Re: [PATCH v4 1/6] i3c: add addr and lvr to i2c_dev_desc structure

vitor
2019-04-02T11:32:56Z

On 02/04/19 12:22, Przemyslaw Gaj wrote:
> Hi,
>
> The 04/02/2019 12:10, vitor wrote:
>> Hi,
>>
>>
>> On 01/04/19 20:24, Boris Brezillon wrote:
>>> On Mon, 1 Apr 2019 19:48:45 +0100
>>> vitor <vitor.soares@synopsys.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> On 01/04/19 19:31, Boris Brezillon wrote:
>>>>> On Mon, 1 Apr 2019 19:17:03 +0100
>>>>> vitor <vitor.soares@synopsys.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On 30/03/19 14:36, Boris Brezillon wrote:
>>>>>>> On Sun, 10 Mar 2019 13:58:38 +0000
>>>>>>> Przemyslaw Gaj <pgaj@cadence.com> wrote:
>>>>>>>
>>>>>>>> I need to store address and lvr value for I2C devices without static definition
>>>>>>>> in DT. This allows secondary master to transmit DEFSLVS command properly.
>>>>>>>>
>>>>>>>> Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
>>>>>>>> ---
>>>>>>>> include/linux/i3c/master.h | 5 +++++
>>>>>>>> 1 file changed, 5 insertions(+)
>>>>>>>>
>>>>>>>> diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
>>>>>>>> index eca8337..3c27d9f 100644
>>>>>>>> --- a/include/linux/i3c/master.h
>>>>>>>> +++ b/include/linux/i3c/master.h
>>>>>>>> @@ -71,6 +71,9 @@ struct i2c_dev_boardinfo {
>>>>>>>> * @common: common part of the I2C device descriptor
>>>>>>>> * @boardinfo: pointer to the boardinfo attached to this I2C device
>>>>>>>> * @dev: I2C device object registered to the I2C framework
>>>>>>>> + * @addr: I2C device address
>>>>>>>> + * @lvr: LVR (Legacy Virtual Register) needed by the I3C core to know about
>>>>>>>> + * the I2C device limitations
>>>>>>>> *
>>>>>>>> * Each I2C device connected on the bus will have an i2c_dev_desc.
>>>>>>>> * This object is created by the core and later attached to the controller
>>>>>>>> @@ -84,6 +87,8 @@ struct i2c_dev_desc {
>>>>>>>> struct i3c_i2c_dev_desc common;
>>>>>>>> const struct i2c_dev_boardinfo *boardinfo;
>>>>>>>> struct i2c_client *dev;
>>>>>>>> + u16 addr;
>>>>>>>> + u8 lvr;
>>>>>>> You also need to remove lvr from i2c_dev_boardinfo and adjust the code
>>>>>>> to use i2c_dev_desc->addr and i2c_dev_desc->lvr in this patch, not in
>>>>>>> patch 3.
>>>>>>>
>>>>>> Why can't we keep the lvr and addr in i2c_dev_boardinfo and need this information on i2c_dev_desc?
>>>>> Because i2c_dev_boardinfo is extracted from the DT and the secondary
>>>>> slaves does not necessarily have this description. The idea is to keep
>>>>> reserving the address slot for the I2C device even if we don't expose
>>>>> it to the upper layers.
>>>> So you are using i2c_dev_boardinfo just for DT devices?
>>> All devices that are described in some way, can be through DT, ACPI or
>>> board-file desc (only DT is supported right now, but we can easily add
>>> support for other formats).
>> We can drop i2c_dev_boardinfo.
>>
> Why you think we can drop it? We are still using it for DT devices.

Until now you need it to hold LVR, if you pass it to i2c_dev_desc, the i2c_board_info can be used for DT.

>
>>>> Because at end we need to register the new i2c devs.
>>> No, only those that have a valid description, because there's nothing
>>> you can expose if you only have the address and LVR values. You at
>>> least need to know which driver this dev should be attached to
>>> (compatible string in your DT) and most drivers also need extra
>>> information (basically all the DT props that are described a the DT
>>> binding).
>> In any case the HC need to know the bus mode, how is this done?
> LVR is passed through DEFSLVS command.

Is HC driver who set the bus mode? Shouldn't be the subsystem when you register all devices?