Ian Lepore e6c435106f Enable ARM_INTRNG on IMX6 platforms, and make the imx_gpio driver an
interrupt controller.

The latter is required for INTRNG, because of the hardware erratum
workaround installed by the linux folks into the imx6 FDT data, which remaps
an ethernet interrupt to the gpio device.  In the non-INTRNG world we
intercept the call to map the interrupt and map it back to the ethernet
hardware (because we don't need linux's workaround), but in the INTRNG world
we lose the hookpoint where that remapping was happening, but we gain the
ability to work the way linux does by having the gpio driver dispatch the
interrupt.
2015-10-18 19:54:11 +00:00

730 lines
17 KiB
C

/*-
* Copyright (c) 2012, 2013 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Oleksandr Rybalko under sponsorship
* from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Freescale i.MX515 GPIO driver.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/gpio.h>
#include <sys/proc.h>
#include <machine/bus.h>
#include <machine/intr.h>
#include <machine/resource.h>
#include <dev/fdt/fdt_common.h>
#include <dev/gpio/gpiobusvar.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include "gpio_if.h"
#ifdef ARM_INTRNG
#include "pic_if.h"
#endif
#define WRITE4(_sc, _r, _v) \
bus_space_write_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r), (_v))
#define READ4(_sc, _r) \
bus_space_read_4((_sc)->sc_iot, (_sc)->sc_ioh, (_r))
#define SET4(_sc, _r, _m) \
WRITE4((_sc), (_r), READ4((_sc), (_r)) | (_m))
#define CLEAR4(_sc, _r, _m) \
WRITE4((_sc), (_r), READ4((_sc), (_r)) & ~(_m))
/* Registers definition for Freescale i.MX515 GPIO controller */
#define IMX_GPIO_DR_REG 0x000 /* Pin Data */
#define IMX_GPIO_OE_REG 0x004 /* Set Pin Output */
#define IMX_GPIO_PSR_REG 0x008 /* Pad Status */
#define IMX_GPIO_ICR1_REG 0x00C /* Interrupt Configuration */
#define IMX_GPIO_ICR2_REG 0x010 /* Interrupt Configuration */
#define GPIO_ICR_COND_LOW 0
#define GPIO_ICR_COND_HIGH 1
#define GPIO_ICR_COND_RISE 2
#define GPIO_ICR_COND_FALL 3
#define IMX_GPIO_IMR_REG 0x014 /* Interrupt Mask Register */
#define IMX_GPIO_ISR_REG 0x018 /* Interrupt Status Register */
#define IMX_GPIO_EDGE_REG 0x01C /* Edge Detect Register */
#define DEFAULT_CAPS (GPIO_PIN_INPUT | GPIO_PIN_OUTPUT)
#define NGPIO 32
struct imx51_gpio_softc {
device_t dev;
device_t sc_busdev;
struct mtx sc_mtx;
struct resource *sc_res[3]; /* 1 x mem, 2 x IRQ */
void *gpio_ih[2];
bus_space_tag_t sc_iot;
bus_space_handle_t sc_ioh;
int gpio_npins;
struct gpio_pin gpio_pins[NGPIO];
struct arm_irqsrc *gpio_pic_irqsrc[NGPIO];
};
static struct ofw_compat_data compat_data[] = {
{"fsl,imx6q-gpio", 1},
{"fsl,imx53-gpio", 1},
{"fsl,imx51-gpio", 1},
{NULL, 0}
};
static struct resource_spec imx_gpio_spec[] = {
{ SYS_RES_MEMORY, 0, RF_ACTIVE },
{ SYS_RES_IRQ, 0, RF_ACTIVE },
{ SYS_RES_IRQ, 1, RF_ACTIVE },
{ -1, 0 }
};
/*
* Helpers
*/
static void imx51_gpio_pin_configure(struct imx51_gpio_softc *,
