Re: [PATCH v5 6/7] i2c: designware: enable SLAVE in platform module
From: Luis Oliveira
Date: Wed Dec 28 2016 - 13:11:03 EST
On 28-Dec-16 17:10, Andy Shevchenko wrote:
> On Wed, 2016-12-28 at 16:41 +0000, Luis Oliveira wrote:
>> On 28-Dec-16 16:31, Andy Shevchenko wrote:
>>> On Wed, 2016-12-28 at 15:53 +0000, Luis Oliveira wrote:
>>>> On 28-Dec-16 15:44, Andy Shevchenko wrote:
>>>>> On Wed, 2016-12-28 at 14:43 +0000, Luis Oliveira wrote:
>>>>>> - Slave mode selected in platform module (devicetree support
>>>>>> only)
>>>>>> - Check for ACPI - not supported in SLAVE mode:
>>>>>> - Changed the ifndef style to the use of ACPI_HANDLE that
>>>>>> returns
>>>>>> NULL
>>>>>> if the device was not enumerated from ACPI namespace.
>>>>>
>>>>> I'm not sure what is wrong with ACPI?
>>>>
>>>> I dont have a way to test it. Just that.
>>>
>>> Okay, can you provide an excerpt to see how it will look like in
>>> DTS?
>>
>> Yes, it looks like this now:
>>
>> i2c@0x2000 {
>> compatible = "snps,designware-i2c";
>> #address-cells = <1>;
>> #size-cells = <0>;
>> reg = <0x2000 0x100>;
>> clock-frequency = <400000>;
>> clocks = <&i2cclk>;
>> interrupts = <0>;
>>
>> eeprom@64 {
>> compatible = "linux,slave-24c02";
>> reg = <0x40000064>;
>> };
>> };
>
> +1 to Carlos' comment.
Agree, I'm on it.
>
>>>
>>>>>> - dev->functionality = I2C_FUNC_10BIT_ADDR |
>>>>>> DW_IC_DEFAULT_FUNCTIONALITY;
>>>>>> -
>>>>>> - i2c_dw_configure_master(pdev);
>>>>>> + if (ACPI_HANDLE(&pdev->dev) == NULL) {
>>>>>
>>>>> I don't think you need this at all.
>>>>
>>>> This is to avoid the use of the "ifdef" style I used before.
>>>
>>> My point is to drop it completely.
>>>
>>>>>
>>>>>> + device_for_each_child_node(&pdev->dev, child)
>>>>>> {
>>>>>
>>>>> This is resource agnostic.
>>>>>
>>>>>> + fwnode_property_read_u32(child,
>>>>>> "reg",
>>>>>> ®);
>>>>>
>>>>> This is as well.
>>>>
>>>> Are you suggesting I use of_ functions?
>>>
>>> Nope. See above.
>
> So, ACPI has a property to support slave mode for I2CSerialBus() macro.
>
> I would propose to create a helper function in i2c-core.c which will be
> responsible for mode detection
>
> ... i2c_slave_mode_detect()
> {
> ...
> if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
> ... (use of_*() here) ...
> } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev))
> dev_dbg(..., "ACPI slave is not supported yet\n");
> ... to master ...
> } else {
> ... default to master ...
> }
> }
> EXPORT_...();
>
> Make it as a separate patch.
>
Oh I see, yes it looks good. I will check it. Thanks