[PATCH] clk: Add functions to get optional clocks
From: sboyd@kernel.org (Stephen Boyd)
Date: 2018-07-27 16:50:20
Also in:
linux-clk, lkml
Quoting Phil Edworthy (2018-07-27 08:38:12)
On 25 July 2018 23:37, Stephen Boyd wrote:quoted
Short answer is they don't. I'd still prefer we have this API though. Can you rework this patch to be a little more invasive into the clk_get() path, perhaps by reworking __of_clk_get_by_name() a little to take an 'optional' argument, so that it only returns NULL when the clk is looked up from DT? The fallback path in clkdev where we have a DT based system looking up a clk through clkdev lookups doesn't seem to be a real scenario that we should worry about here. I think sometimes people use clkdev lookups when they're migrating to DT systems and things aren't wired up properly in DT, but that isn't the norm.Do you mean something like this:
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quoted hunk ↗ jump to hunk
diff --git a/include/linux/clk.h b/include/linux/clk.h index 907202b..830209a 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h@@ -771,6 +771,7 @@ static inline void clk_bulk_disable_unprepare(int num_clks, #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) struct clk *of_clk_get(struct device_node *np, int index); struct clk *of_clk_get_by_name(struct device_node *np, const char *name); +struct clk *of_clk_get_by_name_optional(struct device_node *np, const char *name); struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); #else static inline struct clk *of_clk_get(struct device_node *np, int index)--- A lot of drivers use devm_clk_get() so I think a devm_clk_get_optional() version would be useful. That would probably need an additional clk_get_optional() function.
Yes, this would be the first patch, and then the second patch would add clk_get_optional() and devm_clk_get_optional(). We shouldn't encourage consumers to move from device based to DT node based clk_get() for the optional clk API.