On Tue, Jan 19, 2021 at 10:40:42AM +0000, Daniel Scally wrote:
> On 19/01/2021 09:24, Andy Shevchenko wrote:
> >>>>> +static struct i2c_driver int3472_tps68470 = {
> >>>>> + .driver = {
> >>>>> + .name = "int3472-tps68470",
> >>>>> + .acpi_match_table = int3472_device_id,
> >>>>> + },
> >>>>> + .probe_new = skl_int3472_tps68470_probe,
> >>>>> +};
> >>> I'm not sure we want to have like this. If I'm not mistaken the I?C driver can
> >>> be separated without ACPI IDs (just having I?C IDs) and you may instantiate it
> >>> via i2c_new_client_device() or i2c_acpi_new_device() whichever suits better...
> >> Sorry, I'm a bit confused by this. The i2c device is already
> >> present...we just want the driver to bind to them, so what role do those
> >> functions have there?
> > What I meant is something like
> >
> > *_i2c.c
> > real I?C driver for the TPS chip, but solely with I?C ID table, no ACPI
> > involved (and it sounds like it should be mfd/tps one, in which you
> > just cut out ACPI IDs and convert to pure I?C one, that what I had
> > suggested in the first place)
>
> Ahh; sorry - i misunderstood what you meant there. I understand now I
> think, but there is one complication; the ACPI subsystem already creates
> a client for that i2c adapter and address; i2c_new_client_device()
> includes a check to see whether that adapter / address combination has
> an i2c device already.? So we would have to have the platform driver
> with ACPI ID first find the existing i2c_client and unregister it before
> registering the new one...the existing clients have a name matching the
> ACPI device instance name (e.g i2c-INT3472:00) which we can't use as an
> i2c_device_id of course.
See how INT33FE is being handled. Hint: drivers/acpi/scan.c:~1600
static const struct acpi_device_id i2c_multi_instantiate_ids[] = {
{"BSG1160", },
{"BSG2150", },
{"INT33FE", },
{"INT3515", },
{}
};
So, we quirklist it here and instantiate manually from platform driver (new
coming one).
...
> > You need to modify clk-gpio.c to export
> >
> > clk_hw_register_gpio_gate()
> > clk_hw_register_gpio_mux()
> >
> > (perhaps it will require to add *_unregister() counterparts) and call it from
> > your code.
> >
> > See, for example, how clk_hw_unregister_fixed_rate() is being used. Another
Here I meant of course clk_hw_register_fixed_rate().
> > case is to add a helper directly into clk-gpio and call it instead of
> > clk_hw_*() one, see how clk_register_fractional_divider() is implemented and
> > used.
>
> I'll take a look, thanks
--
With Best Regards,
Andy Shevchenko
On Tue, Jan 19, 2021 at 01:08:37PM +0200, Andy Shevchenko wrote:
> On Tue, Jan 19, 2021 at 10:40:42AM +0000, Daniel Scally wrote:
> > On 19/01/2021 09:24, Andy Shevchenko wrote:
> > >>>>> +static struct i2c_driver int3472_tps68470 = {
> > >>>>> + .driver = {
> > >>>>> + .name = "int3472-tps68470",
> > >>>>> + .acpi_match_table = int3472_device_id,
> > >>>>> + },
> > >>>>> + .probe_new = skl_int3472_tps68470_probe,
> > >>>>> +};
> > >>> I'm not sure we want to have like this. If I'm not mistaken the I²C driver can
> > >>> be separated without ACPI IDs (just having I²C IDs) and you may instantiate it
> > >>> via i2c_new_client_device() or i2c_acpi_new_device() whichever suits better...
> > >> Sorry, I'm a bit confused by this. The i2c device is already
> > >> present...we just want the driver to bind to them, so what role do those
> > >> functions have there?
> > > What I meant is something like
> > >
> > > *_i2c.c
> > > real I²C driver for the TPS chip, but solely with I²C ID table, no ACPI
> > > involved (and it sounds like it should be mfd/tps one, in which you
> > > just cut out ACPI IDs and convert to pure I²C one, that what I had
> > > suggested in the first place)
> >
> > Ahh; sorry - i misunderstood what you meant there. I understand now I
> > think, but there is one complication; the ACPI subsystem already creates
> > a client for that i2c adapter and address; i2c_new_client_device()
> > includes a check to see whether that adapter / address combination has
> > an i2c device already. So we would have to have the platform driver
> > with ACPI ID first find the existing i2c_client and unregister it before
> > registering the new one...the existing clients have a name matching the
> > ACPI device instance name (e.g i2c-INT3472:00) which we can't use as an
> > i2c_device_id of course.
>
> See how INT33FE is being handled. Hint: drivers/acpi/scan.c:~1600
>
> static const struct acpi_device_id i2c_multi_instantiate_ids[] = {
> {"BSG1160", },
> {"BSG2150", },
> {"INT33FE", },
> {"INT3515", },
> {}
> };
>
> So, we quirklist it here and instantiate manually from platform driver (new
> coming one).
