[PATCH v4 0/6] staging: vc04_services: vchiq: Register devices with a custom bus_type

[PATCH v4 0/6] staging: vc04_services: vchiq: Register devices with a custom bus_type

[Umang Jain]

The main patch (6/6) is laregly unchanged from v3.
Specific details are elaborated in its commit message.

This series just introduces five extra patches for dropping include
directives from Makefiles (suggested by Greg KH) and rebased.

Changes in v4: 
- Introduce patches to drop include directives from Makefile

Changes in v3:
- Rework entirely to replace platform devices/driver model

-v2:
https://lore.kernel.org/all/20221222191500.515795-1-umang.jain@ideasonboard.com/

-v1:
https://lore.kernel.org/all/20221220084404.19280-1-umang.jain@ideasonboard.com/

Umang Jain (6):
  staging: vc04_services: Drop __VCCOREVER__ remnants
  vc04_services: bcm2835-audio: Drop include Makefile directive
  vc04_services: bcm2835-camera: Drop include Makefile directive
  vc04_services: vchiq-mmal: Drop include Makefile directive
  vc04_services: interface: Drop include Makefile directive
  staging: vc04_services: vchiq: Register devices with a custom bus_type

 drivers/staging/vc04_services/Makefile        |   2 -
 .../vc04_services/bcm2835-audio/Makefile      |   2 -
 .../vc04_services/bcm2835-audio/bcm2835.c     |  19 ++-
 .../vc04_services/bcm2835-audio/bcm2835.h     |   3 +-
 .../vc04_services/bcm2835-camera/Makefile     |   5 -
 .../bcm2835-camera/bcm2835-camera.c           |  27 ++--
 .../vc04_services/bcm2835-camera/controls.c   |   6 +-
 .../interface/vchiq_arm/vchiq_arm.c           | 121 +++++++++++++++---
 .../interface/vchiq_arm/vchiq_arm.h           |   1 +
 .../interface/vchiq_arm/vchiq_core.h          |   2 +-
 .../interface/vchiq_arm/vchiq_ioctl.h         |   3 +-
 .../staging/vc04_services/vchiq-mmal/Makefile |   5 -
 .../vc04_services/vchiq-mmal/mmal-vchiq.c     |   2 +-
 13 files changed, 131 insertions(+), 67 deletions(-)

-- 
2.39.0

[PATCH v4 1/6] staging: vc04_services: Drop __VCCOREVER__ remnants

[Umang Jain]

Commit 8ba5f91bab63("staging: vc04_services: remove __VCCOREVER__")
was meant to remove all of __VCCOREVER__ definitions but missed to
remove a few. Hence, drop them now.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/staging/vc04_services/bcm2835-audio/Makefile  | 2 +-
 drivers/staging/vc04_services/bcm2835-camera/Makefile | 3 +--
 drivers/staging/vc04_services/vchiq-mmal/Makefile     | 3 +--
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/Makefile b/drivers/staging/vc04_services/bcm2835-audio/Makefile
index d59fe4dde615..fc7ac6112a3e 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/Makefile
+++ b/drivers/staging/vc04_services/bcm2835-audio/Makefile
@@ -2,4 +2,4 @@
 obj-$(CONFIG_SND_BCM2835)	+= snd-bcm2835.o
 snd-bcm2835-objs		:= bcm2835.o bcm2835-ctl.o bcm2835-pcm.o bcm2835-vchiq.o
 
-ccflags-y += -I $(srctree)/$(src)/../include -D__VCCOREVER__=0x04000000
+ccflags-y += -I $(srctree)/$(src)/../include
diff --git a/drivers/staging/vc04_services/bcm2835-camera/Makefile b/drivers/staging/vc04_services/bcm2835-camera/Makefile
index 3a76d6ade428..3494c82b271a 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/Makefile
+++ b/drivers/staging/vc04_services/bcm2835-camera/Makefile
@@ -7,5 +7,4 @@ obj-$(CONFIG_VIDEO_BCM2835) += bcm2835-v4l2.o
 
 ccflags-y += \
 	-I $(srctree)/$(src)/.. \
-	-I $(srctree)/$(src)/../vchiq-mmal/ \
-	-D__VCCOREVER__=0x04000000
+	-I $(srctree)/$(src)/../vchiq-mmal/
diff --git a/drivers/staging/vc04_services/vchiq-mmal/Makefile b/drivers/staging/vc04_services/vchiq-mmal/Makefile
index b2a830f48acc..c7d3b06e17ce 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/Makefile
+++ b/drivers/staging/vc04_services/vchiq-mmal/Makefile
@@ -5,5 +5,4 @@ obj-$(CONFIG_BCM2835_VCHIQ_MMAL) += bcm2835-mmal-vchiq.o
 
 ccflags-y += \
 	-I$(srctree)/$(src)/.. \
-	-I$(srctree)/$(src)/../include \
-	-D__VCCOREVER__=0x04000000
+	-I$(srctree)/$(src)/../include
-- 
2.39.0

