[U-Boot] [PATCH 0/25] Introduce driver model support for SPI, SPI flash, cros_ec

[Jagan Teki]

On Sun, Aug 10, 2014 at 2:59 AM, Simon Glass <sjg at chromium.org> wrote:
> Hi,
>
> On 14 July 2014 18:56, Simon Glass <sjg at chromium.org> wrote:
>> Up until now driver model has not been used for any type of bus. Buses
>> have some unique properties and needs, so we cannot claim that driver
>> model can cover all the common cases unless we have converted a bus over
>> to driver model.
>>
>> SPI is a reasonable choice for this next step. It has a fairly simple
>> API and not too many dependencies. The main one is SPI flash so we may
>> as well convert that also. Since the boards I test with have cros_ec I
>> have also included that, for SPI only.
>>
>> The technique used is make use of driver model's supported data structures
>> to hold information currently kept by each subsystem in a private data
>> structure. Since 'struct spi_slave' relates to the slave device on the bus
>> it is stored in the 'parent' data with each child device of the bus.
>> Since 'struct spi_flash' is a standard interface used for each SPI flash
>> driver, it is stored in the SPI FLash uclass's private data for each
>> device.
>>
>> New defines are created to enable driver model for each subsystem. These
>> are:
>>
>>    CONFIG_DM_SPI
>>    CONFIG_DM_SPI_FLASH
>>    CONFIG_DM_CROS_EC
>>
>> This allows us to move some boards and drivers to driver model, while
>> leaving others behind. A 'big bang' conversion of everything to driver
>> model, event at a subsystem level, is never going to work.
>>
>> On the other hand, we change the driver at the same time as the CONFIG
>> option is enabled. Keeping both version of the driver around involves a
>> flock of #ifdefs, the benefit of which is not apparent to me, since the
>> old code is removed anyway.
>>
>> There is some cost in changing the uclass interface after it is created,
>> so if you have limited time, please spend it reviewing the uclass
>> interfaces in spi.h and spi_flash.h. These need to be supported by each
>> driver, so changing them later may involve changing multiple drivers.
>>
>> To help with conversion of SPI drivers to driver model, documentation is
>> provided which takes the happy camper through the process with an example.
>>
>> As always, driver model patches are available at u-boot-dm.git branch
>> 'working'.
>>
>> Note: This series is not fully ready - e.g. some header files are missing
>> comments. But I wanted to get it out for review early since some SPI work
>> is ongoing which might depend on it.
>
> Are there any comments on this series please? I'd like to apply these
> to dm/master early next week, excluding the exynos ones.

I will be busy in next full week, give me 2 more weeks.
Probably I will give my comments on next to next weekend.

thanks!
-- 
Jagan.