1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-01 08:27:59 +00:00

TEGRA: Add interrupt support for Tegra GPIO controller.

This commit is contained in:
Michal Meloun 2016-04-28 13:00:40 +00:00
parent 4b6f23dfaf
commit 329ee7e3dc
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=298742

View File

@ -30,21 +30,20 @@ __FBSDID("$FreeBSD$");
/*
* Tegra 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/gpio.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/rman.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/gpio.h>
#include <machine/bus.h>
#include <machine/intr.h>
#include <machine/resource.h>
#include <dev/fdt/fdt_common.h>
@ -53,14 +52,15 @@ __FBSDID("$FreeBSD$");
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include "pic_if.h"
#define GPIO_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define GPIO_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define GPIO_LOCK_INIT(_sc) mtx_init(&_sc->sc_mtx, \
device_get_nameunit(_sc->sc_dev), "tegra_gpio", MTX_DEF)
#define GPIO_LOCK_DESTROY(_sc) mtx_destroy(&_sc->sc_mtx);
#define GPIO_ASSERT_LOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_OWNED);
#define GPIO_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
#define GPIO_LOCK(_sc) mtx_lock(&(_sc)->mtx)
#define GPIO_UNLOCK(_sc) mtx_unlock(&(_sc)->mtx)
#define GPIO_LOCK_INIT(_sc) mtx_init(&_sc->mtx, \
device_get_nameunit(_sc->dev), "tegra_gpio", MTX_DEF)
#define GPIO_LOCK_DESTROY(_sc) mtx_destroy(&_sc->mtx);
#define GPIO_ASSERT_LOCKED(_sc) mtx_assert(&_sc->mtx, MA_OWNED);
#define GPIO_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->mtx, MA_NOTOWNED);
#define WR4(_sc, _r, _v) bus_write_4((_sc)->mem_res, (_r), (_v))
#define RD4(_sc, _r) bus_read_4((_sc)->mem_res, (_r))
@ -87,6 +87,11 @@ __FBSDID("$FreeBSD$");
#define GPIO_INT_STA 0x40
#define GPIO_INT_ENB 0x50
#define GPIO_INT_LVL 0x60
#define GPIO_INT_LVL_DELTA (1 << 16)
#define GPIO_INT_LVL_EDGE (1 << 8)
#define GPIO_INT_LVL_HIGH (1 << 0)
#define GPIO_INT_LVL_MASK (GPIO_INT_LVL_DELTA | \
GPIO_INT_LVL_EDGE | GPIO_INT_LVL_HIGH)
#define GPIO_INT_CLR 0x70
#define GPIO_MSK_CNF 0x80
#define GPIO_MSK_OE 0x90
@ -102,19 +107,33 @@ char *tegra_gpio_port_names[] = {
"M", "N", "O", "P", /* Bank 3 */
"Q", "R", "S", "T", /* Bank 4 */
"U", "V", "W", "X", /* Bank 5 */
"Y", "Z", "AA", "BB", /* Bank 5 */
"CC", "DD", "EE" /* Bank 5 */
"Y", "Z", "AA", "BB", /* Bank 6 */
"CC", "DD", "EE" /* Bank 7 */
};
struct tegra_gpio_irqsrc {
struct intr_irqsrc isrc;
u_int irq;
uint32_t cfgreg;
};
struct tegra_gpio_softc;
struct tegra_gpio_irq_cookie {
struct tegra_gpio_softc *sc;
int bank_num;
};
struct tegra_gpio_softc {
device_t dev;
device_t sc_busdev;
struct mtx sc_mtx;
device_t busdev;
struct mtx mtx;
struct resource *mem_res;
struct resource *irq_res;
void *gpio_ih;
struct resource *irq_res[GPIO_NUM_BANKS];
void *irq_ih[GPIO_NUM_BANKS];
struct tegra_gpio_irq_cookie irq_cookies[GPIO_NUM_BANKS];
int gpio_npins;
struct gpio_pin gpio_pins[NGPIO];
struct tegra_gpio_irqsrc *isrcs;
};
static struct ofw_compat_data compat_data[] = {
@ -122,6 +141,11 @@ static struct ofw_compat_data compat_data[] = {
{NULL, 0}
};
/* --------------------------------------------------------------------------
*
* GPIO
*
*/
static inline void
gpio_write_masked(struct tegra_gpio_softc *sc, bus_size_t reg,
struct gpio_pin *pin, uint32_t val)
@ -134,6 +158,7 @@ gpio_write_masked(struct tegra_gpio_softc *sc, bus_size_t reg,
tmp |= (val & 1) << bit; /* value */
bus_write_4(sc->mem_res, reg + GPIO_REGNUM(pin->gp_pin), tmp);
}
static inline uint32_t
gpio_read(struct tegra_gpio_softc *sc, bus_size_t reg, struct gpio_pin *pin)
