780f13a9e1
The U-Boot Design Principles[1] clearly say: Initialize devices only when they are needed within U-Boot, i.e. don't initialize the Ethernet interface(s) unless U-Boot performs a download over Ethernet; don't initialize any IDE or USB devices unless U-Boot actually tries to load files from these, etc. (and don't forget to shut down these devices after using them - otherwise nasty things may happen when you try to boot your OS). So, do not initialize and read the sensors on startup. Signed-off-by: Heiko Schocher <hs@denx.de> cc: Wolfgang Denk <wd@denx.de> cc: Holger Brunck <holger.brunck@keymile.com>
160 lines
3.8 KiB
C
160 lines
3.8 KiB
C
/*
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* (C) Copyright 2001
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* Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* On Semiconductor's LM75 Temperature Sensor
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*/
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#include <common.h>
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#include <i2c.h>
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#include <dtt.h>
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/*
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* Device code
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*/
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#if defined(CONFIG_SYS_I2C_DTT_ADDR)
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#define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR
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#else
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#define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */
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#endif
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#define DTT_READ_TEMP 0x0
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#define DTT_CONFIG 0x1
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#define DTT_TEMP_HYST 0x2
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#define DTT_TEMP_SET 0x3
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int dtt_read(int sensor, int reg)
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{
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int dlen;
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uchar data[2];
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#ifdef CONFIG_DTT_AD7414
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/*
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* On AD7414 the first value upon bootup is not read correctly.
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* This is most likely because of the 800ms update time of the
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* temp register in normal update mode. To get current values
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* each time we issue the "dtt" command including upon powerup
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* we switch into one-short mode.
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*
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* Issue one-shot mode command
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*/
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dtt_write(sensor, DTT_CONFIG, 0x64);
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#endif
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/* Validate 'reg' param */
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if((reg < 0) || (reg > 3))
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return -1;
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/* Calculate sensor address and register. */
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sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
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/* Prepare to handle 2 byte result. */
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if ((reg == DTT_READ_TEMP) ||
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(reg == DTT_TEMP_HYST) ||
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(reg == DTT_TEMP_SET))
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dlen = 2;
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else
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dlen = 1;
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/* Now try to read the register. */
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if (i2c_read(sensor, reg, 1, data, dlen) != 0)
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return -1;
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/* Handle 2 byte result. */
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if (dlen == 2)
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return ((int)((short)data[1] + (((short)data[0]) << 8)));
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return (int)data[0];
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} /* dtt_read() */
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int dtt_write(int sensor, int reg, int val)
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{
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int dlen;
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uchar data[2];
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/* Validate 'reg' param */
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if ((reg < 0) || (reg > 3))
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return 1;
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/* Calculate sensor address and register. */
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sensor = DTT_I2C_DEV_CODE + (sensor & 0x07);
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/* Handle 2 byte values. */
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if ((reg == DTT_READ_TEMP) ||
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(reg == DTT_TEMP_HYST) ||
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(reg == DTT_TEMP_SET)) {
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dlen = 2;
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data[0] = (char)((val >> 8) & 0xff); /* MSB first */
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data[1] = (char)(val & 0xff);
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} else {
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dlen = 1;
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data[0] = (char)(val & 0xff);
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}
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/* Write value to register. */
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if (i2c_write(sensor, reg, 1, data, dlen) != 0)
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return 1;
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return 0;
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} /* dtt_write() */
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int dtt_init_one(int sensor)
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{
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int val;
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/* Setup TSET ( trip point ) register */
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val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
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if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
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return 1;
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/* Setup THYST ( untrip point ) register - Hysteresis */
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val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
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if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
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return 1;
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/* Setup configuraton register */
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#ifdef CONFIG_DTT_AD7414
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/* config = alert active low and disabled */
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val = 0x60;
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#else
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/* config = 6 sample integration, int mode, active low, and enable */
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val = 0x18;
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#endif
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if (dtt_write(sensor, DTT_CONFIG, val) != 0)
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return 1;
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return 0;
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} /* dtt_init_one() */
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int dtt_get_temp(int sensor)
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{
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int const ret = dtt_read(sensor, DTT_READ_TEMP);
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if (ret < 0) {
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printf("DTT temperature read failed.\n");
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return 0;
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}
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return (int)((int16_t) ret / 256);
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} /* dtt_get_temp() */
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