gpio driver

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "stdbool.h": "c"
+    }
+}

.vscode/tasks.json

@@ -2,16 +2,16 @@
     // See https://go.microsoft.com/fwlink/?LinkId=733558
     // for the documentation about the tasks.json format
     "version": "2.0.0",
-    "type":"shell",
-    "command": "make",
-    "echoCommand": true,
-    "problemMatcher": {
-        "base": "gcc",
-    },
     "tasks": [
         {
             "label": "all",
-            "args": ["all"],
+            "type":"shell",
+            "command": "make all -j4",
+            "problemMatcher": {
+                "base": "gcc",
+                "owner": "gcc",
+                "fileLocation":"absolute"
+            },
             "group": {
                 "kind": "build",
                 "isDefault": true
@@ -19,7 +19,23 @@
         },
         {
             "label": "clean",
-            "args": ["clean"],
+            "type":"shell",
+            "command": "make clean -j4",
+            "problemMatcher": {
+                "base": "gcc",
+                "owner": "gcc",
+                "fileLocation":"absolute"
+            },
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
         }
-    ]
-}
+    ],
+    "presentation": {
+        "focus": true,
+        "reveal": "always",
+        "panel": "shared",
+        "clear": true,
+    }
+}

inc/def.h

@@ -1,6 +0,0 @@
-#ifndef __INC_DEF_H__
-#define __INC_DEF_H__
-
-#define HELLO "Hello world!"
-
-#endif // __INC_DEF_H__

inc/gpio.h

@@ -0,0 +1,14 @@
+#ifndef __GPIO_H__
+#define __GPIO_H__
+
+struct gpio {
+    unsigned int pin;
+};
+
+int gpio_open(const struct gpio *gpio);
+int gpio_close(const struct gpio *gpio);
+int gpio_read(const struct gpio *gpio, unsigned int *value);
+int gpio_write(const struct gpio *gpio, unsigned int value);
+void gpio_toggle(const struct gpio *gpio);
+
+#endif

src/gpio.c

@@ -0,0 +1,159 @@
+#include <stdlib.h>
+#include <syslog.h>
+#include <stdbool.h>
+#include <ftdi.h>
+
+#include <gpio.h>
+
+struct ftdi_obj {
+    struct ftdi_context *ftdi;
+    bool is_open;
+    unsigned int vendor_id;
+    unsigned int product_id;
+    unsigned char bit_mask;
+};
+
+static struct ftdi_obj ftdi_obj = {
+    .ftdi = NULL,
+    .is_open = false,
+    .vendor_id = 0x0403,
+    .product_id = 0x6001,
+    .bit_mask = 0,
+};
+
+static int ftdi_open(void)
+{
+    int res;
+
+    if((ftdi_obj.ftdi = ftdi_new()) == 0) {
+        syslog(LOG_ERR, "ftdi_new failed\n");
+        return EXIT_FAILURE;
+    }
+
+    res = ftdi_usb_open(ftdi_obj.ftdi, ftdi_obj.vendor_id, ftdi_obj.product_id);
+    if (res < 0 && res != -5) {
+        syslog(LOG_ERR, "unable to open ftdi device: %d (%s)\n", res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        ftdi_free(ftdi_obj.ftdi);
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
+
+int gpio_open(const struct gpio *gpio)
+{
+    int res;
+    unsigned char init_value = 0;
+    bool init_write = false;
+
+
+    if(NULL == gpio) {
+        syslog(LOG_ERR, "No valid gpio object given.\n");
+        return EXIT_FAILURE;
+    }
+
+    if(!ftdi_obj.is_open) {
+        res = ftdi_open();
+        if(res != EXIT_SUCCESS) {
+            return EXIT_FAILURE;
+        }
+        init_write = true;
+    }
+
+    ftdi_obj.bit_mask |= (unsigned char)gpio->pin;
+    res = ftdi_set_bitmode(ftdi_obj.ftdi, ftdi_obj.bit_mask, BITMODE_BITBANG);
+    if(res < 0) {
+        syslog(LOG_ERR, "unable to set bit bang mode: %d (%s)\n", res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        ftdi_free(ftdi_obj.ftdi);
+        return EXIT_FAILURE;
+    }
+    ftdi_obj.is_open = true;
+
+    if(init_write) {
+        ftdi_write_data(ftdi_obj.ftdi, &init_value, 1);
+    }
+
+    return EXIT_SUCCESS;
+}
+
+int gpio_close(const struct gpio *gpio)
+{
+    if(NULL == gpio) {
+        return EXIT_FAILURE;
+    }
+
+    unsigned char pin = (unsigned char)gpio->pin;
+    ftdi_obj.bit_mask &= ~pin;
+    if(ftdi_obj.bit_mask == 0) {
+        ftdi_usb_close(ftdi_obj.ftdi);
+        ftdi_free(ftdi_obj.ftdi);
+    }
+
+    return EXIT_SUCCESS;
+}
+
+int gpio_read(const struct gpio *gpio, unsigned int *value)
+{
+    int res;
+    unsigned char buf;
+
+    if(NULL == gpio || NULL == value) {
+        return EXIT_FAILURE;
+    }
+
+    res = ftdi_read_data(ftdi_obj.ftdi, &buf, 1);
+    if(res < 0) {
+        syslog(LOG_ERR, "unable to readfrom ftdi device: %d (%s)\n", res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        return EXIT_FAILURE;
+    }
+
+    if(buf & (unsigned char)(gpio->pin)) {
+        *value = 1;
+    } else {
+        *value = 0;
+    }
+
+    return EXIT_SUCCESS;
+}
+
+int gpio_write(const struct gpio *gpio, unsigned int value)
+{
+    int res;
+    unsigned int current_state;
+    unsigned char buf;
+
+    if(NULL == gpio) {
+        return EXIT_FAILURE;
+    }
+
+    res = gpio_read(gpio, &current_state);
+    if(res != EXIT_SUCCESS) {
+        syslog(LOG_ERR, "write failed for 0x%x, error %d (%s)\n", value, res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        return EXIT_FAILURE;
+    }
+
+    buf = (unsigned char)current_state;
+    if(value == 0) {
+        buf &= ~(unsigned char)(gpio->pin);
+    }
+    else {
+        buf |= (unsigned char)(gpio->pin);
+    }
+
+    res = ftdi_write_data(ftdi_obj.ftdi, &buf, 1);
+    if(res < 0) {
+        syslog(LOG_ERR, "write failed for 0x%x, error %d (%s)\n", value, res,
+               ftdi_get_error_string(ftdi_obj.ftdi));
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
+
+void gpio_toggle(const struct gpio *gpio)
+{
+}