{
@ -170,7 +195,7 @@ tegra_gpio_get_bus(device_t dev)
struct tegra_gpio_softc *sc;
sc = device_get_softc(dev);
return (sc->sc_busdev);
return (sc->busdev);
}
static int
@ -308,31 +333,362 @@ tegra_gpio_pin_toggle(device_t dev, uint32_t pin)
return (0);
}
/* --------------------------------------------------------------------------
*
* Interrupts
*
*/
static inline void
intr_write_masked(struct tegra_gpio_softc *sc, bus_addr_t reg,
struct tegra_gpio_irqsrc *tgi, uint32_t val)
{
uint32_t tmp;
int bit;
bit = GPIO_BIT(tgi->irq);
tmp = 0x100 << bit; /* mask */
tmp |= (val & 1) << bit; /* value */
bus_write_4(sc->mem_res, reg + GPIO_REGNUM(tgi->irq), tmp);
}
static inline void
intr_write_modify(struct tegra_gpio_softc *sc, bus_addr_t reg,
struct tegra_gpio_irqsrc *tgi, uint32_t val, uint32_t mask)
{
uint32_t tmp;
int bit;
bit = GPIO_BIT(tgi->irq);
GPIO_LOCK(sc);
tmp = bus_read_4(sc->mem_res, reg + GPIO_REGNUM(tgi->irq));
tmp &= ~(mask << bit);
tmp |= val << bit;
bus_write_4(sc->mem_res, reg + GPIO_REGNUM(tgi->irq), tmp);
GPIO_UNLOCK(sc);
}
static inline void
tegra_gpio_isrc_mask(struct tegra_gpio_softc *sc,
struct tegra_gpio_irqsrc *tgi, uint32_t val)
{
intr_write_masked(sc, GPIO_MSK_INT_ENB, tgi, val);
}
static inline void
tegra_gpio_isrc_eoi(struct tegra_gpio_softc *sc,
struct tegra_gpio_irqsrc *tgi)
{
intr_write_masked(sc, GPIO_INT_CLR, tgi, 1);
}
static inline bool
tegra_gpio_isrc_is_level(struct tegra_gpio_irqsrc *tgi)
{
return (tgi->cfgreg & GPIO_INT_LVL_EDGE);
}
static int
tegra_gpio_intr(void *arg)
{
u_int irq, i, j, val, basepin;
struct tegra_gpio_softc *sc;
uint32_t val;
int i;
struct trapframe *tf;
struct tegra_gpio_irqsrc *tgi;
struct tegra_gpio_irq_cookie *cookie;
sc = arg;
for (i = 0; i < NGPIO; i += GPIO_PINS_IN_REG) {
/* Clear interrupt */
val = bus_read_4(sc->mem_res, GPIO_INT_STA + GPIO_REGNUM(i));
val &= bus_read_4(sc->mem_res, GPIO_INT_ENB + GPIO_REGNUM(i));
bus_write_4(sc->mem_res, GPIO_INT_CLR + GPIO_REGNUM(i), val);
cookie = (struct tegra_gpio_irq_cookie *)arg;
sc = cookie->sc;
tf = curthread->td_intr_frame;
for (i = 0; i < GPIO_REGS_IN_BANK; i++) {
basepin = cookie->bank_num * GPIO_REGS_IN_BANK *
GPIO_PINS_IN_REG + i * GPIO_PINS_IN_REG;
val = bus_read_4(sc->mem_res, GPIO_INT_STA +
GPIO_REGNUM(basepin));
val &= bus_read_4(sc->mem_res, GPIO_INT_ENB +
GPIO_REGNUM(basepin));
/* Interrupt handling */
#ifdef not_yet
for (j = 0; j < GPIO_PINS_IN_REG; j++) {
if (val & (1 << j))
handle_irq(i + j);
if ((val & (1 << j)) == 0)
continue;
irq = basepin + j;
tgi = &sc->isrcs[irq];
if (!tegra_gpio_isrc_is_level(tgi))
tegra_gpio_isrc_eoi(sc, tgi);
if (intr_isrc_dispatch(&tgi->isrc, tf) != 0) {
tegra_gpio_isrc_mask(sc, tgi, 0);
if (tegra_gpio_isrc_is_level(tgi))
tegra_gpio_isrc_eoi(sc, tgi);
device_printf(sc->dev,
"Stray irq %u disabled\n", irq);
}
}
*/
#endif
}
return (FILTER_HANDLED);
}
static int
tegra_gpio_pic_attach(struct tegra_gpio_softc *sc)
{
int error;
uint32_t irq;
const char *name;
sc->isrcs = malloc(sizeof(*sc->isrcs) * sc->gpio_npins, M_DEVBUF,
M_WAITOK | M_ZERO);
name = device_get_nameunit(sc->dev);
for (irq = 0; irq < sc->gpio_npins; irq++) {
sc->isrcs[irq].irq = irq;
sc->isrcs[irq].cfgreg = 0;
error = intr_isrc_register(&sc->isrcs[irq].isrc,
sc->dev, 0, "%s,%u", name, irq);
if (error != 0)
return (error); /* XXX deregister ISRCs */
}
return (intr_pic_register(sc->dev,
OF_xref_from_node(ofw_bus_get_node(sc->dev))));
}
static int
tegra_gpio_pic_detach(struct tegra_gpio_softc *sc)
{
/*
* There has not been established any procedure yet
* how to detach PIC from living system correctly.
