diff options
Diffstat (limited to 'drivers/hwmon/ds1722.c')
-rw-r--r-- | drivers/hwmon/ds1722.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/hwmon/ds1722.c b/drivers/hwmon/ds1722.c new file mode 100644 index 0000000000..c19ee01393 --- /dev/null +++ b/drivers/hwmon/ds1722.c @@ -0,0 +1,142 @@ + +#include <common.h> + +#ifdef CONFIG_DS1722 + +#include <ssi.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; +} + +#endif |