i2c: Restore i2c_smbus_read_block_data

Add back the i2c_smbus_read_block_data helper function, it is needed
by the upcoming lm93 hardware monitoring driver and possibly others.

Signed-off-by: Jean Delvare <khali@linux-fr.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index a58f89a6418..64f8e56d300 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1298,6 +1298,22 @@ s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
 }
 EXPORT_SYMBOL(i2c_smbus_write_word_data);
 
+/* Returns the number of read bytes */
+s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
+                              u8 *values)
+{
+        union i2c_smbus_data data;
+
+        if (i2c_smbus_xfer(client->adapter, client->addr, client->flags,
+                           I2C_SMBUS_READ, command,
+                           I2C_SMBUS_BLOCK_DATA, &data))
+                return -1;
+
+        memcpy(values, &data.block[1], data.block[0]);
+        return data.block[0];
+}
+EXPORT_SYMBOL(i2c_smbus_read_block_data);
+
 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
                                u8 length, const u8 *values)
 {
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 3fe2ad37da3..cae7d618030 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -82,6 +82,9 @@ extern s32 i2c_smbus_write_byte_data(struct i2c_client * client,
 extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
 extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
                                      u8 command, u16 value);
+/* Returns the number of read bytes */
+extern s32 i2c_smbus_read_block_data(struct i2c_client *client,
+                                     u8 command, u8 *values);
 extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
                                       u8 command, u8 length,
                                       const u8 *values);