[PATCH v4 2/6] vc04_services: bcm2835-audio: Drop include Makefile directive

[Umang Jain]

Drop the include directive they can break the build one only wants to
build a subdirectory. Replace with "../" for the includes, in the
bcm2835.h instead.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/staging/vc04_services/bcm2835-audio/Makefile  | 2 --
 drivers/staging/vc04_services/bcm2835-audio/bcm2835.h | 3 ++-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/Makefile b/drivers/staging/vc04_services/bcm2835-audio/Makefile
index fc7ac6112a3e..01ceebdf88e7 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/Makefile
+++ b/drivers/staging/vc04_services/bcm2835-audio/Makefile
@@ -1,5 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_SND_BCM2835)	+= snd-bcm2835.o
 snd-bcm2835-objs		:= bcm2835.o bcm2835-ctl.o bcm2835-pcm.o bcm2835-vchiq.o
-
-ccflags-y += -I $(srctree)/$(src)/../include
diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
index 38b7451d77b2..0a81383c475a 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
@@ -6,11 +6,12 @@
 
 #include <linux/device.h>
 #include <linux/wait.h>
-#include <linux/raspberrypi/vchiq.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm-indirect.h>
 
+#include "../include/linux/raspberrypi/vchiq.h"
+
 #define MAX_SUBSTREAMS   (8)
 #define AVAIL_SUBSTREAMS_MASK  (0xff)
 
-- 
2.39.0

[PATCH v4 3/6] vc04_services: bcm2835-camera: Drop include Makefile directive

[Umang Jain]

Drop the include directive they can break the build one only wants to
build a subdirectory. Replace with "../" for the includes, in the
bcm2835-camera files instead.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/staging/vc04_services/bcm2835-camera/Makefile  |  4 ----
 .../vc04_services/bcm2835-camera/bcm2835-camera.c      | 10 +++++-----
 .../staging/vc04_services/bcm2835-camera/controls.c    |  6 +++---
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-camera/Makefile b/drivers/staging/vc04_services/bcm2835-camera/Makefile
index 3494c82b271a..203b93899b20 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/Makefile
+++ b/drivers/staging/vc04_services/bcm2835-camera/Makefile
@@ -4,7 +4,3 @@ bcm2835-v4l2-$(CONFIG_VIDEO_BCM2835) := \
 	controls.o
 
 obj-$(CONFIG_VIDEO_BCM2835) += bcm2835-v4l2.o
-
-ccflags-y += \
-	-I $(srctree)/$(src)/.. \
-	-I $(srctree)/$(src)/../vchiq-mmal/
diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index 797ebe2a973a..4f81765912ea 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -26,11 +26,11 @@
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 
-#include "mmal-common.h"
-#include "mmal-encodings.h"
-#include "mmal-vchiq.h"
-#include "mmal-msg.h"
-#include "mmal-parameters.h"
+#include "../vchiq-mmal/mmal-common.h"
+#include "../vchiq-mmal/mmal-encodings.h"
+#include "../vchiq-mmal/mmal-vchiq.h"
+#include "../vchiq-mmal/mmal-msg.h"
+#include "../vchiq-mmal/mmal-parameters.h"
 #include "bcm2835-camera.h"
 
 #define MIN_WIDTH 32
diff --git a/drivers/staging/vc04_services/bcm2835-camera/controls.c b/drivers/staging/vc04_services/bcm2835-camera/controls.c
index 5644d1d457b9..6bce45925bf1 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/controls.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/controls.c
@@ -23,9 +23,9 @@
 #include <media/v4l2-event.h>
 #include <media/v4l2-common.h>
 
-#include "mmal-common.h"
-#include "mmal-vchiq.h"
-#include "mmal-parameters.h"
+#include "../vchiq-mmal/mmal-common.h"
+#include "../vchiq-mmal/mmal-vchiq.h"
+#include "../vchiq-mmal/mmal-parameters.h"
 #include "bcm2835-camera.h"
 
