[PATCH 7/30] W1: be able to manually add and remove slaves

Evgeniy Polyakov
2008-07-11T13:53:59Z

sysfs entries were added to manually add and remove slave devices.
This is useful if the automatic bus searching is disabled, and the
device ids are already known.

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

---
drivers/w1/w1.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 136 insertions(+), 1 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 76274ae..24312e0 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -56,6 +56,8 @@ 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);
+
static int w1_master_match(struct device *dev, struct device_driver *drv)
{
return 1;
@@ -349,7 +351,8 @@ 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;
@@ -374,6 +377,134 @@ 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, \
@@ -394,6 +525,8 @@ 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(pullup, 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,
@@ -405,6 +538,8 @@ static struct attribute *w1_master_default_attrs[] = {
&w1_master_attribute_pointer.attr,
&w1_master_attribute_search.attr,
&w1_master_attribute_pullup.attr,
+ &w1_master_attribute_add.attr,
+ &w1_master_attribute_remove.attr,
NULL
};

--
1.4.4.4