Completes first (untested) cut at MAX1704x battery driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4324 42af7a65-404d-4744-a932-0658087f49c3

TODO

@@ -22,7 +22,7 @@ nuttx/
   (1)  Documentation (Documentation/)
   (7)  Build system / Toolchains
   (5)  Linux/Cywgin simulation (arch/sim)
-  (4)  ARM (arch/arm/)
+  (5)  ARM (arch/arm/)
   (1)  ARM/C5471 (arch/arm/src/c5471/)
   (3)  ARM/DM320 (arch/arm/src/dm320/)
   (2)  ARM/i.MX (arch/arm/src/imx/)
@@ -842,6 +842,44 @@ o ARM (arch/arm/)
   Priority:    Low until I get around to implementng security or kernel mode for
                the ARM platform.
 
+  Title:       CORTEX-M3 STACK OVERFLOW
+  Description: There is bit bit logic inf up_fullcontextrestore() that executes on
+               return from interrupts (and other context switches) that looks like:
+
+                 ldr r1, [r0, #(4*REG_CPSR)] /* Fetch the stored CPSR value */
+                 msr cpsr, r1 /* Set the CPSR */
+
+                 /* Now recover r0 and r1 */
+
+                 ldr r0, [sp]
+                 ldr r1, [sp, #4]
+                 add sp, sp, #(2*4)
+
+                 /* Then return to the address at the stop of the stack,
+                  * destroying the stack frame
+                  */
+
+                 ldr pc, [sp], #4
+
+               Under conditions of excessivley high interrupt conditions, many
+               nested interrupts can oocur just after the 'msr cpsr' instruction.
+               At that time, there are 4 bytes on the stack and, with each
+               interrupt, the stack pointer may increment and possibly overflow.
+
+               This can happen only under conditions of continuous interrupts.
+               See this email thread: http://tech.groups.yahoo.com/group/nuttx/message/1261
+               On suggested change is:
+
+                 ldr  r1, [r0, #(4*REG_CPSR)] /* Fetch the stored CPSR value */
+                 msr spsr_cxsf, r1 /* Set the CPSR */
+                 ldmia     r0, {r0-r15}^
+
+               But this has not been proven to be a solution.
+  Status:      Open
+  Priority:    Low.  The conditions of continous interrupts is really the problem.
+               If your design needs continous interrupts like this, please try
+               the above change and, please, submit a patch with the working fix.
+ 
 o ARM/C5471 (arch/arm/src/c5471/)
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

drivers/power/Make.defs

@@ -81,5 +81,4 @@ endif
 
 DEPPATH += $(POWER_DEPPATH)
 VPATH += $(POWER_VPATH)
-CFLAGS += $(POWER_CFLAGS);
-
+CFLAGS += $(POWER_CFLAGS)

drivers/power/battery.c

@@ -170,8 +170,7 @@ static int bat_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
           FAR int *ptr = (FAR int *)((uintptr_t)arg));
           if (ptr)
             {
-              *ptr = dev->ops->state(dev);
-              ret = OK;
+              ret = dev->ops->state(dev, ptr);
             }
         }
         break;
@@ -180,29 +179,26 @@ static int bat_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
           FAR bool *ptr = (FAR bool *)((uintptr_t)arg));
           if (ptr)
             {
-              *ptr = dev->ops->online(dev);
-              ret = OK;
+              ret = dev->ops->online(dev, ptr);
             }
         break;
 
       case BATIOC_VOLTAGE:
         {
-          FAR int *ptr = (FAR int *)((uintptr_t)arg));
+          FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg));
           if (ptr)
             {
-              *ptr = dev->ops->voltage(dev);
-              ret = OK;
+              ret = dev->ops->voltage(dev, ptr);
             }
         }
         break;
 
       case BATIOC_CAPACITY:
         {
-          FAR int *ptr = (FAR int *)((uintptr_t)arg));
+          FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg));
           if (ptr)
             {
-              *ptr = dev->ops->capacity(dev);
-              ret = OK;
+              ret = dev->ops->capacity(dev, ptr);
             }
         }
         break;

drivers/power/max1704x.c

@@ -34,6 +34,12 @@
  *
  ****************************************************************************/
 
