[U-Boot] question about software i2c multi instance

[Bo Shen <voice.shen@atmel.com>]

Hi Heiko,

On 03/20/2015 06:10 PM, Heiko Schocher wrote:
> Hello Bo,
>
> Am 20.03.2015 10:44, schrieb Bo Shen:
>> Hi Heiko,
>>    After check the software i2c code, I found it can not support multi
>> instances, although it has I2C_SOFT_DECLARATIONS2,
>> I2C_SOFT_DECLARATIONS3, I2C_SOFT_DECLARATIONS4.
>>    Because, when do GPIO operation, there is only one pair of
>> CONFIG_SOFT_I2C_GPIO_SCL and CONFIG_SOFT_I2C_GPIO_SDA.
>>    So, if want to support multi instances, it needs to extend the GPIO
>> configuration for SCL/SDA, am I right?
>
> Prefered way should be to use DM, Przemyslaw posted patches
> for the soft-i2c driver, see
> http://lists.denx.de/pipermail/u-boot/2015-March/207641.html
>
> maybe you can try this?

Thanks for your information.
As I try to use the old version of U-Boot, it doesn't support DM well.

> If not, you are right, you must define your own
> I2C_SCL/I2C_SDA/I2C_READ/I2C_INIT
> defines, for example:
>
> #  define I2C_SCL(bit) \
>          do { \
>          switch(I2C_ADAP_HWNR) {
>              case 0:
>
> gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL_0, bit); \
>                  break;
>              case 1:
>
> gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL_1, bit); \
>                  break;
>              [...]
>                  I2C_GPIO_SYNC; \
>          } while (0)

For this, the I2C_SCL and I2C_SDA working, however for I2C_READ, it 
maybe need to modify the definition from micro to function, as the 
I2C_READ can not use do {} while.

Thanks again.

> bye,
> Heiko

Best Regards,
Bo Shen