mcp23008 Initial support

drivers/ioexpander/Kconfig

@@ -90,6 +90,50 @@ config ISO1I813T_MULTIPLE
 
 endif # IOEXPANDER_ISO1I813T
 
+config IOEXPANDER_MCP23X08
+	bool "MCP23008/MCP23S08 I2C/SPI IO expander"
+	default n
+	depends on I2C
+	---help---
+		Enable support for the MCP23008/MCP23S08 IO Expander
+
+if IOEXPANDER_MCP23X08
+
+config MCP23X08_MULTIPLE
+	bool "Multiple MCP23x08 Devices"
+	default n
+	---help---
+		Can be defined to support multiple MCP23x08 devices on board.
+
+config MCP23X08_INT_ENABLE
+	bool "Enable MCP23x08 Interrupt Support"
+	default n
+	select IOEXPANDER_INT_ENABLE
+	---help---
+		Enable driver interrupt functionality
+
+config MCP23X08_INT_NCALLBACKS
+	int "Max number of interrupt callbacks"
+	default 4
+	depends on MCP23X08_INT_ENABLE
+	---help---
+		This is the maximum number of interrupt callbacks supported
+
+config MCP23X08_INT_POLL
+	bool "Enable interrupt poll"
+	default n
+	---help---
+		Enable polling for missed interrupts.
+
+config MCP23X08_INT_POLLDELAY
+	int "Interrupt poll delay (used)"
+	default 500000
+	depends on MCP23X08_INT_POLL
+	---help---
+		This microsecond delay defines the polling rate for missed interrupts.
+
+endif # IOEXPANDER_MCP23X08
+
 config IOEXPANDER_MCP23X17
 	bool "MCP23017/MCP23S17 I2C/SPI IO expander"
 	default n

drivers/ioexpander/Make.defs

@@ -60,6 +60,10 @@ ifeq ($(CONFIG_IOEXPANDER_PCF8575),y)
   CSRCS += pcf8575.c
 endif
 
+ifeq ($(CONFIG_IOEXPANDER_MCP23X08),y)
+  CSRCS += mcp23x08.c
+endif
+
 ifeq ($(CONFIG_IOEXPANDER_MCP23X17),y)
   CSRCS += mcp23x17.c
 endif

