[RFC PATCH 0/4] ARM: dts: renesas: mtd-rom has no clock and power domain

[RFC PATCH 0/4] ARM: dts: renesas: mtd-rom has no clock and power domain

[Wolfram Sang]

Addressing this dtb_check...

arch/arm/boot/dts/renesas/r7s72100-genmai.dtb: flash@18000000 (mtd-rom): Unevaluated properties are not allowed ('clocks', 'power-domains' were unexpected)
	from schema $id: http://devicetree.org/schemas/mtd/mtd-physmap.yaml#

... I came to the solution proposed here that the clocks we cannot
define will be marked as critical. We could also try to add 'clocks' and
'power-domains' to MTD physmap but I could understand some objection to
that. Opinions?


Wolfram Sang (4):
  clk: renesas: mstp: mark 'spibsc' clocks as critical
  ARM: dts: renesas: genmai: mtd-rom has no clock and power domain
  ARM: dts: renesas: gr-peach: mtd-rom has no clock and power domain
  ARM: dts: renesas: rskrza1: mtd-rom has no clock and power domain

 arch/arm/boot/dts/renesas/r7s72100-genmai.dts   | 3 ---
 arch/arm/boot/dts/renesas/r7s72100-gr-peach.dts | 3 ---
 arch/arm/boot/dts/renesas/r7s72100-rskrza1.dts  | 2 --
 drivers/clk/renesas/clk-mstp.c                  | 7 +++++--
 4 files changed, 5 insertions(+), 10 deletions(-)

-- 
2.47.2

[RFC PATCH 1/4] clk: renesas: mstp: mark 'spibsc' clocks as critical

[Wolfram Sang]

They can be used for XIP (grpeach) and we cannot define them in the DT
because MTD physmap does not allow clock properties.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/clk/renesas/clk-mstp.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c
index 2f65fe2c6bdf..5601e104d167 100644
--- a/drivers/clk/renesas/clk-mstp.c
+++ b/drivers/clk/renesas/clk-mstp.c
@@ -157,8 +157,11 @@ static struct clk * __init cpg_mstp_clock_register(const char *name,
 	init.name = name;
 	init.ops = &cpg_mstp_clock_ops;
 	init.flags = CLK_SET_RATE_PARENT;
-	/* INTC-SYS is the module clock of the GIC, and must not be disabled */
-	if (!strcmp(name, "intc-sys")) {
+	/*
+	 * INTC-SYS is the module clock of the GIC, and must not be disabled (r8a73a4)
+	 * SPIBSC<x> is for memory-mapped flash which might be needed for XIP (r7s72100)
+	 */
+	if (!strcmp(name, "intc-sys") || !strncmp(name, "spibsc", 6)) {
 		pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name);
 		init.flags |= CLK_IS_CRITICAL;
 	}
-- 
2.47.2

Re: [RFC PATCH 0/4] ARM: dts: renesas: mtd-rom has no clock and power domain

[Geert Uytterhoeven]

Hi Wolfram,

On Tue, 30 Sept 2025 at 12:17, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> Addressing this dtb_check...
>
> arch/arm/boot/dts/renesas/r7s72100-genmai.dtb: flash@18000000 (mtd-rom): Unevaluated properties are not allowed ('clocks', 'power-domains' were unexpected)
>         from schema $id: http://devicetree.org/schemas/mtd/mtd-physmap.yaml#
>
> ... I came to the solution proposed here that the clocks we cannot
> define will be marked as critical. We could also try to add 'clocks' and
> 'power-domains' to MTD physmap but I could understand some objection to
> that. Opinions?

I would rather add clocks and power-domains to the DT bindings, for
two reasons:
  1. It describes the hardware better,
  2. It avoids keeping the clock running on systems where the FLASH
     is not used.

Does mtd-rom go through drivers/mtd/maps/physmap-core.c?
Then the clock domain is handled through Runtime PM since commit
0bc448b49e8a017e ("mtd: maps: physmap: Add minimal Runtime PM support").

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [RFC PATCH 0/4] ARM: dts: renesas: mtd-rom has no clock and power domain

[Wolfram Sang]

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Hi Geert,

> Does mtd-rom go through drivers/mtd/maps/physmap-core.c?
> Then the clock domain is handled through Runtime PM since commit
> 0bc448b49e8a017e ("mtd: maps: physmap: Add minimal Runtime PM support").

Thank you, Geert, for the pointers. I will have a try.

Happy hacking,

   Wolfram


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