[PATCH v2 0/2] Fix orphan clocks in clk-th1520-ap driver

[PATCH v2 0/2] Fix orphan clocks in clk-th1520-ap driver

[Yao Zi]

clk_orphan_dump shows two suspicious orphan clocks on TH1520 when
booting the kernel with mainline U-Boot,

        $ cat /sys/kernel/debug/clk/clk_orphan_dump | jq 'keys'
        [
          "c910",
          "osc_12m"
        ]

where the correct parents should be c910-i0 for c910, and osc_24m for
osc_12m.

Note that the c910's case cannot be reproduced with vendor U-Boot,
which always reparents c910 to its second parent, cpu-pll1. Another way
to confirm the bug is to examine
/sys/kernel/debug/clk/c910/clk_possible_parents, which obviously doesn't
match c910's definition.

This series corrects the parent description of these two clocks to
eliminate the orphans.

Changed from v1
- Split the two fixes into separate patches
- Add a static qualifier for the new definition of osc_12m
- Link to v1: https://lore.kernel.org/all/20250705052028.24611-1-ziyao@disroot.org/

Thanks for your time and review.

Yao Zi (2):
  clk: thead: th1520-ap: Correctly refer the parent of osc_12m
  clk: thead: th1520-ap: Correctly refer the parent of c910-i0

 drivers/clk/thead/clk-th1520-ap.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

-- 
2.50.0

[PATCH v2 1/2] clk: thead: th1520-ap: Correctly refer the parent of osc_12m

[Yao Zi]

The "osc_12m" fixed factor clock refers the external oscillator by
setting clk_parent_data.fw_name to osc_24m, which is obviously wrong
since no clock-names property is allowed for compatible
thead,th1520-clk-ap.

Refer the oscillator as parent by index instead.

Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
Signed-off-by: Yao Zi <ziyao@disroot.org>
---
 drivers/clk/thead/clk-th1520-ap.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
index ebfb1d59401d..42feb4bb6329 100644
--- a/drivers/clk/thead/clk-th1520-ap.c
+++ b/drivers/clk/thead/clk-th1520-ap.c
@@ -582,7 +582,14 @@ static const struct clk_parent_data peri2sys_apb_pclk_pd[] = {
 	{ .hw = &peri2sys_apb_pclk.common.hw }
 };
 
-static CLK_FIXED_FACTOR_FW_NAME(osc12m_clk, "osc_12m", "osc_24m", 2, 1, 0);
+static struct clk_fixed_factor osc12m_clk = {
+	.div		= 2,
+	.mult		= 1,
+	.hw.init	= CLK_HW_INIT_PARENTS_DATA("osc_12m",
+						   osc_24m_clk,
+						   &clk_fixed_factor_ops,
+						   0),
+};
 
 static const char * const out_parents[] = { "osc_24m", "osc_12m" };
 
-- 
2.50.0

Re: [PATCH v2 1/2] clk: thead: th1520-ap: Correctly refer the parent of osc_12m

[Drew Fustini]

On Thu, Jul 10, 2025 at 09:21:34AM +0000, Yao Zi wrote:
> The "osc_12m" fixed factor clock refers the external oscillator by
> setting clk_parent_data.fw_name to osc_24m, which is obviously wrong
> since no clock-names property is allowed for compatible
> thead,th1520-clk-ap.
> 
> Refer the oscillator as parent by index instead.
> 
> Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
> Signed-off-by: Yao Zi <ziyao@disroot.org>
> ---
>  drivers/clk/thead/clk-th1520-ap.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
> index ebfb1d59401d..42feb4bb6329 100644
> --- a/drivers/clk/thead/clk-th1520-ap.c
> +++ b/drivers/clk/thead/clk-th1520-ap.c
> @@ -582,7 +582,14 @@ static const struct clk_parent_data peri2sys_apb_pclk_pd[] = {
>  	{ .hw = &peri2sys_apb_pclk.common.hw }
>  };
>  
> -static CLK_FIXED_FACTOR_FW_NAME(osc12m_clk, "osc_12m", "osc_24m", 2, 1, 0);
> +static struct clk_fixed_factor osc12m_clk = {
> +	.div		= 2,
> +	.mult		= 1,
> +	.hw.init	= CLK_HW_INIT_PARENTS_DATA("osc_12m",
> +						   osc_24m_clk,
> +						   &clk_fixed_factor_ops,
> +						   0),
> +};
>  
>  static const char * const out_parents[] = { "osc_24m", "osc_12m" };
>  
> -- 
> 2.50.0

Reviewed-by: Drew Fustini <fustini@kernel.org>

Thanks for fixing this. osc_12m now appears under osc_24m in
clk_summary.

