Add I2C driver framework

This I2C driver framework has some major differences compared to libi2c.

* It is compatible to the Linux I2C user-space API.

* It uses generic IMFS nodes and thus reduces the levels of indirection.

* The drivers don't have to mess around with minor numbers to get their
  state information.

* No arbitrary bus controller model is assumed.  The main task of an I2C
  bus controller driver is to process I2C messages.  How this is done is
  private to the driver.

* Scatter/gather operations are supported (I2C_M_NOSTART).

2 files changed, 642 insertions, 0 deletions

diff --git a/cpukit/dev/i2c/i2c-bus.c b/cpukit/dev/i2c/i2c-bus.c
new file mode 100644
index 0000000000..dafd758e05
--- /dev/null
+++ b/cpukit/dev/i2c/i2c-bus.c
@@ -0,0 +1,351 @@
+/**
+ * @file
+ *
+ * @brief Inter-Integrated Circuit (I2C) Bus Implementation
+ *
+ * @ingroup I2CBus
+ */
+
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <dev/i2c/i2c.h>
+
+#include <rtems/imfs.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+void i2c_bus_obtain(i2c_bus *bus)
+{
+  rtems_status_code sc;
+
+  sc = rtems_semaphore_obtain(bus->mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
+  _Assert(sc == RTEMS_SUCCESSFUL);
+  (void) sc;
+}
+
+void i2c_bus_release(i2c_bus *bus)
+{
+  rtems_status_code sc;
+
+  sc = rtems_semaphore_release(bus->mutex);
+  _Assert(sc == RTEMS_SUCCESSFUL);
+  (void) sc;
+}
+
+int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count)
+{
+  int err;
+  uint32_t i;
+  uint32_t j;
+
+  _Assert(msg_count > 0);
+
+  for (i = 0, j = 0; i < msg_count; ++i) {
+    if ((msgs[i].flags & I2C_M_NOSTART) != 0) {
+      if ((msgs[i].flags & I2C_M_RD) != (msgs[j].flags & I2C_M_RD)) {
+        return -EINVAL;
+      }
+
+      if (msgs[i].addr != msgs[j].addr) {
+        return -EINVAL;
+      }
+    } else {
+      j = i;
+    }
+  }
+
+  i2c_bus_obtain(bus);
+  err = (*bus->transfer)(bus, msgs, msg_count);
+  i2c_bus_release(bus);
+
+  return err;
+}
+
+static ssize_t i2c_bus_read(
+  rtems_libio_t *iop,
+  void *buffer,
+  size_t count
+)
+{
+  i2c_bus *bus = IMFS_generic_get_context_by_iop(iop);
+  i2c_msg msg = {
+    .addr = bus->default_address,
+    .flags = I2C_M_RD,
+    .len = (uint16_t) count,
+    .buf = buffer
+  };
+  int err;
+
+  if (bus->ten_bit_address) {
+    msg.flags |= I2C_M_TEN;
+  }
+
+  err = i2c_bus_transfer(bus, &msg, 1);
+  if (err == 0) {
+    return msg.len;
+  } else {
+    rtems_set_errno_and_return_minus_one(-err);
+  }
+}
+
+static ssize_t i2c_bus_write(
+  rtems_libio_t *iop,
+  const void *buffer,
+  size_t count
+)
+{
+  i2c_bus *bus = IMFS_generic_get_context_by_iop(iop);
+  i2c_msg msg = {
+    .addr = bus->default_address,
+    .flags = 0,
+    .len = (uint16_t) count,
+    .buf = RTEMS_DECONST(void *, buffer)
+  };
+  int err;
+
+  if (bus->ten_bit_address) {
+    msg.flags |= I2C_M_TEN;
+  }
+
+  err = i2c_bus_transfer(bus, &msg, 1);
+  if (err == 0) {
+    return msg.len;
+  } else {
+    rtems_set_errno_and_return_minus_one(-err);
+  }
+}
+
+static int i2c_bus_ioctl(
+  rtems_libio_t *iop,
+  ioctl_command_t command,
+  void *arg
+)
+{
+  i2c_bus *bus = IMFS_generic_get_context_by_iop(iop);
+  i2c_rdwr_ioctl_data *rdwr;
+  int err;
+
+  switch (command) {
