Re: [PATCH v4 1/7] media: platform: amd: Introduce amd isp4 capture driver

[Sultan Alsawaf <sultan@kerneltoast.com>]

Hi Bin,

On Thu, Sep 11, 2025 at 06:08:41PM +0800, Bin Du wrote:
> AMD isp4 capture is a v4l2 media device which implements media controller
> interface. It has one sub-device (AMD ISP4 sub-device) endpoint which can
> be connected to a remote CSI2 TX endpoint. It supports only one physical
> interface for now. Also add ISP4 driver related entry info into the
> MAINTAINERS file
> 
> Co-developed-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
> Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
> Signed-off-by: Bin Du <Bin.Du@amd.com>
> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> Tested-by: Alexey Zagorodnikov <xglooom@gmail.com>

[snip]

> +++ b/drivers/media/platform/amd/isp4/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0+
> +
> +config AMD_ISP4
> +	tristate "AMD ISP4 and camera driver"
> +	depends on VIDEO_DEV && VIDEO_V4L2_SUBDEV_API && DRM_AMD_ISP
> +	select VIDEOBUF2_CORE
> +	select VIDEOBUF2_V4L2
> +	select VIDEOBUF2_MEMOPS

VIDEO_V4L2_SUBDEV_API should be selected rather than set as a dependency, per
what other drivers do. You can also sort the dependencies to look cleaner.

Change to:

	depends on VIDEO_DEV && DRM_AMD_ISP
	select VIDEOBUF2_CORE
	select VIDEOBUF2_MEMOPS
	select VIDEOBUF2_V4L2
	select VIDEO_V4L2_SUBDEV_API

> +	help
> +	  This is support for AMD ISP4 and camera subsystem driver.
> +	  Say Y here to enable the ISP4 and camera device for video capture.
> +	  To compile this driver as a module, choose M here. The module will
> +	  be called amd_capture.

[snip]

> +++ b/drivers/media/platform/amd/isp4/isp4.c
> @@ -0,0 +1,121 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2025 Advanced Micro Devices, Inc.
> + */
> +
> +#include <linux/pm_runtime.h>
> +#include <linux/vmalloc.h>
> +#include <media/v4l2-ioctl.h>
> +
> +#include "isp4.h"
> +
> +#define VIDEO_BUF_NUM 5
> +
> +#define ISP4_DRV_NAME "amd_isp_capture"
> +
> +/* interrupt num */
> +static const u32 isp4_ringbuf_interrupt_num[] = {
> +	0, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT9 */
> +	1, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT10 */
> +	3, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT11 */
> +	4, /* ISP_4_1__SRCID__ISP_RINGBUFFER_WPT12 */
> +};
> +
> +#define to_isp4_device(dev) \
> +	((struct isp4_device *)container_of(dev, struct isp4_device, v4l2_dev))

The unnecessary cast on container_of() is removed later in "[PATCH v4 4/7]
media: platform: amd: isp4 subdev and firmware loading handling added".

Remove the cast in this patch instead.

> +
> +static irqreturn_t isp4_irq_handler(int irq, void *arg)
> +{
> +	return IRQ_HANDLED;
> +}
> +
> +static int isp4_capture_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct isp4_device *isp_dev;
> +	int i, irq, ret;
> +
> +	isp_dev = devm_kzalloc(&pdev->dev, sizeof(*isp_dev), GFP_KERNEL);

s/&pdev->dev/dev/

> +	if (!isp_dev)
> +		return -ENOMEM;
> +
> +	isp_dev->pdev = pdev;
> +	dev->init_name = ISP4_DRV_NAME;
> +
> +	for (i = 0; i < ARRAY_SIZE(isp4_ringbuf_interrupt_num); i++) {
> +		irq = platform_get_irq(pdev, isp4_ringbuf_interrupt_num[i]);
> +		if (irq < 0)
> +			return dev_err_probe(dev, -ENODEV,
> +					     "fail to get irq %d\n",
> +					     isp4_ringbuf_interrupt_num[i]);

Return the error from platform_get_irq() here instead of -ENODEV.

> +		ret = devm_request_irq(&pdev->dev, irq, isp4_irq_handler, 0,
> +				       "ISP_IRQ", &pdev->dev);

s/&pdev->dev/dev/

> +		if (ret)
> +			return dev_err_probe(dev, ret, "fail to req irq %d\n",
> +					     irq);
> +	}
> +
> +	/* Link the media device within the v4l2_device */
> +	isp_dev->v4l2_dev.mdev = &isp_dev->mdev;
> +
> +	/* Initialize media device */
> +	strscpy(isp_dev->mdev.model, "amd_isp41_mdev",
> +		sizeof(isp_dev->mdev.model));
> +	snprintf(isp_dev->mdev.bus_info, sizeof(isp_dev->mdev.bus_info),
> +		 "platform:%s", ISP4_DRV_NAME);
> +	isp_dev->mdev.dev = &pdev->dev;

s/&pdev->dev/dev/

> +	media_device_init(&isp_dev->mdev);
> +
> +	/* register v4l2 device */
> +	snprintf(isp_dev->v4l2_dev.name, sizeof(isp_dev->v4l2_dev.name),
> +		 "AMD-V4L2-ROOT");
> +	ret = v4l2_device_register(&pdev->dev, &isp_dev->v4l2_dev);

s/&pdev->dev/dev/

> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "fail register v4l2 device\n");
> +
> +	ret = media_device_register(&isp_dev->mdev);
> +	if (ret) {
> +		dev_err(dev, "fail to register media device %d\n", ret);
> +		goto err_unreg_v4l2;
> +	}
> +
> +	platform_set_drvdata(pdev, isp_dev);
> +
> +	pm_runtime_set_suspended(dev);
> +	pm_runtime_enable(dev);
> +
> +	return 0;
> +
> +err_unreg_v4l2:
> +	v4l2_device_unregister(&isp_dev->v4l2_dev);
> +
> +	return dev_err_probe(dev, ret, "isp probe fail\n");
> +}

[snip]

> +++ b/drivers/media/platform/amd/isp4/isp4.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (C) 2025 Advanced Micro Devices, Inc.
> + */
> +
> +#ifndef _ISP4_H_
> +#define _ISP4_H_
> +
> +#include <linux/mutex.h>

Remove this linux/mutex.h include. It should be moved to isp4_subdev.h instead.

> +#include <media/v4l2-device.h>
> +#include <media/videobuf2-memops.h>
> +#include <media/videobuf2-vmalloc.h>

This media/videobuf2-vmalloc.h include is removed in "[PATCH v4 4/7] media:
platform: amd: isp4 subdev and firmware loading handling added".

Remove it in this patch instead.

> +
> +#define ISP4_GET_ISP_REG_BASE(isp4sd) (((isp4sd))->mmio)
> +
> +struct isp4_device {
> +	struct v4l2_device v4l2_dev;
> +	struct media_device mdev;
> +
> +	struct platform_device *pdev;
> +	struct notifier_block i2c_nb;

i2c_nb is unused, remove it.

> +};
> +
> +#endif /* _ISP4_H_ */
> -- 
> 2.34.1
> 

Sultan