i2c-algo-bit: Emulate SMBus block read

Now that i2c-core lets the i2c bus drivers emulate the SMBus block read
and SMBus block process call transaction types, let's implement that in
the popular i2c bit-banging driver. This will also act as a reference
implementation for other bus drivers which want to do the same.

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

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 28b7e25ca79c..fcef6ff3d287 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -391,6 +391,21 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
                 };
                 scllo(adap);
                 sdahi(adap);
+
+                /* Some SMBus transactions require that we receive the
+                   transaction length as the first read byte. */
+                if (rdcount == 1 && (msg->flags & I2C_M_RECV_LEN)) {
+                        if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
+                                printk(KERN_ERR "i2c-algo-bit: readbytes: "
+                                       "invalid block length (%d)\n", inval);
+                                return -EREMOTEIO;
+                        }
+                        /* The original count value accounts for the extra
+                           bytes, that is, either 1 for a regular transaction,
+                           or 2 for a PEC transaction. */
+                        count += inval;
+                        msg->len += inval;
+                }
         }
         return rdcount;
 }
@@ -509,6 +524,8 @@ bailout:
 static u32 bit_func(struct i2c_adapter *adap)
 {
         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 
+               I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+               I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
                I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
 }