i2c-stub: Implement I2C block support

This is required to test some drivers, for example at24.
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Documentation/i2c/i2c-stub

@@ -2,9 +2,9 @@ MODULE: i2c-stub
 
 DESCRIPTION:
 
-This module is a very simple fake I2C/SMBus driver.  It implements four
-types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, and
-(r/w) word data.
+This module is a very simple fake I2C/SMBus driver.  It implements five
+types of SMBus commands: write quick, (r/w) byte, (r/w) byte data, (r/w)
+word data, and (r/w) I2C block data.
 
 You need to provide chip addresses as a module parameter when loading this
 driver, which will then only react to SMBus commands to these addresses.

drivers/i2c/busses/i2c-stub.c

@@ -48,7 +48,7 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
 	char read_write, u8 command, int size, union i2c_smbus_data * data)
 {
 	s32 ret;
-	int i;
+	int i, len;
 	struct stub_chip *chip = NULL;
 
 	/* Search for the right chip */
@@ -118,6 +118,29 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
 		ret = 0;
 		break;
 
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		len = data->block[0];
+		if (read_write == I2C_SMBUS_WRITE) {
+			for (i = 0; i < len; i++) {
+				chip->words[command + i] &= 0xff00;
+				chip->words[command + i] |= data->block[1 + i];
+			}
+			dev_dbg(&adap->dev, "i2c block data - addr 0x%02x, "
+					"wrote %d bytes at 0x%02x.\n",
+					addr, len, command);
+		} else {
+			for (i = 0; i < len; i++) {
+				data->block[1 + i] =
+					chip->words[command + i] & 0xff;
+			}
+			dev_dbg(&adap->dev, "i2c block data - addr 0x%02x, "
+					"read  %d bytes at 0x%02x.\n",
+					addr, len, command);
+		}
+
+		ret = 0;
+		break;
+
 	default:
 		dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
 		ret = -EOPNOTSUPP;
@@ -130,7 +153,8 @@ static s32 stub_xfer(struct i2c_adapter * adap, u16 addr, unsigned short flags,
 static u32 stub_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
-		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA;
+		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_I2C_BLOCK;
 }
 
 static const struct i2c_algorithm smbus_algorithm = {