struct gpio_pin *, uint32_t);
/*
* Driver stuff
*/
static int imx51_gpio_probe(device_t);
static int imx51_gpio_attach(device_t);
static int imx51_gpio_detach(device_t);
/*
* GPIO interface
*/
static device_t imx51_gpio_get_bus(device_t);
static int imx51_gpio_pin_max(device_t, int *);
static int imx51_gpio_pin_getcaps(device_t, uint32_t, uint32_t *);
static int imx51_gpio_pin_getflags(device_t, uint32_t, uint32_t *);
static int imx51_gpio_pin_getname(device_t, uint32_t, char *);
static int imx51_gpio_pin_setflags(device_t, uint32_t, uint32_t);
static int imx51_gpio_pin_set(device_t, uint32_t, unsigned int);
static int imx51_gpio_pin_get(device_t, uint32_t, unsigned int *);
static int imx51_gpio_pin_toggle(device_t, uint32_t pin);
#ifdef ARM_INTRNG
/*
* this is teardown_intr
*/
static void
gpio_pic_disable_intr(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
u_int irq;
sc = device_get_softc(dev);
irq = isrc->isrc_data;
// XXX Not sure this is necessary
mtx_lock_spin(&sc->sc_mtx);
CLEAR4(sc, IMX_GPIO_IMR_REG, (1U << irq));
WRITE4(sc, IMX_GPIO_ISR_REG, (1U << irq));
mtx_unlock_spin(&sc->sc_mtx);
}
/*
* this is mask_intr
*/
static void
gpio_pic_disable_source(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
mtx_lock_spin(&sc->sc_mtx);
CLEAR4(sc, IMX_GPIO_IMR_REG, (1U << isrc->isrc_data));
mtx_unlock_spin(&sc->sc_mtx);
}
/*
* this is setup_intr
*/
static void
gpio_pic_enable_intr(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
int icfg;
u_int irq, reg, shift, wrk;
sc = device_get_softc(dev);
if (isrc->isrc_trig == INTR_TRIGGER_LEVEL) {
if (isrc->isrc_pol == INTR_POLARITY_LOW)
icfg = GPIO_ICR_COND_LOW;
else
icfg = GPIO_ICR_COND_HIGH;
} else {
if (isrc->isrc_pol == INTR_POLARITY_HIGH)
icfg = GPIO_ICR_COND_FALL;
else
icfg = GPIO_ICR_COND_RISE;
}
irq = isrc->isrc_data;
if (irq < 16) {
reg = IMX_GPIO_ICR1_REG;
shift = 2 * irq;
} else {
reg = IMX_GPIO_ICR2_REG;
shift = 2 * (irq - 16);
}
mtx_lock_spin(&sc->sc_mtx);
CLEAR4(sc, IMX_GPIO_IMR_REG, (1U << irq));
WRITE4(sc, IMX_GPIO_ISR_REG, (1U << irq));
wrk = READ4(sc, reg);
wrk &= ~(0x03 << shift);
wrk |= icfg << shift;
WRITE4(sc, reg, wrk);
mtx_unlock_spin(&sc->sc_mtx);
}
/*
* this is unmask_intr
*/
static void
gpio_pic_enable_source(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
mtx_lock_spin(&sc->sc_mtx);
SET4(sc, IMX_GPIO_IMR_REG, (1U << isrc->isrc_data));
mtx_unlock_spin(&sc->sc_mtx);
}
static void
gpio_pic_post_filter(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
arm_irq_memory_barrier(0);
/* EOI. W1C reg so no r-m-w, no locking needed. */
WRITE4(sc, IMX_GPIO_ISR_REG, (1U << isrc->isrc_data));
}
static void
gpio_pic_post_ithread(device_t dev, struct arm_irqsrc *isrc)
{
arm_irq_memory_barrier(0);
gpio_pic_enable_source(dev, isrc);
}
static void
gpio_pic_pre_ithread(device_t dev, struct arm_irqsrc *isrc)
{
gpio_pic_disable_source(dev, isrc);
}
/*
* intrng calls this to make a new isrc known to us.
