K64 pinmux support is created as a normal driver.
As opposed to the Galileo board, the pin configuration options are
defined by the MCU and are not board-specific. Separate
platform/board-specific configuration code uses the pinmux driver for
the default pin settings. For FRDM-K64F, only the Arduino pins (22 of a
possible 160) are set up.
Some of the I/O pins routed to the Arduino header are also configured as
JTAG/SWD signals by default and are used by the OpenSDAv2 debug
interface. Therefore, a PRESERVE_JTAG_IO_PINS config option was created
for the FRDM-K64 platform to prevent the default pin settings from
re-configuring these pins.
The K64 MCU separates pin configuration and control, implemented in the
pinmux driver, from GPIO. This results in some cross referencing
between the K64 GPIO driver and the K64 pinmux driver due to the
dependencies of one on the other.
This pinmux driver also uses the expanded pinmux function/mode parameter
size to describe pin configuration options with bit fields for the K64,
including up to 8 pin functions, plus interrupt, pullup/down, drive
strength, open-drain and slew rate.
The following GCC warnings in the K64 pinmux driver are prevented when not
compiling with 'no-optimization' (-O0):
warning: 'gpio_dev' may be used uninitialized in this function
[-Wmaybe-uninitialized]
Change-Id: Ie5031d18750143bf895883058b3cd55fd9989fd3
Signed-off-by: Jeff Blais <jeff.blais@windriver.com>
Jeff Blais