+/* "The MAX17040/MAX17041 are ultra-compact, low-cost, host-side fuel-gauge
+ * systems for lithium-ion (Li+) batteries in handheld and portable equipment.
+ * The MAX17040 is configured to operate with a single lithium cell and the
+ * MAX17041 is configured for a dual-cell 2S pack.
+ */
+
 /****************************************************************************
  * Included Files
  ****************************************************************************/
@@ -57,6 +63,89 @@
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
+/* MAX1704x Register Definitions ********************************************/
+/* "All host interaction with the MAX17040/MAX17041 is handled by writing to
+ *  and reading from register locations. The MAX17040/MAX17041 have six 16-bit
+ *  registers: SOC, VCELL, MODE, VERSION, RCOMP, and COMMAND. Register reads
+ *  and writes are only valid if all 16 bits are transferred..."
+ */
+
+/* "VCELL Register.  Battery voltage is measured at the CELL pin input with
+ *  respect to GND over a 0 to 5.00V range for the MAX17040 and 0 to 10.00V
+ *  for the MAX17041 with resolutions of 1.25mV and 2.50mV, respectively..."
+ */
+
+#define MAX1407X_VCELL_ADDR      0x02  /* Bits 4-15: Bits 0-11 of the battery voltage */
+
+/* VCELL conversion macros */
+
+#define MAX14700_VCELL_CONV 82   /* 0.00125 v * 65536 */
+#define MAX14070_VCELL(v)       ((b16_t)(v) * MAX14700_VCELL_CONV)
+
+#define MAX14701_VCELL_CONV 163  /* 0.0025 v * 65536 */
+#define MAX14071_VCELL(v)       ((b16_t)(v) * MAX14701_VCELL_CONV)
+
+/* "SOC Register. The SOC register is a read-only register that displays the 
+ *  state of charge of the cell as calculated by the ModelGauge algorithm. The
+ *  result is displayed as a percentage of the cell’s full capacity...
+ *
+ * "...Units of % can be directly determined by observing only the high byte
+ *  of the SOC register. The low byte provides additional resolution in units
+ *  1/256%.
+ */
+
+#define MAX1407X_SOC_ADDR        0x04  /* Bits 0-15: Full SOC */
+
+/* SoC conversion macros */
+
+#define MAX1407X_SOC(s)         ((b16_t)MAX1407X_SOCB8(s) << 8)
+#define MAX17040_SOC_FULL       itob16(95) /* We say full if Soc >= 95% */
+
+/* "MODE Register.The MODE register allows the host processor to send special
+ *  commands to the IC."
+ */
+
+#define MAX1407X_MODE_ADDR       0x06  /* Bits 0-15: 16-bit MODE */
+
+/* Supported modes */
+
+#define MAX1407X_MODE_QUICKSTART 0x4000
+
+/* "The VERSION register is a read-only register that contains a value
+ *  indicating the production version of the MAX17040/MAX17041."
+ */
+
+#define MAX1407X_VERSION_ADDR    0x08  /* Bits 0-15: 16-bit VERSION */
+
+/* "RCOMP Register. RCOMP is a 16-bit value used to compensate the ModelGauge
+ *  algorithm. RCOMP can be adjusted to optimize performance for different
+ *  lithium chemistries or different operating temperatures... The factory-
+ *  default value for RCOMP is 9700h."
+ */
+
+#define MAX1407X_RCOMP_ADDR      0x0c  /* Bits 0-15: 16-bit RCOMP */
+
+/* "COMMAND Register.  The COMMAND register allows the host processor to send
+ *  special commands to the IC..."
+ */
+
+#define MAX1407X_COMMAND_ADDR    0xfe  /* Bits 0-7:  16-bit COMMAND */
+
+/* Supported copmmands */
+
+#define MAX1407X_COMMAND_POR     0x5400
+
+/* Debug ********************************************************************/
+
+#ifdef CONFIG_DEBUG_MAX1704X
+#  define batdbg dbg
+#else
+#  ifdef CONFIG_CPP_HAVE_VARARGS
+#    define batdbg(x...)
+#  else
+#    define batdbg (void)
+#  endif
+#endif
 