*/
static int
gpio_pic_register(device_t dev, struct arm_irqsrc *isrc, boolean_t *is_percpu)
{
struct imx51_gpio_softc *sc;
u_int irq, tripol;
sc = device_get_softc(dev);
/*
* From devicetree/bindings/gpio/fsl-imx-gpio.txt:
* #interrupt-cells: 2. The first cell is the GPIO number. The second
* cell bits[3:0] is used to specify trigger type and level flags:
* 1 = low-to-high edge triggered.
* 2 = high-to-low edge triggered.
* 4 = active high level-sensitive.
* 8 = active low level-sensitive.
* We can do any single one of these modes, but nothing in combo.
*/
if (isrc->isrc_ncells != 2) {
device_printf(sc->dev, "Invalid #interrupt-cells");
return (EINVAL);
}
irq = isrc->isrc_cells[0];
tripol = isrc->isrc_cells[1];
if (irq >= sc->gpio_npins) {
device_printf(sc->dev, "Invalid interrupt number %d", irq);
return (EINVAL);
}
switch (tripol)
{
case 1:
isrc->isrc_trig = INTR_TRIGGER_EDGE;
isrc->isrc_pol = INTR_POLARITY_HIGH;
break;
case 2:
isrc->isrc_trig = INTR_TRIGGER_EDGE;
isrc->isrc_pol = INTR_POLARITY_LOW;
break;
case 4:
isrc->isrc_trig = INTR_TRIGGER_LEVEL;
isrc->isrc_pol = INTR_POLARITY_HIGH;
break;
case 8:
isrc->isrc_trig = INTR_TRIGGER_LEVEL;
isrc->isrc_pol = INTR_POLARITY_LOW;
break;
default:
device_printf(sc->dev, "unsupported trigger/polarity 0x%2x\n",
tripol);
return (ENOTSUP);
}
isrc->isrc_nspc_type = ARM_IRQ_NSPC_PLAIN;
isrc->isrc_nspc_num = irq;
/*
* 1. The link between ISRC and controller must be set atomically.
* 2. Just do things only once in rare case when consumers
* of shared interrupt came here at the same moment.
*/
mtx_lock_spin(&sc->sc_mtx);
if (sc->gpio_pic_irqsrc[irq] != NULL) {
mtx_unlock_spin(&sc->sc_mtx);
return (sc->gpio_pic_irqsrc[irq] == isrc ? 0 : EEXIST);
}
sc->gpio_pic_irqsrc[irq] = isrc;
isrc->isrc_data = irq;
mtx_unlock_spin(&sc->sc_mtx);
arm_irq_set_name(isrc, "%s,%u", device_get_nameunit(sc->dev), irq);
return (0);
}
static int
gpio_pic_unregister(device_t dev, struct arm_irqsrc *isrc)
{
struct imx51_gpio_softc *sc;
u_int irq;
sc = device_get_softc(dev);
mtx_lock_spin(&sc->sc_mtx);
irq = isrc->isrc_data;
if (sc->gpio_pic_irqsrc[irq] != isrc) {
mtx_unlock_spin(&sc->sc_mtx);
return (sc->gpio_pic_irqsrc[irq] == NULL ? 0 : EINVAL);
}
sc->gpio_pic_irqsrc[irq] = NULL;
isrc->isrc_data = 0;
mtx_unlock_spin(&sc->sc_mtx);
arm_irq_set_name(isrc, "");
return (0);
}
static int
gpio_pic_filter(void *arg)
{
struct imx51_gpio_softc *sc;
uint32_t i, interrupts;
sc = arg;
mtx_lock_spin(&sc->sc_mtx);
interrupts = READ4(sc, IMX_GPIO_ISR_REG) & READ4(sc, IMX_GPIO_IMR_REG);
mtx_unlock_spin(&sc->sc_mtx);
for (i = 0; interrupts != 0; i++, interrupts >>= 1) {
if ((interrupts & 0x1) == 0)
continue;
if (sc->gpio_pic_irqsrc[i])
arm_irq_dispatch(sc->gpio_pic_irqsrc[i], curthread->td_intr_frame);
else
device_printf(sc->dev, "spurious interrupt %d\n", i);
}
return (FILTER_HANDLED);
}
#endif
/*
*
*/
static void
imx51_gpio_pin_configure(struct imx51_gpio_softc *sc, struct gpio_pin *pin,
unsigned int flags)
{
mtx_lock_spin(&sc->sc_mtx);
/*
* Manage input/output
*/
if (flags & (GPIO_PIN_INPUT|GPIO_PIN_OUTPUT)) {
