diff mbox series

[RFC] scmi: pinctrl: support i.MX9

Message ID 20230824070611.3335107-1-peng.fan@oss.nxp.com
State New
Headers show
Series [RFC] scmi: pinctrl: support i.MX9 | expand

Commit Message

Peng Fan (OSS) Aug. 24, 2023, 7:06 a.m. UTC
From: Peng Fan <peng.fan@nxp.com>

Based on : https://lore.kernel.org/all/cover.1691518313.git.oleksii_moisieiev@epam.com/

The upper patchset not support multiple configs in SCMI 3.2, this patch
add that in config_set, not update config_get, I suppose Oleksii will
fix.

This patch is just to introduce i.MX support to see whether people have
comments for the design.

The binding format:
<mux_reg conf_reg input_reg mux_mode input_val>
dts:
	pinctrl_uart1: uart1grp {
		fsl,pins = <
			MX93_PAD_UART1_RXD__LPUART1_RX			0x31e
			MX93_PAD_UART1_TXD__LPUART1_TX			0x31e
		>;
	};

i.MX pinctrl not use generic pinconf, this has been agreeed by
maintainers before. So after moving to SCMI, we will still
keep the same binding format, and i.MX SCMI firmware also use same
format when configure registers. So we need to use i.MX specific
dt_node_to_map function.

I not have good idea how to call imx dt_node_to_map, so just use
extern and of_machine_is_compatible to call imx dt_node_to_map.
Hope you could give some suggestions.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/arm_scmi/pinctrl.c     |  22 ++--
 drivers/pinctrl/freescale/pinctrl-imx.c | 130 +++++++++++++++++++++---
 drivers/pinctrl/pinctrl-scmi.c          |  53 +++++-----
 include/linux/scmi_protocol.h           |   2 +-
 4 files changed, 154 insertions(+), 53 deletions(-)

Comments

Linus Walleij Aug. 24, 2023, 8:43 a.m. UTC | #1
On Thu, Aug 24, 2023 at 9:01 AM Peng Fan (OSS) <peng.fan@oss.nxp.com> wrote:

> This patch is just to introduce i.MX support to see whether people have
> comments for the design.

Very interesting!

> The binding format:
> <mux_reg conf_reg input_reg mux_mode input_val>
> dts:
>         pinctrl_uart1: uart1grp {
>                 fsl,pins = <
>                         MX93_PAD_UART1_RXD__LPUART1_RX                  0x31e
>                         MX93_PAD_UART1_TXD__LPUART1_TX                  0x31e
>                 >;
>         };
>
> i.MX pinctrl not use generic pinconf, this has been agreeed by
> maintainers before.

Yes, it has historical reasons.

> So after moving to SCMI, we will still
> keep the same binding format, and i.MX SCMI firmware also use same
> format when configure registers. So we need to use i.MX specific
> dt_node_to_map function.

I thought the idea with SCMI was to abstract and hide the characteristics of
the underlying hardware. I.e. the firmware is to present groups and
functions and generic config options and then the driver will use these.

This patch, it seems, creates a hybrid between the old freescale driver
and the SCMI firmware communication link where the SCMI is just a
transport mechanism to something inside SCMI that poke the same
registers that userspace could poke, if it could only access these
registers.

I.e using SCMI on this platform isn't creating any abstraction of the
pin control hardware, it is merely making things more complex and
also slower bymaking the registers only accessible from this SCMI link.

But I could have misunderstood it, so please correct me!

Yours,
Linus Walleij
Linus Walleij Aug. 25, 2023, 8:28 a.m. UTC | #2
On Thu, Aug 24, 2023 at 2:47 PM Peng Fan <peng.fan@nxp.com> wrote:
> Me:

>> it is merely making things more complex and also slower
> > bymaking the registers only accessible from this SCMI link.
>
> This is for safety reason, the pinctrl hardware must be handled
> by a system manager entity. So mmio direct access not allowed
> from Cortex-A side.

Yeah I understood as much. But I don't think that the firmware is
really filtering any of the access, it will just poke into any pinctrl
register as instructed anyway so what's the point. Just looks like
a layer of indirection. But I'm not your system manager, so it's not
my decision.

> The SCMI firmware is very straightforward, there is no group or
> function.
>
> It just accepts the format as this:
> MUX_TYPE, MUX VALUE, CONF_TYPE, CONF_VAL, DAISY_TYPE,
> DAISY ID, DAISY_CFG, DAISY_VALUE.
>
> Similar as linux MMIO format.
>
> Our i.MX95 platform will support two settings, one with SCMI
> firmware, one without SCMI. These two settings will share
> the same pinctrl header file.
>
> And to simplify the scmi firmware design(anyway I am not owner
> of the firmware), to make pinctrl header shared w/o scmi,
> we take the current in-upstream freescale imx binding format.

The SCMI people will have to state their position on this.
Like what they consider conformance and what extensions are
allowed. This is more a standardization question than an
implementation question so it's not really my turf.

I was under the impression that the ambition with SCMI firmware
was to abstract away and hide aspects of the hardware behind
a consistent API. This approach drives a truck through that
idea.