Drew

Re: [PATCH v2 1/2] clk: thead: th1520-ap: Correctly refer the parent of osc_12m

[Drew Fustini]

On Thu, Jul 10, 2025 at 02:00:06PM -0700, Drew Fustini wrote:
> On Thu, Jul 10, 2025 at 09:21:34AM +0000, Yao Zi wrote:
> > The "osc_12m" fixed factor clock refers the external oscillator by
> > setting clk_parent_data.fw_name to osc_24m, which is obviously wrong
> > since no clock-names property is allowed for compatible
> > thead,th1520-clk-ap.
> > 
> > Refer the oscillator as parent by index instead.
> > 
> > Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
> > Signed-off-by: Yao Zi <ziyao@disroot.org>
> > ---
> >  drivers/clk/thead/clk-th1520-ap.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
> > index ebfb1d59401d..42feb4bb6329 100644
> > --- a/drivers/clk/thead/clk-th1520-ap.c
> > +++ b/drivers/clk/thead/clk-th1520-ap.c
> > @@ -582,7 +582,14 @@ static const struct clk_parent_data peri2sys_apb_pclk_pd[] = {
> >  	{ .hw = &peri2sys_apb_pclk.common.hw }
> >  };
> >  
> > -static CLK_FIXED_FACTOR_FW_NAME(osc12m_clk, "osc_12m", "osc_24m", 2, 1, 0);
> > +static struct clk_fixed_factor osc12m_clk = {
> > +	.div		= 2,
> > +	.mult		= 1,
> > +	.hw.init	= CLK_HW_INIT_PARENTS_DATA("osc_12m",
> > +						   osc_24m_clk,
> > +						   &clk_fixed_factor_ops,
> > +						   0),
> > +};
> >  
> >  static const char * const out_parents[] = { "osc_24m", "osc_12m" };
> >  
> > -- 
> > 2.50.0
> 
> Reviewed-by: Drew Fustini <fustini@kernel.org>
> 
> Thanks for fixing this. osc_12m now appears under osc_24m in
> clk_summary.
> 
> Drew

Thank you for the patch. I've now applied it to thead-clk-for-next as
commit d274c77ffa20 [1].

Drew

[1] https://github.com/pdp7/linux/commit/d274c77ffa202b70ad01d579f33b73b4de123375

[PATCH v2 2/2] clk: thead: th1520-ap: Correctly refer the parent of c910-i0

[Yao Zi]

The correct parent of c910, c910-i0, is registered with
devm_clk_hw_register_mux_parent_data_table(), which creates a clk_hw
structure from scratch. But it's assigned as c910's parent by
referring &c910_i0_clk.common.hw, confusing the CCF since this clk_hw
structure is never registered.

Refer c910-i0 by its name instead to avoid turning c910 into an orphan
clock.

Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
Signed-off-by: Yao Zi <ziyao@disroot.org>
---
 drivers/clk/thead/clk-th1520-ap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
index 42feb4bb6329..41ed72b1a915 100644
--- a/drivers/clk/thead/clk-th1520-ap.c
+++ b/drivers/clk/thead/clk-th1520-ap.c
@@ -427,7 +427,7 @@ static struct ccu_mux c910_i0_clk = {
 };
 
 static const struct clk_parent_data c910_parents[] = {
-	{ .hw = &c910_i0_clk.common.hw },
+	{ .index = -1, .name = "c910-i0" },
 	{ .hw = &cpu_pll1_clk.common.hw }
 };
 
