2005-11-02 straumanatslacdotstanford.edu

	* libchip/i2c/i2c-2b-eeprom.c, libchip/i2c/i2c-2b-eeprom.h,
	libchip/i2c/i2c-ds1621.c, libchip/i2c/i2c-ds1621.h: New files.
	* libchip/Makefile.am, libchip/preinstall.am, wrapup/Makefile.am:
    added a simple API/library
	for i2c devices and drivers for i2c 2-byte eeproms and a ds1621
	temperature sensor; API is documented in libi2c.h

6 files changed, 307 insertions, 0 deletions

diff --git a/c/src/libchip/Makefile.am b/c/src/libchip/Makefile.am
index c4994535aa..90284212b8 100644
--- a/c/src/libchip/Makefile.am
+++ b/c/src/libchip/Makefile.am
@@ -62,6 +62,15 @@ endif
 EXTRA_DIST += rtc/README.ds1643 rtc/README.icm7170 rtc/README.m48t08 \
     rtc/README.m48t18 rtc/STATUS
 
+# i2c
+if LIBCHIP
+include_libchip_HEADERS += i2c/i2c-ds1621.h i2c/i2c-2b-eeprom.h
+
+noinst_LIBRARIES += libi2cio.a
+libi2cio_a_CPPFLAGS = $(AM_CPPFLAGS)
+libi2cio_a_SOURCES  = i2c/i2c-ds1621.c i2c/i2c-2b-eeprom.c
+endif
+
 # serial
 if LIBCHIP
 include_libchip_HEADERS += serial/mc68681.h serial/ns16550.h serial/z85c30.h \
diff --git a/c/src/libchip/i2c/i2c-2b-eeprom.c b/c/src/libchip/i2c/i2c-2b-eeprom.c
new file mode 100644
index 0000000000..c24463f5d5
--- /dev/null
+++ b/c/src/libchip/i2c/i2c-2b-eeprom.c
@@ -0,0 +1,132 @@
+/* $Id$ */
+
+/* Trivial i2c driver for reading "2-byte eeproms".
+ * On 'open' the read-pointer is reset to 0, subsequent
+ * read operations slurp data from there...
+ */
+
+/* Author: Till Straumann, 2005 */
+
+
+#include <rtems.h>
+#include <rtems/libi2c.h>
+
+#include <libchip/i2c-2b-eeprom.h>
+#include <rtems/libio.h>
+
+#define EEPROM_PG_SZ	32
+#define ALGN(x)	(((unsigned32)(x) + EEPROM_PG_SZ) & ~(EEPROM_PG_SZ-1))
+
+static rtems_status_code
+send_file_ptr (rtems_device_minor_number minor, unsigned pos, int tout)
+{
+  int sc;
+  unsigned char bytes[2];
+
+  bytes[0] = (pos >> 8) & 0xff;
+  bytes[1] = (pos) & 0xff;
+
+  /* poll addressing the next page; if 'tout' is <=0 we only try once
+   * and return the status. If 'tout' is positive, we try 'tout' times
+   * and return RTEMS_TIMEOUT if it didnt work
+   */
+  while ((sc = rtems_libi2c_start_write_bytes (minor, bytes, 2)) < 0) {
+    if (--tout <= 0)
+      return tout ? -sc : RTEMS_TIMEOUT;
+    rtems_task_wake_after (1);
+  }
+  return RTEMS_SUCCESSFUL;
+}
+
+static rtems_status_code
+i2c_2b_eeprom_write (rtems_device_major_number major,
+                     rtems_device_minor_number minor, void *arg)
+{
+  rtems_libio_rw_args_t *rwargs = arg;
+  unsigned off = rwargs->offset;
+  int cnt = rwargs->count;
+  char *buf = rwargs->buffer;
+  int sc;
+  unsigned end;
+  int l;
+
+  if (cnt <= 0)
+    return RTEMS_SUCCESSFUL;
+
+  if ((sc = send_file_ptr (minor, off, 0)))
+    return sc;
+
+  do {
+    /* write up to next page boundary */
+    end = ALGN (off);
+    l = end - off;
+    if (l > cnt)
+      l = cnt;
+
+    sc = rtems_libi2c_write_bytes (minor, buf, l);
+    if (sc < 0)
+      return -sc;
+
+    sc = rtems_libi2c_send_stop (minor);
+    if (sc)
+      return sc;
+
+    rwargs->bytes_moved += l;
+
+    buf += l;
+    cnt -= l;
+    off += l;
+
+    /* poll addressing the next page */
+    if ((sc = send_file_ptr (minor, off, 100)))
+      return sc;
+
+  } while (cnt > 0);
+
+  return rtems_libi2c_send_stop (minor);
+}
+
+static rtems_status_code
