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path: root/drivers/w1/w1_io.c
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Diffstat (limited to 'drivers/w1/w1_io.c')
-rw-r--r--drivers/w1/w1_io.c70
1 files changed, 61 insertions, 9 deletions
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 298ee8b7254..2173336b60a 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -55,15 +55,29 @@ void w1_delay(unsigned long tm)
udelay(tm * w1_delay_parm);
}
+static void w1_write_bit(struct w1_master *dev, int bit);
+static u8 w1_read_bit(struct w1_master *dev);
+
+/**
+ * Generates a write-0 or write-1 cycle and samples the level.
+ */
u8 w1_touch_bit(struct w1_master *dev, int bit)
{
if (dev->bus_master->touch_bit)
return dev->bus_master->touch_bit(dev->bus_master->data, bit);
- else
+ else if (bit)
return w1_read_bit(dev);
+ else {
+ w1_write_bit(dev, 0);
+ return(0);
+ }
}
-void w1_write_bit(struct w1_master *dev, int bit)
+/**
+ * Generates a write-0 or write-1 cycle.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static void w1_write_bit(struct w1_master *dev, int bit)
{
if (bit) {
dev->bus_master->write_bit(dev->bus_master->data, 0);
@@ -78,6 +92,12 @@ void w1_write_bit(struct w1_master *dev, int bit)
}
}
+/**
+ * Writes 8 bits.
+ *
+ * @param dev the master device
+ * @param byte the byte to write
+ */
void w1_write_8(struct w1_master *dev, u8 byte)
{
int i;
@@ -86,10 +106,15 @@ void w1_write_8(struct w1_master *dev, u8 byte)
dev->bus_master->write_byte(dev->bus_master->data, byte);
else
for (i = 0; i < 8; ++i)
- w1_write_bit(dev, (byte >> i) & 0x1);
+ w1_touch_bit(dev, (byte >> i) & 0x1);
}
-u8 w1_read_bit(struct w1_master *dev)
+
+/**
+ * Generates a write-1 cycle and samples the level.
+ * Only call if dev->bus_master->touch_bit is NULL
+ */
+static u8 w1_read_bit(struct w1_master *dev)
{
int result;
@@ -104,6 +129,12 @@ u8 w1_read_bit(struct w1_master *dev)
return result & 0x1;
}
+/**
+ * Reads 8 bits.
+ *
+ * @param dev the master device
+ * @return the byte read
+ */
u8 w1_read_8(struct w1_master * dev)
{
int i;
@@ -113,12 +144,20 @@ u8 w1_read_8(struct w1_master * dev)
res = dev->bus_master->read_byte(dev->bus_master->data);
else
for (i = 0; i < 8; ++i)
- res |= (w1_read_bit(dev) << i);
+ res |= (w1_touch_bit(dev,1) << i);
return res;
}
-void w1_write_block(struct w1_master *dev, u8 *buf, int len)
+/**
+ * Writes a series of bytes.
+ *
+ * @param dev the master device
+ * @param buf pointer to the data to write
+ * @param len the number of bytes to write
+ * @return the byte read
+ */
+void w1_write_block(struct w1_master *dev, const u8 *buf, int len)
{
int i;
@@ -129,6 +168,14 @@ void w1_write_block(struct w1_master *dev, u8 *buf, int len)
w1_write_8(dev, buf[i]);
}
+/**
+ * Reads a series of bytes.
+ *
+ * @param dev the master device
+ * @param buf pointer to the buffer to fill
+ * @param len the number of bytes to read
+ * @return the number of bytes read
+ */
u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
{
int i;
@@ -145,9 +192,15 @@ u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
return ret;
}
+/**
+ * Issues a reset bus sequence.
+ *
+ * @param dev The bus master pointer
+ * @return 0=Device present, 1=No device present or error
+ */
int w1_reset_bus(struct w1_master *dev)
{
- int result = 0;
+ int result;
if (dev->bus_master->reset_bus)
result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
@@ -183,9 +236,8 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
w1_search(dev);
}
-EXPORT_SYMBOL(w1_write_bit);
+EXPORT_SYMBOL(w1_touch_bit);
EXPORT_SYMBOL(w1_write_8);
-EXPORT_SYMBOL(w1_read_bit);
EXPORT_SYMBOL(w1_read_8);
EXPORT_SYMBOL(w1_reset_bus);
EXPORT_SYMBOL(w1_calc_crc8);