 /****************************************************************************
  * Private
@@ -78,13 +167,28 @@ struct max1704x_dev_s
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
+/* I2C support */
+
+static int max1704x_getreg16(FAR struct max1704x_dev_s *priv, uint8_t regaddr)
+                             FAR uint16_t *regval);
+static int max1704x_putreg16(FAR struct max1704x_dev_s *priv, uint8_t regaddr,
+                             uint16_t regval);
+
+static inline int max1704x_getvcell(FAR struct max1704x_dev_s *priv,
+                                    b16_t *vcell);
+static inline int max1704x_getsoc(FAR struct max1704x_dev_s *priv,
+                                  b16_t *soc);
+static inline int max1704x_setquikstart(FAR struct max1704x_dev_s *priv);
+static inline int max1704x_getversion(FAR struct max1704x_dev_s *priv,
+                                      uint16_t *version);
+static inline int max1704x_reset(FAR struct max1704x_dev_s *priv);
 
 /* Battery driver lower half methods */
 
-static enum battery_status_e mx1704x_state(struct battery_dev_s *lower);
-static bool mx1704x_online(struct battery_dev_s *lower);
-static int mx1704x_voltage(struct battery_dev_s *lower);
-static int mx1704x_capacity(struct battery_dev_s *lower);
+static int max1704x_state(struct battery_dev_s *dev, int *status);
+static int max1704x_online(struct battery_dev_s *dev, bool *status);
+static int max1704x_voltage(struct battery_dev_s *dev, b16_t *value);
+static int max1704x_capacity(struct battery_dev_s *dev, b16_t *value);
 
 /****************************************************************************
  * Private Data
@@ -92,10 +196,10 @@ static int mx1704x_capacity(struct battery_dev_s *lower);
 
 static const struct battery_operations_s g_max1704xops =
 {
-  mx1704x_state,
-  mx1704x_online,
-  mx1704x_voltage,
-  mx1704x_capacity
+  max1704x_state,
+  max1704x_online,
+  max1704x_voltage,
+  max1704x_capacity
 };
 
 /****************************************************************************
@@ -103,59 +207,260 @@ static const struct battery_operations_s g_max1704xops =
  ****************************************************************************/
 