+    case I2C_RDWR:
+      rdwr = arg;
+      if (rdwr->nmsgs > 0) {
+        err = i2c_bus_transfer(bus, rdwr->msgs, rdwr->nmsgs);
+      } else {
+        err = 0;
+      }
+      break;
+    case I2C_BUS_OBTAIN:
+      i2c_bus_obtain(bus);
+      err = 0;
+      break;
+    case I2C_BUS_RELEASE:
+      i2c_bus_release(bus);
+      err = 0;
+      break;
+    case I2C_BUS_GET_CONTROL:
+      *(i2c_bus **) arg = bus;
+      err = 0;
+      break;
+    case I2C_FUNCS:
+      *(unsigned long *) arg = bus->functionality;
+      err = 0;
+      break;
+    case I2C_RETRIES:
+      bus->retries = (unsigned long) arg;
+      err = 0;
+      break;
+    case I2C_TIMEOUT:
+      bus->timeout = RTEMS_MILLISECONDS_TO_TICKS(10 * (unsigned long) arg);
+      err = 0;
+      break;
+    case I2C_SLAVE:
+    case I2C_SLAVE_FORCE:
+      bus->default_address = (unsigned long) arg;
+      err = 0;
+      break;
+    case I2C_TENBIT:
+      bus->ten_bit_address = (unsigned long) arg != 0;
+      err = 0;
+      break;
+    case I2C_PEC:
+      bus->use_pec = (unsigned long) arg != 0;
+      err = 0;
+      break;
+    case I2C_BUS_SET_CLOCK:
+      i2c_bus_obtain(bus);
+      err = (*bus->set_clock)(bus, (unsigned long) arg);
+      i2c_bus_release(bus);
+      break;
+    default:
+      err = -ENOTTY;
+      break;
+  }
+
+  if (err == 0) {
+    return 0;
+  } else {
+    rtems_set_errno_and_return_minus_one(-err);
+  }
+}
+
+static const rtems_filesystem_file_handlers_r i2c_bus_handler = {
+  .open_h = rtems_filesystem_default_open,
+  .close_h = rtems_filesystem_default_close,
+  .read_h = i2c_bus_read,
+  .write_h = i2c_bus_write,
+  .ioctl_h = i2c_bus_ioctl,
+  .lseek_h = rtems_filesystem_default_lseek,
+  .fstat_h = IMFS_stat,
+  .ftruncate_h = rtems_filesystem_default_ftruncate,
+  .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
+  .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
+  .fcntl_h = rtems_filesystem_default_fcntl,
+  .kqfilter_h = rtems_filesystem_default_kqfilter,
+  .poll_h = rtems_filesystem_default_poll,
+  .readv_h = rtems_filesystem_default_readv,
+  .writev_h = rtems_filesystem_default_writev
+};
+
+static IMFS_jnode_t *i2c_bus_node_destroy(IMFS_jnode_t *node)
+{
+  i2c_bus *bus;
+
+  bus = IMFS_generic_get_context_by_node(node);
+  (*bus->destroy)(bus);
+
+  return node;
+}
+
+static const IMFS_node_control i2c_bus_node_control = {
+  .imfs_type = IMFS_GENERIC,
+  .handlers = &i2c_bus_handler,
+  .node_initialize = IMFS_node_initialize_generic,
+  .node_remove = IMFS_node_remove_default,
+  .node_destroy = i2c_bus_node_destroy
+};
+
+int i2c_bus_register(
+  i2c_bus *bus,
+  const char *bus_path
+)
+{
+  int rv;
+
+  rv = IMFS_make_generic_node(
+    bus_path,
+    S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO,
+    &i2c_bus_node_control,
+    bus
+  );
+  if (rv != 0) {
+    (*bus->destroy)(bus);
+  }
+
+  return rv;
+}
+
+static int i2c_bus_transfer_default(
+  i2c_bus *bus,
+  i2c_msg *msgs,
+  uint32_t msg_count
+)
+{
+  (void) bus;
+  (void) msgs;
+  (void) msg_count;
+
+  return -EIO;
+}
+
+static int i2c_bus_set_clock_default(i2c_bus *bus, unsigned long clock)
+{
+  (void) bus;
+  (void) clock;
+
+  return -EIO;
+}
+
+static int i2c_bus_do_init(
+  i2c_bus *bus,