 /* The supported V4L2_CID_AUTO_EXPOSURE_BIAS values are from -4.0 to +4.0.
-- 
2.39.0

[PATCH v4 4/6] vc04_services: vchiq-mmal: Drop include Makefile directive

[Umang Jain]

Drop the include directive they can break the build one only wants to
build a subdirectory. Replace with "../" for the includes, in the
mmal-vchiq.c instead.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/staging/vc04_services/vchiq-mmal/Makefile     | 4 ----
 drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c | 2 +-
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/staging/vc04_services/vchiq-mmal/Makefile b/drivers/staging/vc04_services/vchiq-mmal/Makefile
index c7d3b06e17ce..6937f6534c26 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/Makefile
+++ b/drivers/staging/vc04_services/vchiq-mmal/Makefile
@@ -2,7 +2,3 @@
 bcm2835-mmal-vchiq-objs := mmal-vchiq.o
 
 obj-$(CONFIG_BCM2835_VCHIQ_MMAL) += bcm2835-mmal-vchiq.o
-
-ccflags-y += \
-	-I$(srctree)/$(src)/.. \
-	-I$(srctree)/$(src)/../include
diff --git a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
index 6b5879a33780..234e3764db64 100644
--- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
@@ -23,9 +23,9 @@
 #include <linux/slab.h>
 #include <linux/completion.h>
 #include <linux/vmalloc.h>
-#include <linux/raspberrypi/vchiq.h>
 #include <media/videobuf2-vmalloc.h>
 
+#include "../include/linux/raspberrypi/vchiq.h"
 #include "mmal-common.h"
 #include "mmal-vchiq.h"
 #include "mmal-msg.h"
-- 
2.39.0

[PATCH v4 5/6] vc04_services: interface: Drop include Makefile directive

[Umang Jain]

Drop the include directive they can break the build one only wants to
build a subdirectory. Replace with "../" for the includes, in the
interface/ files instead.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/staging/vc04_services/Makefile                         | 2 --
 drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h | 2 +-
 .../staging/vc04_services/interface/vchiq_arm/vchiq_ioctl.h    | 3 ++-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/vc04_services/Makefile b/drivers/staging/vc04_services/Makefile
index 1fd191e2e2a5..44794bdf6173 100644
--- a/drivers/staging/vc04_services/Makefile
+++ b/drivers/staging/vc04_services/Makefile
@@ -15,5 +15,3 @@ obj-$(CONFIG_SND_BCM2835)		+= bcm2835-audio/
 obj-$(CONFIG_VIDEO_BCM2835)		+= bcm2835-camera/
 obj-$(CONFIG_BCM2835_VCHIQ_MMAL)	+= vchiq-mmal/
 
-ccflags-y += -I $(srctree)/$(src)/include
-
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
index ec3505424718..12da398c6115 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
@@ -10,8 +10,8 @@
 #include <linux/kref.h>
 #include <linux/rcupdate.h>
 #include <linux/wait.h>
-#include <linux/raspberrypi/vchiq.h>
 
+#include "../../include/linux/raspberrypi/vchiq.h"
 #include "vchiq_cfg.h"
 
 /* Do this so that we can test-build the code on non-rpi systems */
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_ioctl.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_ioctl.h
index 96f50beace44..17550831f86c 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_ioctl.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_ioctl.h
@@ -5,7 +5,8 @@
 #define VCHIQ_IOCTLS_H
 
 #include <linux/ioctl.h>
-#include <linux/raspberrypi/vchiq.h>
+
+#include "../../include/linux/raspberrypi/vchiq.h"
 
 #define VCHIQ_IOC_MAGIC 0xc4
 #define VCHIQ_INVALID_HANDLE (~0)
-- 
2.39.0

[PATCH v4 6/6] staging: vc04_services: vchiq: Register devices with a custom bus_type

[Umang Jain]

The devices that the vchiq interface registers(bcm2835-audio,
bcm2835-camera) are implemented and exposed by the VC04 firmware.
The device tree describes the VC04 itself with the resources
required to communicate with it through a mailbox interface. However,
the vchiq interface registers these devices as platform devices. This
also means the specific drivers for these devices are also getting
registered as platform drivers. This is not correct and a blatant
abuse of platform device/driver.

Replace the platform device/driver model with a standard device driver
model. A custom bus_type, vchiq_bus_type, is created in the vchiq
interface which matches the devices to their specific device drivers
thereby, establishing driver binding. A struct vchiq_device wraps the
struct device for each device being registered on the bus by the vchiq
interface.

