On Tue, Aug 25, 2026 at 03:47:41PM -0400, Ralph Siemsen wrote:
On Sat, Aug 15, 2026 at 12:21:11AM +0200, Marek Vasut wrote:
On 8/14/26 8:30 PM, Ralph Siemsen wrote:
return ret;
}
- clock = clk_get_rate(&clk);
+ clock = clk_get_rate(&clks.clks[0]);
Can the clock ever be non-first clock , i.e. do you need to handle
clock-names DT property somehow ?
It's not clear to me if the DT binding specifies the order. It says
there must be either 2 or 3 clocks, as well as clock-names properties.
I had another look at the clock ordering. According to [1]
"Order in lists is significant, order in dicts is not."
The binding [2] uses a list for the clock names:
clock-names:
minItems: 2
items:
- const: clk_xin
- const: clk_ahb
- const: gate
And as we can see, the reference clock ("clk_xin") is listed first.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/example-schema.yaml#n47
[2]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/arasan,sdhci.yaml#n116
As a further check, I reversed the order of the clocks, and then ran
"make dtbs_check" to verify against DT schema. It complains:
arch/arm/dts/r9a06g032-rzn1-snarc.dtb: mmc@40100000 (renesas,r9a06g032-sdhci):
clock-names:0: 'clk_xin' was expected
from schema $id: http://devicetree.org/schemas/mmc/arasan,sdhci.yaml
arch/arm/dts/r9a06g032-rzn1-snarc.dtb: mmc@40100000 (renesas,r9a06g032-sdhci):
clock-names:1: 'clk_ahb' was expected
from schema $id: http://devicetree.org/schemas/mmc/arasan,sdhci.yaml
No complaint when the clocks are in the correct order.
We could try using the name ("clk_xin") and if that fails, fall back on
using the first clock.
So I think we don't need this extra complexity after all. It should be
fine to rely on the first clock being the correct one.
Ralph