+  void (*destroy)(i2c_bus *bus)
+)
+{
+  rtems_status_code sc;
+
+  sc = rtems_semaphore_create(
+    rtems_build_name('I', '2', 'C', ' '),
+    1,
+    RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_PRIORITY,
+    0,
+    &bus->mutex
+  );
+  if (sc != RTEMS_SUCCESSFUL) {
+    (*destroy)(bus);
+
+    rtems_set_errno_and_return_minus_one(ENOMEM);
+  }
+
+  bus->transfer = i2c_bus_transfer_default;
+  bus->set_clock = i2c_bus_set_clock_default;
+  bus->destroy = destroy;
+
+  return 0;
+}
+
+void i2c_bus_destroy(i2c_bus *bus)
+{
+  rtems_status_code sc;
+
+  sc = rtems_semaphore_delete(bus->mutex);
+  _Assert(sc == RTEMS_SUCCESSFUL);
+  (void) sc;
+}
+
+void i2c_bus_destroy_and_free(i2c_bus *bus)
+{
+  i2c_bus_destroy(bus);
+  free(bus);
+}
+
+int i2c_bus_init(i2c_bus *bus)
+{
+  memset(bus, 0, sizeof(*bus));
+
+  return i2c_bus_do_init(bus, i2c_bus_destroy);
+}
+
+i2c_bus *i2c_bus_alloc_and_init(size_t size)
+{
+  i2c_bus *bus = NULL;
+
+  if (size >= sizeof(*bus)) {
+    bus = calloc(1, size);
+    if (bus != NULL) {
+      int rv;
+
+      rv = i2c_bus_do_init(bus, i2c_bus_destroy_and_free);
+      if (rv != 0) {
+        return NULL;
+      }
+    }
+  }
+
+  return bus;
+}
diff --git a/cpukit/dev/i2c/i2c-dev.c b/cpukit/dev/i2c/i2c-dev.c
new file mode 100644
index 0000000000..b03effd1df
--- /dev/null
+++ b/cpukit/dev/i2c/i2c-dev.c
@@ -0,0 +1,291 @@
+/**
+ * @file
+ *
+ * @brief Inter-Integrated Circuit (I2C) Bus Implementation
+ *
+ * @ingroup I2CDevice
+ */
+
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <dev/i2c/i2c.h>
+
+#include <rtems/imfs.h>
+#include <rtems/score/assert.h>
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static ssize_t i2c_dev_read(
+  rtems_libio_t *iop,
+  void *buffer,
+  size_t count
+)
+{
+  i2c_dev *dev = IMFS_generic_get_context_by_iop(iop);
+  ssize_t n;
+
+  n = (*dev->read)(dev, buffer, count, iop->offset);
+  if (n > 0) {
+    iop->offset += n;
+  }
+
+  return n;
+}
+
+static ssize_t i2c_dev_write(
+  rtems_libio_t *iop,
+  const void *buffer,
+  size_t count
+)
+{
+  i2c_dev *dev = IMFS_generic_get_context_by_iop(iop);
+  ssize_t n;
+
+  n = (*dev->write)(dev, buffer, count, iop->offset);
+  if (n > 0) {
+    iop->offset += n;
+  }
+
+  return n;
+}
+
+static int i2c_dev_ioctl(
+  rtems_libio_t *iop,
+  ioctl_command_t command,
+  void *arg
+)
+{
+  i2c_dev *dev = IMFS_generic_get_context_by_iop(iop);
+  int err;
+
+  err = (*dev->ioctl)(dev, command, arg);
+
+  if (err == 0) {
+    return 0;
+  } else {
+    rtems_set_errno_and_return_minus_one(-err);
+  }
+}
+
+static int i2c_dev_fstat(
+  const rtems_filesystem_location_info_t *loc,
+  struct stat *buf
+)
+{
+  i2c_dev *dev = IMFS_generic_get_context_by_location(loc);
+
+  buf->st_size = (*dev->get_size)(dev);
+  buf->st_blksize = (*dev->get_block_size)(dev);
+
+  return IMFS_stat(loc, buf);
+}
+
+static const rtems_filesystem_file_handlers_r i2c_dev_handler = {
+  .open_h = rtems_filesystem_default_open,
+  .close_h = rtems_filesystem_default_close,
+  .read_h = i2c_dev_read,
+  .write_h = i2c_dev_write,
+  .ioctl_h = i2c_dev_ioctl,
+  .lseek_h = rtems_filesystem_default_lseek_file,
+  .fstat_h = i2c_dev_fstat,
+  .ftruncate_h = rtems_filesystem_default_ftruncate,
