feat: ble: add battery level characteristic (#66)

App might read battery level from characteristic/service uuid: 0x2A19/0x180F

src/ble/profile.h

@@ -3,5 +3,6 @@
 
 int legacy_registerService();
 int devInfo_registerService();
+int batt_registerService();
 
 #endif /* __BLE_UART_SERVICE_H__ */

src/ble/profile/batt.c

@@ -0,0 +1,52 @@
+#include "utils.h"
+
+#include "../../power.h"
+
+static const uint16_t ServiceUUID = 0x180F;
+static const gattAttrType_t service = {2, (uint8_t *)&ServiceUUID};
+
+static const uint16_t battLv_CharUUID = 0x2A19;
+static uint8 battLv_CharProps = GATT_PROP_READ;
+static uint8 battLv_Val[1];
+
+static gattAttribute_t attr_table[] = {
+	ATTR_DECLAR(primaryServiceUUID, 2, GATT_PERMIT_READ, &service),
+
+	CHAR_DECLAR(&battLv_CharProps),
+	CHAR_VAL_DECLAR(&battLv_CharUUID, 2, GATT_PERMIT_READ, battLv_Val),
+};
+
+static bStatus_t read_handler(uint16_t connHandle, gattAttribute_t *pAttr,
+				uint8_t *p_value, uint16_t *pLen, uint16_t offset,
+				uint16_t maxLen, uint8_t method)
+{
+	uint16_t uuid = BUILD_UINT16(pAttr->type.uuid[0], pAttr->type.uuid[1]);
+
+	if (uuid != battLv_CharUUID) {
+		*pLen = 0;
+		return ATT_ERR_ATTR_NOT_FOUND;
+	}
+
+	*pLen = 1;
+	battLv_Val[0] = batt_raw2percent(batt_raw());
+	tmos_memcpy(p_value, battLv_Val, *pLen);
+
+	return SUCCESS;
+}
+
+static gattServiceCBs_t service_handlers = {
+	read_handler,
+	NULL,
+	NULL
+};
+
+int batt_registerService()
+{
+	uint8 status = SUCCESS;
+
+	status = GATTServApp_RegisterService(attr_table,
+				GATT_NUM_ATTRS(attr_table),
+				GATT_MAX_ENCRYPT_KEY_SIZE,
+				&service_handlers);
+	return (status);
+}

src/ble/profile/legacy.c

@@ -65,7 +65,7 @@ static bStatus_t write_handler(uint16 connHandle, gattAttribute_t *pAttr,
 	return ATT_ERR_ATTR_NOT_FOUND;
 }
 
-gattServiceCBs_t service_handlers = {
+static gattServiceCBs_t service_handlers = {
 	NULL,
 	write_handler,
 	NULL