 /****************************************************************************
- * Name: max1704x_open
+ * Name: max1704x_getreg16
+ *
+ * Description:
+ *   Read a 16-bit value from a MAX1704x register pair.
+ *
+ *   START <I2C write address> ACK <Reg address> ACK
+ *   REPEATED-START <I2C read address> ACK Data0 ACK Data1 NO-ACK STOP
+ *
+ ****************************************************************************/
+
+static int max1704x_getreg16(FAR struct max1704x_dev_s *priv, uint8_t regaddr)
+                             FAR uint16_t *regval)
+{
+  uint8_t buffer[2];
+  int ret;
+
+  /* Write the register address */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+  ret = I2C_WRITE(priv->i2c, &regaddr, 1);
+  if (ret < 0)
+    {
+      batdbg("I2C_WRITE failed: %d\n", ret);
+      return ret;
+    }
+
+  /* Restart and read 16-bits from the register */
+
+  ret = I2C_READ(priv->i2c, buffer, 2);
+  if (ret < 0)
+    {
+      batdbg("I2C_READ failed: %d\n", ret);
+      return ret;
+    }
+
+  /* Return the 16-bit value */
+
+  return (uint16_t)buffer[0] << 8 | (uint16_t)buffer[1];
+  return OK;
+}
+
+/****************************************************************************
+ * Name: max1704x_putreg16
+ *
+ * Description:
+ *   Write a 16-bit value to a MAX1704x register pair.
+ *
+ *   START <I2C write address> ACK <Reg address> ACK Data0 ACK Data1 ACK STOP
+ *
+ ****************************************************************************/
+
+static int max1704x_putreg16(FAR struct max1704x_dev_s *priv, uint8_t regaddr,
+                             uint16_t regval)
+{
+  uint8_t buffer[3];
+  b8_t regb8;
+
+  batdbg("addr: %02x regval: %08x\n", regaddr, regval);
+
+  /* Set up a 3 byte message to send */
+
+  buffer[0] = regaddr;
+  buffer[1] = (uint8_t)(regval >> 8);
+  buffer[2] = (uint8_t)(regval & 0xff);
+
+  /* Write the register address followed by the data (no RESTART) */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+  return I2C_WRITE(priv->i2c, buffer, 3);
+}
+
+/****************************************************************************
+ * Name: max1704x_getvcell
+ *
+ * Description:
+ *   Read the VCELL register and scale the returned value
+ *
+ ****************************************************************************/
+
+static inline int max1704x_getvcell(FAR struct max1704x_dev_s *priv,
+                                    b16_t *vcell)
+{
+  uint16_t regval;
+  int ret;
+
+  ret = max1704x_getreg16(priv, MAX1407X_VCELL_ADDR, &regval);
+  if (ret == OK)
+    {
+     *vcell = MAX14070_VCELL(regval);
+    }
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max1704x_getsoc
+ *
+ * Description:
+ *   Read the SOC register and scale the returned value
+ *
+ ****************************************************************************/
+
+static inline int max1704x_getsoc(FAR struct max1704x_dev_s *priv,
+                                  b16_t *soc)
+{
+  uint16_t regval;
+  int ret;
+
+  ret = max1704x_getreg16(priv, MAX1407X_VCELL_ADDR, &regval);
+  if (ret == OK)
+    {
+     *soc = MAX1407X_SOC(regval);
+    }
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max1704x_setquikstart
+ *
+ * Description:
+ *   Set Quickstart mode
+ *
+ ****************************************************************************/
+
+static inline int max1704x_setquikstart(FAR struct max1704x_dev_s *priv)
+{
+  return max1704x_putreg16(priv, MAX1407X_MODE_ADDR, MAX1407X_MODE_QUICKSTART);
+}
+
+/****************************************************************************
+ * Name: max1704x_getversion
+ *
+ * Description:
+ *   Read the SOC register and scale the returned value
+ *
+ ****************************************************************************/
+
+static inline int max1704x_getversion(FAR struct max1704x_dev_s *priv,
+                                      uint16_t *version)
+{
+  return max1704x_getreg16(priv, MAX1407X_VCELL_ADDR, version);
+}
+
+/****************************************************************************
+ * Name: max1704x_setrcomp
+ *
+ * Description:
+ *   Set Quickstart mode
+ *
+ ****************************************************************************/
+
+static inline int max1704x_setrcomp(FAR struct max1704x_dev_s *priv, uint16_t rcomp)
+{
+  return max1704x_putreg16(priv, MAX1407X_RCOMP_ADDR, rcomp);
+}
+
+/****************************************************************************
+ * Name: max1704x_reset
+ *
+ * Description:
+ *   Reset the MAX1704x
+ *
+ ****************************************************************************/
+
+static inline int max1704x_reset(FAR struct max1704x_dev_s *priv)
+{
+  return max1704x_putreg16(priv, MAX1407X_COMMAND_ADDR, MAX1407X_COMMAND_POR);
+}
+
+/****************************************************************************
+ * Name: max1704x_state
  *
  * Description:
  *   Return the current battery state
  *
  ****************************************************************************/
 
-static enum battery_status_e state(struct battery_dev_s *lower)
+static int max1704x_state(struct battery_dev_s *dev, int *status)
 {
-#warning "Missing logic"
-  return BATTERY_UNKNOWN;
+  FAR struct max1704x_dev_s *priv = (FAR struct max1704x_dev_s *)dev;
+  b16_t soc;
+  int ret;
+
+  /* Only a few of the possible battery states are supported by this driver:
+   *
+   *  BATTERY_UNKNOWN - Returned on error conditions
+   *  BATTERY_IDLE - This is what will usually be reported
+   *  BATTERY_FULL - This will be reported if the SoC is greater than 95%
+   *  BATTERY_CHARGING and BATTERY_DISCHARGING - I don't think this hardware
+   *    knows anything about current (charging or dischargin).
+   */
+
+  ret = max1704x_getsoc(priv, &soc);
+  if (ret < 0)
+    {
+      *status = BATTERY_UNKNOWN;
+      return ret;
+    }
+
+  /* Is the battery fully charged? */
+
+  if (soc > MAX17040_SOC_FULL)
+    {
+      *status = BATTERY_FULL;
+    }
+  else
+    {
+      *status = BATTERY_IDLE;
+    }
+
+  return OK;
 }
 
 /****************************************************************************
- * Name: max1704x_open
+ * Name: max1704x_online
  *
  * Description:
  *   Return true if the batter is online
  *
  ****************************************************************************/
 
-static bool online(struct battery_dev_s *lower)
+static int max1704x_online(struct battery_dev_s *dev, bool *status);
 {
-#warning "Missing logic"
-  return false;
+  /* There is no concept of online/offline in this driver */
+
+  *status = true
+  return OK;
 }
 
