Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

[Lee Jones]

On Thu, 21 Oct 2021, Dmitry Osipenko wrote:

> Driver was upstreamed in 2013 and never got a user, remove it.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/mfd/Kconfig          |  14 -
>  drivers/mfd/Makefile         |   1 -
>  drivers/mfd/tps80031.c       | 526 -----------------------------
>  include/linux/mfd/tps80031.h | 637 -----------------------------------
>  4 files changed, 1178 deletions(-)
>  delete mode 100644 drivers/mfd/tps80031.c
>  delete mode 100644 include/linux/mfd/tps80031.h

> -static const struct i2c_device_id tps80031_id_table[] = {
> -	{ "tps80031", TPS80031 },
> -	{ "tps80032", TPS80032 },
> -	{ }
> -};

This is an I2C driver, right?

I was under the impression that Linux could do auto-probing on I2C
devices?  Such that they do not require platform code or DT in order
to bind?

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

[Dmitry Osipenko]

22.10.2021 11:05, Lee Jones пишет:
> On Thu, 21 Oct 2021, Dmitry Osipenko wrote:
> 
>> Driver was upstreamed in 2013 and never got a user, remove it.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  drivers/mfd/Kconfig          |  14 -
>>  drivers/mfd/Makefile         |   1 -
>>  drivers/mfd/tps80031.c       | 526 -----------------------------
>>  include/linux/mfd/tps80031.h | 637 -----------------------------------
>>  4 files changed, 1178 deletions(-)
>>  delete mode 100644 drivers/mfd/tps80031.c
>>  delete mode 100644 include/linux/mfd/tps80031.h
> 
>> -static const struct i2c_device_id tps80031_id_table[] = {
>> -	{ "tps80031", TPS80031 },
>> -	{ "tps80032", TPS80032 },
>> -	{ }
>> -};
> 
> This is an I2C driver, right?
> 
> I was under the impression that Linux could do auto-probing on I2C
> devices?  Such that they do not require platform code or DT in order
> to bind?
> 

It's I2C driver. I'm not sure about auto-probing because something
should provide information about device to Linux. It's possible to
detect/scan whether there is device sitting on I2C address, but there is
no auto-discovery mechanism, AFAIK.

TPS80031 device will fail to bind to this driver because it explicitly
requires platform data which should be NULL if device is probed solely
by I2C ID.

Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

[Wolfram Sang]

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> It's I2C driver. I'm not sure about auto-probing because something
> should provide information about device to Linux. It's possible to
> detect/scan whether there is device sitting on I2C address, but there is
> no auto-discovery mechanism, AFAIK.

Well, in general, it could be manually instantiated from userspace...

> 
> TPS80031 device will fail to bind to this driver because it explicitly
> requires platform data which should be NULL if device is probed solely
> by I2C ID.

..but I agree in this case. The driver has this code:

        if (!pdata) {
                dev_err(&client->dev, "tps80031 requires platform data\n");
                return -EINVAL;
        }

and git grep shows no user having platform data.

Shouldn't 'drivers/regulator/tps80031-regulator.c' and
'./rtc/rtc-tps80031.c' be removed as well?


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Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

[Dmitry Osipenko]

22.10.2021 11:46, Wolfram Sang пишет:
> 
>> It's I2C driver. I'm not sure about auto-probing because something
>> should provide information about device to Linux. It's possible to
>> detect/scan whether there is device sitting on I2C address, but there is
>> no auto-discovery mechanism, AFAIK.
> 
> Well, in general, it could be manually instantiated from userspace...
> 
>>
>> TPS80031 device will fail to bind to this driver because it explicitly
>> requires platform data which should be NULL if device is probed solely
>> by I2C ID.
> 
> ..but I agree in this case. The driver has this code:
> 
>         if (!pdata) {
>                 dev_err(&client->dev, "tps80031 requires platform data\n");
>                 return -EINVAL;
>         }
> 
> and git grep shows no user having platform data.
> 
> Shouldn't 'drivers/regulator/tps80031-regulator.c' and
> './rtc/rtc-tps80031.c' be removed as well?
> 

They are removed by the other 2 patches of this series [1].

[1] https://lore.kernel.org/all/20211021192258.21968-1-digetx@gmail.com/

Re: [PATCH v1 3/3] mfd: tps80031: Remove driver

[Lee Jones]

On Fri, 22 Oct 2021, Dmitry Osipenko wrote:

> 22.10.2021 11:05, Lee Jones пишет:
> > On Thu, 21 Oct 2021, Dmitry Osipenko wrote:
> > 
> >> Driver was upstreamed in 2013 and never got a user, remove it.
> >>
> >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> >> ---
> >>  drivers/mfd/Kconfig          |  14 -
> >>  drivers/mfd/Makefile         |   1 -
> >>  drivers/mfd/tps80031.c       | 526 -----------------------------
> >>  include/linux/mfd/tps80031.h | 637 -----------------------------------
> >>  4 files changed, 1178 deletions(-)
> >>  delete mode 100644 drivers/mfd/tps80031.c
> >>  delete mode 100644 include/linux/mfd/tps80031.h
> > 
> >> -static const struct i2c_device_id tps80031_id_table[] = {
> >> -	{ "tps80031", TPS80031 },
> >> -	{ "tps80032", TPS80032 },
> >> -	{ }
> >> -};
> > 
> > This is an I2C driver, right?
> > 
> > I was under the impression that Linux could do auto-probing on I2C
> > devices?  Such that they do not require platform code or DT in order
> > to bind?
> > 
> 
> It's I2C driver. I'm not sure about auto-probing because something
> should provide information about device to Linux. It's possible to
> detect/scan whether there is device sitting on I2C address, but there is
> no auto-discovery mechanism, AFAIK.
> 
> TPS80031 device will fail to bind to this driver because it explicitly
> requires platform data which should be NULL if device is probed solely
> by I2C ID.

This is a fair point.

I'll take the patch, thanks.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog