w1: add touch block command

Writes and returns sampled data back to userspace.

Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 35 insertions, 4 deletions

diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 97304bd83ec9..d8a9709f3449 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -210,6 +210,7 @@ u8 w1_read_8(struct w1_master *);
 int w1_reset_bus(struct w1_master *);
 u8 w1_calc_crc8(u8 *, int);
 void w1_write_block(struct w1_master *, const u8 *, int);
+void w1_touch_block(struct w1_master *, u8 *, int);
 u8 w1_read_block(struct w1_master *, u8 *, int);
 int w1_reset_select_slave(struct w1_slave *sl);
 void w1_next_pullup(struct w1_master *, int);
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 5139c25ca962..442bd8bbd4a5 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -238,7 +238,6 @@ EXPORT_SYMBOL_GPL(w1_read_8);
  * @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)
 {
@@ -256,6 +255,31 @@ void w1_write_block(struct w1_master *dev, const u8 *buf, int len)
 EXPORT_SYMBOL_GPL(w1_write_block);
 
 /**
+ * Touches 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
+ */
+void w1_touch_block(struct w1_master *dev, u8 *buf, int len)
+{
+        int i, j;
+        u8 tmp;
+
+        for (i = 0; i < len; ++i) {
+                tmp = 0;
+                for (j = 0; j < 8; ++j) {
+                        if (j == 7)
+                                w1_pre_write(dev);
+                        tmp |= w1_touch_bit(dev, (buf[i] >> j) & 0x1) << j;
+                }
+
+                buf[i] = tmp;
+        }
+}
+EXPORT_SYMBOL_GPL(w1_touch_block);
+
+/**
  * Reads a series of bytes.
  *
  * @param dev     the master device
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index 2e07b59b9859..cae556c8577b 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -108,6 +108,10 @@ static int w1_process_command_slave(struct w1_slave *sl, struct cn_msg *msg,
                 cmd->cmd, cmd->len);
 
         switch (cmd->cmd) {
+                case W1_CMD_TOUCH:
+                        w1_touch_block(sl->master, cmd->data, cmd->len);
+                        w1_send_read_reply(sl, msg, hdr, cmd);
+                        break;
                 case W1_CMD_READ:
                         w1_read_block(sl->master, cmd->data, cmd->len);
                         w1_send_read_reply(sl, msg, hdr, cmd);
@@ -208,9 +212,6 @@ static void w1_cn_callback(void *data)
                         break;
                 }
 
-                if (!mlen)
-                        goto out_cont;
-
                 if (m->type == W1_MASTER_CMD) {
                         dev = w1_search_master_id(m->id.mst.id);
                 } else if (m->type == W1_SLAVE_CMD) {
@@ -227,6 +228,10 @@ static void w1_cn_callback(void *data)
                         goto out_cont;
                 }
 
+                err = 0;
+                if (!mlen)
+                        goto out_cont;
+
                 mutex_lock(&dev->mutex);
 
                 if (sl && w1_reset_select_slave(sl)) {
diff --git a/drivers/w1/w1_netlink.h b/drivers/w1/w1_netlink.h
index 21913dfc0f3a..99dd21ba14c6 100644
--- a/drivers/w1/w1_netlink.h
+++ b/drivers/w1/w1_netlink.h
@@ -56,6 +56,7 @@ struct w1_netlink_msg
 #define W1_CMD_WRITE            0x1
 #define W1_CMD_SEARCH           0x2
 #define W1_CMD_ALARM_SEARCH     0x3
+#define W1_CMD_TOUCH            0x4
 
 struct w1_netlink_cmd
 {