Each device registered will expose a 'name' read-only device attribute
in sysfs (/sys/bus/vchiq-bus/devices). New devices and drivers can be
added by registering on vchiq_bus_type and adding a corresponding
device name entry in the static list of devices, vchiq_devices. There
is currently no way to enumerate the VCHIQ devices that are available
from the firmware.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 .../vc04_services/bcm2835-audio/bcm2835.c     |  19 ++-
 .../bcm2835-camera/bcm2835-camera.c           |  17 ++-
 .../interface/vchiq_arm/vchiq_arm.c           | 121 +++++++++++++++---
 .../interface/vchiq_arm/vchiq_arm.h           |   1 +
 4 files changed, 117 insertions(+), 41 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
index 00bc898b0189..9f3af84f5d5d 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
@@ -1,12 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2011 Broadcom Corporation.  All rights reserved. */
 
-#include <linux/platform_device.h>
-
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 
+#include "../interface/vchiq_arm/vchiq_arm.h"
 #include "bcm2835.h"
 
 static bool enable_hdmi;
@@ -268,9 +267,8 @@ static int snd_add_child_devices(struct device *device, u32 numchans)
 	return 0;
 }
 
-static int snd_bcm2835_alsa_probe(struct platform_device *pdev)
+static int snd_bcm2835_alsa_probe(struct device *dev)
 {
-	struct device *dev = &pdev->dev;
 	int err;
 
 	if (num_channels <= 0 || num_channels > MAX_SUBSTREAMS) {
@@ -292,30 +290,29 @@ static int snd_bcm2835_alsa_probe(struct platform_device *pdev)
 
 #ifdef CONFIG_PM
 
-static int snd_bcm2835_alsa_suspend(struct platform_device *pdev,
+static int snd_bcm2835_alsa_suspend(struct device *pdev,
 				    pm_message_t state)
 {
 	return 0;
 }
 
-static int snd_bcm2835_alsa_resume(struct platform_device *pdev)
+static int snd_bcm2835_alsa_resume(struct device *pdev)
 {
 	return 0;
 }
 
 #endif
 
-static struct platform_driver bcm2835_alsa_driver = {
+static struct device_driver bcm2835_alsa_driver = {
 	.probe = snd_bcm2835_alsa_probe,
 #ifdef CONFIG_PM
 	.suspend = snd_bcm2835_alsa_suspend,
 	.resume = snd_bcm2835_alsa_resume,
 #endif
-	.driver = {
-		.name = "bcm2835_audio",
-	},
+	.name = "bcm2835_audio",
+	.bus = &vchiq_bus_type,
 };
-module_platform_driver(bcm2835_alsa_driver);
+module_driver(bcm2835_alsa_driver, driver_register, driver_unregister);
 
 MODULE_AUTHOR("Dom Cobley");
 MODULE_DESCRIPTION("Alsa driver for BCM2835 chip");
diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index 4f81765912ea..199a49f9ec1e 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -24,8 +24,8 @@
 #include <media/v4l2-event.h>
 #include <media/v4l2-common.h>
 #include <linux/delay.h>
-#include <linux/platform_device.h>
 
+#include "../interface/vchiq_arm/vchiq_arm.h"
 #include "../vchiq-mmal/mmal-common.h"
 #include "../vchiq-mmal/mmal-encodings.h"
 #include "../vchiq-mmal/mmal-vchiq.h"
@@ -1841,7 +1841,7 @@ static struct v4l2_format default_v4l2_format = {
 	.fmt.pix.sizeimage = 1024 * 768,
 };
 
-static int bcm2835_mmal_probe(struct platform_device *pdev)
+static int bcm2835_mmal_probe(struct device *device)
 {
 	int ret;
 	struct bcm2835_mmal_dev *dev;
@@ -1896,7 +1896,7 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
 						       &camera_instance);
 		ret = v4l2_device_register(NULL, &dev->v4l2_dev);
 		if (ret) {
-			dev_err(&pdev->dev, "%s: could not register V4L2 device: %d\n",
+			dev_err(device, "%s: could not register V4L2 device: %d\n",
 				__func__, ret);
 			goto free_dev;
 		}
@@ -1976,7 +1976,7 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int bcm2835_mmal_remove(struct platform_device *pdev)
+static int bcm2835_mmal_remove(struct device *device)
 {
 	int camera;
 	struct vchiq_mmal_instance *instance = gdev[0]->instance;
@@ -1990,15 +1990,14 @@ static int bcm2835_mmal_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct platform_driver bcm2835_camera_driver = {
+static struct device_driver bcm2835_camera_driver = {
+	.name		= "bcm2835-camera",
 	.probe		= bcm2835_mmal_probe,
 	.remove		= bcm2835_mmal_remove,
-	.driver		= {
-		.name	= "bcm2835-camera",
-	},
+	.bus		= &vchiq_bus_type,
 };
 