+i2c_2b_eeprom_read (rtems_device_major_number major,
+                    rtems_device_minor_number minor, void *arg)
+{
+  int sc;
+  rtems_libio_rw_args_t *rwargs = arg;
+
+  if (RTEMS_SUCCESSFUL != (sc = send_file_ptr (minor, rwargs->offset, 0)))
+    return -sc;
+
+  sc = rtems_libi2c_start_read_bytes (minor, rwargs->buffer, rwargs->count);
+
+  if (sc < 0) {
+    rwargs->bytes_moved = 0;
+    return -sc;
+  }
+  rwargs->bytes_moved = sc;
+
+  return rtems_libi2c_send_stop (minor);
+}
+
+static rtems_driver_address_table myops = {
+  read_entry:  i2c_2b_eeprom_read,
+  write_entry: i2c_2b_eeprom_write,
+};
+
+static rtems_libi2c_drv_t my_drv_tbl = {
+  ops:         &myops,
+  size:        sizeof (my_drv_tbl),
+};
+
+/* provide a second table for R/O access */
+static rtems_driver_address_table my_ro_ops = {
+  read_entry:  i2c_2b_eeprom_read,
+};
+
+static rtems_libi2c_drv_t my_ro_drv_tbl = {
+  ops:         &my_ro_ops,
+  size:        sizeof (my_ro_drv_tbl),
+};
+
+
+rtems_libi2c_drv_t *i2c_2b_eeprom_driver_descriptor = &my_drv_tbl;
+rtems_libi2c_drv_t *i2c_2b_eeprom_ro_driver_descriptor = &my_ro_drv_tbl;
diff --git a/c/src/libchip/i2c/i2c-2b-eeprom.h b/c/src/libchip/i2c/i2c-2b-eeprom.h
new file mode 100644
index 0000000000..e5c72554c3
--- /dev/null
+++ b/c/src/libchip/i2c/i2c-2b-eeprom.h
@@ -0,0 +1,32 @@
+/* $Id$ */
+#ifndef I2C_2B_EEPROM_DRIVER_H
+#define I2C_2B_EEPROM_DRIVER_H
+
+/* Trivial i2c driver for reading and writing "2-byte eeproms".
+ * On 'open' the file-pointer is reset to 0, subsequent
+ * read/write operations slurp/write data from there...
+ */
+
+/* Author: Till Straumann, 2005 */
+
+
+#include <rtems.h>
+#include <rtems/libi2c.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* pass one of these to rtems_libi2c_register_drv() */
+
+/* These ops provide no write access */
+extern rtems_libi2c_drv_t *i2c_2b_eeprom_ro_driver_descriptor;
+
+/* Use these for writing and reading */
+extern rtems_libi2c_drv_t *i2c_2b_eeprom_driver_descriptor;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/c/src/libchip/i2c/i2c-ds1621.c b/c/src/libchip/i2c/i2c-ds1621.c
new file mode 100644
index 0000000000..fc76e83750
--- /dev/null
+++ b/c/src/libchip/i2c/i2c-ds1621.c
@@ -0,0 +1,87 @@
+/* $Id$ */
+
+/* Trivial i2c driver for the maxim DS1621 temperature sensor;
+ * just implements reading constant conversions with 8-bit
+ * resolution.
+ * Demonstrates the implementation of a i2c high-level driver.
+ */
+
+/* Author: Till Straumann, 2005 */
+#include <rtems.h>
+#include <rtems/libi2c.h>
+
+#include <libchip/i2c-ds1621.h>
+
+#include <rtems/libio.h>
+
+
+static rtems_status_code
+ds1621_init (rtems_device_major_number major, rtems_device_minor_number minor,
+             void *arg)
+{
+  int sc;
+  char csr[2] = { DS1621_CMD_CSR_ACCESS, 0 }, cmd;
+
+  /* First start command acquires a lock for the bus */
+
+  /* Initialize; switch continuous conversion on */
+  sc = rtems_libi2c_start_write_bytes (minor, csr, 1);
+  if (sc < 0)
+    return -sc;
+
+  sc = rtems_libi2c_start_read_bytes (minor, csr + 1, 1);
+  if (sc < 0)
+    return -sc;
+
+  csr[1] &= ~DS1621_CSR_1SHOT;
+
+  sc = rtems_libi2c_start_write_bytes (minor, csr, 2);
+  if (sc < 0)
+    return -sc;
+
+  /* Start conversion */
+  cmd = DS1621_CMD_START_CONV;
+
+  sc = rtems_libi2c_start_write_bytes (minor, &cmd, 1);
