mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-11 15:37:23 +00:00
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>
127 lines
3 KiB
C
127 lines
3 KiB
C
/*
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* (C) Copyright 2006
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* Heiko Schocher, DENX Software Enginnering <hs@denx.de>
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*
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* based on dtt/lm75.c which is ...
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*
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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 LM81 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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#define DTT_I2C_DEV_CODE 0x2c /* ON Semi's LM81 device */
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#define DTT_READ_TEMP 0x27
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#define DTT_CONFIG_TEMP 0x4b
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#define DTT_TEMP_MAX 0x39
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#define DTT_TEMP_HYST 0x3a
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#define DTT_CONFIG 0x40
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int dtt_read(int sensor, int reg)
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{
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int dlen = 1;
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uchar data[2];
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/*
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* Calculate sensor address and register.
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*/
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sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
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/*
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* Now try to read the register.
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*/
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if (i2c_read(sensor, reg, 1, data, dlen) != 0)
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return -1;
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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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uchar data;
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/*
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* Calculate sensor address and register.
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*/
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sensor = DTT_I2C_DEV_CODE + (sensor & 0x03); /* calculate address of lm81 */
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data = (char)(val & 0xff);
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/*
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* Write value to register.
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*/
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if (i2c_write(sensor, reg, 1, &data, 1) != 0)
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return 1;
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return 0;
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} /* dtt_write() */
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#define DTT_MANU 0x3e
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#define DTT_REV 0x3f
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#define DTT_CONFIG 0x40
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#define DTT_ADR 0x48
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int dtt_init_one(int sensor)
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{
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int man;
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int adr;
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int rev;
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if (dtt_write (sensor, DTT_CONFIG, 0x01) < 0)
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return 1;
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/* The LM81 needs 400ms to get the correct values ... */
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udelay (400000);
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man = dtt_read (sensor, DTT_MANU);
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if (man != 0x01)
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return 1;
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adr = dtt_read (sensor, DTT_ADR);
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if (adr < 0)
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return 1;
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rev = dtt_read (sensor, DTT_REV);
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if (adr < 0)
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return 1;
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debug ("DTT: Found LM81@%x Rev: %d\n", adr, rev);
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return 0;
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} /* dtt_init_one() */
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#define TEMP_FROM_REG(temp) \
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((temp)<256?((((temp)&0x1fe) >> 1) * 10) + ((temp) & 1) * 5: \
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((((temp)&0x1fe) >> 1) -255) * 10 - ((temp) & 1) * 5) \
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int dtt_get_temp(int sensor)
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{
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int val = dtt_read (sensor, DTT_READ_TEMP);
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int tmpcnf = dtt_read (sensor, DTT_CONFIG_TEMP);
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return (TEMP_FROM_REG((val << 1) + ((tmpcnf & 0x80) >> 7))) / 10;
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} /* dtt_get_temp() */
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