Do not depend on gpio, add a new driver name to GENERIC and depend on this (and the SOC_ option).

Could you add the gpio_pin_access_32/gpio_pin_config_32 while you're at it please ?

You have DEFAULT_CAPS as a mask to check against.

gp_flags = flags and remove the line above.

I don't see this property in the binding docs

You should right the pin name, as a default do :
snprintf(name, GPIOMAXNAME, "pin %d", pin);

You should lock and use the internal function to avoid any race.

This part did not check if capabilities are supported but checked if some impossible condition doesn't happen, such as both input and output flag set.
Since this could have gotten confusing I moved the check outside pin count check and added comment.

I removed it.

This comment still applies, add a new ls1046_gpio driver in GENERIC and depend on it here.