 /****************************************************************************
- * Name: max1704x_open
+ * Name: max1704x_voltage
  *
  * Description:
  *   Current battery voltage
  *
  ****************************************************************************/
 
-static int voltage(struct battery_dev_s *lower);
+static int max1704x_voltage(struct battery_dev_s *dev, b16_t *value);
 {
-#warning "Missing logic"
-  return 0;
+  FAR struct max1704x_dev_s *priv = (FAR struct max1704x_dev_s *)dev;
+  return max1704x_getvcell(priv, value);
 }
 
 /****************************************************************************
- * Name: max1704x_open
+ * Name: max1704x_capacity
  *
  * Description:
  *   Battery capacity
  *
  ****************************************************************************/
 
-static int capacity(struct battery_dev_s *lower);
+static int max1704x_capacity(struct battery_dev_s *dev, b16_t *value);
 {
-#warning "Missing logic"
-  return 0;
+  FAR struct max1704x_dev_s *priv = (FAR struct max1704x_dev_s *)dev;
+  return max1704x_getsoc(priv, value);
 }
 
 /****************************************************************************
@@ -191,15 +496,27 @@ FAR struct battery_dev_s *max1704x_initialize(FAR struct i2c_dev_s *i2c,
   FAR struct max1704x_dev_s *priv;
   int ret;
 
-  /* Initialize theMAX1704x device structure */
+  /* Initialize the MAX1704x device structure */
 
   priv = (FAR struct max1704x_dev_s *)kzalloc(sizeof(struct max1704x_dev_s));
   if (priv)
     {
+      /* Initialize the MAX1704x device structure */
+
       sem_init(&priv->batsem, 0, 1);
       priv->ops  = &g_max1704xops;
       priv->i2c  = i2c;
       priv->addr = addr;
+
+      /* Reset the MAX1704x (mostly just to make sure that we can talk to it) */
+
+      ret = max1704x_reset(priv);
+      if (ret < 0)
+        {
+          batdbg("Failed to reset the MAX1704x: %d\n", ret);
+          kfree(priv);
+          return NULL;
+        }
     }
   return (FAR struct battery_dev_s *)priv;
 }

include/nuttx/power/battery.h

@@ -45,6 +45,7 @@
 #include <nuttx/ioctl.h>
 
 #include <semaphore.h>
+#include <fixedmath.h>
 
 #ifdef CONFIG_BATTERY
 
@@ -74,10 +75,13 @@
  *   Input value:  A pointer to type int.
  * BATIOC_ONLINE - Return 1 if the battery is online; 0 if offline.
  *   Input value:  A pointer to type bool.
- * BATIOC_VOLTAGE - Return the current battery voltage.
- *   Input value:  A pointer to type int.
- * BATIOC_CAPACITY - Return the current battery capacity.
- *   Input value:  A pointer to type int.
+ * BATIOC_VOLTAGE - Return the current battery voltage.  The returned value
+ *   is a fixed preceision number in units of volts.
+ *   Input value:  A pointer to type b16_t.
+ * BATIOC_CAPACITY - Return the current battery capacity or State of Charge
+ *   (SoC).  The returned value is a fixed precision percentage of the
+ *   batteries full capacity.
+ *   Input value:  A pointer to type b16_t.
  */
 
 #define BATIOC_STATE    _BATIOC(0x0001)
@@ -104,21 +108,21 @@ enum battery_status_e
 struct battery_dev_s;
 struct battery_operations_s
 {
-  /* Return the current battery state */
+  /* Return the current battery state (see enum battery_status_e) */
 
-  enum battery_status_e state(struct battery_dev_s *dev);
+  int state(struct battery_dev_s *dev, int *status);
 
   /* Return true if the batter is online */
 
-  bool online(struct battery_dev_s *dev);
+  int online(struct battery_dev_s *dev, bool *status);
 
   /* Current battery voltage */
 
-  int voltage(struct battery_dev_s *dev);
+  int voltage(struct battery_dev_s *dev, b16_t *value);
 
   /* Battery capacity */
 
-  int capacity(struct battery_dev_s *dev);
+  int capacity(struct battery_dev_s *dev, b16_t *value);
 };
 
 /* This structure defines the battery driver state structure */