Add driver for National Semiconductor LM73 temperature sensor

This driver is based on the driver for the LM75.

Signed-off-by: Larry Johnson <lrj@acm.org>

drivers/hwmon/Makefile

@@ -34,6 +34,7 @@ COBJS-y += adm1021.o
 COBJS-y += ds1621.o
 COBJS-y += ds1722.o
 COBJS-y += ds1775.o
+COBJS-y += lm73.o
 COBJS-y += lm75.o
 COBJS-y += lm81.o
 

drivers/hwmon/lm73.c

@@ -0,0 +1,181 @@
+/*
+ * (C) Copyright 2007
+ * Larry Johnson, lrj@acm.org
+ *
+ * based on dtt/lm75.c which is ...
+ *
+ * (C) Copyright 2001
+ * Bill Hunter,  Wave 7 Optics, williamhunter@mediaone.net
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * National Semiconductor LM73 Temperature Sensor
+ */
+
+#include <common.h>
+
+#ifdef CONFIG_DTT_LM73
+#if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \
+	(CFG_EEPROM_PAGE_WRITE_BITS < 1)
+# error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than  1 to use CONFIG_DTT_LM73"
+#endif
+
+#include <i2c.h>
+#include <dtt.h>
+
+/*
+ * Device code
+ */
+#define DTT_I2C_DEV_CODE 0x48	/* National Semi's LM73 device */
+
+int dtt_read(int sensor, int reg)
+{
+	int dlen;
+	uchar data[2];
+
+	/*
+	 * Validate 'reg' param and get register size.
+	 */
+	switch (reg) {
+	case DTT_CONFIG:
+	case DTT_CONTROL:
+		dlen = 1;
+		break;
+	case DTT_READ_TEMP:
+	case DTT_TEMP_HIGH:
+	case DTT_TEMP_LOW:
+	case DTT_ID:
+		dlen = 2;
+		break;
+	default:
+		return -1;
+	}
+	/*
+	 * Calculate sensor address and register.
+	 */
+	sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);	/* calculate LM73 addr */
+	/*
+	 * Now try to read the register.
+	 */
+	if (i2c_read(sensor, reg, 1, data, dlen) != 0)
+		return -1;
+	/*
+	 * Handle 2 byte result.
+	 */
+	if (2 == dlen)
+		return ((int)((short)data[1] + (((short)data[0]) << 8)));
+
+	return (int)data[0];
+} /* dtt_read() */
+
+int dtt_write(int sensor, int reg, int val)
+{
+	int dlen;
+	uchar data[2];
+
+	/*
+	 * Validate 'reg' param and handle register size
+	 */
+	switch (reg) {
+	case DTT_CONFIG:
+	case DTT_CONTROL:
+		dlen = 1;
+		data[0] = (char)(val & 0xff);
+		break;
+	case DTT_TEMP_HIGH:
+	case DTT_TEMP_LOW:
+		dlen = 2;
+		data[0] = (char)((val >> 8) & 0xff);	/* MSB first */
+		data[1] = (char)(val & 0xff);
+		break;
+	default:
+		return -1;
+	}
+	/*
+	 * Calculate sensor address and register.
+	 */
+	sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);	/* calculate LM73 addr */
+	/*
+	 * Write value to register.
+	 */
+	return i2c_write(sensor, reg, 1, data, dlen) != 0;
+} /* dtt_write() */
+
+static int _dtt_init(int sensor)
+{
+	int val;
+
+	/*
+	 * Validate the Identification register
+	 */
+	if (0x0190 != dtt_read(sensor, DTT_ID))
+		return 1;
+	/*
+	 * Setup THIGH (upper-limit) and TLOW (lower-limit) registers
+	 */
+	val = CFG_DTT_MAX_TEMP << 7;
+	if (dtt_write(sensor, DTT_TEMP_HIGH, val))
+		return 1;
+
+	val = CFG_DTT_MIN_TEMP << 7;
+	if (dtt_write(sensor, DTT_TEMP_LOW, val))
+		return 1;
+	/*
+	 * Setup configuraton register
+	 */
+	/* config = alert active low, disabled, and reset */
+	val = 0x64;
+	if (dtt_write(sensor, DTT_CONFIG, val))
+		return 1;
+	/*
+	 * Setup control/status register
+	 */
+	/* control = temp resolution 0.25C */
+	val = 0x00;
+	if (dtt_write(sensor, DTT_CONTROL, val))
+		return 1;
+
+	dtt_read(sensor, DTT_CONTROL);	/* clear temperature flags */
+	return 0;
+} /* _dtt_init() */
+
+int dtt_init(void)
+{
+	int i;
+	unsigned char sensors[] = CONFIG_DTT_SENSORS;
+	const char *const header = "DTT:   ";
+
+	for (i = 0; i < sizeof(sensors); i++) {
+		if (_dtt_init(sensors[i]) != 0)
+			printf("%s%d FAILED INIT\n", header, i + 1);
+		else
+			printf("%s%d is %i C\n", header, i + 1,
+			       dtt_get_temp(sensors[i]));
+	}
+	return 0;
+} /* dtt_init() */
+
+int dtt_get_temp(int sensor)
+{
+	return (dtt_read(sensor, DTT_READ_TEMP) + 0x0040) >> 7;
+} /* dtt_get_temp() */
+
+#endif /* CONFIG_DTT_LM73 */

include/dtt.h

@@ -31,7 +31,8 @@
     defined(CONFIG_DTT_DS1621) || \
     defined(CONFIG_DTT_DS1775) || \
     defined(CONFIG_DTT_LM81) || \
-    defined(CONFIG_DTT_ADM1021)
+    defined(CONFIG_DTT_ADM1021) || \
+    defined(CONFIG_DTT_LM73)
 
 #define CONFIG_DTT				/* We have a DTT */
 
@@ -119,4 +120,13 @@ extern int dtt_get_temp(int sensor);
 #define DTT_ADM1021_DEVID	0x41
 #endif
 
+#if defined(CONFIG_DTT_LM73)
+#define DTT_READ_TEMP		0x0
+#define DTT_CONFIG		0x1
+#define DTT_TEMP_HIGH		0x2
+#define DTT_TEMP_LOW		0x3
+#define DTT_CONTROL		0x4
+#define DTT_ID			0x7
+#endif
+
 #endif /* _DTT_H_ */