Merged in david_alessio/nuttx/feature/devc-at24cs-uuid (pull request #1013)

register a character driver for UUID of AT24CSxx chips

Allows the UUID to read as a file or displayed from an nsh prompt
with:  hexdump /dev/eeprom.uuid

Approved-by: Alan Carvalho de Assis <acassis@gmail.com>
Approved-by: Gregory Nutt <gnutt@nuttx.org>

drivers/eeprom/Kconfig

@@ -41,6 +41,15 @@ config EE24XX_FREQUENCY
 	default 100000
 	depends on I2C_EE_24XX
 
+config AT24CS_UUID
+    bool "Device driver support for Atmel AT24CSxx UUID"
+    default n
+	depends on I2C_EE_24XX
+	---help---
+		The Atmel AT24CSxx family have a 128-bit UUID which appears as
+		another I2C slave whose address is offset from the EEPROM by +8.
+		This option registers a char device driver with the ".uuid" suffix.
+
 endif # I2C_EE_24XX
 
 endif # EEPROM

drivers/eeprom/i2c_xx24xx.c

@@ -92,6 +92,7 @@
 #include <sys/types.h>
 #include <debug.h>
 #include <errno.h>
+#include <string.h>
 #include <nuttx/fs/fs.h>
 
 #include <nuttx/kmalloc.h>
@@ -161,6 +162,11 @@ static ssize_t ee24xx_write(FAR struct file *filep, FAR const char *buffer,
 static int     ee24xx_ioctl(FAR struct file *filep, int cmd,
                             unsigned long arg);
 
+#ifdef CONFIG_AT24CS_UUID
+static ssize_t at24cs_read_uuid(FAR struct file *filep, FAR char *buffer,
+                                size_t buflen);
+#endif
+
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -210,6 +216,19 @@ static const struct file_operations ee24xx_fops =
   NULL          /* poll */
 };
 
+#ifdef CONFIG_AT24CS_UUID
+static const struct file_operations at24cs_uuid_fops =
+{
+  ee24xx_open,      /* piggyback on the ee24xx_open */
+  ee24xx_close,     /* piggyback on the ee24xx_close */
+  at24cs_read_uuid, /* read */
+  NULL,             /* write */
+  NULL,             /* seek */
+  NULL,             /* ioctl */
+  NULL              /* poll */
+};
+#endif
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -540,6 +559,79 @@ done:
   return ret;
 }
 
+#ifdef CONFIG_AT24CS_UUID
+/****************************************************************************
+ * Name: at24cs_read_uuid
+ ****************************************************************************/
+#define UUID_SIZE   16
+
+static ssize_t at24cs_read_uuid(FAR struct file *filep, FAR char *buffer,
+                                size_t len)
+{
+  FAR struct ee24xx_dev_s *eedev;
+  FAR struct inode        *inode = filep->f_inode;
+  struct i2c_msg_s         msgs[2];
+  uint8_t                  regindx;
+  int                      ret;
+
+  DEBUGASSERT(inode && inode->i_private);
+  eedev = (FAR struct ee24xx_dev_s *)inode->i_private;
+
+  ee24xx_semtake(eedev);
+
+  /* trim len if read would go beyond end of device */
+
+  if ((filep->f_pos + len) > UUID_SIZE)
+    {
+      len = UUID_SIZE - filep->f_pos;
+    }
+
+  if (len == 0)
+    {
+      /* We are at end of file */
+
+      ret = 0;
+      goto done;
+    }
+
+  /* Write data address */
+
+  finfo("READ %d bytes at pos %d\n", len, filep->f_pos);
+
+  regindx           = 0x80;             /* reg index of UUID[0] */
+
+  msgs[0].frequency = eedev->freq;
+  msgs[0].addr      = eedev->addr + 8;  /* slave addr of UUID */
+  msgs[0].flags     = 0;
+  msgs[0].buffer    = &regindx;
+  msgs[0].length    = 1;
+
+  /* Read data */
+
+  msgs[1].frequency = msgs[0].frequency;
+  msgs[1].addr      = msgs[0].addr;
+  msgs[1].flags     = I2C_M_READ;
+  msgs[1].buffer    = (uint8_t *)buffer;
+  msgs[1].length    = len;
+
+  ret = I2C_TRANSFER(eedev->i2c, msgs, 2);
+  if (ret < 0)
+    {
+      goto done;
+    }
+
+  ret = len;
+
+  /* Update the file position */
+
+  filep->f_pos += len;
+
+done:
+  ee24xx_semgive(eedev);
+  return ret;
+}
+#endif
+
 /****************************************************************************
  * Name: ee24xx_write
  ****************************************************************************/
@@ -705,6 +797,10 @@ int ee24xx_initialize(FAR struct i2c_master_s *bus, uint8_t devaddr,
                       FAR char *devname, int devtype, int readonly)
 {
   FAR struct ee24xx_dev_s *eedev;
+#ifdef CONFIG_AT24CS_UUID
+  FAR char                *uuidname;
+  int                     ret;
+#endif
 
   /* Check device type early */
 
@@ -759,7 +855,7 @@ int ee24xx_initialize(FAR struct i2c_master_s *bus, uint8_t devaddr,
           ferr("Device 24xx1025 is not supported for the moment, TODO.\n");
 
           eedev->haddrshift = 2;
-          free(eedev);
+          kmm_free(eedev);
           return -ENODEV;
         }
     }
@@ -768,5 +864,29 @@ int ee24xx_initialize(FAR struct i2c_master_s *bus, uint8_t devaddr,
         devname, eedev->size, eedev->pgsize, eedev->addrlen,
         eedev->readonly ? "readonly" : "");
 
+#ifdef CONFIG_AT24CS_UUID
+  uuidname = kmm_zalloc(strlen(devname) + 8);
+  if (!uuidname)
+    {
+      return -ENOMEM;
+    }
+
+  /* register the UUID I2C slave with the same name as the parent
+   * EEPROM chip, but with the ".uuid" suffix
+   */
+
+  strcpy(uuidname, devname);
+  strcat(uuidname, ".uuid");
+  ret = register_driver(uuidname, &at24cs_uuid_fops, 0444, eedev);
+
+  kmm_free(uuidname);
+
+  if (OK != ret)
+    {
+      ferr("register uuid failed, ret = %d\n", ret);
+      return ret;
+    }
+#endif
+
   return register_driver(devname, &ee24xx_fops, 0666, eedev);
 }