+  .fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
+  .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
+  .fcntl_h = rtems_filesystem_default_fcntl,
+  .kqfilter_h = rtems_filesystem_default_kqfilter,
+  .poll_h = rtems_filesystem_default_poll,
+  .readv_h = rtems_filesystem_default_readv,
+  .writev_h = rtems_filesystem_default_writev
+};
+
+static IMFS_jnode_t *i2c_dev_node_destroy(IMFS_jnode_t *node)
+{
+  i2c_dev *dev;
+
+  dev = IMFS_generic_get_context_by_node(node);
+  (*dev->destroy)(dev);
+
+  return node;
+}
+
+static const IMFS_node_control i2c_dev_node_control = {
+  .imfs_type = IMFS_GENERIC,
+  .handlers = &i2c_dev_handler,
+  .node_initialize = IMFS_node_initialize_generic,
+  .node_remove = IMFS_node_remove_default,
+  .node_destroy = i2c_dev_node_destroy
+};
+
+int i2c_dev_register(
+  i2c_dev *dev,
+  const char *dev_path
+)
+{
+  int rv;
+
+  rv = IMFS_make_generic_node(
+    dev_path,
+    S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO,
+    &i2c_dev_node_control,
+    dev
+  );
+  if (rv != 0) {
+    (*dev->destroy)(dev);
+  }
+
+  return rv;
+}
+
+static ssize_t i2c_dev_read_default(
+  i2c_dev *dev,
+  void *buf,
+  size_t n,
+  off_t offset
+)
+{
+  (void) dev;
+  (void) buf;
+  (void) n;
+  (void) offset;
+
+  return -EIO;
+}
+
+static ssize_t i2c_dev_write_default(
+  i2c_dev *dev,
+  const void *buf,
+  size_t n,
+  off_t offset
+)
+{
+  (void) dev;
+  (void) buf;
+  (void) n;
+  (void) offset;
+
+  return -EIO;
+}
+
+static int i2c_dev_ioctl_default(
+  i2c_dev *dev,
+  ioctl_command_t command,
+  void *arg
+)
+{
+  (void) dev;
+  (void) command;
+  (void) arg;
+
+  return -ENOTTY;
+}
+
+static off_t i2c_dev_get_size_default(i2c_dev *dev)
+{
+  (void) dev;
+
+  return 0;
+}
+
+static blksize_t i2c_dev_get_block_size_default(i2c_dev *dev)
+{
+  (void) dev;
+
+  return 1;
+}
+
+static int i2c_dev_do_init(
+  i2c_dev *dev,
+  const char *bus_path,
+  uint16_t address,
+  void (*destroy)(i2c_dev *dev)
+)
+{
+  int fd;
+  int rv;
+
+  fd = open(bus_path, O_RDWR);
+  if (fd < 0) {
+    (*destroy)(dev);
+
+    return -1;
+  }
+
+  rv = ioctl(fd, I2C_BUS_GET_CONTROL, &dev->bus);
+  if (rv != 0) {
+    (*destroy)(dev);
+
+    return -1;
+  }
+
+  dev->read = i2c_dev_read_default;
+  dev->write = i2c_dev_write_default;
+  dev->ioctl = i2c_dev_ioctl_default;
+  dev->get_size = i2c_dev_get_size_default;
+  dev->get_block_size = i2c_dev_get_block_size_default;
+  dev->destroy = destroy;
+  dev->bus_fd = fd;
+  dev->address = address;
+
+  return 0;
+}
+
+void i2c_dev_destroy(i2c_dev *dev)
+{
+  int rv;
+
+  rv = close(dev->bus_fd);
+  _Assert(rv == 0);
+  (void) rv;
+}
+
+void i2c_dev_destroy_and_free(i2c_dev *dev)
+{
+  i2c_dev_destroy(dev);
+  free(dev);
+}
+
+int i2c_dev_init(i2c_dev *dev, const char *bus_path, uint16_t address)
+{
+  return i2c_dev_do_init(dev, bus_path, address, i2c_dev_destroy);
+}
+
+i2c_dev *i2c_dev_alloc_and_init(
+  size_t size,
+  const char *bus_path,
+  uint16_t address
+)
+{
+  i2c_dev *dev = NULL;
+
+  if (size >= sizeof(*dev)) {
+    dev = calloc(1, size);
+    if (dev != NULL) {
+      int rv;
+
+      rv = i2c_dev_do_init(dev, bus_path, address, i2c_dev_destroy_and_free);
+      if (rv != 0) {
+        return NULL;
+      }
+    }
+  }
+
+  return dev;
+}