pin->gp_flags &= ~(GPIO_PIN_INPUT|GPIO_PIN_OUTPUT);
if (flags & GPIO_PIN_OUTPUT) {
pin->gp_flags |= GPIO_PIN_OUTPUT;
SET4(sc, IMX_GPIO_OE_REG, (1U << pin->gp_pin));
}
else {
pin->gp_flags |= GPIO_PIN_INPUT;
CLEAR4(sc, IMX_GPIO_OE_REG, (1U << pin->gp_pin));
}
}
mtx_unlock_spin(&sc->sc_mtx);
}
static device_t
imx51_gpio_get_bus(device_t dev)
{
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
return (sc->sc_busdev);
}
static int
imx51_gpio_pin_max(device_t dev, int *maxpin)
{
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
*maxpin = sc->gpio_npins - 1;
return (0);
}
static int
imx51_gpio_pin_getcaps(device_t dev, uint32_t pin, uint32_t *caps)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
*caps = sc->gpio_pins[i].gp_caps;
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_pin_getflags(device_t dev, uint32_t pin, uint32_t *flags)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
*flags = sc->gpio_pins[i].gp_flags;
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_pin_getname(device_t dev, uint32_t pin, char *name)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
memcpy(name, sc->gpio_pins[i].gp_name, GPIOMAXNAME);
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_pin_setflags(device_t dev, uint32_t pin, uint32_t flags)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
imx51_gpio_pin_configure(sc, &sc->gpio_pins[i], flags);
return (0);
}
static int
imx51_gpio_pin_set(device_t dev, uint32_t pin, unsigned int value)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
if (value)
SET4(sc, IMX_GPIO_DR_REG, (1U << i));
else
CLEAR4(sc, IMX_GPIO_DR_REG, (1U << i));
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_pin_get(device_t dev, uint32_t pin, unsigned int *val)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
*val = (READ4(sc, IMX_GPIO_DR_REG) >> i) & 1;
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_pin_toggle(device_t dev, uint32_t pin)
{
struct imx51_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
for (i = 0; i < sc->gpio_npins; i++) {
if (sc->gpio_pins[i].gp_pin == pin)
break;
}
if (i >= sc->gpio_npins)
return (EINVAL);
mtx_lock_spin(&sc->sc_mtx);
WRITE4(sc, IMX_GPIO_DR_REG,
(READ4(sc, IMX_GPIO_DR_REG) ^ (1U << i)));
mtx_unlock_spin(&sc->sc_mtx);
return (0);
}
static int
imx51_gpio_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
device_set_desc(dev, "Freescale i.MX GPIO Controller");
return (BUS_PROBE_DEFAULT);
}
return (ENXIO);
}
static int
imx51_gpio_attach(device_t dev)
{
struct imx51_gpio_softc *sc;
int i, irq, unit;
sc = device_get_softc(dev);
sc->dev = dev;
sc->gpio_npins = NGPIO;
mtx_init(&sc->sc_mtx, device_get_nameunit(sc->dev), NULL, MTX_SPIN);
if (bus_alloc_resources(dev, imx_gpio_spec, sc->sc_res)) {
device_printf(dev, "could not allocate resources\n");
bus_release_resources(dev, imx_gpio_spec, sc->sc_res);
mtx_destroy(&sc->sc_mtx);
return (ENXIO);
}
sc->sc_iot = rman_get_bustag(sc->sc_res[0]);
sc->sc_ioh = rman_get_bushandle(sc->sc_res[0]);
/*
* Mask off all interrupts in hardware, then set up interrupt handling.