Yours,
Linus Walleij
Peng Fan Aug. 25, 2023, 8:43 a.m. UTC | #3
> Subject: Re: [RFC] scmi: pinctrl: support i.MX9
> 
> On Thu, Aug 24, 2023 at 2:47 PM Peng Fan <peng.fan@nxp.com> wrote:
> > Me:
> 
> >> it is merely making things more complex and also slower
> > > bymaking the registers only accessible from this SCMI link.
> >
> > This is for safety reason, the pinctrl hardware must be handled by a
> > system manager entity. So mmio direct access not allowed from Cortex-A
> > side.
> 
> Yeah I understood as much. But I don't think that the firmware is really
> filtering any of the access, it will just poke into any pinctrl register as
> instructed anyway so what's the point. Just looks like a layer of indirection.

No, the firmware has a check on whether a pin is allowed to be configured
by the agent that wanna to configure the pin. 

> But I'm not your system manager, so it's not my decision.
> 
> > The SCMI firmware is very straightforward, there is no group or
> > function.
> >
> > It just accepts the format as this:
> > MUX_TYPE, MUX VALUE, CONF_TYPE, CONF_VAL, DAISY_TYPE, DAISY ID,
> > DAISY_CFG, DAISY_VALUE.
> >
> > Similar as linux MMIO format.
> >
> > Our i.MX95 platform will support two settings, one with SCMI firmware,
> > one without SCMI. These two settings will share the same pinctrl
> > header file.
> >
> > And to simplify the scmi firmware design(anyway I am not owner of the
> > firmware), to make pinctrl header shared w/o scmi, we take the current
> > in-upstream freescale imx binding format.
> 
> The SCMI people will have to state their position on this.
> Like what they consider conformance and what extensions are allowed. This
> is more a standardization question than an implementation question so it's
> not really my turf.

The i.MX95 SCMI firmware uses OEM extension type. So I just follow
what the firmware did and support it in linux. Anyway let's
wait Sudeep's reply.

Thanks,
Peng.

> 
> I was under the impression that the ambition with SCMI firmware was to
> abstract away and hide aspects of the hardware behind a consistent API.
> This approach drives a truck through that idea.
> 
> Yours,
> Linus Walleij
Cristian Marussi Sept. 7, 2023, 10:05 a.m. UTC | #4
On Wed, Sep 06, 2023 at 02:43:46PM +0900, AKASHI Takahiro wrote:
> On Wed, Aug 30, 2023 at 02:37:48PM +0100, Cristian Marussi wrote:
> > On Wed, Aug 30, 2023 at 12:48:37PM +0000, Peng Fan wrote:
> > > Hi Cristian,
> > > 
> > 
> > Hi,
> > 

