avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/drivers/hwmon/ds1621.c

@@ -0,0 +1,155 @@
+/*
+ * (C) Copyright 2001
+ * Erik Theisen,  Wave 7 Optics, etheisen@mindspring.com.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Dallas Semiconductor's DS1621/1631 Digital Thermometer and Thermostat.
+ */
+
+#include <common.h>
+#include <i2c.h>
+#include <dtt.h>
+
+/*
+ * Device code
+ */
+#define DTT_I2C_DEV_CODE 	0x48	/* Dallas Semi's DS1621 */
+#define DTT_READ_TEMP		0xAA
+#define DTT_READ_COUNTER	0xA8
+#define DTT_READ_SLOPE		0xA9
+#define DTT_WRITE_START_CONV	0xEE
+#define DTT_WRITE_STOP_CONV	0x22
+#define DTT_TEMP_HIGH		0xA1
+#define DTT_TEMP_LOW		0xA2
+#define DTT_CONFIG		0xAC
+
+/*
+ * Config register bits
+ */
+#define DTT_CONFIG_1SHOT	0x01
+#define DTT_CONFIG_POLARITY	0x02
+#define DTT_CONFIG_R0		0x04	/* ds1631 only */
+#define DTT_CONFIG_R1		0x08	/* ds1631 only */
+#define DTT_CONFIG_NVB		0x10
+#define DTT_CONFIG_TLF		0x20
+#define DTT_CONFIG_THF		0x40
+#define DTT_CONFIG_DONE		0x80
+
+
+int dtt_read(int sensor, int reg)
+{
+	int dlen;
+	uchar data[2];
+
+	/* Calculate sensor address and command */
+	sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1621*/
+
+	/* Prepare to handle 2 byte result */
+	switch(reg) {
+	case DTT_READ_TEMP:
+	case DTT_TEMP_HIGH:
+	case DTT_TEMP_LOW:
+		dlen = 2;
+		break;
+	default:
+		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 (short)((data[0] << 8) | data[1]);
+
+	return (int)data[0];
+}
+
+
+int dtt_write(int sensor, int reg, int val)
+{
+	int dlen;
+	uchar data[2];
+
+	/* Calculate sensor address and register */
+	sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
+
+	/* Handle various data sizes. */
+	switch(reg) {
+	case DTT_READ_TEMP:
+	case DTT_TEMP_HIGH:
+	case DTT_TEMP_LOW:
+		dlen = 2;
+		data[0] = (char)((val >> 8) & 0xff);	/* MSB first */
+		data[1] = (char)(val & 0xff);
+		break;
+	case DTT_WRITE_START_CONV:
+	case DTT_WRITE_STOP_CONV:
+		dlen = 0;
+		data[0] = (char)0;
+		data[1] = (char)0;
+		break;
+	default:
+		dlen = 1;
+		data[0] = (char)(val & 0xff);
+	}
+
+	/* Write value to device */
+	if (i2c_write(sensor, reg, 1, data, dlen) != 0)
+		return 1;
+
+	/* Poll NV memory busy bit in case write was to register stored in EEPROM */
+	while(i2c_reg_read(sensor, DTT_CONFIG) & DTT_CONFIG_NVB)
+		;
+
+	return 0;
+}
+
+
+int dtt_init_one(int sensor)
+{
+	int val;
+
+	/* Setup High Temp */
+	val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80;
+	if (dtt_write(sensor, DTT_TEMP_HIGH, val) != 0)
+		return 1;
+
+	/* Setup Low Temp - hysteresis */
+	val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
+	if (dtt_write(sensor, DTT_TEMP_LOW, val) != 0)
+		return 1;
+
+	/*
+	 * Setup configuraton register
+	 *
+	 * Clear THF & TLF, Reserved = 1, Polarity = Active Low, One Shot = YES
+	 *
+	 * We run in polled mode, since there isn't any way to know if this
+	 * lousy device is ready to provide temperature readings on power up.
+	 */
+	val = 0x9;
+	if (dtt_write(sensor, DTT_CONFIG, val) != 0)
+		return 1;
+
+	return 0;
+}
+
+int dtt_get_temp(int sensor)
+{
+	int i;
+
+	/* Start a conversion, may take up to 1 second. */
+	dtt_write(sensor, DTT_WRITE_START_CONV, 0);
+	for (i = 0; i <= 10; i++) {
+		udelay(100000);
+		if (dtt_read(sensor, DTT_CONFIG) & DTT_CONFIG_DONE)
+			break;
+	}
+
+	return (dtt_read(sensor, DTT_READ_TEMP) / 256);
+}