arm: fix compiler warnings

There were unused variables, incorrect pointer operations
and plan broken string comparison.

Now there's only one - for unused uart3_enabled in beaglebone.c,
but we want to keep it for declaration consistency.

Also fixes #757.

Signed-off-by: Alex Tereschenko <alext.mkrs@gmail.com>

include/arm/am335x.h

@@ -63,9 +63,9 @@ mraa_result_t mraa_am335x_mmap_write(mraa_gpio_context dev, int value);
 /**
  * Unsetup register of mmap_gpio[]
  *
- * @return static mraa_result_t indicating success of actions.
+ * @return mraa_result_t indicating success of actions.
  */
-static mraa_result_t mraa_am335x_mmap_unsetup();
+mraa_result_t mraa_am335x_mmap_unsetup();
 
 /**
  * Read from gpio_context 'dev'

src/arm/96boards.c

@@ -39,6 +39,7 @@
 #define PLATFORM_NAME_DB410C "DB410C"
 #define PLATFORM_NAME_HIKEY "HIKEY"
 #define PLATFORM_NAME_BBGUM "BBGUM"
+#define MAX_SIZE 64
 
 int db410c_ls_gpio_pins[MRAA_96BOARDS_LS_GPIO_COUNT] = {
     36, 12, 13, 69, 115, 4, 24, 25, 35, 34, 28, 33,
@@ -79,9 +80,8 @@ mraa_96boards_pininfo(mraa_board_t* board, int index, int sysfs_pin, char* fmt,
 mraa_board_t*
 mraa_96boards()
 {
-    int i, pin;
+    int i;
     int* ls_gpio_pins = NULL;
-    char ch;
 
     mraa_board_t* b = (mraa_board_t*) calloc(1, sizeof(mraa_board_t));
     if (b == NULL) {
@@ -97,18 +97,18 @@ mraa_96boards()
         if (mraa_file_contains(DT_BASE "/model", "Qualcomm Technologies, Inc. APQ 8016 SBC")) {
             b->platform_name = PLATFORM_NAME_DB410C;
             ls_gpio_pins = db410c_ls_gpio_pins;
-            b->uart_dev[0].device_path = db410c_serialdev[0];
+            b->uart_dev[0].device_path = (char *)db410c_serialdev[0];
-            b->uart_dev[1].device_path = db410c_serialdev[1];
+            b->uart_dev[1].device_path = (char *)db410c_serialdev[1];
         } else if (mraa_file_contains(DT_BASE "/model", "HiKey Development Board")) {
             b->platform_name = PLATFORM_NAME_HIKEY;
             ls_gpio_pins = hikey_ls_gpio_pins;
-            b->uart_dev[0].device_path = hikey_serialdev[0];
+            b->uart_dev[0].device_path = (char *)hikey_serialdev[0];
-            b->uart_dev[1].device_path = hikey_serialdev[1];
+            b->uart_dev[1].device_path = (char *)hikey_serialdev[1];
         } else if (mraa_file_contains(DT_BASE "/model", "s900")) {
             b->platform_name = PLATFORM_NAME_BBGUM;
             ls_gpio_pins = bbgum_ls_gpio_pins;
-            b->uart_dev[0].device_path = bbgum_serialdev[0];
+            b->uart_dev[0].device_path = (char *)bbgum_serialdev[0];
-            b->uart_dev[1].device_path = bbgum_serialdev[1];
+            b->uart_dev[1].device_path = (char *)bbgum_serialdev[1];
         }
     }
 
@@ -117,7 +117,7 @@ mraa_96boards()
     b->def_uart_dev = 0;
 
     // I2C
-    if (b->platform_name == PLATFORM_NAME_BBGUM) {
+    if (strncmp(b->platform_name, PLATFORM_NAME_BBGUM, MAX_SIZE) == 0) {
         b->i2c_bus_count = MRAA_96BOARDS_LS_I2C_COUNT;
         b->def_i2c_bus = 0;
         b->i2c_bus[0].bus_id = 1;

src/arm/am335x.c

@@ -50,7 +50,7 @@ mraa_am335x_mmap_write(mraa_gpio_context dev, int value)
     return MRAA_SUCCESS;
 }
 