Hi,

> > > > Subject: Re: [RFC] scmi: pinctrl: support i.MX9
> > > > 
> > > > On Fri, Aug 25, 2023 at 08:43:38AM +0000, Peng Fan wrote:
> > > > > > Subject: Re: [RFC] scmi: pinctrl: support i.MX9
> > > > > >
> > > > > > On Thu, Aug 24, 2023 at 2:47 PM Peng Fan <peng.fan@nxp.com> wrote:
> > > > > > > Me:
> > > > 
> > > > Hi Peng,
> > > > 
> > > > > >
> > > > > > >> it is merely making things more complex and also slower
> > > > > > > > bymaking the registers only accessible from this SCMI link.
> > > > > > >
> > > > > > > This is for safety reason, the pinctrl hardware must be handled by
> > > > > > > a system manager entity. So mmio direct access not allowed from
> > > > > > > Cortex-A side.
> > > > > >
> > > > > > Yeah I understood as much. But I don't think that the firmware is
> > > > > > really filtering any of the access, it will just poke into any
> > > > > > pinctrl register as instructed anyway so what's the point. Just looks like a
> > > > layer of indirection.
> > > > >
> > > > > No, the firmware has a check on whether a pin is allowed to be
> > > > > configured by the agent that wanna to configure the pin.
> > > > >
> > > > > > But I'm not your system manager, so it's not my decision.
> > > > > >
> > > > > > > The SCMI firmware is very straightforward, there is no group or
> > > > > > > function.
> > > > > > >
> > > > > > > It just accepts the format as this:
> > > > > > > MUX_TYPE, MUX VALUE, CONF_TYPE, CONF_VAL, DAISY_TYPE, DAISY
> > > > ID,
> > > > > > > DAISY_CFG, DAISY_VALUE.
> > > > > > >
> > > > > > > Similar as linux MMIO format.
> > > > > > >
> > > > > > > Our i.MX95 platform will support two settings, one with SCMI
> > > > > > > firmware, one without SCMI. These two settings will share the same
> > > > > > > pinctrl header file.
> > > > > > >
> > > > > > > And to simplify the scmi firmware design(anyway I am not owner of
> > > > > > > the firmware), to make pinctrl header shared w/o scmi, we take the
> > > > > > > current in-upstream freescale imx binding format.
> > > > > >
> > > > > > The SCMI people will have to state their position on this.
> > > > > > Like what they consider conformance and what extensions are allowed.
> > > > > > This is more a standardization question than an implementation
> > > > > > question so it's not really my turf.
> > > > >
> > > > > The i.MX95 SCMI firmware uses OEM extension type. So I just follow
> > > > > what the firmware did and support it in linux. Anyway let's wait
> > > > > Sudeep's reply.
> > > > >
> > > > 
> > > > So my unsderstanding on this matter as of now is that:
> > > > 
> > > > 1. the current SCMI Pinctrl specification can support your usecase by using
> > > >    OEM Types and multiple pins/values CONFIG_GET/SET commands
> > > 
> > > Yes, based on the Oleksii patchset with my local multiple configs support.
> > > 
> > 
> > Yes, I know, I pointed out on his series that the protocol has still to
> > be fixed to be aligned with the latest BETA2 spec (we changed the spec
> > on the fly while he was already posting indeed..)
> > 
> > > > 
> > > > 2. the Kernel SCMI protocol layer (driver/firmware/arm_scmi/pinctrl.c)
> > > >    is equally fine and can support your usecase, AFTER Oleksii fixes it to
> > > >    align it to the latest v3.2-BETA2 specification changes.
> > > >    IOW, this means that, using the SCMI Pinctrl protocol operations
> > > >    exposed in scmi_protocol.h, from somewhere, you are able to properly
> > > >    configure multiple pins/values with your specific OEM types.
> > > 
> > > Yes.
> > 
> > Good.
> > 
> > > 
> > > > 
> > > > 3. The SCMI Pinctrl driver (by Oleksii) built on top of the pinctrl protocol
> > > >    operations is instead NOT suitable for your usecase since it uses the Linux
> > > >    Generic Pinconf and IMX does not make use of it, and instead IMX has
> > > >    its own bindings and related parsing logic.
> > > 
> > > Yes.
> > > 
> > > > 
> > > > Am I right ?
> > > 
> > > You are right.
> > > 
> > > > 
> > > > If this is the case, I would NOT try to abuse the current SCMI Pinctrl Generic
> > > > driver (by Oleksii) by throwing into it a bunch of IMX specific DT parsing,
> > > > also because you'll end-up NOT using most of the generic SCMI Pinctrl driver
> > > > but just reusing a bit of the probe (customized with your own DT maps
> > > > parsing)
> > > 
> > > Only DT map to parse the dts and map to config array. Others are same,
> > > so need to export some symbols for pinctrl-scmi-imx.c driver if build imx
> > > scmi driver.
> > >
> > 
> > Yes, but you are basically using some exported symbol to parse the DT in
> > your way and then you do not use anything of the various
> > functions/groups stuff...you just leverage some of the probing stuff and
> > then issue you OEM Type configs....I mean most of the picntrl-scmi
> > driver would be unused anyway in this scenario.
> > 
> > > > 
> > > > Instead, given that the spec[1.] and the protocol layer[2.] are fine for your
> > > > use case and you indeed have already a custom way to parse your DT
> > > > mappings, I would say that you could just write your own custom SCMI
> > > > driver ( ? pinctrl-imx-scmi), distinct and much more simple than the generic
> > > > one, that does its own IMX DT parsing and calls just the SCMI protocol
> > > > operations that it needs in the way that your platform expects: so basically
> > > > another Pinctrl SCMI driver that does not use the generic pinconf DT
> > > > configuration BUT DO USE the underlying SCMI Pinctrl protocol (via its
> > > > exposed protocol operations...)
> > > 
> > > I am ok with this approach, but I need use the other ID, saying 0x99, not 0x19,
> > > because 0x19 will bind with the pinctrl-scmi.c driver, I could not reuse
> > > this ID for i.MX pinctrl-scmi-imx driver. Otherwise there will be issue if both
> > > driver are built in kernel image.
> > > 
> > 
> > Ok here I lost you.
> > 
> > The protocol ID 0x19 is bound to the protocol layer and identifies the
> > standard Pinctrl protocol: usually you use a 0x99 to define and describe
> > you own specific NEW vendor protocol, BUT here you are saying you are fine to
> > use std Pinctrl spec AND the protocol operations as exposed in pinctrl.c, so
> > I dont see why you should use a new vendor protocol_id to basically
> > expose the same operations. (and I also dont see how you can do that
> > without hacks in the current codebase)
> > 
> > You CAN have multiple SCMI drivers using the same protocol at the same
> > time (even more than one protocol at the same time), even though we try
> > to avoid it if there are no good reason to have more than one driver, there
> > is nothing in the spec or in the current SCMI platform or agent stacks that
> > inhibits such scenario (and I use iot heavily for my offline testing
> > indeed.)
> > 
> > Look at:
> > 
> >  - drivers/hwmon/scmi-hwmon 
> >  - drivers/iio/common/scmi_sensors/scmi_iio.c
> > 
> > and you'll see that these 2 drivers uses the same SENSOR protocol, just for
> > different sensor types so they do not interfere one with each other.
> 
> Then, how are those two devices identified in a device tree?

At SCMI probe time the SCMI core stack creates one device for each
'protocol_id/name' as provided by the registered SCMI drivers in
their respective scmi_device_id/id_tableS, as long as the requested
protocol is active in the DT (protocol@XX defined) and the 'name'
is not duplicated; each of these devices, sharing the same SCMI
protocol, are created sharing also the same DT node protocol@XX.

Their respective SCMI drivers are subsequently separately matched on
protocol_id/name and then probed as usual: it is up to the drivers not
to step on each other feet by competing for the same SCMI resources...
...like issuing comflicting request for the same reosurce domain
on the same protocol.

I suppose, though, a lot depends on how the respective drivers interact
with their subsystems, like IIO SCMI does not really need any info
from DT, and the hwmon uses just the phandle to pick the sensor_domain_id
to associate, as an example, to thermal sensors.

