[PATCH v2 0/7] Create a new sound card to access MICFIL based on rpmsg channel

[PATCH v2 0/7] Create a new sound card to access MICFIL based on rpmsg channel

[Chancel Liu]

At a previous time, we have successfully created a virtual sound card
based on rpmsg. The sound card works under this mechanism Cortex-A core
tells the Cortex-M core the format, rate, channel, .etc configuration
of the PCM parameters and Cortex-M controls real hardware devices such
as SAI and DMA. From the view of Linux side, the sound card is bound to
a rpmsg channel through which it can access SAI.

Here these patches are introduced to create a new virtual sound card to
access MICFIL based on a new created rpmsg channel. It's easy to create
a new rpmsg channel for MICFIL through rpmsg name service announcment.
Also the other ASoC components bound to this rpmsg MICFIL sound card
will be registered with these patches.

If other sound cards using different hardware devices needs to be
created over rpmsg in the future, these patches can be referred.

changes in v2:
- Rename property in bindings file according to Krzysztof's comments
- Update codes and comments according to Shengjiu's comments

Chancel Liu (7):
  ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg
    channel
  ASoC: imx-audio-rpmsg: Create rpmsg channel for MICFIL
  ASoC: imx-pcm-rpmsg: Register different platform drivers
  ASoC: imx-pcm-rpmsg: Multi-channel support for sound card based on
    rpmsg
  ASoC: fsl_rpmsg: Register different ASoC machine devices
  ASoC: fsl_rpmsg: Multi-channel support in CPU DAI driver
  ASoC: imx-rpmsg: Assign platform driver used by machine driver to link
    with

 .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37 ++++++++++++++++++-
 sound/soc/fsl/fsl_rpmsg.c                     |  6 +--
 sound/soc/fsl/imx-audio-rpmsg.c               |  3 +-
 sound/soc/fsl/imx-pcm-rpmsg.c                 | 10 +++--
 sound/soc/fsl/imx-rpmsg.c                     |  6 ++-
 5 files changed, 52 insertions(+), 10 deletions(-)

--
2.25.1

[PATCH v2 1/7] ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

[Chancel Liu]

Add a string property to assign the rpmsg channel this sound card sits
on. It also represents the name of ASoC platform driver. This property
can be omitted if there is only one sound card and it sits on
"rpmsg-audio-channel".

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37 ++++++++++++++++++-
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
index d370c98a62c7..3744ae794c00 100644
--- a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
+++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
@@ -11,8 +11,11 @@ maintainers:
 
 description: |
   fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
-  are SAI, DMA controlled by Cortex M core. What we see from Linux
-  side is a device which provides audio service by rpmsg channel.
+  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
+  Linux side is a device which provides audio service by rpmsg channel.
+  We can create different sound cards which access different hardwares
+  such as SAI, MICFIL, .etc through building rpmsg channels between
+  Cortex-A and Cortex-M.
 
 properties:
   compatible:
@@ -85,6 +88,17 @@ properties:
       This is a boolean property. If present, the receiving function
       will be enabled.
 
+  fsl,rpmsg-channel-name:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      A string property to assign rpmsg channel this sound card sits on.
+      It also represents the name of ASoC platform driver. This property
+      can be omitted if there is only one sound card and it sits on
+      "rpmsg-audio-channel".
+    enum:
+      - rpmsg-audio-channel
+      - rpmsg-micfil-channel
+
 required:
   - compatible
   - model
@@ -107,3 +121,22 @@ examples:
                  <&clk IMX8MN_AUDIO_PLL2_OUT>;
         clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
     };
+
+  - |
+    #include <dt-bindings/clock/imx8mm-clock.h>
+
+    rpmsg_micfil: audio-controller {
+        compatible = "fsl,imx8mm-rpmsg-audio";
+        model = "micfil-audio";
+        fsl,rpmsg-channel-name = "rpmsg-micfil-channel";
+        fsl,enable-lpa;
+        fsl,rpmsg-in;
+        clocks = <&clk IMX8MM_CLK_PDM_IPG>,
+                 <&clk IMX8MM_CLK_PDM_ROOT>,
+                 <&clk IMX8MM_CLK_SDMA3_ROOT>,
+                 <&clk IMX8MM_AUDIO_PLL1_OUT>,
+                 <&clk IMX8MM_AUDIO_PLL2_OUT>;
+        clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
+    };
+
+...
-- 
2.25.1

