Hello.
On 06/23/2015 01:42 AM, Sergei Shtylyov wrote:
Calling sh_pfc_get_pin_index() to calculate a pin index based on the
collected pin range data is unnecessary when we're dealing with
'pfc->info->pins' and 'chip->pins' arrays as those always reperesent the
pins starting from index 0 sequentially. Being a mere optimization at
this time, this change will become crucial when we'll allow the "holes" in
those arrays...
Pin information is stored in per-SoC pins arrays (a.k.a. pfc->info->pins). The
driver support two models to number pins:
- The sequential model, in which pins are numbered sequentially starting at 0.
Pin numbers are equal to the index in the array.
And I didn't touch this case.
- The explicit numbering model, in which each pin entry has an explicit number
(stored in struct sh_pfc_pin.pin). Pins numbers are not necessarily equal to
the index of the pin entry in the array.
Ah... I was just looking at _GP_GPIO() which still assigns sequential pin
#'s equal to the indices.
And forgot about SH_PFC_PIN_NAMED()...
The sh_pfc_get_pin_index() function converts a pin number to the pin index in
the pins array.
Let's consider the sh_pfc_pinconf_validate() from which your patch removes the
call to sh_pfc_get_pin_index() and uses the pin number directly. The function
is called from the .pin_config_get() and .pin_config_set() handlers. One
possible call path is
pinconf_pins_show() -> pinconf_dump_pin() -> pinconf_dump_pins() ->
pinconf_generic_dump_pins() -> pinconf_generic_dump_one() ->
pin_config_get_for_pin() -> .pin_config_get()
The pin value passed to the .pin_config_get() function is pctldev->desc->
pins[i].number, which is the pin number, not its index. It thus looks like
this patch introduces a bug.
There might be something obvious I'm not getting though, so please feel free
to prove me wrong.
The bug seems more like theoretical one at this point (unless you have the
examples with non-sequential pin #'s)...
No, with non-GPIO pins it seems to be an actual bug.
What if we remove the explicit array index from _GP_GPIO() and so don't
have the holes at all?
WBR, Sergei
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