> That is the point in Peng's case and why he wants to have a dedicated
> protocol id (I don't agree to this, though.)
> If we follow Cristian's idea, we may want to have two dt nodes, say
> pinctrl-scmi-generic and pinctrl-scmi-imx, as phandles for other device
> nodes to refer to pins, respectively.
> I think there is currently no mechanism (or binding?) to allow this
> except adding a protocol id.
>

Beside the uglyness of having 2 different DT bindings schemas for 2
different drivers coexisting in the same parent protocol node, it is
still not clear to me why this cant be done technically without the need
of a new dummy 0x99 protocol_node, given that each driver can use its
own parsing logic in its probe, which is what Peng is doing in
dt_node_to_map indeed ...even though, maybe, the result would be so
ugly and/or not accepatble from bindings point of view that we will
not want to do it at the end anyway....I mean maybe it is just the
attempt itself to combine the Generic Pinctrl approach with the highly
specific IMX approach that inevitably leads to these clashes...

...I maybe missing something, though, so I'll made some experiments on
my side about this before I'll keep on blabbing :P

Thanks,
Cristian
AKASHI Takahiro Sept. 13, 2023, 9:52 a.m. UTC | #5
On Thu, Sep 07, 2023 at 11:05:52AM +0100, Cristian Marussi wrote:
> On Wed, Sep 06, 2023 at 02:43:46PM +0900, AKASHI Takahiro wrote:
> > On Wed, Aug 30, 2023 at 02:37:48PM +0100, Cristian Marussi wrote:
> > > On Wed, Aug 30, 2023 at 12:48:37PM +0000, Peng Fan wrote:
> > > > Hi Cristian,
> > > > 
> > > 
> > > Hi,
> > > 
> 
> Hi,
> 
> > > > > Subject: Re: [RFC] scmi: pinctrl: support i.MX9
> > > > > 
> > > > > On Fri, Aug 25, 2023 at 08:43:38AM +0000, Peng Fan wrote:
> > > > > > > Subject: Re: [RFC] scmi: pinctrl: support i.MX9
> > > > > > >
> > > > > > > On Thu, Aug 24, 2023 at 2:47 PM Peng Fan <peng.fan@nxp.com> wrote:
> > > > > > > > Me:
> > > > > 
> > > > > Hi Peng,
> > > > > 
> > > > > > >
> > > > > > > >> it is merely making things more complex and also slower
> > > > > > > > > bymaking the registers only accessible from this SCMI link.
> > > > > > > >
> > > > > > > > This is for safety reason, the pinctrl hardware must be handled by
> > > > > > > > a system manager entity. So mmio direct access not allowed from
> > > > > > > > Cortex-A side.
> > > > > > >
> > > > > > > Yeah I understood as much. But I don't think that the firmware is
> > > > > > > really filtering any of the access, it will just poke into any
> > > > > > > pinctrl register as instructed anyway so what's the point. Just looks like a
> > > > > layer of indirection.
> > > > > >
> > > > > > No, the firmware has a check on whether a pin is allowed to be
> > > > > > configured by the agent that wanna to configure the pin.
> > > > > >
> > > > > > > But I'm not your system manager, so it's not my decision.
> > > > > > >
> > > > > > > > The SCMI firmware is very straightforward, there is no group or
> > > > > > > > function.
> > > > > > > >
> > > > > > > > It just accepts the format as this:
> > > > > > > > MUX_TYPE, MUX VALUE, CONF_TYPE, CONF_VAL, DAISY_TYPE, DAISY
> > > > > ID,
> > > > > > > > DAISY_CFG, DAISY_VALUE.
> > > > > > > >
> > > > > > > > Similar as linux MMIO format.
> > > > > > > >
> > > > > > > > Our i.MX95 platform will support two settings, one with SCMI
> > > > > > > > firmware, one without SCMI. These two settings will share the same
> > > > > > > > pinctrl header file.
> > > > > > > >
> > > > > > > > And to simplify the scmi firmware design(anyway I am not owner of
> > > > > > > > the firmware), to make pinctrl header shared w/o scmi, we take the
> > > > > > > > current in-upstream freescale imx binding format.
> > > > > > >
> > > > > > > The SCMI people will have to state their position on this.
> > > > > > > Like what they consider conformance and what extensions are allowed.
> > > > > > > This is more a standardization question than an implementation
> > > > > > > question so it's not really my turf.
> > > > > >
> > > > > > The i.MX95 SCMI firmware uses OEM extension type. So I just follow
> > > > > > what the firmware did and support it in linux. Anyway let's wait
> > > > > > Sudeep's reply.
> > > > > >
> > > > > 
> > > > > So my unsderstanding on this matter as of now is that:
> > > > > 
> > > > > 1. the current SCMI Pinctrl specification can support your usecase by using
> > > > >    OEM Types and multiple pins/values CONFIG_GET/SET commands
> > > > 
> > > > Yes, based on the Oleksii patchset with my local multiple configs support.
> > > > 
> > > 
> > > Yes, I know, I pointed out on his series that the protocol has still to
> > > be fixed to be aligned with the latest BETA2 spec (we changed the spec