[PATCH v2 2/7] ASoC: imx-audio-rpmsg: Create rpmsg channel for MICFIL

[Chancel Liu]

Rpmsg channel for MICFIL can also be created through rpmsg name service
announcement. If this driver is probed, Cortex-A can access MICFIL
which is actually controlled by Cortex-M through rpmsg channel for
MICFIL. This driver also helps register ASoC platform device thus use
of PLATFORM_DEVID_AUTO macro in API can automatically create device for
each rpmsg channel.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/imx-audio-rpmsg.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/imx-audio-rpmsg.c b/sound/soc/fsl/imx-audio-rpmsg.c
index 905c3a071300..d5234ac4b09b 100644
--- a/sound/soc/fsl/imx-audio-rpmsg.c
+++ b/sound/soc/fsl/imx-audio-rpmsg.c
@@ -88,7 +88,7 @@ static int imx_audio_rpmsg_probe(struct rpmsg_device *rpdev)
 	/* Register platform driver for rpmsg routine */
 	data->rpmsg_pdev = platform_device_register_data(&rpdev->dev,
 							 IMX_PCM_DRV_NAME,
-							 PLATFORM_DEVID_NONE,
+							 PLATFORM_DEVID_AUTO,
 							 NULL, 0);
 	if (IS_ERR(data->rpmsg_pdev)) {
 		dev_err(&rpdev->dev, "failed to register rpmsg platform.\n");
@@ -110,6 +110,7 @@ static void imx_audio_rpmsg_remove(struct rpmsg_device *rpdev)
 
 static struct rpmsg_device_id imx_audio_rpmsg_id_table[] = {
 	{ .name	= "rpmsg-audio-channel" },
+	{ .name = "rpmsg-micfil-channel" },
 	{ },
 };
 
-- 
2.25.1

[PATCH v2 3/7] ASoC: imx-pcm-rpmsg: Register different platform drivers

[Chancel Liu]

This patch can register different ASoC platform drivers if there are
several rpmsg channels. Thus sound cards based on different rpmsg
channels can link to their respective platform drivers. Besides, the
name of driver is equal to the name of rpmsg channel.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/imx-pcm-rpmsg.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/imx-pcm-rpmsg.c b/sound/soc/fsl/imx-pcm-rpmsg.c
index 35049043e532..3157cd5a837e 100644
--- a/sound/soc/fsl/imx-pcm-rpmsg.c
+++ b/sound/soc/fsl/imx-pcm-rpmsg.c
@@ -684,7 +684,7 @@ static int imx_rpmsg_pcm_probe(struct platform_device *pdev)
 	info->rpdev = container_of(pdev->dev.parent, struct rpmsg_device, dev);
 	info->dev = &pdev->dev;
 	/* Setup work queue */
-	info->rpmsg_wq = alloc_ordered_workqueue("rpmsg_audio",
+	info->rpmsg_wq = alloc_ordered_workqueue(info->rpdev->id.name,
 						 WQ_HIGHPRI |
 						 WQ_UNBOUND |
 						 WQ_FREEZABLE);
@@ -723,11 +723,15 @@ static int imx_rpmsg_pcm_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;
 
-	component = snd_soc_lookup_component(&pdev->dev, IMX_PCM_DRV_NAME);
+	component = snd_soc_lookup_component(&pdev->dev, NULL);
 	if (!component) {
 		ret = -EINVAL;
 		goto fail;
 	}
+
+	/* platform component name is used by machine driver to link with */
+	component->name = info->rpdev->id.name;
+
 #ifdef CONFIG_DEBUG_FS
 	component->debugfs_prefix = "rpmsg";
 #endif
-- 
2.25.1

[PATCH v2 4/7] ASoC: imx-pcm-rpmsg: Multi-channel support for sound card based on rpmsg

[Chancel Liu]

Some sound card based on rpmsg may support multi-channel. The number of
channels can be sent to Cortex-M in rpmsg for process.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/imx-pcm-rpmsg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/fsl/imx-pcm-rpmsg.c b/sound/soc/fsl/imx-pcm-rpmsg.c
index 3157cd5a837e..2f310994f7ee 100644
--- a/sound/soc/fsl/imx-pcm-rpmsg.c
+++ b/sound/soc/fsl/imx-pcm-rpmsg.c
@@ -178,7 +178,7 @@ static int imx_rpmsg_pcm_hw_params(struct snd_soc_component *component,
 		msg->s_msg.param.channels = RPMSG_CH_STEREO;
 		break;
 	default:
-		ret = -EINVAL;
+		msg->s_msg.param.channels = params_channels(params);
 		break;
 	}
 