This is documented as used for devices that have multiple I2cSerialBus
resources. That's not the case for the INT3472 as far as I can tell. I
don't think we should abuse this mechanism.
Don't forget that the TPS68470 I2C driver needs to be ACPI-aware, as it
has to register an OpRegion for ACPI-based Chrome OS devices. On other
platforms (including DT platforms), it should only register regulators,
clocks and GPIOs. Given the differences between those platforms, I don't
think a TPS68470 driver that would fake being unaware of being probed
through ACPI would be a good idea. We can always refactor the code later
when we'll have a non-ACPI based platform using the TPS68470, without
such a platform there's no way we can test the I2C driver without ACPI
anyway.
> ...
>
> > > You need to modify clk-gpio.c to export
> > >
> > > clk_hw_register_gpio_gate()
> > > clk_hw_register_gpio_mux()
> > >
> > > (perhaps it will require to add *_unregister() counterparts) and call it from
> > > your code.
> > >
> > > See, for example, how clk_hw_unregister_fixed_rate() is being used. Another
>
> Here I meant of course clk_hw_register_fixed_rate().
>
> > > case is to add a helper directly into clk-gpio and call it instead of
> > > clk_hw_*() one, see how clk_register_fractional_divider() is implemented and
> > > used.
> >
> > I'll take a look, thanks
--
Regards,
Laurent Pinchart
On Tue, Jan 19, 2021 at 06:48:15PM +0200, Laurent Pinchart wrote:
> On Tue, Jan 19, 2021 at 01:08:37PM +0200, Andy Shevchenko wrote:
> > On Tue, Jan 19, 2021 at 10:40:42AM +0000, Daniel Scally wrote:
> > > On 19/01/2021 09:24, Andy Shevchenko wrote:
> > > >>>>> +static struct i2c_driver int3472_tps68470 = {
> > > >>>>> + .driver = {
> > > >>>>> + .name = "int3472-tps68470",
> > > >>>>> + .acpi_match_table = int3472_device_id,
> > > >>>>> + },
> > > >>>>> + .probe_new = skl_int3472_tps68470_probe,
> > > >>>>> +};
> > > >>> I'm not sure we want to have like this. If I'm not mistaken the I?C driver can
> > > >>> be separated without ACPI IDs (just having I?C IDs) and you may instantiate it
> > > >>> via i2c_new_client_device() or i2c_acpi_new_device() whichever suits better...
> > > >> Sorry, I'm a bit confused by this. The i2c device is already
> > > >> present...we just want the driver to bind to them, so what role do those
> > > >> functions have there?
> > > > What I meant is something like
> > > >
> > > > *_i2c.c
> > > > real I?C driver for the TPS chip, but solely with I?C ID table, no ACPI
> > > > involved (and it sounds like it should be mfd/tps one, in which you
> > > > just cut out ACPI IDs and convert to pure I?C one, that what I had
> > > > suggested in the first place)
> > >
> > > Ahh; sorry - i misunderstood what you meant there. I understand now I
> > > think, but there is one complication; the ACPI subsystem already creates
> > > a client for that i2c adapter and address; i2c_new_client_device()
> > > includes a check to see whether that adapter / address combination has
> > > an i2c device already.? So we would have to have the platform driver
> > > with ACPI ID first find the existing i2c_client and unregister it before
> > > registering the new one...the existing clients have a name matching the
> > > ACPI device instance name (e.g i2c-INT3472:00) which we can't use as an
> > > i2c_device_id of course.
> >
> > See how INT33FE is being handled. Hint: drivers/acpi/scan.c:~1600
> >
> > static const struct acpi_device_id i2c_multi_instantiate_ids[] = {
> > {"BSG1160", },
> > {"BSG2150", },
> > {"INT33FE", },
> > {"INT3515", },
> > {}
> > };
> >
> > So, we quirklist it here and instantiate manually from platform driver (new
> > coming one).
>
> This is documented as used for devices that have multiple I2cSerialBus
> resources. That's not the case for the INT3472 as far as I can tell. I
> don't think we should abuse this mechanism.
This is quite a similar case to that one. Let's avoid yak shaving, right?
> Don't forget that the TPS68470 I2C driver needs to be ACPI-aware, as it
> has to register an OpRegion for ACPI-based Chrome OS devices. On other
> platforms (including DT platforms), it should only register regulators,
> clocks and GPIOs. Given the differences between those platforms, I don't
> think a TPS68470 driver that would fake being unaware of being probed
> through ACPI would be a good idea. We can always refactor the code later
> when we'll have a non-ACPI based platform using the TPS68470, without
> such a platform there's no way we can test the I2C driver without ACPI
> anyway.
Are you agree that MFD approach should stay? How then we can manage to have an
MFD driver cohabit with our new driver? I proposed a clean solution which will
handle all possible cases via quirk driver. Having two drivers enumerated by
different scenarios is a call for troubles (we have already with one of that
sensors).
And there is no "faking" anything, it's rather gating it depending on the
platform.
--
With Best Regards,
Andy Shevchenko