On Tue, 19 Jan 2016 11:09:34 -0600, minyard@xxxxxxx wrote:
> From: Corey Minyard <cminyard@xxxxxxxxxx>
>
> The HSTCFG register save/restore was done in i2c_block_transaction,
> but all the checks were already done in i801_access, so move it into
> those checks.
>
> Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-i801.c | 33 ++++++++++++++-------------------
> 1 file changed, 14 insertions(+), 19 deletions(-)
Did you test this patch?
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 62cf1e5..9143fcf 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -652,20 +652,6 @@ static int i801_block_transaction(struct i801_priv *priv,
> int command, int hwpec)
> {
> int result = 0;
> - unsigned char hostc;
> -
> - if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
> - if (read_write == I2C_SMBUS_WRITE) {
This is the write case...
> - /* 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)) {
... and this is the read case.
> - dev_err(&priv->pci_dev->dev,
> - "I2C block read is unsupported!\n");
> - return -EOPNOTSUPP;
> - }
> - }
>
> if (read_write == I2C_SMBUS_WRITE
> || command == I2C_SMBUS_I2C_BLOCK_DATA) {
> @@ -692,11 +678,6 @@ static int i801_block_transaction(struct i801_priv *priv,
> read_write,
> command);
>
> - if (command == I2C_SMBUS_I2C_BLOCK_DATA
> - && read_write == I2C_SMBUS_WRITE) {
> - /* restore saved configuration register value */
> - pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc);
> - }
> return result;
> }
>
> @@ -710,6 +691,7 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
> int ret, xact = 0;
> struct i801_priv *priv = i2c_get_adapdata(adap);
> int result;
> + int hostc = -1;
>
> hwpec = (priv->features & FEATURE_SMBUS_PEC) && (flags & I2C_CLIENT_PEC)
> && size != I2C_SMBUS_QUICK
> @@ -757,9 +739,19 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
> * bit should be cleared here, even when reading */
> outb_p((addr & 0x7f) << 1, SMBHSTADD(priv));
> if (read_write == I2C_SMBUS_READ) {
However after your changes, this is the READ case...
> + unsigned char thostc;
> /* NB: page 240 of ICH5 datasheet also shows
> * that DATA1 is the cmd field when reading */
> outb_p(command, SMBHSTDAT1(priv));
> + /* set I2C_EN bit in configuration register */
> + pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &thostc);
> + pci_write_config_byte(priv->pci_dev, SMBHSTCFG,
> + thostc | SMBHSTCFG_I2C_EN);
> + hostc = thostc;
> + } else if (!(priv->features & FEATURE_I2C_BLOCK_READ)) {
... and this is the WRITE case. Looks very wrong.
> + dev_err(&priv->pci_dev->dev,
> + "I2C block read is unsupported!\n");
> + return -EOPNOTSUPP;
> } else
> outb_p(command, SMBHSTCMD(priv));
> block = 1;
> @@ -795,6 +787,9 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
> outb_p(inb_p(SMBAUXCTL(priv)) &
> ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));
>
> + if (hostc >= 0)
> + pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc);
> +
> if (block)
> return ret;
> if (ret)
More generally, I'm only half convinced that the change is beneficial.
Yes, you avoid duplicate tests in the block case. However this is at
the expense of an initialization and a test in the common path.
I do agree that testing for unsupported functionality should be moved
back into i801_access() for consistency, as this is where the general
test for unsupported transaction types is.
--
Jean Delvare
SUSE L3 Support
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