*/
device_printf(sc->dev, "%s: not implemented yet\n", __func__);
return (EBUSY);
}
static void
tegra_gpio_pic_disable_intr(device_t dev, struct intr_irqsrc *isrc)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
tegra_gpio_isrc_mask(sc, tgi, 0);
}
static void
tegra_gpio_pic_enable_intr(device_t dev, struct intr_irqsrc *isrc)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
tegra_gpio_isrc_mask(sc, tgi, 1);
}
static int
tegra_gpio_pic_map_fdt(struct tegra_gpio_softc *sc, u_int ncells,
pcell_t *cells, u_int *irqp, uint32_t *regp)
{
uint32_t reg;
/*
* The first cell is the interrupt number.
* The second cell is used to specify flags:
* bits[3:0] 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.
*/
if (ncells != 2 || cells[0] >= sc->gpio_npins)
return (EINVAL);
/*
* All interrupt types could be set for an interrupt at one moment.
* At least, the combination of 'low-to-high' and 'high-to-low' edge
* triggered interrupt types can make a sense.
*/
if (cells[1] == 1)
reg = GPIO_INT_LVL_EDGE | GPIO_INT_LVL_HIGH;
else if (cells[1] == 2)
reg = GPIO_INT_LVL_EDGE;
else if (cells[1] == 3)
reg = GPIO_INT_LVL_EDGE | GPIO_INT_LVL_DELTA;
else if (cells[1] == 4)
reg = GPIO_INT_LVL_HIGH;
else if (cells[1] == 8)
reg = 0;
else
return (EINVAL);
*irqp = cells[0];
if (regp != NULL)
*regp = reg;
return (0);
}
static int
tegra_gpio_pic_map_gpio(struct tegra_gpio_softc *sc, u_int gpio_pin_num,
u_int gpio_pin_flags, u_int intr_mode, u_int *irqp, uint32_t *regp)
{
uint32_t reg;
if (gpio_pin_num >= sc->gpio_npins)
return (EINVAL);
switch (intr_mode) {
case GPIO_INTR_CONFORM:
case GPIO_INTR_LEVEL_LOW:
reg = 0;
break;
case GPIO_INTR_LEVEL_HIGH:
reg = GPIO_INT_LVL_HIGH;
break;
case GPIO_INTR_EDGE_RISING:
reg = GPIO_INT_LVL_EDGE | GPIO_INT_LVL_HIGH;
break;
case GPIO_INTR_EDGE_FALLING:
reg = GPIO_INT_LVL_EDGE;
break;
case GPIO_INTR_EDGE_BOTH:
reg = GPIO_INT_LVL_EDGE | GPIO_INT_LVL_DELTA;
break;
default:
return (EINVAL);
}
*irqp = gpio_pin_num;
if (regp != NULL)
*regp = reg;
return (0);
}
static int
tegra_gpio_pic_map_intr(device_t dev, struct intr_map_data *data,
struct intr_irqsrc **isrcp)
{
int rv;
u_int irq;
struct tegra_gpio_softc *sc;
sc = device_get_softc(dev);
if (data->type == INTR_MAP_DATA_FDT)
rv = tegra_gpio_pic_map_fdt(sc, data->fdt.ncells,
data->fdt.cells, &irq, NULL);
else if (data->type == INTR_MAP_DATA_GPIO)
rv = tegra_gpio_pic_map_gpio(sc, data->gpio.gpio_pin_num,
data->gpio.gpio_pin_flags, data->gpio.gpio_intr_mode,
&irq, NULL);
else
return (ENOTSUP);
if (rv == 0)
*isrcp = &sc->isrcs[irq].isrc;
return (rv);
}
static void
tegra_gpio_pic_post_filter(device_t dev, struct intr_irqsrc *isrc)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
if (tegra_gpio_isrc_is_level(tgi))
tegra_gpio_isrc_eoi(sc, tgi);
}
static void
tegra_gpio_pic_post_ithread(device_t dev, struct intr_irqsrc *isrc)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
tegra_gpio_isrc_mask(sc, tgi, 1);
