[U-Boot] [PATCH] M28: Added guarding for reserved bits in GPIO driver

[Robert Deliën]

> Careful here !!
> 
> The driver _should_ work for MX233 too! What I'd like to see is you introducing 
> a function like:
> 
> int mxs_gpio_is_valid(gpio)
> {
> char mxs_banks[PINCTRL_BANKS] = PINCTRL_BANK_COUNTS;
> 
> if (PAD_PIN(gpio) > mxs_bank[PAD_BANK(gpio)])
> return -EINVAL;
> 
> return 0;
> }

There's a bit of a paradox here: If a name is translated into a pin, bank numbers above 7 and pin numbers above 31 will have wrapped around in translation and won't be caught here. I could check for wrapping in the translating function and check for valid numbers within the assigned bit range here, but I'd rather not see validity check spread over two functions.

> And define PINCTRL_BANK_COUNTS in the section of mxs_gpio.c where all the 
> remaining mx28 and mx233 specific defines are hoarded (near the top of the 
> file).

At that spot I've put in Mike's (very similar) solution now:
static const int mxs_bank_pins[] = {
	MXS_BANK0_PINS,
	MXS_BANK1_PINS,
	MXS_BANK2_PINS,
#ifdef(CONFIG_MX28)
	MXS_BANK3_PINS,
	MXS_BANK4_PINS,
#endif
};

I'm considering to remove the macro PINCTRL_BANKS now, and use ARRAY_SIZE(mxs_bank_pins) instead, as it yields the same number and leads to a single point of definition.