> > > on the fly while he was already posting indeed..)
> > > 
> > > > > 
> > > > > 2. the Kernel SCMI protocol layer (driver/firmware/arm_scmi/pinctrl.c)
> > > > >    is equally fine and can support your usecase, AFTER Oleksii fixes it to
> > > > >    align it to the latest v3.2-BETA2 specification changes.
> > > > >    IOW, this means that, using the SCMI Pinctrl protocol operations
> > > > >    exposed in scmi_protocol.h, from somewhere, you are able to properly
> > > > >    configure multiple pins/values with your specific OEM types.
> > > > 
> > > > Yes.
> > > 
> > > Good.
> > > 
> > > > 
> > > > > 
> > > > > 3. The SCMI Pinctrl driver (by Oleksii) built on top of the pinctrl protocol
> > > > >    operations is instead NOT suitable for your usecase since it uses the Linux
> > > > >    Generic Pinconf and IMX does not make use of it, and instead IMX has
> > > > >    its own bindings and related parsing logic.
> > > > 
> > > > Yes.
> > > > 
> > > > > 
> > > > > Am I right ?
> > > > 
> > > > You are right.
> > > > 
> > > > > 
> > > > > If this is the case, I would NOT try to abuse the current SCMI Pinctrl Generic
> > > > > driver (by Oleksii) by throwing into it a bunch of IMX specific DT parsing,
> > > > > also because you'll end-up NOT using most of the generic SCMI Pinctrl driver
> > > > > but just reusing a bit of the probe (customized with your own DT maps
> > > > > parsing)
> > > > 
> > > > Only DT map to parse the dts and map to config array. Others are same,
> > > > so need to export some symbols for pinctrl-scmi-imx.c driver if build imx
> > > > scmi driver.
> > > >
> > > 
> > > Yes, but you are basically using some exported symbol to parse the DT in
> > > your way and then you do not use anything of the various
> > > functions/groups stuff...you just leverage some of the probing stuff and
> > > then issue you OEM Type configs....I mean most of the picntrl-scmi
> > > driver would be unused anyway in this scenario.
> > > 
> > > > > 
> > > > > Instead, given that the spec[1.] and the protocol layer[2.] are fine for your
> > > > > use case and you indeed have already a custom way to parse your DT
> > > > > mappings, I would say that you could just write your own custom SCMI
> > > > > driver ( ? pinctrl-imx-scmi), distinct and much more simple than the generic
> > > > > one, that does its own IMX DT parsing and calls just the SCMI protocol
> > > > > operations that it needs in the way that your platform expects: so basically
> > > > > another Pinctrl SCMI driver that does not use the generic pinconf DT
> > > > > configuration BUT DO USE the underlying SCMI Pinctrl protocol (via its
> > > > > exposed protocol operations...)
> > > > 
> > > > I am ok with this approach, but I need use the other ID, saying 0x99, not 0x19,
> > > > because 0x19 will bind with the pinctrl-scmi.c driver, I could not reuse
> > > > this ID for i.MX pinctrl-scmi-imx driver. Otherwise there will be issue if both
> > > > driver are built in kernel image.
> > > > 
> > > 
> > > Ok here I lost you.
> > > 
> > > The protocol ID 0x19 is bound to the protocol layer and identifies the
> > > standard Pinctrl protocol: usually you use a 0x99 to define and describe
> > > you own specific NEW vendor protocol, BUT here you are saying you are fine to
> > > use std Pinctrl spec AND the protocol operations as exposed in pinctrl.c, so
> > > I dont see why you should use a new vendor protocol_id to basically
> > > expose the same operations. (and I also dont see how you can do that
> > > without hacks in the current codebase)
> > > 
> > > You CAN have multiple SCMI drivers using the same protocol at the same
> > > time (even more than one protocol at the same time), even though we try
> > > to avoid it if there are no good reason to have more than one driver, there
> > > is nothing in the spec or in the current SCMI platform or agent stacks that
> > > inhibits such scenario (and I use iot heavily for my offline testing
> > > indeed.)
> > > 
> > > Look at:
> > > 
> > >  - drivers/hwmon/scmi-hwmon 
> > >  - drivers/iio/common/scmi_sensors/scmi_iio.c
> > > 
> > > and you'll see that these 2 drivers uses the same SENSOR protocol, just for
> > > different sensor types so they do not interfere one with each other.
> > 
> > Then, how are those two devices identified in a device tree?
> 
> At SCMI probe time the SCMI core stack creates one device for each
> 'protocol_id/name' as provided by the registered SCMI drivers in
> their respective scmi_device_id/id_tableS, as long as the requested
> protocol is active in the DT (protocol@XX defined) and the 'name'
> is not duplicated; each of these devices, sharing the same SCMI
> protocol, are created sharing also the same DT node protocol@XX.