-module_platform_driver(bcm2835_camera_driver)
+module_driver(bcm2835_camera_driver, driver_register, driver_unregister)
 
 MODULE_DESCRIPTION("Broadcom 2835 MMAL video capture");
 MODULE_AUTHOR("Vincent Sanders");
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 22de23f3af02..86c8e5df7cf6 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -12,6 +12,8 @@
 #include <linux/cdev.h>
 #include <linux/fs.h>
 #include <linux/device.h>
+#include <linux/device/bus.h>
+#include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
@@ -65,9 +67,6 @@ int vchiq_susp_log_level = VCHIQ_LOG_ERROR;
 DEFINE_SPINLOCK(msg_queue_spinlock);
 struct vchiq_state g_state;
 
-static struct platform_device *bcm2835_camera;
-static struct platform_device *bcm2835_audio;
-
 struct vchiq_drvdata {
 	const unsigned int cache_line_size;
 	struct rpi_firmware *fw;
@@ -132,6 +131,51 @@ struct vchiq_pagelist_info {
 	unsigned int scatterlist_mapped;
 };
 
+struct vchiq_device {
+	const char *name;
+	struct device dev;
+};
+
+static ssize_t vchiq_dev_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct vchiq_device *device = container_of(dev, struct vchiq_device, dev);
+
+	return sprintf(buf, "%s", device->name);
+}
+
+static DEVICE_ATTR_RO(vchiq_dev);
+
+static struct attribute *vchiq_dev_attrs[] = {
+	&dev_attr_vchiq_dev.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(vchiq_dev);
+
+static const struct device_type vchiq_device_type = {
+	.groups         = vchiq_dev_groups
+};
+
+static int vchiq_bus_type_match(struct device *dev, struct device_driver *drv)
+{
+	if (dev->bus == &vchiq_bus_type &&
+	    strcmp(dev_name(dev), drv->name) == 0)
+		return 1;
+	return 0;
+}
+
+struct bus_type vchiq_bus_type = {
+	.name   = "vchiq-bus",
+	.match  = vchiq_bus_type_match,
+};
+EXPORT_SYMBOL(vchiq_bus_type);
+
+static const char *const vchiq_devices[] = {
+	"bcm2835_audio",
+	"bcm2835-camera",
+};
+
 static void __iomem *g_regs;
 /* This value is the size of the L2 cache lines as understood by the
  * VPU firmware, which determines the required alignment of the
@@ -1763,26 +1807,52 @@ static const struct of_device_id vchiq_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, vchiq_of_match);
 
-static struct platform_device *
+static void
+vchiq_release_device(struct device *dev)
+{
+	struct vchiq_device *device;
+
+	device = container_of(dev, struct vchiq_device, dev);
+	kfree(device);
+}
+
+static int
 vchiq_register_child(struct platform_device *pdev, const char *name)
 {
-	struct platform_device_info pdevinfo;
-	struct platform_device *child;
+	struct vchiq_device *device = NULL;
+	int ret;
 
-	memset(&pdevinfo, 0, sizeof(pdevinfo));
+	device = kzalloc(sizeof(*device), GFP_KERNEL);
+	if (!device)
+		return -ENOMEM;
 
-	pdevinfo.parent = &pdev->dev;
-	pdevinfo.name = name;
-	pdevinfo.id = PLATFORM_DEVID_NONE;
-	pdevinfo.dma_mask = DMA_BIT_MASK(32);
+	device->name = name;
+	device->dev.init_name = name;
+	device->dev.parent = &pdev->dev;
+	device->dev.bus = &vchiq_bus_type;
+	device->dev.type = &vchiq_device_type;
+	device->dev.release = vchiq_release_device;
+
+	ret = dma_set_mask_and_coherent(&device->dev, DMA_BIT_MASK(32));
+	if (ret < 0) {
+		vchiq_release_device(&device->dev);
+		return ret;
+	}
 
-	child = platform_device_register_full(&pdevinfo);
-	if (IS_ERR(child)) {
-		dev_warn(&pdev->dev, "%s not registered\n", name);
-		child = NULL;
+	ret = device_register(&device->dev);
+	if (ret) {
+		put_device(&device->dev);
+		return -EINVAL;
 	}
 