+  if (sc < 0)
+    return -sc;
+
+  /* sending 'stop' relinquishes the bus mutex -- don't hold it
+   * across system calls!
+   */
+  return rtems_libi2c_send_stop (minor);
+}
+
+static rtems_status_code
+ds1621_read (rtems_device_major_number major, rtems_device_minor_number minor,
+             void *arg)
+{
+  int sc;
+  rtems_libio_rw_args_t *rwargs = arg;
+  char cmd = DS1621_CMD_READ_TEMP;
+
+  sc = rtems_libi2c_start_write_bytes (minor, &cmd, 1);
+  if (sc < 0)
+    return -sc;
+  if (sc < 1)
+    return RTEMS_IO_ERROR;
+  sc = rtems_libi2c_start_read_bytes (minor, rwargs->buffer, 1);
+  if (sc < 0) {
+    rwargs->bytes_moved = 0;
+    return -sc;
+  }
+  rwargs->bytes_moved = 1;
+  return rtems_libi2c_send_stop (minor);
+}
+
+static rtems_driver_address_table myops = {
+  initialization_entry: ds1621_init,
+  read_entry:           ds1621_read,
+};
+
+static rtems_libi2c_drv_t my_drv_tbl = {
+  ops:                  &myops,
+  size:                 sizeof (my_drv_tbl),
+};
+
+rtems_libi2c_drv_t *i2c_ds1621_driver_descriptor = &my_drv_tbl;
diff --git a/c/src/libchip/i2c/i2c-ds1621.h b/c/src/libchip/i2c/i2c-ds1621.h
new file mode 100644
index 0000000000..802af03727
--- /dev/null
+++ b/c/src/libchip/i2c/i2c-ds1621.h
@@ -0,0 +1,39 @@
+/* $Id$ */
+#ifndef I2C_DS_1621_DRIVER_H
+#define I2C_DS_1621_DRIVER_H
+
+/* Trivial i2c driver for the maxim DS1621 temperature sensor;
+ * just implements reading constant conversions with 8-bit
+ * resolution.
+ * Demonstrates the implementation of a i2c high-level driver.
+ */
+
+/* Author: Till Straumann, 2005 */
+
+#define DS1621_CMD_READ_TEMP 	0xaa
+#define	DS1621_CMD_CSR_ACCESS	0xac
+#define DS1621_CMD_START_CONV	0xee
+
+/* CSR bits */
+#define DS1621_CSR_DONE			(1<<7)
+#define DS1621_CSR_TEMP_HI		(1<<6)  /* T >= hi register */
+#define DS1621_CSR_TEMP_LO		(1<<5)  /* T <= lo register */
+#define DS1621_CSR_NVMEM_BSY	(1<<4)  /* non-volatile memory busy */
+#define DS1621_CSR_OUT_POL		(1<<1)  /* Thermostat output active polarity */
+#define DS1621_CSR_1SHOT		(1<<0)  /* Oneshot mode     */
+
+#include <rtems.h>
+#include <rtems/libi2c.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* for registration with libi2c */
+extern rtems_libi2c_drv_t *i2c_ds1621_driver_descriptor;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/c/src/libchip/preinstall.am b/c/src/libchip/preinstall.am
index 3e5c1947bf..c563522367 100644
--- a/c/src/libchip/preinstall.am
+++ b/c/src/libchip/preinstall.am
@@ -77,6 +77,14 @@ $(PROJECT_INCLUDE)/libchip/rtc.h: rtc/rtc.h $(PROJECT_INCLUDE)/libchip/$(dirstam
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/libchip/rtc.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/libchip/rtc.h
 
+$(PROJECT_INCLUDE)/libchip/i2c-ds1621.h: i2c/i2c-ds1621.h $(PROJECT_INCLUDE)/libchip/$(dirstamp)
+	$(INSTALL_DATA) $< $@
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/libchip/i2c-ds1621.h
+
+$(PROJECT_INCLUDE)/libchip/i2c-2b-eeprom.h: i2c/i2c-2b-eeprom.h $(PROJECT_INCLUDE)/libchip/$(dirstamp)
+	$(INSTALL_DATA) $< $@
+PREINSTALL_FILES += $(PROJECT_INCLUDE)/libchip/i2c-2b-eeprom.h
+
 $(PROJECT_INCLUDE)/libchip/icm7170.h: rtc/icm7170.h $(PROJECT_INCLUDE)/libchip/$(dirstamp)
 	$(INSTALL_DATA) $< $(PROJECT_INCLUDE)/libchip/icm7170.h
 PREINSTALL_FILES += $(PROJECT_INCLUDE)/libchip/icm7170.h