struct ulpi_ops is defined as follows:
struct ulpi_ops {
struct device *dev;
int (*read)(struct ulpi_ops *ops, u8 addr);
int (*write)(struct ulpi_ops *ops, u8 addr, u8 val);
};
Upon calling ulpi_register_interface(), the struct device argument is
put inside the struct ulpi_ops argument's dev field. Later, when
calling the actual read()/write() operations, the struct ulpi_ops is
passed to them and they use the stored device to access whatever
private data they need.
This means that if one wishes to reuse the same oprations for multiple
interfaces (e.g if we have multiple instances of the same controller),
any but the last interface registered will not operate properly (and
the one that does work will be at the mercy of the others to not mess
it up).
I understand that barely any driver uses this bus right now, but I
suppose it's there to be used at some point. We might as well fix the
design here before we hit this bug.
I would like to create a patch series to fix this by passing the given
struct device directly to the operation functions via ulpi->dev.parent
in ulpi_read() and ulpi_write(), but I'm not sure about the correct
order of the patches that make such a series. Do I change the api and
all users in one patch? one patch for api and one for each user?
Any comments and guidelines are welcome :)
Respectfully,
Tal Shorer
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