That's fine.

> Their respective SCMI drivers are subsequently separately matched on
> protocol_id/name and then probed as usual: it is up to the drivers not
> to step on each other feet by competing for the same SCMI resources...
> ...like issuing comflicting request for the same reosurce domain
> on the same protocol.

That's fine.
My question/idea is simple; how two pinctrl drivers, if possible, be
represented in a single device tree. To allow the case of Peng Fan,
for example, I suppose that we need some DT binding like:

    scmi {
        scmi_pinctrl: protocol@19 {
            compatible = "arm, scmi-pinctrl-generic"; // not sure if needed

            pinmux ... // standard binding
            ...
        }
    }
    scmi_pinctrl_fsl {
        compatible = "fsl,scmi-pinctrl-imx9";

        fsl,pinmux = <&scmi_pinctrl, ...>,
                     <&scmi_pinctrl, ...>;
        ...
    }

"scmi_pinctrl_fsl" driver may reuse generic SCMI pinctrl helper functions,
except dt_node_to_map, in pictrl_ops.

-Takahiro Akashi

> I suppose, though, a lot depends on how the respective drivers interact
> with their subsystems, like IIO SCMI does not really need any info
> from DT, and the hwmon uses just the phandle to pick the sensor_domain_id
> to associate, as an example, to thermal sensors.
> 
> > That is the point in Peng's case and why he wants to have a dedicated
> > protocol id (I don't agree to this, though.)
> > If we follow Cristian's idea, we may want to have two dt nodes, say
> > pinctrl-scmi-generic and pinctrl-scmi-imx, as phandles for other device
> > nodes to refer to pins, respectively.
> > I think there is currently no mechanism (or binding?) to allow this
> > except adding a protocol id.
> >
> 
> Beside the uglyness of having 2 different DT bindings schemas for 2
> different drivers coexisting in the same parent protocol node, it is
> still not clear to me why this cant be done technically without the need
> of a new dummy 0x99 protocol_node, given that each driver can use its
> own parsing logic in its probe, which is what Peng is doing in
> dt_node_to_map indeed ...even though, maybe, the result would be so
> ugly and/or not accepatble from bindings point of view that we will
> not want to do it at the end anyway....I mean maybe it is just the
> attempt itself to combine the Generic Pinctrl approach with the highly
> specific IMX approach that inevitably leads to these clashes...
> 
> ...I maybe missing something, though, so I'll made some experiments on
> my side about this before I'll keep on blabbing :P
> 
> Thanks,
> Cristian
diff mbox series

Patch

diff --git a/drivers/firmware/arm_scmi/pinctrl.c b/drivers/firmware/arm_scmi/pinctrl.c
index 868a2f9821be..93109997614d 100644
--- a/drivers/firmware/arm_scmi/pinctrl.c
+++ b/drivers/firmware/arm_scmi/pinctrl.c
@@ -6,13 +6,14 @@ 
  */
 
 #include <linux/module.h>
+#include <linux/pinctrl/pinconf-generic.h>
 #include <linux/scmi_protocol.h>
 #include <linux/slab.h>
 
 #include "protocols.h"
 
-#define REG_TYPE_BITS GENMASK(9, 8)
-#define REG_CONFIG GENMASK(7, 0)
+#define REG_TYPE_CONFIG GENMASK(1, 0)
+#define REG_NUM_CONFIG GENMASK(9, 2)
 
 #define GET_GROUPS_NR(x)	le32_get_bits((x), GENMASK(31, 16))
 #define GET_PINS_NR(x)		le32_get_bits((x), GENMASK(15, 0))
@@ -36,10 +37,11 @@  enum scmi_pinctrl_protocol_cmd {
 	PINCTRL_SET_PERMISSIONS = 0xb
 };
 
+#define MAX_CONFIG_ENTRY 10
 struct scmi_msg_conf_set {
 	__le32 identifier;
 	__le32 attributes;
-	__le32 config_value;
+	__le32 config_value[MAX_CONFIG_ENTRY * 2];
 };
 
 struct scmi_msg_conf_get {
@@ -320,9 +322,11 @@  static int scmi_pinctrl_config_get(const struct scmi_protocol_handle *ph,
 
 	tx = t->tx.buf;
 	tx->identifier = cpu_to_le32(selector);
+	/*
 	attributes = FIELD_PREP(REG_TYPE_BITS, type) |
 		FIELD_PREP(REG_CONFIG, config_type);
 	tx->attributes = cpu_to_le32(attributes);
+	*/
 
 	ret = ph->xops->do_xfer(ph, t);
 	if (!ret)
@@ -335,7 +339,7 @@  static int scmi_pinctrl_config_get(const struct scmi_protocol_handle *ph,
 static int scmi_pinctrl_config_set(const struct scmi_protocol_handle *ph,
 				   u32 selector,
 				   enum scmi_pinctrl_selector_type type,
-				   u8 config_type, unsigned long config_value)
+				   unsigned long *configs, unsigned int num_configs)
 {
 	struct scmi_xfer *t;
 	struct scmi_msg_conf_set *tx;
@@ -355,10 +359,14 @@  static int scmi_pinctrl_config_set(const struct scmi_protocol_handle *ph,
 
 	tx = t->tx.buf;
 	tx->identifier = cpu_to_le32(selector);
-	attributes = FIELD_PREP(REG_TYPE_BITS, type) |
-		FIELD_PREP(REG_CONFIG, config_type);
+	for (int i = 0; i < num_configs; i++) {
+		tx->config_value[i * 2] = cpu_to_le32(pinconf_to_config_param(configs[i]));
+		tx->config_value[i * 2 + 1] = cpu_to_le32(pinconf_to_config_argument(configs[i]));
+	}
+
+	attributes = FIELD_PREP(REG_TYPE_CONFIG, type) |
+		FIELD_PREP(REG_NUM_CONFIG, num_configs);
 	tx->attributes = cpu_to_le32(attributes);
-	tx->config_value = cpu_to_le32(config_value);
 
 	ret = ph->xops->do_xfer(ph, t);
 
diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
index 9bc16943014f..dd0a66a17184 100644
--- a/drivers/pinctrl/freescale/pinctrl-imx.c
+++ b/drivers/pinctrl/freescale/pinctrl-imx.c
@@ -14,6 +14,7 @@ 
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/pinctrl/pinconf-generic.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/seq_file.h>
@@ -33,6 +34,29 @@ 
 #define IMX_NO_PAD_CTL	0x80000000	/* no pin config need */
 #define IMX_PAD_SION 0x40000000		/* set SION */
 
