[U-Boot] [PATCH 3/3] Kconfig: i2c: add entry for driver-model software i2c

[Przemyslaw Marczak <p.marczak@samsung.com>]

Hello Masahiro,

On 03/25/2015 04:35 AM, Masahiro Yamada wrote:
> Hi.
>
>
>
> 2015-03-10 19:30 GMT+09:00 Przemyslaw Marczak <p.marczak@samsung.com>:
>> Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
>> Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
>
> I am no longer working for Panasonic.
> The old email address will get unavailable at the end of March.
>
> Going forward, please use my new address, yamada.masahiro at socionext.com
>
>
>

Ok, will update this.

>>
>> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
>> index 0a52ed9..dd7eb3c 100644
>> --- a/drivers/i2c/Kconfig
>> +++ b/drivers/i2c/Kconfig
>> @@ -13,6 +13,49 @@ config DM_I2C_COMPAT
>>            to convert all code for a board in a single commit. It should not
>>            be enabled for any board in an official release.
>>
>> +config DM_I2C_SOFT
>> +       bool "Enable Driver Model for Software I2C Driver"
>> +       depends on DM_I2C
>> +       help
>> +         Enable the i2c bus driver emulation by using GPIO.
>
> Very nice!
>
>> +         The bus configuration is given by the device-tree, like below.
>> +
>> +         /* First, define the alias number to have continuous bus numbering */
>> +         aliases {
>> +           [...]
>> +           i2c5 = "/i2c at 13500000";
>> +           i2c6 = "/soft-i2c at 1";
>> +           [...]
>> +         }
>
> This description is not specific to this CONFIG option.
>
> The relation between the aliases node and the sequence number
> is well-documented in doc/driver-model/README.txt.
>
> Should we repeat it here?
>
>

Yes, you are right. I wanted to put here all informations, required to 
make it working with devices, since I think it could facilitate the 
development for the others.
Will remove this.

>> +         /* And next define the basic bus attributes */
>> +         soft-i2c at 1 {
>> +           #address-cells = <1>;
>> +           #size-cells = <0>;
>> +           compatible = "soft-i2c";
>> +           clock-frequency = <50000>;
>> +           /* Define the proper GPIO pins */
>> +           clock-pin = <&gpa0 0 GPIO_ACTIVE_HIGH>;
>> +           data-pin = <&gpa0 1 GPIO_ACTIVE_HIGH>;
>> +
>> +           /* Optionally, define some driver node (bus child) */
>> +           somedev at 0x44 {
>> +               compatible = "somedev";
>> +               reg = <0x44>;
>> +               [...]
>> +           };
>> +         }
>
> This is binding information, right?
>
> Stuff like that is usually documented in a separate text file.
>
> In Linux, Documentation/devicetree/bindings/i2c/
> In U-boot, doc/device-tree-bindings/i2c/
>

Right, will move into proper path.

>
>
>> +         The device can be accessed by the i2c command:
>> +         # i2c dev 8                   (bus number set by alias)
>> +         # i2c probe <0x44>            (address is optionally)
>> +         # i2c md 0x44 0x0             (dump dev registers at address 0x0)
>> +         # Valid chip addresses: 0x44  (success!)
>> +         ...
>
>
> This is the usage of "i2c" command.
> It is not specific to this option, either.
 >

Ok.

>
>
>
>> +         Driving the bus lines is done by dm gpio calls in the preprocessor
>> +         macros. Each, can be redefined by the user.
>> +
>>   config SYS_I2C_UNIPHIER
>>          bool "UniPhier I2C driver"
>>          depends on ARCH_UNIPHIER && DM_I2C
>> --
>> 1.9.1
>>
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>
>
>

Thanks for review!

Best regards,
-- 
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marczak at samsung.com