clk: Make of_parse_clkspec() return -ENOENT on errors
Stephen Boyd
maintainerPATCH 1/1 clk: Make of_parse_clkspec() return -ENOENT on errors
The return value of of_parse_clkspec() is peculiar. If the function is called with a NULL argument for 'name' it will return -ENOENT, but if it's called with a non-NULL argument for 'name' it will return -EINVAL. This peculiarity is documented by commit 5c56dfe63b6e ("clk: Add comment about __of_clk_get_by_name() error values").
Let's further document this function so that it's clear what the return value is and how to use the arguments to parse clk specifiers.
--- drivers/clk/clk.c | 43 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 37 insertions(+), 6 deletions(-)
drivers/clk/clk.c +37 -6
@@ -4316,12 +4316,43 @@ void devm_of_clk_del_provider(struct device *dev) }EXPORT_SYMBOL (devm_of_clk_del_provider); -/* -* Beware the return values when np is valid, but no clock provider is found. -* If name == NULL, the function returns -ENOENT. -* If name != NULL, the function returns -EINVAL. This is because -* of_parse_phandle_with_args() is called even if of_property_match_string() -* returns an error. +/** +* of_parse_clkspec() - Parse a DT clock specifier for a given device node +* @np: device node to parse clock specifier from +* @index: index of phandle to parse clock out of. If index < 0, @name is used +* @name: clock name to find and parse. If name is NULL, the index is used +* @out_args: Result of parsing the clock specifier +* +* Parses a device node's "clocks" and "clock-names" properties to find the +* phandle and cells for the index or name that is desired. The resulting clock +* specifier is placed into @out_args, or an errno is returned when there's a +* parsing error. The @index argument is ignored if @name is non-NULL. +* +* Example: +* +* phandle1: clock-controller@1 { +* #clock-cells = <2>; +* } +* +* phandle2: clock-controller@2 { +* #clock-cells = <1>; +* } +* +* clock-consumer@3 { +* clocks = <&phandle1 1 2 &phandle2 3>; +* clock-names = "name1", "name2"; +* } +* +* To get a device_node for `clock-controller@2' node you may call this +* function a few different ways: +* +* of_parse_clkspec(clock-consumer@3, -1, "name2", &args); +* of_parse_clkspec(clock-consumer@3, 1, NULL, &args); +* of_parse_clkspec(clock-consumer@3, 1, "name2", &args); +* +* Return: 0 upon successfully parsing the clock specifier. Otherwise, -ENOENT +* if @name is NULL or -EINVAL if @name is non-NULL and it can't be found in +* the "clock-names" property of @np. */ static int of_parse_clkspec (const struct device_node *np,int index,const char *name,struct of_phandle_args *out_args)
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Stephen Boyd
maintainerHrmm.. the subject is misleading. Let me reword it and resend.
Quoting Stephen Boyd (2019-08-19 15:29:15)
Quoted 11 lines
The return value of
of_parse_clkspec()is peculiar. If the function is called with a NULL argument for 'name' it will return-ENOENT, but if it's called with a non-NULL argument for 'name' it will return-EINVAL. This peculiarity is documented by commit5c56dfe63b6e("clk: Add comment about__of_clk_get_by_name()error values").Let's further document this function so that it's clear what the return value is and how to use the arguments to parse clk specifiers.
Cc Phil Edworthy <[email protected]>Signed-off-by Stephen Boyd <[email protected]>