On Mon, Feb 11, 2019 at 5:32 PM Fabrice Gasnier [off-list ref] wrote:

On 1/28/19 2:20 PM, Fabrice Gasnier wrote:

quoted

On 1/16/19 4:11 PM, Arnd Bergmann wrote:

quoted

On Wed, Jan 16, 2019 at 3:10 PM Fabrice Gasnier [off-list ref] wrote:

What I mean is that nodes that listed as 'compatible="syscon"' get
probed by the syscon driver even when no other driver references
them, and that in turn would acquire the clock, right?

When no other driver references them, nothing happens at probe time on
the clock: no calls to get/prepare... the clock.

=> The clock will remain unrequested & unused until another driver calls
one of "of_syscon_register()" variants:
- syscon_node_to_regmap
- syscon_regmap_lookup_by_compatible
- syscon_regmap_lookup_by_phandle

When another driver references them (e.g. one of the above calls), then
it will acquire the optional clock and use it, e.g.:
- clk_prepare() upon of_syscon_register() variants
- clk_enable & clk_disable when accessing the registers

I hope this clarifies.

I would appreciate to have your feedback.

Yes, I think that's all we need here, thanks for the clarification,
and sorry for dropping the ball on this again.

Acked-by: Arnd Bergmann <arnd@arndb.de>


      Arnd

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