mbxxx eeprom driver

This patch adds the eeprom driver needed to access M24C64
eeprom which is on some mbxxx boards.
Signed-off-by: Maria Laura Stefanizzi <laura28582@gmail.com>

platform/mbxxx/Makefile.mbxxx

@@ -1,4 +1,4 @@
-ARCH= irq.c sensors.c acc-sensor.c button-sensor.c temperature-sensor.c mems.c contact-sensor.c i2c.c
+ARCH= irq.c sensors.c acc-sensor.c button-sensor.c temperature-sensor.c mems.c contact-sensor.c i2c.c eeprom.c
 
 
 CONTIKI_TARGET_DIRS = . dev

platform/mbxxx/dev/eeprom.c

@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2013, IDentification Automation Laboratory
+ * IDALab (http://www.idalab.unisalento.it)
+ * Department of Innovation Engineering - University of Salento
+ *
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+/**
+ * \file  eeprom.c
+ * \brief ST M24C64W EEPROM driver.
+ * \author Maria Laura Stefanizzi <laura28582@gmail.com>
+ * \date   2013-11-20
+ */
+
+#include PLATFORM_HEADER
+#include <dev/eeprom.h>
+#include <dev/i2c.h>
+
+
+#define EE_HW_ADDRESS            0xA0
+#define EE_PAGESIZE              32
+#define EE_PAGEMASK              0x1F
+#define EE_MAX_TRIALS            300
+
+/* Write Cycle polling
+ * 
+ * During the internal Write cycle, the device disconnects itself from the bus,
+ * and writes a copy of the data from its internal latches to the memory cells.
+ */
+static inline void
+eeprom_wait(void)
+{
+  uint32_t trials = 0;
+
+  /* Keep looping till the slave acknowledge his address or maximum number of
+     trials is reached */
+  do {
+    /* Generate start */
+    i2c_start();
+
+    /* Device select in in write mode */
+    i2c_write(EE_HW_ADDRESS | 0x0);
+
+    /* Check if the maximum allowed number of trials has been reached */
+    if(trials++ == EE_MAX_TRIALS) {
+      /* If the maximum number of trials has been reached, exit the function */
+      break;
+    }
+  } while((SC2_STAT(SC_TWIRXNAK)) == SC_TWIRXNAK);
+  /* eeprom reply with an ACK then it has terminated the internal Write cycle */
+
+  i2c_stop();
+}
+
+/**
+ * eeprom initializzation function
+ */
+void
+eeprom_init(void)
+{
+  /* Nothing must be done here */
+}
+
+/**
+ * Write data to eeprom
+ * @param addr The eeprom memory address
+ * @param buf It is the buffer of bytes that will be written to the eeprom
+ * @param size It is the number of byte to write
+ */
+void
+eeprom_write(eeprom_addr_t addr, unsigned char *buf, int size)
+{
+  unsigned int i = 0;
+  unsigned int curaddr;
+
+  curaddr = addr;
+  for(i = 0; i < size; i++) {
+    /* If we are writing the first byte or are on a EE_PAGEMASK page boundary
+       we have to start a new write. */
+    if(i == 0 || (curaddr & EE_PAGEMASK) == 0) {
+
+      i2c_start();
+      i2c_write(EE_HW_ADDRESS | 0x0);
+
+      /* Write the new address to the bus. */
+      i2c_write((curaddr & 0xFF00) >> 8);
+      i2c_write(curaddr & 0xFF);
+    }
+
+    /* Write byte. */
+    i2c_write(buf[i] & 0xFF);
+
+    /* If we are writing the last byte totally or of a 32b page
+       generate a stop condition */
+    if(i == size - 1 || (curaddr & EE_PAGEMASK) == EE_PAGEMASK) {
+      i2c_stop();
+      eeprom_wait();
+    }
+
+    curaddr++;
+  }
+}
+
+/**
+ * Read data from eeprom
+ * @param addr The eeprom memory address
+ * @param buf It is the destination buffer in witch the bytes will be written
+ * @param size It is the number of byte to read
+ */
+void
+eeprom_read(eeprom_addr_t addr, unsigned char *buf, int size)
+{
+  uint8_t i;
+
+  i2c_start();
+
+  /* Select eeprom with write mode bit enabled */
+  i2c_write(EE_HW_ADDRESS | 0x0);
+
+  /* Send address */
+  i2c_write((addr & 0xFF00) >> 8);
+  i2c_write(addr & 0xFF);
+
+  i2c_start();
+
+  /* Select eeprom with write mode bit disabled */
+  i2c_write(EE_HW_ADDRESS | 0x1);
+
+  for(i = 0; i < size; i++) {
+    if(i < (size - 1)) {
+      /* Read data and send ACK */
+      *(buf + i) = i2c_read(1);
+    } else {
+      /* Last data, don't send ACK */
+      *(buf + i) = i2c_read(0);
+    }
+  }
+
+  i2c_stop();
+}
+
+/** @} */

platform/mbxxx/platform-conf.h

@@ -84,6 +84,7 @@ typedef unsigned long clock_time_t;
 #define CLOCK_CONF_SECOND 1000
 
 typedef unsigned long rtimer_clock_t;
+
 #define RTIMER_CLOCK_LT(a,b)     ((signed short)((a)-(b)) < 0)
 
 #define LEDS_CONF_RED_PIN     boardDescription->io->leds[1].gpioPin
@@ -97,6 +98,7 @@ typedef unsigned long rtimer_clock_t;
 #define UIP_ARCH_CHKSUM          0
 
 #define UIP_CONF_BYTE_ORDER      UIP_LITTLE_ENDIAN
+#define EEPROM_CONF_SIZE	8000
 
 #endif /* PLATFORM_CONF_H_ */
 /** @} */