Hi Simon,
2016-01-21 0:24 GMT+09:00 Simon Glass sjg@chromium.org:
Hi Masahiro,
On 19 January 2016 at 22:38, Masahiro Yamada yamada.masahiro@socionext.com wrote:
Hi Simon,
+/**
- clk_get_by_index() - look up a clock referenced by a device
- Parse a device's 'clocks' list, returning information on the indexed clock,
- ensuring that it is activated.
- @dev: Device containing the clock reference
- @index: Clock index to return (0 = first)
- @clk_devp: Returns clock device
- @return: Peripheral ID for the device to control. This is the first
argument after the clock node phandle. If there is no arguemnt,
returns 0. Return -ve error code on any error- */
+int clk_get_by_index(struct udevice *dev, int index, struct udevice **clk_devp); #endif /* _CLK_H_ */
I want #ifdef in the header too, like mine http://patchwork.ozlabs.org/patch/566812/
I am not keen on that idea since it clutters up header files and we'll get a link error anyway if something is missing. Anyway, I've added it.
I am afraid there is misunderstanding here.
Please see my patch carefully.
What I mean is like this:
#if ... declaration of function prototype #else static inline empty function #endif
This is a common technique to avoid a link error.
Do you think this function will be called when device tree is not enabled? I cannot see how it would have any meaning in that case. What is the purpose?
In order to avoid build errors.
I think this coding style is often used.
For example, you can see include/linux/clk.h in Linux.
#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_from_provider(struct of_phandle_args *clkspec); #else static inline struct clk *of_clk_get(struct device_node *np, int index) { return ERR_PTR(-ENOENT); } static inline struct clk *of_clk_get_by_name(struct device_node *np, const char *name) { return ERR_PTR(-ENOENT); } #endif
If every driver entry in Kconfig specifies "depends on OF_CONTROL" correctly, no link error would happen for this.
So, I leave this decision to you. If you do not like #ifdef in header files, just rip it off.