Re: [PATCH 5/7] hw/arm/mps2: Add I2C busses on FPGA APB

[Philippe Mathieu-Daudé]

On 6/16/20 12:21 PM, Peter Maydell wrote:
> On Tue, 16 Jun 2020 at 07:32, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>
>> There are 4 different I2C peripherals on the FPGA APB.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>  hw/arm/mps2.c | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/hw/arm/mps2.c b/hw/arm/mps2.c
>> index 4a49bfa9b9..6224d7a63c 100644
>> --- a/hw/arm/mps2.c
>> +++ b/hw/arm/mps2.c
>> @@ -321,6 +321,7 @@ static void mps2_common_init(MachineState *machine)
>>          create_unimplemented_device("cmsdk-ahb-gpio", gpiobase[i], 0x1000);
>>      }
>>
>> +    /* FPGA APB */
>>      sysbus_init_child_obj(OBJECT(mms), "scc", &mms->scc,
>>                            sizeof(mms->scc), TYPE_MPS2_SCC);
>>      sccdev = DEVICE(&mms->scc);
>> @@ -330,6 +331,12 @@ static void mps2_common_init(MachineState *machine)
>>      object_property_set_bool(OBJECT(&mms->scc), true, "realized",
>>                               &error_fatal);
>>      sysbus_mmio_map(SYS_BUS_DEVICE(sccdev), 0, 0x4002f000);
>> +    for (i = 0; i < 4; i++) {
>> +        static const hwaddr i2cbase[] = {0x40022000, 0x40023000,
>> +                                         0x40029000, 0x4002a000};
>> +
>> +        sysbus_create_simple("versatile_i2c", i2cbase[i], NULL);
>> +    }
> 
> Is this device really the same as the I2C controller h/w
> on the versatile board ?

It seems the opposite way around, the I2C controller modeled as
'versatile_i2c' is the real 'ARM SBCon two-wire serial bus interface'
bitbanging I2C. IIUC the name 'ARM SBCon two-wire serial bus interface'
became official /after/ the versatile was released, so 'versatile-i2c'
is the popular name.

Yes, the MPS2(+) implement the ARM SBCon two-wire serial bus interface.

I'll see to add a TYPE_SBCON_I2C alias, it might be easier.

> 
> thanks
> -- PMM
>