gpio driver

.vscode/launch.json

@@ -1,27 +0,0 @@
-{
-    // Use IntelliSense to learn about possible attributes.
-    // Hover to view descriptions of existing attributes.
-    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
-    "version": "0.2.0",
-    "configurations": [
-        {
-            "name": "(gdb) Launch",
-            "type": "cppdbg",
-            "request": "launch",
-            "program": "${workspaceFolder}/bin/test",
-            "args": [],
-            "stopAtEntry": false,
-            "cwd": "${workspaceFolder}",
-            "environment": [],
-            "externalConsole": false,
-            "MIMode": "gdb",
-            "setupCommands": [
-                {
-                    "description": "Enable pretty-printing for gdb",
-                    "text": "-enable-pretty-printing",
-                    "ignoreFailures": true
-                }
-            ]
-        }
-    ]
-}

src/gpio.c

@@ -41,24 +41,6 @@ static int ftdi_open(void)
     return EXIT_SUCCESS;
 }
 
-static int gpio_read_mask(const struct gpio *gpio, unsigned char *mask)
-{
-    int res;
-
-    if(NULL == gpio || NULL == mask) {
-        return EXIT_FAILURE;
-    }
-
-    res = ftdi_read_data(ftdi_obj.ftdi, mask, 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;
-    }
-
-    return EXIT_SUCCESS;
-}
-
 int gpio_open(const struct gpio *gpio)
 {
     int res;
@@ -80,7 +62,6 @@ int gpio_open(const struct gpio *gpio)
     }
 
     ftdi_obj.bit_mask |= (unsigned char)gpio->pin;
-    syslog(LOG_DEBUG, "bitmask: 0x%02x\n", ftdi_obj.bit_mask);
     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,
@@ -122,8 +103,8 @@ int gpio_read(const struct gpio *gpio, unsigned int *value)
         return EXIT_FAILURE;
     }
 
-    res = gpio_read_mask(gpio, &buf);
-    if(res != EXIT_SUCCESS) {
+    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;
@@ -141,27 +122,27 @@ int gpio_read(const struct gpio *gpio, unsigned int *value)
 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_mask(gpio, &buf);
+    res = gpio_read(gpio, &current_state);
     if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "write failed for 0x%02x, error %d (%s)\n", buf, res,
+        syslog(LOG_ERR, "write failed for 0x%x, error %d (%s)\n", value, res,
                ftdi_get_error_string(ftdi_obj.ftdi));
         return EXIT_FAILURE;
     }
 
-    syslog(LOG_DEBUG, "current state: 0x%02x\n", buf);
+    buf = (unsigned char)current_state;
     if(value == 0) {
         buf &= ~(unsigned char)(gpio->pin);
     }
     else {
         buf |= (unsigned char)(gpio->pin);
     }
-    syslog(LOG_DEBUG, "new state: 0x%02x\n", buf);
 
     res = ftdi_write_data(ftdi_obj.ftdi, &buf, 1);
     if(res < 0) {

src/main.c

@@ -5,66 +5,39 @@
 
 #include <gpio.h>
 
-/*
-#define GPIO1 0x08  // TX  (brown)
-#define GPIO2 0x01  // TX  (orange)
-#define GPIO3 0x02  // RX  (yellow)
-#define GPIO4 0x14  // RTS (green on FTDI) + DTR (on SparkFun breakout)
-*/
-
-static const struct gpio gpio_1 = {
-    .pin = 0x08, /* CTS (brown wire on FTDI cable) */
-};
-static const struct gpio gpio_2 = {
-    .pin = 0x01, /* TX (orange wire on FTDI cable) */
+static const struct gpio gpio = {
+    .pin = 0x08,
 };
 
 int main(int argc, char *argv[])
 {
-    int res, cnt;
+    int res;
     unsigned int value;
 
     openlog("ftdi_gpio", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
 
-    res = gpio_open(&gpio_1);
-    res |= gpio_open(&gpio_2);
+    res = gpio_open(&gpio);
     if(res != EXIT_SUCCESS) {
-        syslog(LOG_ERR, "Unable to open gpio\n");
+        syslog(LOG_ERR, "Unable to open gpio pin %u\n", gpio.pin);
         return res;
     }
 
-    for(cnt = 0; cnt < 10; cnt++) {
-        value = cnt & 0x01;
-        res = gpio_write(&gpio_1, value);
-        if(cnt % 2) {
-            res |= gpio_write(&gpio_2, value);
-        }
-        if(res != EXIT_SUCCESS) {
-            syslog(LOG_ERR, "Unable to write to gpio\n");
-            gpio_close(&gpio_1);
-            gpio_close(&gpio_2);
-            return res;
-        }
-
-        res = gpio_read(&gpio_1, &value);
-        if(res != EXIT_SUCCESS) {
-            syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio_1.pin);
-            gpio_close(&gpio_1);
-            return res;
-        }
-        printf("read 1 value: 0x%02x\n", value);
-        if(cnt % 2) {
-            res = gpio_read(&gpio_2, &value);
-            if(res != EXIT_SUCCESS) {
-                syslog(LOG_ERR, "Unable to read from gpio pin %u\n", gpio_2.pin);
-                gpio_close(&gpio_2);
-                return res;
-            }
-            printf("read 2 value: 0x%02x\n", value);
-        }
-        sleep(1);
+    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;
     }
-    gpio_close(&gpio_1);
+
+    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);
+
+    gpio_close(&gpio);
 
     return EXIT_SUCCESS;
 }