-static mraa_result_t
+mraa_result_t
 mraa_am335x_mmap_unsetup()
 {
     if (mmap_gpio[0] == NULL) {

src/arm/banana.c

@@ -107,7 +107,6 @@ mraa_banana_mmap_write(mraa_gpio_context dev, int value)
 {
     uint32_t readvalue =
     *(volatile uint32_t*) (mmap_reg + SUNXI_GPIO_DAT + (dev->pin / 32) * SUNXI_GPIO_PORT_OFFSET);
-    volatile uint32_t* addr;
     if (value) {
         *(volatile uint32_t*) (mmap_reg + SUNXI_GPIO_DAT + (dev->pin / 32) * SUNXI_GPIO_PORT_OFFSET) =
         (uint32_t)((1 << (dev->pin % 32)) | readvalue);
@@ -559,20 +558,20 @@ mraa_banana()
     b->def_uart_dev = 0;
     if ((uart3 >= 0) && (platform_detected == PLATFORM_BANANA_PI)) {
         b->def_uart_dev = b->uart_dev_count;
-        b->uart_dev[b->uart_dev_count].device_path = serialdev[uart3];
+        b->uart_dev[b->uart_dev_count].device_path = (char *)serialdev[uart3];
         b->uart_dev[b->uart_dev_count].rx = 11;
         b->uart_dev[b->uart_dev_count].tx = 13;
         b->uart_dev_count++;
     }
     if ((uart4 >= 0) && (platform_detected == PLATFORM_BANANA_PRO)) {
         b->def_uart_dev = b->uart_dev_count;
-        b->uart_dev[b->uart_dev_count].device_path = serialdev[uart4];
+        b->uart_dev[b->uart_dev_count].device_path = (char *)serialdev[uart4];
         b->uart_dev[b->uart_dev_count].rx = 10;
         b->uart_dev[b->uart_dev_count].tx = 8;
         b->uart_dev_count++;
     }
     if (uart7 >= 0) {
-        b->uart_dev[b->uart_dev_count].device_path = serialdev[uart7];
+        b->uart_dev[b->uart_dev_count].device_path = (char *)serialdev[uart7];
         if (platform_detected == PLATFORM_BANANA_PRO) {
             b->uart_dev[b->uart_dev_count].rx = 31;
             b->uart_dev[b->uart_dev_count].tx = 32;
@@ -583,7 +582,7 @@ mraa_banana()
         b->uart_dev_count++;
     }
     if (uart2 >= 0) {
-        b->uart_dev[b->uart_dev_count].device_path = serialdev[uart2];
+        b->uart_dev[b->uart_dev_count].device_path = (char *)serialdev[uart2];
         b->uart_dev[b->uart_dev_count].rx = 11;
         b->uart_dev[b->uart_dev_count].tx = 13;
         b->uart_dev_count++;

src/arm/beaglebone.c

@@ -207,13 +207,14 @@ mraa_beaglebone_uart_init_pre(int index)
     if (!mraa_file_exist(devpath)) {
         ret = MRAA_ERROR_INVALID_HANDLE;
     }
-    if (mraa_file_exist(devpath))
+    if (mraa_file_exist(devpath)) {
        if (set_pin_mode(plat->uart_dev[index].rx, "uart") == MRAA_SUCCESS &&
             set_pin_mode(plat->uart_dev[index].tx, "uart") == MRAA_SUCCESS) {
             return MRAA_SUCCESS;
         }
-    else
+    } else {
         syslog(LOG_ERR, "uart: Device not initialized");
+    }
     return ret;
 }
 

src/arm/phyboard.c

@@ -98,7 +98,6 @@ mraa_pwm_context
 mraa_phyboard_pwm_init_replace(int pin)
 {
     char devpath[MAX_SIZE];
-    int length = strlen(SYSFS_CLASS_PWM) + 5;
 
     if (plat == NULL) {
         syslog(LOG_ERR, "pwm: Platform Not Initialised");

src/arm/raspberry_pi.c

@@ -117,7 +117,6 @@ mraa_raspberry_pi_i2c_init_pre(unsigned int bus)
 mraa_result_t
 mraa_raspberry_pi_mmap_write(mraa_gpio_context dev, int value)
 {
-    volatile uint32_t* addr;
     if (value) {
         *(volatile uint32_t*) (mmap_reg + BCM283X_GPSET0 + (dev->pin / 32) * 4) =
         (uint32_t)(1 << (dev->pin % 32));