Question

我已经开始为OpenBSD从NXP编写I2C设备PCF8574的驱动程序。

驱动程序可以很好地编译并在启动时加载，但是我得到了以下消息：

pcfgpio0 at iic0 addr 0x40
gpio at pcfgpio0 not configured

如何配置驱动程序以在用户区使用它？

这是我的司机：

/* Driver for the NXP PCF8574(A) Remote 8-bit I/O expander */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/gpio.h>

#include <dev/i2c/i2cvar.h>
#include <dev/gpio/gpiovar.h>

#define PCFGPIO_NPINS       8

struct pcfgpio_softc {
    struct device           sc_dev;
    i2c_tag_t               sc_tag;
    i2c_addr_t              sc_addr;
    int                     sc_node;

    u_int8_t                sc_npins;

    struct gpio_chipset_tag sc_gpio_gc;
    gpio_pin_t              sc_gpio_pins[PCFGPIO_NPINS];
};

int pcfgpio_match(struct device *, void *, void *);
void pcfgpio_attach(struct device *, struct device *, void *);
uint8_t pcfgpio_read(struct pcfgpio_softc *);
void pcfgpio_write(struct pcfgpio_softc *, uint8_t);
int pcfgpio_pin_read(void *, int);
void pcfgpio_pin_write(void *, int, int);
void pcfgpio_pin_ctl(void *, int, int);

struct cfattach pcfgpio_ca = {
    sizeof(struct pcfgpio_softc), pcfgpio_match, pcfgpio_attach
};

struct cfdriver pcfgpio_cd = {
    NULL, "pcfgpio", DV_DULL
};

int
pcfgpio_match(struct device *parent, void *match, void *aux)
{
    struct i2c_attach_args *ia = aux;

    if ((strcmp(ia->ia_name, "nxp,pcf8574") == 0) ||
        (strcmp(ia->ia_name, "nxp,pcf8574a") == 0))
        return (1);
    return (0);
}

void
pcfgpio_attach(struct device *parent, struct device *self, void *aux)
{
    struct pcfgpio_softc *sc = (struct pcfgpio_softc *)self;
    struct i2c_attach_args *ia = aux;
    struct gpiobus_attach_args gba;
    int i;

    sc->sc_tag = ia->ia_tag;
    sc->sc_addr = ia->ia_addr;
    sc->sc_npins = PCFGPIO_NPINS;
    sc->sc_node = *(int *)ia->ia_cookie;

    printf("\n");

    for (i = 0; i < sc->sc_npins; i++) {
        sc->sc_gpio_pins[i].pin_num = i;
        sc->sc_gpio_pins[i].pin_caps = GPIO_PIN_INOUT | 
            GPIO_PIN_OPENDRAIN | GPIO_PIN_INVOUT;

        sc->sc_gpio_pins[i].pin_flags = GPIO_PIN_INPUT;
        sc->sc_gpio_pins[i].pin_state = 0;
    }

    pcfgpio_write(sc, 0xFF);

    sc->sc_gpio_gc.gp_cookie = sc;
    sc->sc_gpio_gc.gp_pin_read = pcfgpio_pin_read;
    sc->sc_gpio_gc.gp_pin_write = pcfgpio_pin_write;
    sc->sc_gpio_gc.gp_pin_ctl = pcfgpio_pin_ctl;

    gba.gba_name = "gpio";
    gba.gba_gc = &sc->sc_gpio_gc;
    gba.gba_pins = sc->sc_gpio_pins;
    gba.gba_npins = sc->sc_npins;
    config_found(&sc->sc_dev, &gba, gpiobus_print);
}

uint8_t
pcfgpio_read(struct pcfgpio_softc *sc)
{
    uint8_t val;

    iic_acquire_bus(sc->sc_tag, 0);
    if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
        NULL, 0, &val, sizeof(val), 0)) {
        printf("%s: pcfgpio_read: failed to read\n",
            sc->sc_dev.dv_xname);
        iic_release_bus(sc->sc_tag, 0);
        return (0);
    }
    iic_release_bus(sc->sc_tag, 0);
    return val;
}