src/main.c

@@ -1,58 +1,43 @@
+#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <syslog.h>
-#include <ftdi.h>
 
-#include <def.h>
+#include <gpio.h>
+
+static const struct gpio gpio = {
+    .pin = 0x08,
+};
 
-#define LED 0x08
 int main(int argc, char *argv[])
 {
-    struct ftdi_context *ftdi;
-    int f, retval, cnt;
-    unsigned char buf[1];
+    int res;
+    unsigned int value;
 
     openlog("ftdi_gpio", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
-    setlogmask(LOG_DEBUG);
 
-    if ((ftdi = ftdi_new()) == 0) {
-        syslog(LOG_ERR, "ftdi_new failed\n");
-        return EXIT_FAILURE;
+    res = gpio_open(&gpio);
+    if(res != EXIT_SUCCESS) {
+        syslog(LOG_ERR, "Unable to open gpio pin %u\n", gpio.pin);
+        return res;
     }
 
-    f = ftdi_usb_open(ftdi, 0x0403, 0x6001);
-
-    if (f < 0 && f != -5) {
-        syslog(LOG_ERR, "unable to open ftdi device: %d (%s)\n", f, ftdi_get_error_string(ftdi));
-        retval = 1;
-        goto done;
+    res = gpio_write(&gpio, 0x00);
+    if(res != EXIT_SUCCESS) {
+        syslog(LOG_ERR, "Unable to write to gpio pin %u\n", gpio.pin);
+        gpio_close(&gpio);
+        return res;
     }
 
-    f = ftdi_set_bitmode(ftdi, LED, BITMODE_BITBANG);
-    if(f < 0) {
-        syslog(LOG_ERR, "unable to set bit bang mode: %d (%s)\n", f, ftdi_get_error_string(ftdi));
-        retval = 1;
-        goto done;
+    res = gpio_read(&gpio, &value);
+    if(res != EXIT_SUCCESS) {
+        syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio.pin);
+        gpio_close(&gpio);
+        return res;
     }
+    printf("read value: 0x%02x\n", value);
 
-    buf[0] = 0;
-    for(cnt = 0; cnt < 10; cnt++) {
-        buf[0] ^= LED,
-        f = ftdi_write_data(ftdi, buf, 1);
-        if(f < 0) {
-            syslog(LOG_ERR, "write failed for 0x%x, error %d (%s)\n",buf[0], f, ftdi_get_error_string(ftdi));
-            cnt = 10;
-        } else {
-            syslog(LOG_DEBUG, "set LED to: %u\n", (unsigned int)buf[0]);
-        }
-        
-        sleep(1);
-    }
+    gpio_close(&gpio);
 
-    ftdi_usb_close(ftdi);
-done:
-    ftdi_free(ftdi);
-    closelog();
-
-    return retval;
+    return EXIT_SUCCESS;
 }