[U-Boot] [RFC PATCH 0/12] RFC: dm: Add I2C support

[Heiko Schocher <hs@denx.de>]

Hello Tom,

Am 24.10.2014 17:03, schrieb Tom Rini:
> On Sun, Oct 12, 2014 at 11:39:26PM -0600, Simon Glass wrote:
>
>> (Note this is RFC since the uclass interface needs discussion and also
>> because only sandbox is implemented so far. But I thought it best to get
>> this out there as soon as I wrote it as it may influence the PMIC library,
>> etc.)
>>
>> This series is an initial attempt to add I2C support to driver model. It
>> has become apparent that this is a high priority as it is widely used. It
>> follows along to some extent from the SPI conversion.
>>
>> Several changes are made from the original I2C implementations.
>>
>> Firstly It is not necessary to specify the chip address with every call,
>> since each chip knows its own address - it is stored in struct dm_i2c_chip
>> which is attached to each chip on the I2C bus. However, this information
>> *is* passed to the driver since I presume most drivers need it and it would
>> be cumbersome to look up in every call.
>>
>> Secondly there is no concept of a 'current' I2C bus so all associated logic
>> is removed. With driver model i2c_set_bus_num() and i2c_get_bus_num() are
>> not available. Since the chip device specifies both the bus and the chip
>> address, there is no need for this concept. It also causes problems when
>> one driver changes the current bus and forgets to change it back.
>>
>> Thirdly initialisation is handled by driver model's normal probe() method
>> on each device so there should be no need for i2c_init_all(), i2c_init(),
>> i2c_init_board(), i2c_board_late_init() and board_i2c_init().
>>
>> I2C muxes are not yet supported. To support these we will need to maintain
>> state of the current mux settings to avoid resetting every mux every time.
>> Probably we need to add a sandbox I2C mux driver to permit testing of this.
>> This can probably be done later.
>>
>> Platform data is not yet supported either, only device tree. The
>> U_BOOT_I2C_MKENT_COMPLETE() and U_BOOT_I2C_ADAP_COMPLETE() macros are not
>> used. Also struct i2c_adapter is not defined anymore. This will need to be
>> addressed, perhaps as part of converting over a board that does not use
>> device tree.
>>
>> This series is available at u-boot-dm/i2c-working.
>
> Nothing jumped out at me.  Heiko?

Looking in this patches soon... sorry for the delay.

bye,
Heiko
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