-- 
2.50.0

Re: [PATCH v2 2/2] clk: thead: th1520-ap: Correctly refer the parent of c910-i0

[Drew Fustini]

On Thu, Jul 10, 2025 at 09:21:35AM +0000, Yao Zi wrote:
> The correct parent of c910, c910-i0, is registered with
> devm_clk_hw_register_mux_parent_data_table(), which creates a clk_hw
> structure from scratch. But it's assigned as c910's parent by
> referring &c910_i0_clk.common.hw, confusing the CCF since this clk_hw
> structure is never registered.
> 
> Refer c910-i0 by its name instead to avoid turning c910 into an orphan
> clock.
> 
> Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
> Signed-off-by: Yao Zi <ziyao@disroot.org>
> ---
>  drivers/clk/thead/clk-th1520-ap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
> index 42feb4bb6329..41ed72b1a915 100644
> --- a/drivers/clk/thead/clk-th1520-ap.c
> +++ b/drivers/clk/thead/clk-th1520-ap.c
> @@ -427,7 +427,7 @@ static struct ccu_mux c910_i0_clk = {
>  };
>  
>  static const struct clk_parent_data c910_parents[] = {
> -	{ .hw = &c910_i0_clk.common.hw },
> +	{ .index = -1, .name = "c910-i0" },

Thanks for the patch. Unfortunately, I chatted with Stephen about this
on irc and we need to avoid using strings in clk_parent_data. I'm trying
to see how to correctly assign the pointer in the c910_parents[] after
c910_io_clk has been registered.

Thanks,
Drew

Re: [PATCH v2 2/2] clk: thead: th1520-ap: Correctly refer the parent of c910-i0

[Yao Zi]

On Fri, Jul 11, 2025 at 01:52:15AM -0700, Drew Fustini wrote:
> On Thu, Jul 10, 2025 at 09:21:35AM +0000, Yao Zi wrote:
> > The correct parent of c910, c910-i0, is registered with
> > devm_clk_hw_register_mux_parent_data_table(), which creates a clk_hw
> > structure from scratch. But it's assigned as c910's parent by
> > referring &c910_i0_clk.common.hw, confusing the CCF since this clk_hw
> > structure is never registered.
> > 
> > Refer c910-i0 by its name instead to avoid turning c910 into an orphan
> > clock.
> > 
> > Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks")
> > Signed-off-by: Yao Zi <ziyao@disroot.org>
> > ---
> >  drivers/clk/thead/clk-th1520-ap.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c
> > index 42feb4bb6329..41ed72b1a915 100644
> > --- a/drivers/clk/thead/clk-th1520-ap.c
> > +++ b/drivers/clk/thead/clk-th1520-ap.c
> > @@ -427,7 +427,7 @@ static struct ccu_mux c910_i0_clk = {
> >  };
> >  
> >  static const struct clk_parent_data c910_parents[] = {
> > -	{ .hw = &c910_i0_clk.common.hw },
> > +	{ .index = -1, .name = "c910-i0" },
> 
> Thanks for the patch. Unfortunately, I chatted with Stephen about this
> on irc and we need to avoid using strings in clk_parent_data. I'm trying
> to see how to correctly assign the pointer in the c910_parents[] after
> c910_io_clk has been registered.

If we stop using *_register_mux() for all the muxes, the problem should
go away: the key cause is that *_register_mux() always allocates a new
clk_mux structure, which in turn contains a new clk_hw structure.

We could avoid the ccu_mux structure, instead defining clk_muxes
directly and register them with devm_clk_hw_register(), for example,

	static struct clk_mux c910_i0_clk = {
		.reg		= 0x100,
		.mask		= BIT(0),
		.shift		= 1,
		.hw.init	= CLK_HW_INIT_PARENT_DATA("c910-i0",
							  c910_i0_parents,
							  &clk_mux_ops,
							  0),
	};

	c910_i0_clk.reg += base;
	ret = devm_clk_hw_register(dev, &c910_i0_clk.hw);

(not tested, just for demostration)

Now no new clk_hw structure is created and we could refer to muxes by
its hw member when defining other clocks.

> Thanks,
> Drew

Regards,
Yao Zi