Hi Pali,
On 12/24/23 22:55, Pali Rohár wrote:
> On Sunday 24 December 2023 22:36:19 Hans de Goede wrote:
>> +static int smo8800_find_i801(struct device *dev, void *data)
>> +{
>> + static const u16 i801_idf_pci_device_ids[] = {
>> + 0x1d70, /* Patsburg (PCH) */
>> + 0x1d71, /* Patsburg (PCH) */
>> + 0x1d72, /* Patsburg (PCH) */
>> + 0x8d7d, /* Wellsburg (PCH) */
>> + 0x8d7e, /* Wellsburg (PCH) */
>> + 0x8d7f, /* Wellsburg (PCH) */
>> + };
>
> I'm not happy with seeing another hardcoded list of device ids in the
> driver. Are not we able to find compatible i801 adapter without need to
> hardcode this list there in smo driver?
I agree that having this hardcoded is not ideal.
The problem is that for a couple of generations (Patsburg is for
Sandy Bridge and Ivybridge and Wellsburg is for Haswell and Broadwell)
intel had multiple i2c-i801 controllers / I2C-busses in the PCH
and the i2c_client needs to be instantiated on the primary
i2c-i801 (compatible) controller.
Luckily Intel has only done this for these 2 generations PCH
all older and newer PCHs only have 1 i2c-i801 I2C bus.
So even though having this hardcoded is not ideal,
the list should never change since it is only for
this 2 somewhat old PCH generations and new generations
are not impacted. So I believe that this is the best
solution.
Regards,
Hans
> And if really not, what about
> sharing (or exporting) list from the i801 driver?
>
> I'm just worried that this PCI id list will increase in the future and
> it would be required to add a new and new id into it...
>
>> + struct i2c_adapter *adap, **adap_ret = data;
>> + struct pci_dev *pdev;
>> + int i;
>> +
>> + adap = i2c_verify_adapter(dev);
>> + if (!adap)
>> + return 0;
>> +
>> + if (!strstarts(adap->name, "SMBus I801 adapter"))
>> + return 0;
>> +
>> + /* The parent of an I801 adapter is always a PCI device */
>> + pdev = to_pci_dev(adap->dev.parent);
>> + for (i = 0; i < ARRAY_SIZE(i801_idf_pci_device_ids); i++) {
>> + if (pdev->device == i801_idf_pci_device_ids[i])
>> + return 0; /* Only register client on main SMBus channel */
>> + }
>> +
>> + *adap_ret = i2c_get_adapter(adap->nr);
>> + return 1;
>> +}
>
