[PATCH v4 7/8] soc: starfive: Add socinfo driver for JHB100 SoC

[Conor Dooley]

On Fri, Aug 14, 2026 at 01:13:38AM +0000, Changhuang Liang wrote:
> Hi,Conor
> 
> Thanks for the review.
> 
> > On Thu, Aug 13, 2026 at 08:10:12AM +0000, Changhuang Liang wrote:
> > > Hi ,Conor
> > >
> > > Thanks for the review.
> > >
> > > > On Wed, Aug 12, 2026 at 10:37:16AM +0000, Changhuang Liang wrote:
> > > > > Hi, Conor
> > > > >
> > > > > Thanks for the review.
> > > > >
> > > > > > On Tue, Aug 11, 2026 at 05:36:19AM +0000, Changhuang Liang wrote:
> > > > > >
> > > > > > > > On Sat, Aug 08, 2026 at 06:50:53PM -0700, Changhuang Liang
> > wrote:
> > > > > >
> > > > > > > > > +static int __init starfive_socinfo_init(void) {
> > > > > > > > > +	struct soc_device_attribute *attrs;
> > > > > > > > > +	struct soc_device *soc_dev;
> > > > > > > > > +	const char *machine = NULL;
> > > > > > > > > +	struct device_node *np;
> > > > > > > > > +	struct regmap *regmap;
> > > > > > > > > +	char rev_char;
> > > > > > > > > +	u32 rev_id;
> > > > > > > > > +	int ret;
> > > > > > > > > +
> > > > > > > > > +	np = of_find_compatible_node(NULL, NULL,
> > > > > > > > > +"starfive,jhb100-sys0-syscon");
> > > > > > > >
> > > > > > > > Remind me again why this is not just probed as an mfd cell
> > > > > > > > from the syscon driver?
> > > > > > > >
> > > > > > > > (Hint: please put this info in the commit message).
> > > > > > >
> > > > > > > The discussion result with Krzysztof at that time is recorded here:
> > > > > > > https://lore.kernel.org/all/20260405-strong-watchful-marmot-fd
> > > > > > > fad6
> > > > > > > @quo
> > > > > > > ll/
> > > > > > >
> > > > > > > One register should not be treated as a separate device node.
> > > > > >
> > > > > > That's a different question. In the case of an mfd cell probed
> > > > > > from the syscon driver there would be no devicetree
> > > > > > modifications required compared to what you have now. e.g.
> > > > > > sg2044-topsys.c
> > > > >
> > > > > This seems feasible, and I can introduce this modification in the
> > > > > next
> > > > version.
> > > >
> > > >
> > > > In fact, you don't even need the mfd cell, because your driver is
> > > > going to be in drivers/soc/starfive anyway? You can just bind
> > > > directly to the
> > > > sys0 syscon I think.
> > >
> > > I suddenly realized that I missed one issue:
> > > starfive,jhb100-sys0-syscon is already bound to the PLL driver by default, I
> > can't use it to bind another device anymore.
> > >
> > > which is why I used
> > >
> > > np = of_find_compatible_node(NULL, NULL,
> > > "starfive,jhb100-sys0-syscon");
> > >
> > > in jhb100-socinfo.c.
> > >
> > > So it seems the MFD cell approach isn't really feasible either?
> > 
> > You could, in that case, probe the clock driver using the mfd_cell like
> > sg2044-topsys. What else other than the pll controls and the soc info register
> > is in this register region?
> 
> We don't have any other drivers right now in this register region.

I'm not asking about what's got a driver right now though, I am wondering
what else the registers in this region are for.

> 
> So does that mean I can revise it to the format below:
> 
> static const struct mfd_cell jhb100_sys0_subdev[] = {
> 	{
> 		.name = "jhb100-sys0-pll",
> 	},

> 	{
> 		.name = "jhb100-socinfo",

Why would this be needed? The driver with the mfd_cell would be the same
one that provides the soc info, no?

> 	},
> };
> 
> static const struct mfd_cell jhb100_per0_subdev[] = {
> 	{
> 		.name = "jhb100-per0-pll",

Why do these other ones need to be modified?

> 	},
> };
> 
> static const struct mfd_cell jhb100_per1_subdev[] = {
> 	{
> 		.name = "jhb100-per1-pll",
> 	},
> };
> 
> static const struct mfd_cell jhb100_ pcierp _subdev[] = {
> 	{
> 		.name = "jhb100-pcierp-reset",
> 	},
> };
> 
> Best Regards,
> Changhuang
> 
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