}
static void
tegra_gpio_pic_pre_ithread(device_t dev, struct intr_irqsrc *isrc)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
tegra_gpio_isrc_mask(sc, tgi, 0);
if (tegra_gpio_isrc_is_level(tgi))
tegra_gpio_isrc_eoi(sc, tgi);
}
static int
tegra_gpio_pic_setup_intr(device_t dev, struct intr_irqsrc *isrc,
struct resource *res, struct intr_map_data *data)
{
u_int irq;
uint32_t cfgreg;
int rv;
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
if (data == NULL)
return (ENOTSUP);
/* Get and check config for an interrupt. */
if (data->type == INTR_MAP_DATA_FDT)
rv = tegra_gpio_pic_map_fdt(sc, data->fdt.ncells,
data->fdt.cells, &irq, &cfgreg);
else if (data->type == INTR_MAP_DATA_GPIO)
rv = tegra_gpio_pic_map_gpio(sc, data->gpio.gpio_pin_num,
data->gpio.gpio_pin_flags, data->gpio.gpio_intr_mode,
&irq, &cfgreg);
else
return (ENOTSUP);
if (rv != 0)
return (EINVAL);
/*
* If this is a setup for another handler,
* only check that its configuration match.
*/
if (isrc->isrc_handlers != 0)
return (tgi->cfgreg == cfgreg ? 0 : EINVAL);
tgi->cfgreg = cfgreg;
intr_write_modify(sc, GPIO_INT_LVL, tgi, cfgreg, GPIO_INT_LVL_MASK);
tegra_gpio_pic_enable_intr(dev, isrc);
return (0);
}
static int
tegra_gpio_pic_teardown_intr(device_t dev, struct intr_irqsrc *isrc,
struct resource *res, struct intr_map_data *data)
{
struct tegra_gpio_softc *sc;
struct tegra_gpio_irqsrc *tgi;
sc = device_get_softc(dev);
tgi = (struct tegra_gpio_irqsrc *)isrc;
if (isrc->isrc_handlers == 0)
tegra_gpio_isrc_mask(sc, tgi, 0);
return (0);
}
static int
tegra_gpio_probe(device_t dev)
{
@ -347,23 +703,39 @@ tegra_gpio_probe(device_t dev)
return (ENXIO);
}
/* --------------------------------------------------------------------------
*
* Bus
*
*/
static int
tegra_gpio_detach(device_t dev)
{
struct tegra_gpio_softc *sc;
int i;
sc = device_get_softc(dev);
KASSERT(mtx_initialized(&sc->sc_mtx), ("gpio mutex not initialized"));
KASSERT(mtx_initialized(&sc->mtx), ("gpio mutex not initialized"));
for (i = 0; i < GPIO_NUM_BANKS; i++) {
if (sc->irq_ih[i] != NULL)
bus_teardown_intr(dev, sc->irq_res[i], sc->irq_ih[i]);
}
if (sc->isrcs != NULL)
tegra_gpio_pic_detach(sc);
gpiobus_detach_bus(dev);
if (sc->gpio_ih != NULL)
bus_teardown_intr(dev, sc->irq_res, sc->gpio_ih);
if (sc->irq_res != NULL)
bus_release_resource(dev, SYS_RES_IRQ, 0, sc->irq_res);
for (i = 0; i < GPIO_NUM_BANKS; i++) {
if (sc->irq_res[i] != NULL)
bus_release_resource(dev, SYS_RES_IRQ, 0,
sc->irq_res[i]);
}
if (sc->mem_res != NULL)
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->mem_res);
mtx_destroy(&sc->sc_mtx);
GPIO_LOCK_DESTROY(sc);
return(0);
}
@ -375,7 +747,8 @@ tegra_gpio_attach(device_t dev)
int i, rid;
sc = device_get_softc(dev);
mtx_init(&sc->sc_mtx, device_get_nameunit(dev), NULL, MTX_DEF);
sc->dev = dev;
GPIO_LOCK_INIT(sc);
/* Allocate bus_space resources. */
rid = 0;
@ -387,28 +760,13 @@ tegra_gpio_attach(device_t dev)
return (ENXIO);
