[U-Boot] [PATCH 2/2] fsl: esdhc: support driver model

[Peng Fan]

Hi Simon,

On Fri, Mar 11, 2016 at 05:33:05PM -0700, Simon Glass wrote:
>Hi Peng,
>
>On 10 March 2016 at 01:57, Peng Fan <van.freenix at gmail.com> wrote:
>> Support Driver Model for fsl esdhc driver.
>>
>> In order to minimize the change, reuse the fsl_esdhc_initialize function.
>> This new way is to fill an fsl_esdhc_cfg struture and pass it
>> to fsl_esdhc_initialize, just like the code in different board codes.
>>
>> Introduce a 'struct mmc *mmc' entry in fsl_esdhc_cfg structure,
>> otherwise fsl_esdhc_initialize may need to be restructured which will
>> cause lots changes for board code.
>>
>> Since clk driver is not implemented, use mxc_get_clock here to
>> fill cfg->sdhc_clk. Anyway we can utilize the pinctrl imx driver
>> now, except the SPL part, we can drop the pinmux settings from
>> board file for mmc.
>>
>> There are so many "ifdef" in the file, maybe we can use driver data
>> or quirks to cover these. But to minimize changes for this patch,
>> these are not included. Later we can try to discard the nasty
>> ifdef.
>>
>> Has been tested on i.MX6UL 9x9 EVK board:
>> "
>> =>dm tree
>> ....
>>  simple_bus  [ + ]    |   `-- aips-bus at 02100000
>>   mmc        [ + ]    |       |-- usdhc at 02190000
>>   mmc        [ + ]    |       |-- usdhc at 02194000
>> ....
>> => mmc list
>> FSL_SDHC: 0 (SD)
>> FSL_SDHC: 1 (SD)
>> "
>>
>> Signed-off-by: Peng Fan <van.freenix at gmail.com>
>> Cc: York Sun <york.sun at nxp.com>
>> Cc: Yangbo Lu <yangbo.lu at nxp.com>
>> Cc: Hector Palacios <hector.palacios at digi.com>
>> Cc: Eric Nelson <eric at nelint.com>
>> Cc: Stefano Babic <sbabic at denx.de>
>> Cc: Fabio Estevam <fabio.estevam at nxp.com>
>> Cc: Pantelis Antoniou <panto at antoniou-consulting.com>
>> Cc: Simon Glass <sjg at chromium.org>
>> ---
>>  drivers/mmc/fsl_esdhc.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/fsl_esdhc.h     |  1 +
>>  2 files changed, 82 insertions(+)
>
>I'm nervous about this patch. It is calling board code from a driver,
>which we should avoid.

No. I may need to write more in the commit log.
The current way without driver model is
board code fill fsl_esdhc_cfg strucure and then call fsl_esdhc_initialize
which is in driver/mmc/fsl_esdhc.c.

In order to minimize changes, in this patch, the probe function
will fill fsl_esdhc_cfg structure and call fsl_esdhc_initialize.

Then we can drop the function call to fsl_esdhc_initialize in different board code.

I originally want to rewrite fsl_esdhc_cfg structure, may give it a new name
such as fsl_esdhc_platdata or priv, but this may incur lots changes in
board code, because board code also refers to this structure. So I keep in.

>Perhaps it would be better to start by refactoring things to fix the
>problems you mention, and then come back to this patch? I'm worried
>we'll end up with a driver model conversion that never gets properly
>finished if we do things in the wrong order.

Please kind take my upper words. I am still thinking add "non-removable",
"cd-gpios" related code in this patch, so I'll write a new version patch. 

Thanks,
Peng.

>
>Regards,
>Simon