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authorMichael Arndt <michael@scriptkiller.de>2013-02-17 20:31:27 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-18 12:47:12 -0800
commit9c95bb6f25ff802081125f24bf0c756252fa27b2 (patch)
tree4372971eb0b6dbf806343da4982b09fbeafe6a80 /drivers/w1
parentdef1820d25fa93cf5fca10bf45f22cdb11be41f2 (diff)
downloadlinux-9c95bb6f25ff802081125f24bf0c756252fa27b2.tar.gz
w1: ds2482: Added 1-Wire pull-up support to the driver
Signed-off-by: Michael Arndt <michael@scriptkiller.de> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/w1')
-rw-r--r--drivers/w1/masters/ds2482.c51
1 files changed, 45 insertions, 6 deletions
diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c
index 6429b9e9fb8..e033491fe30 100644
--- a/drivers/w1/masters/ds2482.c
+++ b/drivers/w1/masters/ds2482.c
@@ -51,10 +51,10 @@
* The top 4 bits always read 0.
* To write, the top nibble must be the 1's compl. of the low nibble.
*/
-#define DS2482_REG_CFG_1WS 0x08
-#define DS2482_REG_CFG_SPU 0x04
-#define DS2482_REG_CFG_PPM 0x02
-#define DS2482_REG_CFG_APU 0x01
+#define DS2482_REG_CFG_1WS 0x08 /* 1-wire speed */
+#define DS2482_REG_CFG_SPU 0x04 /* strong pull-up */
+#define DS2482_REG_CFG_PPM 0x02 /* presence pulse masking */
+#define DS2482_REG_CFG_APU 0x01 /* active pull-up */
/**
@@ -132,6 +132,17 @@ struct ds2482_data {
/**
+ * Helper to calculate values for configuration register
+ * @param conf the raw config value
+ * @return the value w/ complements that can be written to register
+ */
+static inline u8 ds2482_calculate_config(u8 conf)
+{
+ return conf | ((~conf & 0x0f) << 4);
+}
+
+
+/**
* Sets the read pointer.
* @param pdev The ds2482 client pointer
* @param read_ptr see DS2482_PTR_CODE_xxx above
@@ -399,7 +410,7 @@ static u8 ds2482_w1_reset_bus(void *data)
/* If the chip did reset since detect, re-config it */
if (err & DS2482_REG_STS_RST)
ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
- 0xF0);
+ ds2482_calculate_config(0x00));
}
mutex_unlock(&pdev->access_lock);
@@ -407,6 +418,32 @@ static u8 ds2482_w1_reset_bus(void *data)
return retval;
}
+static u8 ds2482_w1_set_pullup(void *data, int delay)
+{
+ struct ds2482_w1_chan *pchan = data;
+ struct ds2482_data *pdev = pchan->pdev;
+ u8 retval = 1;
+
+ /* if delay is non-zero activate the pullup,
+ * the strong pullup will be automatically deactivated
+ * by the master, so do not explicitly deactive it
+ */
+ if (delay) {
+ /* both waits are crucial, otherwise devices might not be
+ * powered long enough, causing e.g. a w1_therm sensor to
+ * provide wrong conversion results
+ */
+ ds2482_wait_1wire_idle(pdev);
+ /* note: it seems like both SPU and APU have to be set! */
+ retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
+ ds2482_calculate_config(DS2482_REG_CFG_SPU |
+ DS2482_REG_CFG_APU));
+ ds2482_wait_1wire_idle(pdev);
+ }
+
+ return retval;
+}
+
static int ds2482_probe(struct i2c_client *client,
const struct i2c_device_id *id)
@@ -452,7 +489,8 @@ static int ds2482_probe(struct i2c_client *client,
data->w1_count = 8;
/* Set all config items to 0 (off) */
- ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG, 0xF0);
+ ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG,
+ ds2482_calculate_config(0x00));
mutex_init(&data->access_lock);
@@ -468,6 +506,7 @@ static int ds2482_probe(struct i2c_client *client,
data->w1_ch[idx].w1_bm.touch_bit = ds2482_w1_touch_bit;
data->w1_ch[idx].w1_bm.triplet = ds2482_w1_triplet;
data->w1_ch[idx].w1_bm.reset_bus = ds2482_w1_reset_bus;
+ data->w1_ch[idx].w1_bm.set_pullup = ds2482_w1_set_pullup;
err = w1_add_master_device(&data->w1_ch[idx].w1_bm);
if (err) {