-	return child;
+	return 0;
+}
+
+static int
+vchiq_unregister_child(struct device *dev, void *data)
+{
+	device_unregister(dev);
+	return 0;
 }
 
 static int vchiq_probe(struct platform_device *pdev)
@@ -1790,7 +1860,7 @@ static int vchiq_probe(struct platform_device *pdev)
 	struct device_node *fw_node;
 	const struct of_device_id *of_id;
 	struct vchiq_drvdata *drvdata;
-	int err;
+	int i, err;
 
 	of_id = of_match_node(vchiq_of_match, pdev->dev.of_node);
 	drvdata = (struct vchiq_drvdata *)of_id->data;
@@ -1832,8 +1902,12 @@ static int vchiq_probe(struct platform_device *pdev)
 		goto error_exit;
 	}
 
-	bcm2835_camera = vchiq_register_child(pdev, "bcm2835-camera");
-	bcm2835_audio = vchiq_register_child(pdev, "bcm2835_audio");
+	for (i = 0; i < ARRAY_SIZE(vchiq_devices); i++) {
+		err = vchiq_register_child(pdev, vchiq_devices[i]);
+		if (!err)
+			dev_err(&pdev->dev, "Failed to register %s vchiq device\n",
+				vchiq_devices[i]);
+	}
 
 	return 0;
 
@@ -1845,8 +1919,8 @@ static int vchiq_probe(struct platform_device *pdev)
 
 static int vchiq_remove(struct platform_device *pdev)
 {
-	platform_device_unregister(bcm2835_audio);
-	platform_device_unregister(bcm2835_camera);
+	bus_for_each_dev(&vchiq_bus_type, NULL, NULL, vchiq_unregister_child);
+
 	vchiq_debugfs_deinit();
 	vchiq_deregister_chrdev();
 
@@ -1866,6 +1940,10 @@ static int __init vchiq_driver_init(void)
 {
 	int ret;
 
+	ret = bus_register(&vchiq_bus_type);
+	if (ret)
+		pr_err("Failed to register %s\n", vchiq_bus_type.name);
+
 	ret = platform_driver_register(&vchiq_driver);
 	if (ret)
 		pr_err("Failed to register vchiq driver\n");
@@ -1876,6 +1954,7 @@ module_init(vchiq_driver_init);
 
 static void __exit vchiq_driver_exit(void)
 {
+	bus_unregister(&vchiq_bus_type);
 	platform_driver_unregister(&vchiq_driver);
 }
 module_exit(vchiq_driver_exit);
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
index 2fb31f9b527f..98c3af32774a 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
@@ -81,6 +81,7 @@ extern int vchiq_susp_log_level;
 
 extern spinlock_t msg_queue_spinlock;
 extern struct vchiq_state g_state;
+extern struct bus_type vchiq_bus_type;
 
 extern struct vchiq_state *
 vchiq_get_state(void);
-- 
2.39.0

Re: [PATCH v4 0/6] staging: vc04_services: vchiq: Register devices with a custom bus_type

[Greg Kroah-Hartman]

On Thu, Jan 19, 2023 at 12:48:05AM +0530, Umang Jain wrote:
> The main patch (6/6) is laregly unchanged from v3.
> Specific details are elaborated in its commit message.
> 
> This series just introduces five extra patches for dropping include
> directives from Makefiles (suggested by Greg KH) and rebased.
> 
> Changes in v4: 
> - Introduce patches to drop include directives from Makefile
> 
> Changes in v3:
> - Rework entirely to replace platform devices/driver model
> 
> -v2:
> https://lore.kernel.org/all/20221222191500.515795-1-umang.jain@ideasonboard.com/
> 
> -v1:
> https://lore.kernel.org/all/20221220084404.19280-1-umang.jain@ideasonboard.com/
> 
> Umang Jain (6):
>   staging: vc04_services: Drop __VCCOREVER__ remnants
>   vc04_services: bcm2835-audio: Drop include Makefile directive
>   vc04_services: bcm2835-camera: Drop include Makefile directive
>   vc04_services: vchiq-mmal: Drop include Makefile directive
>   vc04_services: interface: Drop include Makefile directive
>   staging: vc04_services: vchiq: Register devices with a custom bus_type

Your patch subject lines are odd here, many drop the "staging: " prefix.
Please fix up.

thanks,

greg k-h