-- 
2.25.1

[PATCH v2 5/7] ASoC: fsl_rpmsg: Register different ASoC machine devices

[Chancel Liu]

This driver helps register ASoC machine device thus use of
PLATFORM_DEVID_AUTO macro in API can automatically create device for
each sound card based on rpmsg.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/fsl_rpmsg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_rpmsg.c b/sound/soc/fsl/fsl_rpmsg.c
index bf94838bdbef..fde3d5006ce0 100644
--- a/sound/soc/fsl/fsl_rpmsg.c
+++ b/sound/soc/fsl/fsl_rpmsg.c
@@ -235,7 +235,7 @@ static int fsl_rpmsg_probe(struct platform_device *pdev)
 
 	rpmsg->card_pdev = platform_device_register_data(&pdev->dev,
 							 "imx-audio-rpmsg",
-							 PLATFORM_DEVID_NONE,
+							 PLATFORM_DEVID_AUTO,
 							 NULL,
 							 0);
 	if (IS_ERR(rpmsg->card_pdev)) {
-- 
2.25.1

[PATCH v2 6/7] ASoC: fsl_rpmsg: Multi-channel support in CPU DAI driver

[Chancel Liu]

Some sound card based on rpmsg may support multi-channel. This patch
expands the maximum channels to 32.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/fsl_rpmsg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/fsl_rpmsg.c b/sound/soc/fsl/fsl_rpmsg.c
index fde3d5006ce0..46c7868a2653 100644
--- a/sound/soc/fsl/fsl_rpmsg.c
+++ b/sound/soc/fsl/fsl_rpmsg.c
@@ -117,14 +117,14 @@ static struct snd_soc_dai_driver fsl_rpmsg_dai = {
 	.playback = {
 		.stream_name = "CPU-Playback",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = SNDRV_PCM_RATE_KNOT,
 		.formats = FSL_RPMSG_FORMATS,
 	},
 	.capture = {
 		.stream_name = "CPU-Capture",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = SNDRV_PCM_RATE_KNOT,
 		.formats = FSL_RPMSG_FORMATS,
 	},
-- 
2.25.1

[PATCH v2 7/7] ASoC: imx-rpmsg: Assign platform driver used by machine driver to link with

[Chancel Liu]

Each ASoC platform driver is named by rpmsg channel. ASoC machine
driver can parse "fsl,rpmsg-channel-name" property to figure out which
ASoC platform driver it should link with.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
---
 sound/soc/fsl/imx-rpmsg.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/imx-rpmsg.c b/sound/soc/fsl/imx-rpmsg.c
index 2e117311e582..57684064c9da 100644
--- a/sound/soc/fsl/imx-rpmsg.c
+++ b/sound/soc/fsl/imx-rpmsg.c
@@ -36,6 +36,7 @@ static int imx_rpmsg_probe(struct platform_device *pdev)
 	struct platform_device *rpmsg_pdev = to_platform_device(dev);
 	struct device_node *np = rpmsg_pdev->dev.of_node;
 	struct of_phandle_args args;
+	const char *platform_name;
 	struct imx_rpmsg *data;
 	int ret = 0;
 
@@ -81,7 +82,10 @@ static int imx_rpmsg_probe(struct platform_device *pdev)
 	}
 
 	data->dai.cpus->dai_name = dev_name(&rpmsg_pdev->dev);
-	data->dai.platforms->name = IMX_PCM_DRV_NAME;
+	if (!of_property_read_string(np, "fsl,rpmsg-channel-name", &platform_name))
+		data->dai.platforms->name = platform_name;
+	else
+		data->dai.platforms->name = "rpmsg-audio-channel";
 	data->dai.playback_only = true;
 	data->dai.capture_only = true;
 	data->card.num_links = 1;
-- 
2.25.1

Re: [PATCH v2 1/7] ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

[Rob Herring]