+/*
+ * Each pin represented in fsl,pins consists of a number of u32 PIN_FUNC_ID
+ * and 1 u32 CONFIG, the total size is PIN_FUNC_ID + CONFIG for each pin.
+ * For generic_pinconf case, there's no extra u32 CONFIG.
+ *
+ * PIN_FUNC_ID format:
+ * Default:
+ *     <mux_reg conf_reg input_reg mux_mode input_val>
+ * SHARE_MUX_CONF_REG:
+ *     <mux_conf_reg input_reg mux_mode input_val>
+ * IMX_USE_SCU:
+ *	<pin_id mux_mode>
+ */
+#define FSL_PIN_SIZE 24
+#define FSL_PIN_SHARE_SIZE 20
+#define FSL_SCU_PIN_SIZE 12
+
+/* SCMI pin control types, aligned with SCMI firmware */
+#define IMX_PIN_TYPE_MUX	192
+#define IMX_PIN_TYPE_CONFIG	193
+#define IMX_PIN_TYPE_DAISY_ID	194
+#define IMX_PIN_TYPE_DAISY_CFG	195
+
 static inline const struct group_desc *imx_pinctrl_find_group_by_name(
 				struct pinctrl_dev *pctldev,
 				const char *name)
@@ -55,6 +79,96 @@  static void imx_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
 	seq_printf(s, "%s", dev_name(pctldev->dev));
 }
 
+#define IMX_SCMI_NUM_CFG 4
+int imx_scmi_dt_node_to_map(struct pinctrl_dev *pctldev, struct device_node *np,
+			    struct pinctrl_map **map, unsigned *num_maps)
+{
+	struct pinctrl_map *new_map;
+	const __be32 *list;
+	unsigned long *configs = NULL;
+	unsigned long cfg[IMX_SCMI_NUM_CFG];
+	int map_num, size, pin_size, pin_id, num_pins;
+	int mux_reg, conf_reg, input_reg, mux_val, conf_val, input_val;
+	int i, j;
+	uint32_t ncfg;
+	static uint32_t daisy_off;
+
+	if (!daisy_off) {
+		if (of_machine_is_compatible("fsl,imx93"))
+			daisy_off = 0x360;
+		else if (of_machine_is_compatible("fsl,imx95"))
+			daisy_off = 0x408;
+		else
+			dev_err(pctldev->dev, "platform not support scmi pinctrl\n");
+	}
+
+	list = of_get_property(np, "fsl,pins", &size);
+	if (!list) {
+		dev_err(pctldev->dev, "no fsl,pins property in node %pOF\n", np);
+		return -EINVAL;
+	}
+
+	pin_size = FSL_PIN_SIZE;
+
+	if (!size || size % pin_size) {
+		dev_err(pctldev->dev, "Invalid fsl,pins or pins property in node %pOF\n", np);
+		return -EINVAL;
+	}
+
+	num_pins = size / pin_size;
+	map_num = num_pins;
+
+	new_map = kmalloc_array(map_num, sizeof(struct pinctrl_map),
+				GFP_KERNEL);
+	if (!new_map)
+		return -ENOMEM;
+
+	*map = new_map;
+	*num_maps = map_num;
+
+	/* create config map */
+	for (i = 0; i < num_pins; i++) {
+		j = 0;
+		ncfg = IMX_SCMI_NUM_CFG;
+		mux_reg = be32_to_cpu(*list++);
+		conf_reg = be32_to_cpu(*list++);
+		input_reg = be32_to_cpu(*list++);
+		mux_val = be32_to_cpu(*list++);
+		input_val = be32_to_cpu(*list++);
+		conf_val = be32_to_cpu(*list++);
+		if (conf_val & IMX_PAD_SION)
+			mux_val |= IOMUXC_CONFIG_SION;
+
+		pin_id = mux_reg / 4;
+
+		cfg[j++] = pinconf_to_config_packed(IMX_PIN_TYPE_MUX, mux_val);
+
+		if (!conf_reg || (conf_val & IMX_NO_PAD_CTL)) {
+			ncfg--;
+		} else {
+			cfg[j++] = pinconf_to_config_packed(IMX_PIN_TYPE_CONFIG, conf_val);
+		}
+
+		if (!input_reg) {
+			ncfg -= 2;
+		} else {
+			cfg[j++] = pinconf_to_config_packed(IMX_PIN_TYPE_DAISY_ID,
+							    (input_reg - daisy_off) / 4);
+			cfg[j++] = pinconf_to_config_packed(IMX_PIN_TYPE_DAISY_CFG, input_val);
+		}
+
+		configs = kmemdup(cfg, ncfg * sizeof(unsigned long), GFP_KERNEL);
+
+		new_map[i].type = PIN_MAP_TYPE_CONFIGS_PIN;
+		new_map[i].data.configs.group_or_pin = pin_get_name(pctldev, pin_id);
+		new_map[i].data.configs.configs = configs;
+		new_map[i].data.configs.num_configs = ncfg;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(imx_scmi_dt_node_to_map);
+
 static int imx_dt_node_to_map(struct pinctrl_dev *pctldev,
 			struct device_node *np,
 			struct pinctrl_map **map, unsigned *num_maps)
@@ -441,22 +555,6 @@  static const struct pinconf_ops imx_pinconf_ops = {
 	.pin_config_group_dbg_show = imx_pinconf_group_dbg_show,
 };
 
