u-boot/drivers/hwmon/adt7460.c
Heiko Schocher 780f13a9e1 hwmon: do not init sensors on startup
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>
2011-08-04 23:30:38 +02:00

83 lines
1.9 KiB
C

/*
* (C) Copyright 2008
* Ricado Ribalda-Universidad Autonoma de Madrid, ricardo.ribalda@uam.es
* This work has been supported by: QTechnology http://qtec.com/
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <common.h>
#include <i2c.h>
#include <dtt.h>
#define ADT7460_ADDRESS 0x2c
#define ADT7460_INVALID 128
#define ADT7460_CONFIG 0x40
#define ADT7460_REM1_TEMP 0x25
#define ADT7460_LOCAL_TEMP 0x26
#define ADT7460_REM2_TEMP 0x27
int dtt_read(int sensor, int reg)
{
u8 dir = reg;
u8 data;
if (i2c_read(ADT7460_ADDRESS, dir, 1, &data, 1) == -1)
return -1;
if (data == ADT7460_INVALID)
return -1;
return data;
}
int dtt_write(int sensor, int reg, int val)
{
u8 dir = reg;
u8 data = val;
if (i2c_write(ADT7460_ADDRESS, dir, 1, &data, 1) == -1)
return -1;
return 0;
}
int dtt_init_one(int sensor)
{
printf("ADT7460 at I2C address 0x%2x\n", ADT7460_ADDRESS);
if (dtt_write(0, ADT7460_CONFIG, 1) == -1) {
puts("Error initialiting ADT7460\n");
return -1;
}
return 0;
}
int dtt_get_temp(int sensor)
{
int aux;
u8 table[] =
{ ADT7460_REM1_TEMP, ADT7460_LOCAL_TEMP, ADT7460_REM2_TEMP };
if (sensor > 2) {
puts("DTT sensor does not exist\n");
return -1;
}
aux = dtt_read(0, table[sensor]);
if (aux == -1) {
puts("DTT temperature read failed\n");
return -1;
}
return aux;
}