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SubjectRe: [v2,02/10] i2c-i801: Move hostcfg set/reset to i801_access()
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On 06/09/2016 04:39 AM, Benjamin Tissoires wrote:
> On May 29 2016 or thereabouts, Corey Minyard wrote:
>> From: Corey Minyard <cminyard@mvista.com>
>>
>> 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.
>>
>> This results in a small savings of code, and moves some special
>> handing for I2C transactions into code that is already handling
>> special things for I2C transactions.
>>
>> Signed-off-by: Corey Minyard <cminyard@mvista.com>
>> ---
>> drivers/i2c/busses/i2c-i801.c | 41 +++++++++++++++++++----------------------
>> 1 file changed, 19 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
>> index 818c0c8..205f9d0 100644
>> --- a/drivers/i2c/busses/i2c-i801.c
>> +++ b/drivers/i2c/busses/i2c-i801.c
>> @@ -661,20 +661,6 @@ 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) {
>> - /* 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;
>> - }
>> - }
>>
>> if (read_write == I2C_SMBUS_WRITE
>> || command == I2C_SMBUS_I2C_BLOCK_DATA) {
>> @@ -699,11 +685,6 @@ 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;
>> }
>>
>> @@ -715,6 +696,7 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
>> int hwpec;
>> int block = 0;
>> int ret = 0, xact = 0;
>> + int hostc = -1;
>> struct i801_priv *priv = i2c_get_adapdata(adap);
>>
>> pm_runtime_get_sync(&priv->pci_dev->dev);
>> @@ -764,12 +746,24 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
>> /* NB: page 240 of ICH5 datasheet shows that the R/#W
>> * bit should be cleared here, even when reading */
>> outb_p((addr & 0x7f) << 1, SMBHSTADD(priv));
>> - if (read_write == I2C_SMBUS_READ) {
>> + if (read_write == I2C_SMBUS_WRITE) {
>> + unsigned char thostc;
>> +
>> + outb_p(command, SMBHSTCMD(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)) {
> nitpick: I'd prefer seeing:
> if (write) {
> foo
> } else {
> if (!FEATURE_I2C_BLOCK_READ) {
> goto out
> }
> bar
> }
>
> It's equivalent but I feel like it's easier to understand.

First, thanks for all the reviews. I really appreciate it.

On this particular change, it's moved from another location unchanged,
and it follows the style of the rest of the file. I personally think
it's better
to leave it like it is.

-corey

> Other than that, no strong opinion on the patch itself, but it's correct
> (the code path stays the same):
> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>
> Cheers,
> Benjamin
>
>> + dev_err(&priv->pci_dev->dev,
>> + "I2C block read is unsupported!\n");
>> + ret = -EOPNOTSUPP;
>> + goto out;
>> + } else
>> /* NB: page 240 of ICH5 datasheet also shows
>> * that DATA1 is the cmd field when reading */
>> outb_p(command, SMBHSTDAT1(priv));
>> - } else
>> - outb_p(command, SMBHSTCMD(priv));
>> block = 1;
>> break;
>> default:
>> @@ -798,6 +792,9 @@ 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)
>> goto out;
>> if (ret)

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