u-boot/drivers/hwmon/lm63.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

177 lines
3.7 KiB
C

/*
* (C) Copyright 2007-2008
* Dirk Eibach, Guntermann & Drunck GmbH, eibach@gdsys.de
* based on lm75.c by Bill Hunter
*
* 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
*/
/*
* National LM63/LM64 Temperature Sensor
* Main difference: LM 64 has -16 Kelvin temperature offset
*/
#include <common.h>
#include <i2c.h>
#include <dtt.h>
#define DTT_I2C_LM63_ADDR 0x4C /* National LM63 device */
#define DTT_READ_TEMP_RMT_MSB 0x01
#define DTT_CONFIG 0x03
#define DTT_READ_TEMP_RMT_LSB 0x10
#define DTT_TACHLIM_LSB 0x48
#define DTT_TACHLIM_MSB 0x49
#define DTT_FAN_CONFIG 0x4A
#define DTT_PWM_FREQ 0x4D
#define DTT_PWM_LOOKUP_BASE 0x50
struct pwm_lookup_entry {
u8 temp;
u8 pwm;
};
/*
* Device code
*/
int dtt_read(int sensor, int reg)
{
int dlen;
uchar data[2];
/*
* Calculate sensor address and register.
*/
if (!sensor)
sensor = DTT_I2C_LM63_ADDR; /* legacy config */
dlen = 1;
/*
* Now try to read the register.
*/
if (i2c_read(sensor, reg, 1, data, dlen) != 0)
return -1;
return (int)data[0];
} /* dtt_read() */
int dtt_write(int sensor, int reg, int val)
{
int dlen;
uchar data[2];
/*
* Calculate sensor address and register.
*/
if (!sensor)
sensor = DTT_I2C_LM63_ADDR; /* legacy config */
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 is_lm64(int sensor)
{
return sensor && (sensor != DTT_I2C_LM63_ADDR);
}
int dtt_init_one(int sensor)
{
int i;
int val;
struct pwm_lookup_entry pwm_lookup[] = CONFIG_DTT_PWM_LOOKUPTABLE;
/*
* Set PWM Frequency to 2.5% resolution
*/
val = 20;
if (dtt_write(sensor, DTT_PWM_FREQ, val) != 0)
return 1;
/*
* Set Tachometer Limit
*/
val = CONFIG_DTT_TACH_LIMIT;
if (dtt_write(sensor, DTT_TACHLIM_LSB, val & 0xff) != 0)
return 1;
if (dtt_write(sensor, DTT_TACHLIM_MSB, (val >> 8) & 0xff) != 0)
return 1;
/*
* Make sure PWM Lookup-Table is writeable
*/
if (dtt_write(sensor, DTT_FAN_CONFIG, 0x20) != 0)
return 1;
/*
* Setup PWM Lookup-Table
*/
for (i = 0; i < sizeof(pwm_lookup) / sizeof(struct pwm_lookup_entry);
i++) {
int address = DTT_PWM_LOOKUP_BASE + 2 * i;
val = pwm_lookup[i].temp;
if (is_lm64(sensor))
val -= 16;
if (dtt_write(sensor, address, val) != 0)
return 1;
val = dtt_read(sensor, address);
val = pwm_lookup[i].pwm;
if (dtt_write(sensor, address + 1, val) != 0)
return 1;
}
/*
* Enable PWM Lookup-Table, PWM Clock 360 kHz, Tachometer Mode 2
*/
val = 0x02;
if (dtt_write(sensor, DTT_FAN_CONFIG, val) != 0)
return 1;
/*
* Enable Tach input
*/
val = dtt_read(sensor, DTT_CONFIG) | 0x04;
if (dtt_write(sensor, DTT_CONFIG, val) != 0)
return 1;
return 0;
}
int dtt_get_temp(int sensor)
{
s16 temp = (dtt_read(sensor, DTT_READ_TEMP_RMT_MSB) << 8)
| (dtt_read(sensor, DTT_READ_TEMP_RMT_LSB));
if (is_lm64(sensor))
temp += 16 << 8;
/* Ignore LSB for now, U-Boot only prints natural numbers */
return temp >> 8;
}