drivers/ioexpander/mcp23x08.h

@@ -0,0 +1,166 @@
+/****************************************************************************
+ * drivers/ioexpander/mcp23x08.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __DRIVERS_IOEXPANDER_MCP23X08_H
+#define __DRIVERS_IOEXPANDER_MCP23X08_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <nuttx/wdog.h>
+#include <nuttx/clock.h>
+#include <nuttx/mutex.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/ioexpander/ioexpander.h>
+#include <nuttx/ioexpander/mcp23x08.h>
+
+#include <nuttx/i2c/i2c_master.h>
+#include <nuttx/irq.h>
+
+#if defined(CONFIG_IOEXPANDER) && defined(CONFIG_IOEXPANDER_MCP23X08)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Configuration ************************************************************/
+
+/* Prerequisites:
+ *   CONFIG_I2C
+ *     I2C support is required
+ *   CONFIG_IOEXPANDER
+ *     Enables I/O expander support
+ *
+ * CONFIG_IOEXPANDER_MCP23X08
+ *   Enables support for the MCP23X08 driver (Needs CONFIG_INPUT)
+ * CONFIG_MCP23X08_MULTIPLE
+ *   Can be defined to support multiple MCP23X08 devices on board.
+ * CONFIG_MCP23X08_INT_NCALLBACKS
+ *   Maximum number of supported pin interrupt callbacks.
+ * CONFIG_MCP23X08_INT_POLL
+ *   Enables a poll for missed interrupts
+ * CONFIG_MCP23X08_INT_POLLDELAY
+ *   If CONFIG_MCP23X08_INT_POLL=y, then this is the delay in microseconds
+ *   between polls for missed interrupts.
+ */
+
+#ifndef CONFIG_I2C
+#  error "CONFIG_I2C is required by MCP23X08"
+#endif
+
+#ifdef CONFIG_IOEXPANDER_INT_ENABLE
+#  ifndef CONFIG_MCP23X08_INT_NCALLBACKS
+#    define CONFIG_MCP23X08_INT_NCALLBACKS 4
+#  endif
+#endif
+
+#ifdef CONFIG_IOEXPANDER_INT_ENABLE
+#  ifndef CONFIG_SCHED_WORKQUEUE
+#    error Work queue support required.  CONFIG_SCHED_WORKQUEUE must be selected.
+#  endif
+#endif
+
+#ifndef CONFIG_MCP23X08_INT_POLLDELAY
+#  define CONFIG_MCP23X08_INT_POLLDELAY 500000
+#endif
+
+/* MCP23X08 Definitions *****************************************************/
+
+/* I2C frequency */
+
+#define MCP23X08_I2C_MAXFREQUENCY        400000       /* 400KHz */
+
+/* MCP23X08 *****************************************************************/
+
+/* If IOCON.BANK = 0 Addressing Mode */
+
+#define MCP23X08_IODIR                  0x00
+#define MCP23X08_IPOL                   0x01
+#define MCP23X08_GPINTEN                0x02
+#define MCP23X08_DEFVAL                 0x03
+#define MCP23X08_INTCON                 0x04
+#define MCP23X08_IOCON                  0x05
+#define MCP23X08_GPPU                   0x06
+#define MCP23X08_INTF                   0x07
+#define MCP23X08_INTCAP                 0x08
+#define MCP23X08_GPIO                   0x09
+#define MCP23X08_OLAT                   0x0a
+
+#define MCP23X08_IOCON_INTPOL           (1 << 1) /* Polarity of INT output pin */
+#define MCP23X08_IOCON_ODR              (1 << 2) /* Config INT pin as open-drain */
+#define MCP23X08_IOCON_HAEN             (1 << 3) /* HW Address enable bit */
+#define MCP23X08_IOCON_DISSLW           (1 << 4) /* Disable Slew Rate for SDA output */
+#define MCP23X08_IOCON_SEQOP            (1 << 5) /* Disable Sequential Operation */
+
+#define MCP23X08_NR_GPIO_MAX            8
+
+#define MCP23X08_POLLDELAY       (CONFIG_MCP23X08_INT_POLLDELAY / USEC_PER_TICK)
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+#ifdef CONFIG_IOEXPANDER_INT_ENABLE
+/* This type represents on registered pin interrupt callback */
+
+struct mcp23x08_callback_s
+{
+  ioe_pinset_t pinset;              /* Set of pin interrupts that will generate
+                                     * the callback. */
+  ioe_callback_t cbfunc;            /* The saved callback function pointer */
+  FAR void *cbarg;                  /* Callback argument */
+};
+#endif
+
+/* This structure represents the state of the MCP23X08 driver */
+
+struct mcp23x08_dev_s
+{
+  struct ioexpander_dev_s dev;          /* Nested structure to allow casting
+                                         * as public gpio expander.
+                                         */
+#ifdef CONFIG_MCP23X08_MULTIPLE
+  FAR struct mcp23x08_dev_s *flink;     /* Supports a singly linked list of drivers */
+#endif
+
+  FAR struct mcp23x08_config_s *config; /* Board configuration data */
+  FAR struct i2c_master_s *i2c;         /* Saved I2C driver instance */
+  mutex_t lock;                         /* Mutual exclusion */
+
+#ifdef CONFIG_IOEXPANDER_INT_ENABLE
+#ifdef CONFIG_MCP23X08_INT_POLL
+  struct wdog_s wdog;                /* Timer used to poll for missed interrupts */
+#endif
+
+  ioe_pinset_t input;                /* Last input registers */
+  ioe_pinset_t intstat;              /* Pending interrupts */
+  struct work_s work;                /* Supports the interrupt handling "bottom half" */
+
+  /* Saved callback information for each I/O expander client */
+
+  struct mcp23x08_callback_s cb[CONFIG_MCP23X08_INT_NCALLBACKS];
+#endif
+};
+
+#endif /* CONFIG_IOEXPANDER && CONFIG_IOEXPANDER_MCP23X08 */
+#endif /* __DRIVERS_IOEXPANDER_MCP23X08_H */