#include <common.h> | |
#include <asm/ic/ssi.h> | |
#include <ds1722.h> | |
static void ds1722_select(int dev) | |
{ | |
ssi_set_interface(4096, 0, 0, 0); | |
ssi_chip_select(0); | |
udelay(1); | |
ssi_chip_select(dev); | |
udelay(1); | |
} | |
u8 ds1722_read(int dev, int addr) | |
{ | |
u8 res; | |
ds1722_select(dev); | |
ssi_tx_byte(addr); | |
res = ssi_rx_byte(); | |
ssi_chip_select(0); | |
return res; | |
} | |
void ds1722_write(int dev, int addr, u8 data) | |
{ | |
ds1722_select(dev); | |
ssi_tx_byte(0x80|addr); | |
ssi_tx_byte(data); | |
ssi_chip_select(0); | |
} | |
u16 ds1722_temp(int dev, int resolution) | |
{ | |
static int useconds[] = { | |
75000, 150000, 300000, 600000, 1200000 | |
}; | |
char temp; | |
u16 res; | |
/* set up the desired resulotion ... */ | |
ds1722_write(dev, 0, 0xe0 | (resolution << 1)); | |
/* wait while the chip measures the tremperature */ | |
udelay(useconds[resolution]); | |
res = (temp = ds1722_read(dev, 2)) << 8; | |
if (temp < 0) { | |
temp = (16 - (ds1722_read(dev, 1) >> 4)) & 0x0f; | |
} else { | |
temp = (ds1722_read(dev, 1) >> 4); | |
} | |
switch (temp) { | |
case 0: | |
/* .0000 */ | |
break; | |
case 1: | |
/* .0625 */ | |
res |=1; | |
break; | |
case 2: | |
/* .1250 */ | |
res |=1; | |
break; | |
case 3: | |
/* .1875 */ | |
res |=2; | |
break; | |
case 4: | |
/* .2500 */ | |
res |=3; | |
break; | |
case 5: | |
/* .3125 */ | |
res |=3; | |
break; | |
case 6: | |
/* .3750 */ | |
res |=4; | |
break; | |
case 7: | |
/* .4375 */ | |
res |=4; | |
break; | |
case 8: | |
/* .5000 */ | |
res |=5; | |
break; | |
case 9: | |
/* .5625 */ | |
res |=6; | |
break; | |
case 10: | |
/* .6250 */ | |
res |=6; | |
break; | |
case 11: | |
/* .6875 */ | |
res |=7; | |
break; | |
case 12: | |
/* .7500 */ | |
res |=8; | |
break; | |
case 13: | |
/* .8125 */ | |
res |=8; | |
break; | |
case 14: | |
/* .8750 */ | |
res |=9; | |
break; | |
case 15: | |
/* .9375 */ | |
res |=9; | |
break; | |
} | |
return res; | |
} | |
int ds1722_probe(int dev) | |
{ | |
u16 temp = ds1722_temp(dev, DS1722_RESOLUTION_12BIT); | |
printf("%d.%d deg C\n\n", (char)(temp >> 8), temp & 0xff); | |
return 0; | |
} |