On x86 builds the absense of <linux/io.h> makes static analyzer and compiler
unhappy which fails to build the driver.
CHECK drivers/pinctrl/intel/pinctrl-merrifield.c
drivers/pinctrl/intel/pinctrl-merrifield.c:518:17:
error: undefined identifier 'readl'
drivers/pinctrl/intel/pinctrl-merrifield.c:570:17:
error: undefined identifier 'readl'
drivers/pinctrl/intel/pinctrl-merrifield.c:575:9:
error: undefined identifier 'writel'
drivers/pinctrl/intel/pinctrl-merrifield.c:645:17:
error: undefined identifier 'readl'
CC drivers/pinctrl/intel/pinctrl-merrifield.o
drivers/pinctrl/intel/pinctrl-merrifield.c: In function ‘mrfld_pin_dbg_show’:
drivers/pinctrl/intel/pinctrl-merrifield.c:518:10:
error: implicit declaration of function ‘readl’
[-Werror=implicit-function-declaration]
value = readl(bufcfg);
^
drivers/pinctrl/intel/pinctrl-merrifield.c: In function ‘mrfld_update_bufcfg’:
drivers/pinctrl/intel/pinctrl-merrifield.c:575:2:
error: implicit declaration of function ‘writel’
[-Werror=implicit-function-declaration]
writel(value, bufcfg);
^
cc1: some warnings being treated as errors