Hello,
I have written a driver for the I2C device PCF8574(A) from
NXP and I have tested the driver (with gpioctl) on a PINE64 ROCK64
board and a small test circuit. The driver works.
I hope you can need the driver.
Index: sys/dev/i2c/files.i2c
===================================================================
RCS file: /cvs/src/sys/dev/i2c/files.i2c,v
retrieving revision 1.61
diff -u -p -u -p -r1.61 files.i2c
--- sys/dev/i2c/files.i2c 9 Jul 2018 18:48:52 -0000 1.61
+++ sys/dev/i2c/files.i2c 6 Aug 2018 13:56:21 -0000
@@ -224,3 +224,8 @@ file dev/i2c/bmc150.c bgw
device islrtc
attach islrtc at i2c
file dev/i2c/isl1208.c islrtc
+
+# NXP PCF8574 I/O port expander
+device pcfgpio: gpiobus
+attach pcfgpio at i2c
+file dev/i2c/pcf8574.c pcfgpio
Index: sys/dev/i2c/pcf8574.c
===================================================================
RCS file: sys/dev/i2c/pcf8574.c
diff -N sys/dev/i2c/pcf8574.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ sys/dev/i2c/pcf8574.c 6 Aug 2018 13:56:21 -0000
@@ -0,0 +1,172 @@
+/* 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;
+}
--
Best regards,
Johannes