On Wed, Sep 14, 2022 at 06:51:39PM +0800, Chancel Liu wrote:
> Add a string property to assign the rpmsg channel this sound card sits
> on. It also represents the name of ASoC platform driver. This property
> can be omitted if there is only one sound card and it sits on
> "rpmsg-audio-channel".
> 
> Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
> ---
>  .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37 ++++++++++++++++++-
>  1 file changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> index d370c98a62c7..3744ae794c00 100644
> --- a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> @@ -11,8 +11,11 @@ maintainers:
>  
>  description: |
>    fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
> -  are SAI, DMA controlled by Cortex M core. What we see from Linux
> -  side is a device which provides audio service by rpmsg channel.
> +  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
> +  Linux side is a device which provides audio service by rpmsg channel.
> +  We can create different sound cards which access different hardwares
> +  such as SAI, MICFIL, .etc through building rpmsg channels between
> +  Cortex-A and Cortex-M.
>  
>  properties:
>    compatible:
> @@ -85,6 +88,17 @@ properties:
>        This is a boolean property. If present, the receiving function
>        will be enabled.
>  
> +  fsl,rpmsg-channel-name:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    description: |
> +      A string property to assign rpmsg channel this sound card sits on.
> +      It also represents the name of ASoC platform driver. This property

That's a Linux detail which doesn't belong in DT.

> +      can be omitted if there is only one sound card and it sits on
> +      "rpmsg-audio-channel".
> +    enum:
> +      - rpmsg-audio-channel
> +      - rpmsg-micfil-channel
> +
>  required:
>    - compatible
>    - model
> @@ -107,3 +121,22 @@ examples:
>                   <&clk IMX8MN_AUDIO_PLL2_OUT>;
>          clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
>      };
> +
> +  - |
> +    #include <dt-bindings/clock/imx8mm-clock.h>
> +
> +    rpmsg_micfil: audio-controller {
> +        compatible = "fsl,imx8mm-rpmsg-audio";
> +        model = "micfil-audio";
> +        fsl,rpmsg-channel-name = "rpmsg-micfil-channel";
> +        fsl,enable-lpa;
> +        fsl,rpmsg-in;
> +        clocks = <&clk IMX8MM_CLK_PDM_IPG>,
> +                 <&clk IMX8MM_CLK_PDM_ROOT>,
> +                 <&clk IMX8MM_CLK_SDMA3_ROOT>,
> +                 <&clk IMX8MM_AUDIO_PLL1_OUT>,
> +                 <&clk IMX8MM_AUDIO_PLL2_OUT>;
> +        clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
> +    };
> +
> +...
> -- 
> 2.25.1
> 
> 

RE: Re: [PATCH v2 1/7] ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

[Chancel Liu]

> > Add a string property to assign the rpmsg channel this sound card sits
> > on. It also represents the name of ASoC platform driver. This property
> > can be omitted if there is only one sound card and it sits on
> > "rpmsg-audio-channel".
> >
> > Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
> > ---
> >  .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37 ++++++++++++++++++-
> >  1 file changed, 35 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> > index d370c98a62c7..3744ae794c00 100644
> > --- a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> > +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> > @@ -11,8 +11,11 @@ maintainers:
> >
> >  description: |
> >    fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
> > -  are SAI, DMA controlled by Cortex M core. What we see from Linux
> > -  side is a device which provides audio service by rpmsg channel.
> > +  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
> > +  Linux side is a device which provides audio service by rpmsg channel.
> > +  We can create different sound cards which access different hardwares
> > +  such as SAI, MICFIL, .etc through building rpmsg channels between
> > +  Cortex-A and Cortex-M.
> >
> >  properties:
> >    compatible:
> > @@ -85,6 +88,17 @@ properties:
> >        This is a boolean property. If present, the receiving function
> >        will be enabled.
> >
> > +  fsl,rpmsg-channel-name:
> > +    $ref: /schemas/types.yaml#/definitions/string
> > +    description: |
> > +      A string property to assign rpmsg channel this sound card sits on.
> > +      It also represents the name of ASoC platform driver. This property
> 
> That's a Linux detail which doesn't belong in DT.
> 

We pass hardware parameters in dts node to set up clocks or other
configurations. These configurations are finally sent to Cortex-M by
rpmsg channel because Cortex-M actually controls real hardware devices.
If there's only one sound card sits on one rpmsg channel we will not
need this property. But if there are several sound cards we need to
specify correct rpmsg channel. Thus hardware configurations can be
properly sent to Cortex-M. From this level to speak, this property is
hardware-related since rpmsg channel represents the real hardware audio
controller.

Here I attach the discussion in version 1 patches for your information:
---
This property aims to tell the ASoC driver which rpmsg channel the
sound card depends on. If there are several sound cards sit on rpmsg,
we should pass correct information in dts node to specify the name of
rpmsg channel. That is why I meant to add this property. 

