1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/ds1722.c b/drivers/ds1722.c
new file mode 100644
index 0000000..34eb80c
--- /dev/null
+++ b/drivers/ds1722.c
@@ -0,0 +1,142 @@
+
+#include <common.h>
+
+#include <ssi.h>
+
+#ifdef CONFIG_DS1722
+
+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