i2c: octeon: Remove zero-length message support

Zero-length message support (SMBUS QUICK or i2c) never worked with
the Octeon hardware. Disable SMBUS QUICK support and bail out in
case of a zero-length i2c request.

After this change 'i2c-detect -q' will return an error on Octeon but
the previously reported results were wrong anyway.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 6a4f0581a7e0bb294ad91ffdc1401ea4ca7fc717..4fc471ce173e6bac53cd8b33618e7d6ea4c4f1ef 100644 (file)
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -838,9 +838,6 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
        int i, result, length = *rlength;
        bool final_read = false;
 
-       if (length < 1)
-               return -EINVAL;
-
        octeon_i2c_data_write(i2c, (target << 1) | 1);
        octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
 
@@ -926,6 +923,12 @@ static int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
        for (i = 0; ret == 0 && i < num; i++) {
                struct i2c_msg *pmsg = &msgs[i];
 
+               /* zero-length messages are not supported */
+               if (!pmsg->len) {
+                       ret = -EOPNOTSUPP;
+                       break;
+               }
+
                ret = octeon_i2c_start(i2c);
                if (ret)
                        return ret;
@@ -999,7 +1002,7 @@ static struct i2c_bus_recovery_info octeon_i2c_recovery_info = {
 
 static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
 {
-       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+       return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
               I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
 }