[PATCH 10/35] W1: be able to manually add and remove slaves

[David Fries <david@fries.net>]

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w1.c 1.11 1.12 1.14
I'm intending to be working with a static network and run without the
bus searching, but bus searching is currently the only way to add
slave devices.  This allows any slave to be added or removed.  There
is one file for adding and another for removing.  If the files are
read a short comment including the expected serial number format is
returned.

Signed-off-by: David Fries <david@fries.net>
---
 drivers/w1/w1.c |  140 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 137 insertions(+), 3 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 5d8c2c7..3ca1f4d 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -56,6 +56,9 @@ module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
 DEFINE_MUTEX(w1_mlock);
 LIST_HEAD(w1_masters);
 
+static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
+void w1_slave_detach(struct w1_slave *sl);
+
 static int w1_master_match(struct device *dev, struct device_driver *drv)
 {
 	return 1;
@@ -321,7 +324,8 @@ static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct d
 	return count;
 }
 
-static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t w1_master_attribute_show_slaves(struct device *dev,
+	struct device_attribute *attr, char *buf)
 {
 	struct w1_master *md = dev_to_w1_master(dev);
 	int c = PAGE_SIZE;
@@ -346,6 +350,134 @@ static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device
 	return PAGE_SIZE - c;
 }
 
+static ssize_t w1_master_attribute_show_add(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	int c = PAGE_SIZE;
+	c -= snprintf(buf+PAGE_SIZE - c, c,
+		"write device id xx-xxxxxxxxxxxx to add slave\n");
+	return PAGE_SIZE - c;
+}
+
+static int w1_atoreg_num(struct device * dev, const char *buf, size_t count,
+	struct w1_reg_num *rn)
+{
+	unsigned int family;
+	u64 id;
+	int i;
+	u64 rn64_le;
+	/* The CRC value isn't read from the user because the sysfs directory
+	 * doesn't include it and most messages from the bus search don't
+	 * print it either.  It would be unreasonable for the user to then
+	 * provide it.
+	 */
+	const char *error_msg="bad slave string format, expecting "
+		"ff-dddddddddddd\n";
+
+	if(buf[2]!='-') {
+		dev_err(dev, "%s", error_msg);
+		return -EINVAL;
+	}
+	i=sscanf(buf, "%02x-%012llx", &family, &id);
+	if(i!=2) {
+		dev_err(dev, "%s", error_msg);
+		return -EINVAL;
+	}
+	rn->family=family;
+	rn->id=id;
+
+	rn64_le=cpu_to_le64(*(u64*)rn);
+	rn->crc=w1_calc_crc8((u8 *)&rn64_le, 7);
+
+	#if 0
+	dev_info(dev, "With CRC device is %02x.%012llx.%02x.\n",
+		  rn->family, (unsigned long long)rn->id, rn->crc);
+	#endif
+
+	return 0;
+}
+
+/* Searches the slaves in the w1_master and returns a pointer or NULL.
+ * Note: must hold the mutex
+ */
+static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
+	struct w1_reg_num *rn)
+{
+	struct w1_slave *sl;
+	list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+		if (sl->reg_num.family == rn->family &&
+				sl->reg_num.id == rn->id &&
+				sl->reg_num.crc == rn->crc) {
+			return sl;
+		}
+	}
+	return NULL;
+}
+
+static ssize_t w1_master_attribute_store_add(struct device * dev,
+						struct device_attribute *attr,
+						const char * buf, size_t count)
+{
+	struct w1_master *md = dev_to_w1_master(dev);
+	struct w1_reg_num rn;
+	struct w1_slave *sl;
+	ssize_t result=count;
+
+	if(w1_atoreg_num(dev, buf, count, &rn))
+		return -EINVAL;
+
+	mutex_lock(&md->mutex);
+	sl=w1_slave_search_device(md, &rn);
+	/* It would be nice to do a targeted search one the one-wire bus
+	 * for the new device to see if it is out there or not.  But the
+	 * current search doesn't support that.
+	 */
+	if(sl) {
+		dev_info(dev, "Device %s already exists\n", sl->name);
+		result=-EINVAL;
+	} else {
+		w1_attach_slave_device(md, &rn);
+	}
+	mutex_unlock(&md->mutex);
+
+	return result;
+}
+
+static ssize_t w1_master_attribute_show_remove(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	int c = PAGE_SIZE;
+	c -= snprintf(buf+PAGE_SIZE - c, c,
+		"write device id xx-xxxxxxxxxxxx to remove slave\n");
+	return PAGE_SIZE - c;
+}
+
+static ssize_t w1_master_attribute_store_remove(struct device * dev,
+						struct device_attribute *attr,
+						const char * buf, size_t count)
+{
+	struct w1_master *md = dev_to_w1_master(dev);
+	struct w1_reg_num rn;
+	struct w1_slave *sl;
+	ssize_t result=count;
+
+	if(w1_atoreg_num(dev, buf, count, &rn))
+		return -EINVAL;
+
+	mutex_lock(&md->mutex);
+	sl=w1_slave_search_device(md, &rn);
+	if(sl) {
+		w1_slave_detach(sl);
+	} else {
+		dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
+			(unsigned long long)rn.id);
+		result=-EINVAL;
+	}
+	mutex_unlock(&md->mutex);
+
+	return result;
+}
+
 #define W1_MASTER_ATTR_RO(_name, _mode)				\
 	struct device_attribute w1_master_attribute_##_name =	\
 		__ATTR(w1_master_##_name, _mode,		\
@@ -365,6 +497,8 @@ static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
 static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
+static W1_MASTER_ATTR_RW(add, S_IRUGO | S_IWUGO);
+static W1_MASTER_ATTR_RW(remove, S_IRUGO | S_IWUGO);
 
 static struct attribute *w1_master_default_attrs[] = {
 	&w1_master_attribute_name.attr,
@@ -375,6 +509,8 @@ static struct attribute *w1_master_default_attrs[] = {
 	&w1_master_attribute_timeout.attr,
 	&w1_master_attribute_pointer.attr,
 	&w1_master_attribute_search.attr,
+	&w1_master_attribute_add.attr,
+	&w1_master_attribute_remove.attr,
 	NULL
 };
 
@@ -670,9 +806,7 @@ void w1_reconnect_slaves(struct w1_family *f, int attach)
 
 static void w1_slave_found(struct w1_master *dev, u64 rn)
 {
-	int slave_count;
 	struct w1_slave *sl;
-	struct list_head *ent;
 	struct w1_reg_num *tmp;
 	u64 rn_le = cpu_to_le64(rn);
 
-- 
1.4.4.4

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