}
rid = 0;
sc->irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE);
if (sc->irq_res == NULL) {
device_printf(dev, "Cannot allocate IRQ resources\n");
tegra_gpio_detach(dev);
return (ENXIO);
}
sc->dev = dev;
sc->gpio_npins = NGPIO;
if ((bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC,
tegra_gpio_intr, NULL, sc, &sc->gpio_ih))) {
device_printf(dev,
"WARNING: unable to register interrupt handler\n");
tegra_gpio_detach(dev);
return (ENXIO);
}
for (i = 0; i < sc->gpio_npins; i++) {
sc->gpio_pins[i].gp_pin = i;
sc->gpio_pins[i].gp_caps = GPIO_PIN_INPUT | GPIO_PIN_OUTPUT;
sc->gpio_pins[i].gp_caps = GPIO_PIN_INPUT | GPIO_PIN_OUTPUT |
GPIO_INTR_LEVEL_LOW | GPIO_INTR_LEVEL_HIGH |
GPIO_INTR_EDGE_RISING | GPIO_INTR_EDGE_FALLING |
GPIO_INTR_EDGE_BOTH;
snprintf(sc->gpio_pins[i].gp_name, GPIOMAXNAME, "gpio_%s.%d",
tegra_gpio_port_names[ i / GPIO_PINS_IN_REG],
i % GPIO_PINS_IN_REG);
@ -417,8 +775,43 @@ tegra_gpio_attach(device_t dev)
GPIO_PIN_OUTPUT : GPIO_PIN_INPUT;
}
sc->sc_busdev = gpiobus_attach_bus(dev);
if (sc->sc_busdev == NULL) {
/* Init interrupt related registes. */
for (i = 0; i < sc->gpio_npins; i += GPIO_PINS_IN_REG) {
bus_write_4(sc->mem_res, GPIO_INT_ENB + GPIO_REGNUM(i), 0);
bus_write_4(sc->mem_res, GPIO_INT_STA + GPIO_REGNUM(i), 0xFF);
bus_write_4(sc->mem_res, GPIO_INT_CLR + GPIO_REGNUM(i), 0xFF);
}
/* Allocate interrupts. */
for (i = 0; i < GPIO_NUM_BANKS; i++) {
sc->irq_cookies[i].sc = sc;
sc->irq_cookies[i].bank_num = i;
rid = i;
sc->irq_res[i] = bus_alloc_resource_any(dev, SYS_RES_IRQ,
&rid, RF_ACTIVE);
if (sc->irq_res[i] == NULL) {
device_printf(dev, "Cannot allocate IRQ resources\n");
tegra_gpio_detach(dev);
return (ENXIO);
}
if ((bus_setup_intr(dev, sc->irq_res[i],
INTR_TYPE_MISC | INTR_MPSAFE, tegra_gpio_intr, NULL,
&sc->irq_cookies[i], &sc->irq_ih[i]))) {
device_printf(dev,
"WARNING: unable to register interrupt handler\n");
tegra_gpio_detach(dev);
return (ENXIO);
}
}
if (tegra_gpio_pic_attach(sc) != 0) {
device_printf(dev, "WARNING: unable to attach PIC\n");
tegra_gpio_detach(dev);
return (ENXIO);
}
sc->busdev = gpiobus_attach_bus(dev);
if (sc->busdev == NULL) {
tegra_gpio_detach(dev);
return (ENXIO);
}
@ -451,6 +844,16 @@ static device_method_t tegra_gpio_methods[] = {
DEVMETHOD(device_attach, tegra_gpio_attach),
DEVMETHOD(device_detach, tegra_gpio_detach),
/* Interrupt controller interface */
DEVMETHOD(pic_disable_intr, tegra_gpio_pic_disable_intr),
DEVMETHOD(pic_enable_intr, tegra_gpio_pic_enable_intr),
DEVMETHOD(pic_map_intr, tegra_gpio_pic_map_intr),
DEVMETHOD(pic_setup_intr, tegra_gpio_pic_setup_intr),
DEVMETHOD(pic_teardown_intr, tegra_gpio_pic_teardown_intr),
DEVMETHOD(pic_post_filter, tegra_gpio_pic_post_filter),
DEVMETHOD(pic_post_ithread, tegra_gpio_pic_post_ithread),
DEVMETHOD(pic_pre_ithread, tegra_gpio_pic_pre_ithread),
/* GPIO protocol */
DEVMETHOD(gpio_get_bus, tegra_gpio_get_bus),
DEVMETHOD(gpio_pin_max, tegra_gpio_pin_max),