Initial revision

1 files changed, 181 insertions, 0 deletions

diff --git a/dtt/lm75.c b/dtt/lm75.c
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+/*
+ * (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
+ */
+
+/*
+ * On Semiconductor's LM75 Temperature Sensor
+ */
+
+#include <common.h>
+
+#ifdef CONFIG_DTT_LM75
+#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_LM75"
+#endif
+
+#include <i2c.h>
+#include <dtt.h>
+
+
+/*
+ * Device code
+ */
+#define DTT_I2C_DEV_CODE 0x48			/* ON Semi's LM75 device */
+
+int dtt_read(int sensor, int reg)
+{
+    int dlen;
+    uchar data[2];
+
+    /*
+     * Validate 'reg' param
+     */
+    if((reg < 0) || (reg > 3))
+	return -1;
+
+    /*
+     * Calculate sensor address and register.
+     */
+    sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
+
+    /*
+     * Prepare to handle 2 byte result.
+     */
+    if ((reg == DTT_READ_TEMP) ||
+	(reg == DTT_TEMP_HYST) ||
+	(reg == DTT_TEMP_SET))
+	dlen = 2;
+    else
+	dlen = 1;
+
+    /*
+     * Now try to read the register.
+     */
+    if (i2c_read(sensor, reg, 1, data, dlen) != 0)
+	return -1;
+
+    /*
+     * Handle 2 byte result.
+     */
+    if (dlen == 2)
+	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
+     */
+    if ((reg < 0) || (reg > 3))
+	return 1;
+
+    /*
+     * Calculate sensor address and register.
+     */
+    sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
+
+    /*
+     * Handle 2 byte values.
+     */
+    if ((reg == DTT_READ_TEMP) ||
+	(reg == DTT_TEMP_HYST) ||
+	(reg == DTT_TEMP_SET)) {
+	dlen = 2;
+	data[0] = (char)((val >> 8) & 0xff);	/* MSB first */
+	data[1] = (char)(val & 0xff);
+    } else {
+	dlen = 1;
+	data[0] = (char)(val & 0xff);
+    }
+
+    /*
+     * Write value to register.
+     */
+    if (i2c_write(sensor, reg, 1, data, dlen) != 0)
+	return 1;
+
+    return 0;
+} /* dtt_write() */
+
+
+static int _dtt_init(int sensor)
+{
+    int val;
+
+    /*
+     * Setup TSET ( trip point ) register
+     */
+    val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
+    if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
+	return 1;
+
+    /*
+     * Setup THYST ( untrip point ) register - Hysteresis
+     */
+    val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
+    if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
+	return 1;
+
+    /*
+     * Setup configuraton register
+     */
+    /* config = 6 sample integration, int mode, active low, and enable */
+    val = 0x18;
+    if (dtt_write(sensor, DTT_CONFIG, val) != 0)
+	return 1;
+
+    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) / 256);
+} /* dtt_get_temp() */
+
+#endif /* CONFIG_DTT_LM75 */
+