*/
WRITE4(sc, IMX_GPIO_IMR_REG, 0);
for (irq = 0; irq < 2; irq++) {
#ifdef ARM_INTRNG
if ((bus_setup_intr(dev, sc->sc_res[1 + irq], INTR_TYPE_CLK,
gpio_pic_filter, NULL, sc, &sc->gpio_ih[irq]))) {
device_printf(dev,
"WARNING: unable to register interrupt handler\n");
imx51_gpio_detach(dev);
return (ENXIO);
}
#endif
}
unit = device_get_unit(dev);
for (i = 0; i < sc->gpio_npins; i++) {
sc->gpio_pins[i].gp_pin = i;
sc->gpio_pins[i].gp_caps = DEFAULT_CAPS;
sc->gpio_pins[i].gp_flags =
(READ4(sc, IMX_GPIO_OE_REG) & (1U << i)) ? GPIO_PIN_OUTPUT :
GPIO_PIN_INPUT;
snprintf(sc->gpio_pins[i].gp_name, GPIOMAXNAME,
"imx_gpio%d.%d", unit, i);
}
#ifdef ARM_INTRNG
arm_pic_register(dev, OF_xref_from_node(ofw_bus_get_node(dev)));
#endif
sc->sc_busdev = gpiobus_attach_bus(dev);
if (sc->sc_busdev == NULL) {
imx51_gpio_detach(dev);
return (ENXIO);
}
return (0);
}
static int
imx51_gpio_detach(device_t dev)
{
int irq;
struct imx51_gpio_softc *sc;
sc = device_get_softc(dev);
gpiobus_detach_bus(dev);
for (irq = 1; irq <= 2; irq++) {
if (sc->gpio_ih[irq])
bus_teardown_intr(dev, sc->sc_res[irq], sc->gpio_ih[irq]);
}
bus_release_resources(dev, imx_gpio_spec, sc->sc_res);
mtx_destroy(&sc->sc_mtx);
return(0);
}
static device_method_t imx51_gpio_methods[] = {
DEVMETHOD(device_probe, imx51_gpio_probe),
DEVMETHOD(device_attach, imx51_gpio_attach),
DEVMETHOD(device_detach, imx51_gpio_detach),
#ifdef ARM_INTRNG
/* Interrupt controller interface */
DEVMETHOD(pic_disable_intr, gpio_pic_disable_intr),
DEVMETHOD(pic_disable_source, gpio_pic_disable_source),
DEVMETHOD(pic_enable_intr, gpio_pic_enable_intr),
DEVMETHOD(pic_enable_source, gpio_pic_enable_source),
DEVMETHOD(pic_post_filter, gpio_pic_post_filter),
DEVMETHOD(pic_post_ithread, gpio_pic_post_ithread),
DEVMETHOD(pic_pre_ithread, gpio_pic_pre_ithread),
DEVMETHOD(pic_register, gpio_pic_register),
DEVMETHOD(pic_unregister, gpio_pic_unregister),
#endif
/* GPIO protocol */
DEVMETHOD(gpio_get_bus, imx51_gpio_get_bus),
DEVMETHOD(gpio_pin_max, imx51_gpio_pin_max),
DEVMETHOD(gpio_pin_getname, imx51_gpio_pin_getname),
DEVMETHOD(gpio_pin_getflags, imx51_gpio_pin_getflags),
DEVMETHOD(gpio_pin_getcaps, imx51_gpio_pin_getcaps),
DEVMETHOD(gpio_pin_setflags, imx51_gpio_pin_setflags),
DEVMETHOD(gpio_pin_get, imx51_gpio_pin_get),
DEVMETHOD(gpio_pin_set, imx51_gpio_pin_set),
DEVMETHOD(gpio_pin_toggle, imx51_gpio_pin_toggle),
{0, 0},
};
static driver_t imx51_gpio_driver = {
"gpio",
imx51_gpio_methods,
sizeof(struct imx51_gpio_softc),
};
static devclass_t imx51_gpio_devclass;
DRIVER_MODULE(imx51_gpio, simplebus, imx51_gpio_driver, imx51_gpio_devclass,
0, 0);