Actually this property is hardware-related. As we discussed before,
this kind of sound card based on rpmsg works under this mechanism
Cortex-A core tells the Cortex-M core configuration of the PCM
parameters then Cortex-M controls real hardware devices. This property
specifying rpmsg channel represents the real hardware audio controller.
---

That's my idea adding this property. Do you have any suggstion?

Regards, 
Chancel Liu

> > +      can be omitted if there is only one sound card and it sits on
> > +      "rpmsg-audio-channel".
> > +    enum:
> > +      - rpmsg-audio-channel
> > +      - rpmsg-micfil-channel
> > +
> >  required:
> >    - compatible
> >    - model
> > @@ -107,3 +121,22 @@ examples:
> >                   <&clk IMX8MN_AUDIO_PLL2_OUT>;
> >          clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
> >      };
> > +
> > +  - |
> > +    #include <dt-bindings/clock/imx8mm-clock.h>
> > +
> > +    rpmsg_micfil: audio-controller {
> > +        compatible = "fsl,imx8mm-rpmsg-audio";
> > +        model = "micfil-audio";
> > +        fsl,rpmsg-channel-name = "rpmsg-micfil-channel";
> > +        fsl,enable-lpa;
> > +        fsl,rpmsg-in;
> > +        clocks = <&clk IMX8MM_CLK_PDM_IPG>,
> > +                 <&clk IMX8MM_CLK_PDM_ROOT>,
> > +                 <&clk IMX8MM_CLK_SDMA3_ROOT>,
> > +                 <&clk IMX8MM_AUDIO_PLL1_OUT>,
> > +                 <&clk IMX8MM_AUDIO_PLL2_OUT>;
> > +        clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
> > +    };
> > +
> > +...
> > --
> > 2.25.1
> >
> >

Re: [PATCH v2 1/7] ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

[Krzysztof Kozlowski]

On 23/09/2022 11:56, Chancel Liu wrote:
>>> Add a string property to assign the rpmsg channel this sound card sits
>>> on. It also represents the name of ASoC platform driver. This property
>>> can be omitted if there is only one sound card and it sits on
>>> "rpmsg-audio-channel".
>>>
>>> Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
>>> ---
>>>  .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37 ++++++++++++++++++-
>>>  1 file changed, 35 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
>> b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
>>> index d370c98a62c7..3744ae794c00 100644
>>> --- a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
>>> +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
>>> @@ -11,8 +11,11 @@ maintainers:
>>>
>>>  description: |
>>>    fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
>>> -  are SAI, DMA controlled by Cortex M core. What we see from Linux
>>> -  side is a device which provides audio service by rpmsg channel.
>>> +  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
>>> +  Linux side is a device which provides audio service by rpmsg channel.
>>> +  We can create different sound cards which access different hardwares
>>> +  such as SAI, MICFIL, .etc through building rpmsg channels between
>>> +  Cortex-A and Cortex-M.
>>>
>>>  properties:
>>>    compatible:
>>> @@ -85,6 +88,17 @@ properties:
>>>        This is a boolean property. If present, the receiving function
>>>        will be enabled.
>>>
>>> +  fsl,rpmsg-channel-name:
>>> +    $ref: /schemas/types.yaml#/definitions/string
>>> +    description: |
>>> +      A string property to assign rpmsg channel this sound card sits on.
>>> +      It also represents the name of ASoC platform driver. This property
>>
>> That's a Linux detail which doesn't belong in DT.
>>
> 
> We pass hardware parameters in dts node to set up clocks or other
> configurations. These configurations are finally sent to Cortex-M by
> rpmsg channel because Cortex-M actually controls real hardware devices.
> If there's only one sound card sits on one rpmsg channel we will not
> need this property. But if there are several sound cards we need to
> specify correct rpmsg channel. Thus hardware configurations can be
> properly sent to Cortex-M. From this level to speak, this property is
> hardware-related since rpmsg channel represents the real hardware audio
> controller.
> 
> Here I attach the discussion in version 1 patches for your information:
> ---
> This property aims to tell the ASoC driver which rpmsg channel the
> sound card depends on. If there are several sound cards sit on rpmsg,
> we should pass correct information in dts node to specify the name of
> rpmsg channel. That is why I meant to add this property. 
> 
> Actually this property is hardware-related. As we discussed before,
> this kind of sound card based on rpmsg works under this mechanism
> Cortex-A core tells the Cortex-M core configuration of the PCM
> parameters then Cortex-M controls real hardware devices. This property
> specifying rpmsg channel represents the real hardware audio controller.
> ---
> 
> That's my idea adding this property. Do you have any suggstion?