-/*
- * Each pin represented in fsl,pins consists of a number of u32 PIN_FUNC_ID
- * and 1 u32 CONFIG, the total size is PIN_FUNC_ID + CONFIG for each pin.
- *
- * PIN_FUNC_ID format:
- * Default:
- *     <mux_reg conf_reg input_reg mux_mode input_val>
- * SHARE_MUX_CONF_REG:
- *     <mux_conf_reg input_reg mux_mode input_val>
- * IMX_USE_SCU:
- *	<pin_id mux_mode>
- */
-#define FSL_PIN_SIZE 24
-#define FSL_PIN_SHARE_SIZE 20
-#define FSL_SCU_PIN_SIZE 12
-
 static void imx_pinctrl_parse_pin_mmio(struct imx_pinctrl *ipctl,
 				       unsigned int *pin_id, struct imx_pin *pin,
 				       const __be32 **list_p,
diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
index a9304402ddf1..92cf10241aa8 100644
--- a/drivers/pinctrl/pinctrl-scmi.c
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -8,6 +8,7 @@ 
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/seq_file.h>
 #include <linux/scmi_protocol.h>
 #include <linux/slab.h>
@@ -77,13 +78,28 @@  static int pinctrl_scmi_get_group_pins(struct pinctrl_dev *pctldev,
 }
 
 #ifdef CONFIG_OF
+#ifdef CONFIG_PINCTRL_IMX
+extern int imx_scmi_dt_node_to_map(struct pinctrl_dev *pctldev, struct device_node *np,
+				   struct pinctrl_map **map, unsigned *num_maps);
+#else
+static inline int imx_scmi_dt_node_to_map(struct pinctrl_dev *pctldev,
+					  struct device_node *np,
+					  struct pinctrl_map **map, unsigned *num_maps)
+{
+	return -ENOTSUPP;
+}
+#endif
 static int pinctrl_scmi_dt_node_to_map(struct pinctrl_dev *pctldev,
 				       struct device_node *np_config,
 				       struct pinctrl_map **map,
 				       u32 *num_maps)
 {
+	if ((of_machine_is_compatible("fsl,imx93") || of_machine_is_compatible("fsl,imx95")))
+		return imx_scmi_dt_node_to_map(pctldev, np_config, map, num_maps);
+
 	return pinconf_generic_dt_node_to_map(pctldev, np_config, map, num_maps,
 					      PIN_MAP_TYPE_INVALID);
+
 }
 
 static void pinctrl_scmi_dt_free_map(struct pinctrl_dev *pctldev, struct pinctrl_map *map,
@@ -242,25 +258,15 @@  static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
 				    unsigned long *configs,
 				    unsigned int num_configs)
 {
-	int i, ret;
+	int ret;
 	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
-	enum pin_config_param config_type;
-	unsigned long config_value;
 
 	if (!configs || num_configs == 0)
 		return -EINVAL;
 
-	for (i = 0; i < num_configs; i++) {
-		config_type = pinconf_to_config_param(configs[i]);
-		config_value = pinconf_to_config_argument(configs[i]);
-
-		ret = pinctrl_ops->config_set(pmx->ph, _pin, PIN_TYPE, config_type, config_value);
-		if (ret) {
-			dev_err(pmx->dev, "Error parsing config %ld\n",
-				configs[i]);
-			break;
-		}
-	}
+	ret = pinctrl_ops->config_set(pmx->ph, _pin, PIN_TYPE, configs, num_configs);
+	if (ret)
+		dev_err(pmx->dev, "Error parsing config %d\n", ret);
 
 	return ret;
 }
@@ -270,26 +276,15 @@  static int pinctrl_scmi_pinconf_group_set(struct pinctrl_dev *pctldev,
 					  unsigned long *configs,
 					  unsigned int num_configs)
 {
-	int i, ret;
+	int ret;
 	struct scmi_pinctrl *pmx =  pinctrl_dev_get_drvdata(pctldev);
-	enum pin_config_param config_type;
-	unsigned long config_value;
 
 	if (!configs || num_configs == 0)
 		return -EINVAL;
 
-	for (i = 0; i < num_configs; i++) {
-		config_type = pinconf_to_config_param(configs[i]);
-		config_value = pinconf_to_config_argument(configs[i]);
-
-		ret = pinctrl_ops->config_set(pmx->ph, group, GROUP_TYPE, config_type,
-					      config_value);
-		if (ret) {
-			dev_err(pmx->dev, "Error parsing config = %ld",
-				configs[i]);
-			break;
-		}
-	}
+	ret = pinctrl_ops->config_set(pmx->ph, group, GROUP_TYPE, configs, num_configs);
+	if (ret)
+		dev_err(pmx->dev, "Error parsing config %d", ret);
 
 	return ret;
 };
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 99c1405decd7..e58d207b56b6 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -730,7 +730,7 @@  struct scmi_pinctrl_proto_ops {
 			  u8 config_type, unsigned long *config_value);
 	int (*config_set)(const struct scmi_protocol_handle *ph, u32 selector,
 			  enum scmi_pinctrl_selector_type type,
-			  u8 config_type, unsigned long config_value);
+			  unsigned long *configs, unsigned int num_configs);
 	int (*pin_request)(const struct scmi_protocol_handle *ph, u32 pin);
 	int (*pin_free)(const struct scmi_protocol_handle *ph, u32 pin);
 };