[U-Boot] [PATCH v3 0/29] Introduce driver model support for SPI, SPI flash, cros_ec

[Simon Glass]

Hi Jagan,

On 9 October 2014 04:33, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> On 9 October 2014 02:03, Simon Glass <sjg at chromium.org> wrote:
>> Hi,
>>
>> On 29 September 2014 13:34, 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, even at a subsystem level, is never going to work.
>>>
>>> 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 assist with the conversion of other SPI drivers, a README file is
>>> added to walk through the process.
>>>
>>> So far, sandbox, exynos and tegra drivers are converted over.
>>>
>>> As always, driver model patches are available at u-boot-dm.git branch
>>> 'working'. There is a branch for just this series called 'spi-working'.
>>
>> I think this has had enough time out there. So I will push this to
>> dm/next later this week.
>
> Sorry - I need to review a lot wrt v3.
> I do understand that it has been in enough time, but this causes a
> significant changes on
> entire framework, please hold on for a while I need to think with
> respect on qspi stuff with in
> the spi framework.

Well I'm not sure it supports setting of the flags that are needed for
that. I don't have a platform to test with anyway.

On the other hand adding that support to driver model could easily be
a separate effort. I don't see a good reason to hold up the core SPI /
SPI flash support.

Regards,
Simon