> > +
> >   static int spacemit_ccu_register(struct device *dev,
> >   				 struct regmap *regmap,
> >   				 struct regmap *lock_regmap,
> > @@ -1106,6 +1118,18 @@ static const struct of_device_id of_k1_ccu_match[] = {
> >   		.compatible	= "spacemit,k1-syscon-apmu",
> >   		.data		= &k1_ccu_apmu_data,
> >   	},
> > +	{
> > +		.compatible	= "spacemit,k1-syscon-rcpu",
> > +		.data		= &k1_ccu_rcpu_data,
> > +	},
> > +	{
> > +		.compatible	= "spacemit,k1-syscon-rcpu2",
> > +		.data		= &k1_ccu_rcpu2_data,
> > +	},
> > +	{
> > +		.compatible	= "spacemit,k1-syscon-apbc2",
> > +		.data		= &k1_ccu_apbc2_data,
> > +	},
> >   	{ }
> >   };
> >   MODULE_DEVICE_TABLE(of, of_k1_ccu_match);
> > diff --git a/drivers/reset/spacemit/k1.c b/drivers/reset/spacemit/k1.c
> > index 19a34f151b214..27434a1928261 100644
> > --- a/drivers/reset/spacemit/k1.c
> > +++ b/drivers/reset/spacemit/k1.c
> > @@ -137,6 +137,57 @@ static const struct ccu_reset_controller_data k1_apmu_reset_data = {
> >   	.count		= ARRAY_SIZE(apmu_resets),
> >   };
> >   
> > +static const struct ccu_reset_data rcpu_resets[] = {
> > +	[RESET_RCPU_SSP0]	= RESET_DATA(RCPU_SSP0_CLK_RST,	0, BIT(0)),
> > +	[RESET_RCPU_I2C0]	= RESET_DATA(RCPU_I2C0_CLK_RST,	0, BIT(0)),
> > +	[RESET_RCPU_UART1]	= RESET_DATA(RCPU_UART1_CLK_RST, 0, BIT(0)),
> > +	[RESET_RCPU_IR]		= RESET_DATA(RCPU_CAN_CLK_RST,	0, BIT(0)),
> > +	[RESET_RCPU_CAN]	= RESET_DATA(RCPU_IR_CLK_RST,	0, BIT(0)),
> > +	[RESET_RCPU_UART0]	= RESET_DATA(RCPU_UART0_CLK_RST, 0, BIT(0)),
> > +	[RESET_RCPU_HDMI_AUDIO]	= RESET_DATA(AUDIO_HDMI_CLK_CTRL, 0, BIT(0)),
> > +};
> > +
> > +static const struct ccu_reset_controller_data k1_rcpu_reset_data = {
> > +	/* No clocks in the RCPU CCU */
>
> This information is not useful in the reset driver.

Yes, I think this was just copy-pasted from the previous code.
This won't be there in the next version.

					-Alex

> regards
> Philipp