I think you misunderstood the comment. Rob's comment was directly below
a line which he referred to. That line contained a statement referring
to Linux drivers. Anything related to Linux drivers does not belong to DT.


Best regards,
Krzysztof

RE: [EXT] Re: [PATCH v2 1/7] ASoC: dt-bindings: fsl_rpmsg: Add a property to assign the rpmsg channel

[Chancel Liu]

> >>> Add a string property to assign the rpmsg channel this sound card sits
> >>> on. It also represents the name of ASoC platform driver. This property
> >>> can be omitted if there is only one sound card and it sits on
> >>> "rpmsg-audio-channel".
> >>>
> >>> Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
> >>> ---
> >>>  .../devicetree/bindings/sound/fsl,rpmsg.yaml  | 37
> ++++++++++++++++++-
> >>>  1 file changed, 35 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> >> b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> >>> index d370c98a62c7..3744ae794c00 100644
> >>> --- a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> >>> +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml
> >>> @@ -11,8 +11,11 @@ maintainers:
> >>>
> >>>  description: |
> >>>    fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
> >>> -  are SAI, DMA controlled by Cortex M core. What we see from Linux
> >>> -  side is a device which provides audio service by rpmsg channel.
> >>> +  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
> >>> +  Linux side is a device which provides audio service by rpmsg channel.
> >>> +  We can create different sound cards which access different hardwares
> >>> +  such as SAI, MICFIL, .etc through building rpmsg channels between
> >>> +  Cortex-A and Cortex-M.
> >>>
> >>>  properties:
> >>>    compatible:
> >>> @@ -85,6 +88,17 @@ properties:
> >>>        This is a boolean property. If present, the receiving function
> >>>        will be enabled.
> >>>
> >>> +  fsl,rpmsg-channel-name:
> >>> +    $ref: /schemas/types.yaml#/definitions/string
> >>> +    description: |
> >>> +      A string property to assign rpmsg channel this sound card sits on.
> >>> +      It also represents the name of ASoC platform driver. This property
> >>
> >> That's a Linux detail which doesn't belong in DT.
> >>
> >
> > We pass hardware parameters in dts node to set up clocks or other
> > configurations. These configurations are finally sent to Cortex-M by
> > rpmsg channel because Cortex-M actually controls real hardware devices.
> > If there's only one sound card sits on one rpmsg channel we will not
> > need this property. But if there are several sound cards we need to
> > specify correct rpmsg channel. Thus hardware configurations can be
> > properly sent to Cortex-M. From this level to speak, this property is
> > hardware-related since rpmsg channel represents the real hardware audio
> > controller.
> >
> > Here I attach the discussion in version 1 patches for your information:
> > ---
> > This property aims to tell the ASoC driver which rpmsg channel the
> > sound card depends on. If there are several sound cards sit on rpmsg,
> > we should pass correct information in dts node to specify the name of
> > rpmsg channel. That is why I meant to add this property.
> >
> > Actually this property is hardware-related. As we discussed before,
> > this kind of sound card based on rpmsg works under this mechanism
> > Cortex-A core tells the Cortex-M core configuration of the PCM
> > parameters then Cortex-M controls real hardware devices. This property
> > specifying rpmsg channel represents the real hardware audio controller.
> > ---
> >
> > That's my idea adding this property. Do you have any suggstion?
> 
> I think you misunderstood the comment. Rob's comment was directly below
> a line which he referred to. That line contained a statement referring
> to Linux drivers. Anything related to Linux drivers does not belong to DT.
> 
> 
> Best regards,
> Krzysztof

Thanks for explaining the meaning and giving more details. I will
delete the statement referring to linux drivers. Indeed this property
is designed to assign the rpmsg channel name.
Does it look better if I modify the code like this:

+  fsl,rpmsg-channel-name:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      A string property to assign rpmsg channel this sound card sits on.
+      This property can be omitted if there is only one sound card and it sits
+      on "rpmsg-audio-channel".
+    enum:
+      - rpmsg-audio-channel
+      - rpmsg-micfil-channel

Regards, 
Chancel Liu