Hi Andy,
On 8/26/24 10:10 PM, Andy Shevchenko wrote:
> Wed, Aug 14, 2024 at 02:29:39PM +0100, Richard Fitzgerald kirjoitti:
>> Change the Kconfig dependency so that it doesn't require both I2C and SPI
>> subsystems to be built. Make a few small changes to the code so that the
>> code for a bus is only called if the bus is being built.
>>
>> When SPI support was added to serial-multi-instantiate it created a
>> dependency that both CONFIG_I2C and CONFIG_SPI must be enabled.
>> Typically they are, but there's no reason why this should be a
>> requirement. A specific kernel build could have only I2C devices
>> or only SPI devices. It should be possible to use serial-multi-instantiate
>> if only I2C or only SPI is enabled.
>>
>> The dependency formula used is:
>>
>> depends on (I2C && !SPI) || (!I2C && SPI) || (I2C && SPI)
>>
>> The advantage of this approach is that if I2C=m or SPI=m then
>> SERIAL_MULTI_INSTANTIATE is limited to n/m.
>
> ...
>
>> static void smi_devs_unregister(struct smi *smi)
>> {
>> +#if IS_REACHABLE(CONFIG_I2C)
>
> There is no explanation why ugly ifdeffery is used here, while normal
> conditionals elsewhere.
Note that this has already been merged as is, as you've figured
out yourself the reason to use #ifdef here is because
there is no i2c_unregister_device() prototype declared when
CONFIG_I2C=n
>
>> while (smi->i2c_num--)
>> i2c_unregister_device(smi->i2c_devs[smi->i2c_num]);
>> +#endif
>>
>> - while (smi->spi_num--)
>> - spi_unregister_device(smi->spi_devs[smi->spi_num]);
>> + if (IS_REACHABLE(CONFIG_SPI)) {
>> + while (smi->spi_num--)
>> + spi_unregister_device(smi->spi_devs[smi->spi_num]);
>> + }
>> }
>
> There are ways to solve this:
> 1) add a stub for I2C=n for i2c_unregister_device();
Yes that would be an option to clean this up a bit as a follow-up
patch series.
Note no need for a stub, just move the declaration out of
the #if IS_ENABLED(CONFIG_I2C) block, using if (IS_REACHABLE)
only requires a prototype.
> 2) resplit this driver to have several built modules:
> core, I2C parts, SPI parts.
>
Regards,
Hans
