[U-Boot] [PATCH 6/6] i2c: designware_i2c: Add support for PCI(e) based I2C cores (x86)

[Stefan Roese]

Hi Bin,

On 21.03.2016 13:43, Bin Meng wrote:
> On Mon, Mar 21, 2016 at 8:04 PM, Stefan Roese <sr at denx.de> wrote:
>> Hi Bin,
>>
>> On 21.03.2016 10:03, Stefan Roese wrote:
>>
>> <snip>
>>
>>>>>     static int designware_i2c_probe_chip(struct udevice *bus, uint chip_addr,
>>>>> @@ -476,14 +519,45 @@ static int designware_i2c_probe(struct udevice *bus)
>>>>>     {
>>>>>            struct dw_i2c *priv = dev_get_priv(bus);
>>>>>
>>>>> +#ifdef CONFIG_X86
>>>>> +       /* Save base address from PCI BAR */
>>>>> +       priv->regs = (struct i2c_regs *)
>>>>> +               dm_pci_map_bar(bus, PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
>>>>> +       /* Use BayTrail specific timing values */
>>>>> +       priv->scl_sda_cfg = &byt_config;
>>>>> +#else
>>>>
>>>> How about:
>>>>
>>>>        if (device_is_on_pci_bus(dev)) {
>>>>        do the PCI I2C stuff here;
>>>>        }
>>>
>>> I've tried this but it generated compilation errors on socfpga, as the
>>> dm_pci_xxx functions are not available there. So it definitely needs
>>> some #ifdef here. I could go with your suggestion and use
>>> #if CONFIG_DM_PCI as well.
>>>
>>>> See driver/net/designware.c for example.
>>>>
>>>>>            /* Save base address from device-tree */
>>>>>            priv->regs = (struct i2c_regs *)dev_get_addr(bus);
>>>>> +#endif
>>
>> Enabling this code for x86 via if (device_is_on_pci_bus(dev)) results
>> in this ugly compilation warning:
>>
>> drivers/i2c/designware_i2c.c: In function ‘designware_i2c_probe’:
>> drivers/i2c/designware_i2c.c:530:16: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>>     priv->regs = (struct i2c_regs *)dev_get_addr(bus);
>>                  ^
>>
>> This is because x86 defines fdt_addr_t / phys_addr_t as 64bit. So
>> I'm wondering, how dev_get_addr() should get used on x86. Has it
>> been used anywhere here at all? Should we perhaps go back to
>> a 32bit phy_addr representation again? So that dev_get_addr()
>> matches the (void *) size again?
>>
>
> dev_get_addr() is being used on x86 drivers. See
> ns16550_serial_ofdata_to_platdata() for example. There is no build
> warning for the ns16550 driver.

I see, thanks. Its used differently there though. Let me see, if I
cook something up...

Thanks,
Stefan