The driver model supports two ways for passing device parameters; Device Tree and platform_data (board file). Each driver should generally support both of them because some popular IPs are used on various platforms.
Assume the following scenario: - The driver Foo is used on SoC Bar and SoC Baz - The SoC Bar uses Device Tree control (CONFIG_OF_CONTROL=y) - The SoC Baz does not support Device Tree; uses a board file
In this situation, the device driver Foo should work with/without the device tree control. The driver should have .of_match and .ofdata_to_platdata members for SoC Bar, while they are meaningless for SoC Baz; therefore those device-tree control code should go inside #ifdef CONFIG_OF_CONTROL.
The driver code will be like this:
#ifdef CONFIG_OF_CONTROL static const struct udevice_id foo_of_match = { { .compatible = "foo_driver" }, {}, }
static int foo_ofdata_to_platdata(struct udevice *dev) { ... } #endif
U_BOOT_DRIVER(foo_driver) = { ... .of_match = of_match_ptr(foo_of_match), .ofdata_to_platdata = of_match_ptr(foo_ofdata_to_platdata), ... }
This idea has been borrowed from Linux. (In Linux, this macro is defined in include/linux/of.h)
Signed-off-by: Masahiro Yamada yamada.m@jp.panasonic.com ---
include/dm/device.h | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/include/dm/device.h b/include/dm/device.h index c8a4072..e08d496 100644 --- a/include/dm/device.h +++ b/include/dm/device.h @@ -96,6 +96,12 @@ struct udevice_id { ulong data; };
+#ifdef CONFIG_OF_CONTROL +#define of_match_ptr(_ptr) (_ptr) +#else +#define of_match_ptr(_ptr) NULL +#endif /* CONFIG_OF_CONTROL */ + /** * struct driver - A driver for a feature or peripheral *