[PATCH v3 3/5] i2c: i801: Split i801_block_transaction

Heiner Kallweit
2024-02-02T07:02:55Z

i2c and smbus block transaction handling have little in common,
therefore split this function to improve code readability.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
drivers/i2c/busses/i2c-i801.c | 112 +++++++++++++++-------------------
1 file changed, 50 insertions(+), 62 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 156bace92..24eb187db 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -802,77 +802,65 @@ static int i801_simple_transaction(struct i801_priv *priv, union i2c_smbus_data
return 0;
}

-/* Block transaction function */
-static int i801_block_transaction(struct i801_priv *priv, union i2c_smbus_data *data,
- u8 addr, u8 hstcmd, char read_write, int command)
+static int i801_smbus_block_transaction(struct i801_priv *priv, union i2c_smbus_data *data,
+ u8 addr, u8 hstcmd, char read_write, int command)
{
- int result = 0;
- unsigned char hostc;
-
if (read_write == I2C_SMBUS_READ && command == I2C_SMBUS_BLOCK_DATA)
data->block[0] = I2C_SMBUS_BLOCK_MAX;
else if (data->block[0] < 1 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
return -EPROTO;

- switch (command) {
- case I2C_SMBUS_BLOCK_DATA:
- i801_set_hstadd(priv, addr, read_write);
- outb_p(hstcmd, SMBHSTCMD(priv));
- break;
- case I2C_SMBUS_I2C_BLOCK_DATA:
- /*
- * NB: page 240 of ICH5 datasheet shows that the R/#W
- * bit should be cleared here, even when reading.
- * However if SPD Write Disable is set (Lynx Point and later),
- * the read will fail if we don't set the R/#W bit.
- */
- i801_set_hstadd(priv, addr,
- priv->original_hstcfg & SMBHSTCFG_SPD_WD ?
- read_write : I2C_SMBUS_WRITE);
- if (read_write == I2C_SMBUS_READ) {
- /* NB: page 240 of ICH5 datasheet also shows
- * that DATA1 is the cmd field when reading
- */
- outb_p(hstcmd, SMBHSTDAT1(priv));
- } else
- outb_p(hstcmd, SMBHSTCMD(priv));
-
- if (read_write == I2C_SMBUS_WRITE) {
- /* set I2C_EN bit in configuration register */
- pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &hostc);
- pci_write_config_byte(priv->pci_dev, SMBHSTCFG,
- hostc | SMBHSTCFG_I2C_EN);
- } else if (!(priv->features & FEATURE_I2C_BLOCK_READ)) {
- dev_err(&priv->pci_dev->dev,
- "I2C block read is unsupported!\n");
- return -EOPNOTSUPP;
- }
- break;
- case I2C_SMBUS_BLOCK_PROC_CALL:
+ if (command == I2C_SMBUS_BLOCK_PROC_CALL)
/* Needs to be flagged as write transaction */
i801_set_hstadd(priv, addr, I2C_SMBUS_WRITE);
+ else
+ i801_set_hstadd(priv, addr, read_write);
+ outb_p(hstcmd, SMBHSTCMD(priv));
+
+ if (priv->features & FEATURE_BLOCK_BUFFER)
+ return i801_block_transaction_by_block(priv, data, read_write, command);
+ else
+ return i801_block_transaction_byte_by_byte(priv, data, read_write, command);
+}
+
+static int i801_i2c_block_transaction(struct i801_priv *priv, union i2c_smbus_data *data,
+ u8 addr, u8 hstcmd, char read_write, int command)
+{
+ int result;
+ u8 hostc;
+
+ if (data->block[0] < 1 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
+ return -EPROTO;
+ /*
+ * NB: page 240 of ICH5 datasheet shows that the R/#W bit should be cleared here,
+ * even when reading. However if SPD Write Disable is set (Lynx Point and later),
+ * the read will fail if we don't set the R/#W bit.
+ */
+ i801_set_hstadd(priv, addr,
+ priv->original_hstcfg & SMBHSTCFG_SPD_WD ? read_write : I2C_SMBUS_WRITE);
+
+ /* NB: page 240 of ICH5 datasheet shows that DATA1 is the cmd field when reading */
+ if (read_write == I2C_SMBUS_READ)
+ outb_p(hstcmd, SMBHSTDAT1(priv));
+ else
outb_p(hstcmd, SMBHSTCMD(priv));
- break;
+
+ if (read_write == I2C_SMBUS_WRITE) {
+ /* set I2C_EN bit in configuration register */
+ pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &hostc);
+ pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc | SMBHSTCFG_I2C_EN);
+ } else if (!(priv->features & FEATURE_I2C_BLOCK_READ)) {
+ pci_err(priv->pci_dev, "I2C block read is unsupported!\n");
+ return -EOPNOTSUPP;
}

- /* Experience has shown that the block buffer can only be used for
- SMBus (not I2C) block transactions, even though the datasheet
- doesn't mention this limitation. */
- if ((priv->features & FEATURE_BLOCK_BUFFER) &&
- command != I2C_SMBUS_I2C_BLOCK_DATA)
- result = i801_block_transaction_by_block(priv, data,
- read_write,
- command);
- else
- result = i801_block_transaction_byte_by_byte(priv, data,
- read_write,
- command);
+ /* Block buffer isn't supported for I2C block transactions */
+ result = i801_block_transaction_byte_by_byte(priv, data, read_write, command);

- if (command == I2C_SMBUS_I2C_BLOCK_DATA
- && read_write == I2C_SMBUS_WRITE) {
- /* restore saved configuration register value */
+ /* restore saved configuration register value */
+ if (read_write == I2C_SMBUS_WRITE)
pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc);
- }
+
return result;
}

@@ -903,10 +891,10 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
outb_p(inb_p(SMBAUXCTL(priv)) & (~SMBAUXCTL_CRC),
SMBAUXCTL(priv));

- if (size == I2C_SMBUS_BLOCK_DATA ||
- size == I2C_SMBUS_I2C_BLOCK_DATA ||
- size == I2C_SMBUS_BLOCK_PROC_CALL)
- ret = i801_block_transaction(priv, data, addr, command, read_write, size);
+ if (size == I2C_SMBUS_BLOCK_DATA || size == I2C_SMBUS_BLOCK_PROC_CALL)
+ ret = i801_smbus_block_transaction(priv, data, addr, command, read_write, size);
+ else if (size == I2C_SMBUS_I2C_BLOCK_DATA)
+ ret = i801_i2c_block_transaction(priv, data, addr, command, read_write, size);
else
ret = i801_simple_transaction(priv, data, addr, command, read_write, size);

--
2.43.0