i2c: mlxcpld: Add support for extended transaction length

Add support for extended length of read and write transactions.
New FPGA logic allows to increase size of the read and write
transactions length. This feature is verified through capability
register 'CPBLTY_REG'. Two bits 5 and 6 of the register are used for
length capability detection. Value '10' indicates support of extended
transaction length - 128 bytes for read transactions and 132 for write
transactions.

Signed-off-by: Vadim Pasternak <[email protected]>
Reviewed-by: Michael Shych <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>

Author: vadimp-nvidia

drivers/i2c/busses/i2c-mlxcpld.c

@@ -22,6 +22,7 @@
 #define MLXCPLD_I2C_BUS_NUM		1
 #define MLXCPLD_I2C_DATA_REG_SZ		36
 #define MLXCPLD_I2C_DATA_SZ_BIT		BIT(5)
+#define MLXCPLD_I2C_DATA_EXT2_SZ_BIT	BIT(6)
 #define MLXCPLD_I2C_DATA_SZ_MASK	GENMASK(6, 5)
 #define MLXCPLD_I2C_SMBUS_BLK_BIT	BIT(7)
 #define MLXCPLD_I2C_MAX_ADDR_LEN	4
@@ -466,6 +467,13 @@ static const struct i2c_adapter_quirks mlxcpld_i2c_quirks_ext = {
 	.max_comb_1st_msg_len = 4,
 };
 
+static const struct i2c_adapter_quirks mlxcpld_i2c_quirks_ext2 = {
+	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
+	.max_read_len = (MLXCPLD_I2C_DATA_REG_SZ - 4) * 4,
+	.max_write_len = (MLXCPLD_I2C_DATA_REG_SZ - 4) * 4 + MLXCPLD_I2C_MAX_ADDR_LEN,
+	.max_comb_1st_msg_len = 4,
+};
+
 static struct i2c_adapter mlxcpld_i2c_adapter = {
 	.owner          = THIS_MODULE,
 	.name           = "i2c-mlxcpld",
@@ -547,6 +555,8 @@ static int mlxcpld_i2c_probe(struct platform_device *pdev)
 	/* Check support for extended transaction length */
 	if ((val & MLXCPLD_I2C_DATA_SZ_MASK) == MLXCPLD_I2C_DATA_SZ_BIT)
 		mlxcpld_i2c_adapter.quirks = &mlxcpld_i2c_quirks_ext;
+	else if ((val & MLXCPLD_I2C_DATA_SZ_MASK) == MLXCPLD_I2C_DATA_EXT2_SZ_BIT)
+		mlxcpld_i2c_adapter.quirks = &mlxcpld_i2c_quirks_ext2;
 	/* Check support for smbus block transaction */
 	if (val & MLXCPLD_I2C_SMBUS_BLK_BIT)
 		priv->smbus_block = true;