void
pcfgpio_write(struct pcfgpio_softc *sc, uint8_t val)
{
    iic_acquire_bus(sc->sc_tag, 0);
    if (iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
        &val, sizeof val, NULL, 0, 0)) {
        printf("%s: pcfgpio_write: failed to write\n",
            sc->sc_dev.dv_xname);
        iic_release_bus(sc->sc_tag, 0);
        return;
    }
    iic_release_bus(sc->sc_tag, 0);
}

int
pcfgpio_pin_read(void *arg, int pin)
{
    struct pcfgpio_softc *sc = arg;
    uint8_t tmp;

    if (pin >= sc->sc_npins)
        return 0;
    if (!ISSET(sc->sc_gpio_pins[pin].pin_flags, GPIO_PIN_INPUT))
        pcfgpio_pin_write(sc, pin, GPIO_PIN_HIGH);
    tmp = pcfgpio_read(sc);
    if (tmp & (1 << pin))
        sc->sc_gpio_pins[pin].pin_state = GPIO_PIN_HIGH;
    else
        sc->sc_gpio_pins[pin].pin_state = GPIO_PIN_LOW;
    return sc->sc_gpio_pins[pin].pin_state;
}

void
pcfgpio_pin_write(void *arg, int pin, int val)
{
    struct pcfgpio_softc *sc = arg;
    int i;
    uint8_t tmp = 0x00;

    if (pin >= sc->sc_npins)
        return;
    for (i = 0; i < sc->sc_npins; i++)
        if (sc->sc_gpio_pins[i].pin_state == GPIO_PIN_LOW)
            tmp |= (1 << i);
    if (val == GPIO_PIN_HIGH) {
        tmp &= ~(1 << pin);
        pcfgpio_write(sc, tmp);
        sc->sc_gpio_pins[pin].pin_state = GPIO_PIN_HIGH;
    } else {
        tmp |= 1 << pin;
        pcfgpio_write(sc, tmp);
        sc->sc_gpio_pins[pin].pin_state = GPIO_PIN_LOW;
    }
}

void
pcfgpio_pin_ctl(void *arg, int pin, int flags)
{
    struct pcfgpio_softc *sc = arg;

    if (ISSET(flags, GPIO_PIN_INPUT)) {
        pcfgpio_pin_write(sc, pin, GPIO_PIN_HIGH);
        sc->sc_gpio_pins[pin].pin_flags = GPIO_PIN_INPUT;
    } else
        sc->sc_gpio_pins[pin].pin_flags = GPIO_PIN_OUTPUT;
}

我也试图将其添加到内核配置中：

gpio* at pcfgpio?

但是我得到这个错误：

$ config PCF8574                            
cd /usr/obj/sys/arch/arm64/compile/PCF8574 && config -s /usr/src/sys -b /usr/src/sys/arch/arm64/compile/PCF8574/obj /usr/src/sys/arch/arm64/conf/PCF8574
/usr/src/sys/arch/arm64/conf/PCF8574:11: gpio's cannot attach to pcfgpio's
*** Stop.
*** Error 1 in /usr/src/sys/arch/arm64/compile/PCF8574 (Makefile:1462 'config')
$

我该如何解决？缺少什么？

谢谢！

Answer 1

好的，我已经解决了这个问题。

我忘记将标识符gpiobus添加到文件/usr/src/sys/dev/i2c/files.i2c：

# NXP PCF8574 I/O port expander
device  pcfgpio: gpiobus
attach  pcfgpio at i2c
file    dev/i2c/pcf8574.c           pcfgpio

现在，以下内核配置可以正常运行了：

gpio* at pcfgpio?

驱动程序现在在用户区工作。对不起，浪费您的时间。

OpenBSD驱动程序开发：如何配置GPIO驱动程序以在用户环境中使用它？

1 个答案: