Re: [PATCH v12 5/6] staging: bcm2835-camera: Register bcm2835-camera with vchiq_bus_type

Umang Jain
2023-10-09T04:26:39Z

Hi Greg,

Sorry for late reply, as I was traveling and then was on vacation for
rest of the week.

On 10/5/23 1:34 PM, Greg Kroah-Hartman wrote:
> On Sat, Sep 23, 2023 at 08:01:59PM +0530, Umang Jain wrote:
>> Register the bcm2835-camera with the vchiq_bus_type instead of using
>> platform driver/device.
>>
>> Since we moved away bcm2835-camera from platform driver/device,
>> we have to set the DMA mask explicitly. Set the DMA mask at probe
>> time.
>>
>> Also the VCHIQ firmware doesn't support device enumeration, hence
>> one has to maintain a list of devices to be registered in the interface.
>>
>> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
>> ---
>> .../bcm2835-camera/bcm2835-camera.c | 21 ++++++++++---------
>> .../interface/vchiq_arm/vchiq_arm.c | 11 +++++++---
>> 2 files changed, 19 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
>> index fcad5118f3e8..c873eace1437 100644
>> --- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
>> +++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
>> @@ -11,6 +11,7 @@
>> * Luke Diamand @ Broadcom
>> */
>>
>> +#include <linux/dma-mapping.h>
>> #include <linux/errno.h>
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> @@ -24,8 +25,8 @@
>> #include <media/v4l2-event.h>
>> #include <media/v4l2-common.h>
>> #include <linux/delay.h>
>> -#include <linux/platform_device.h>
>>
>> +#include "../interface/vchiq_arm/vchiq_bus.h"
>> #include "../vchiq-mmal/mmal-common.h"
>> #include "../vchiq-mmal/mmal-encodings.h"
>> #include "../vchiq-mmal/mmal-vchiq.h"
>> @@ -1841,7 +1842,7 @@ 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 vchiq_device *device)
>> {
>> int ret;
>> struct bcm2835_mmal_dev *dev;
>> @@ -1852,9 +1853,9 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
>> unsigned int resolutions[MAX_BCM2835_CAMERAS][2];
>> int i;
>>
>> - ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
>> + ret = dma_set_mask_and_coherent(&device->dev, DMA_BIT_MASK(32));
>> if (ret) {
>> - dev_err(&pdev->dev, "dma_set_mask_and_coherent failed: %d\n", ret);
>> + dev_err(&device->dev, "dma_set_mask_and_coherent failed: %d\n", ret);
>> return ret;
>> }
>>
>> @@ -1902,7 +1903,7 @@ 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->dev, "%s: could not register V4L2 device: %d\n",
>> __func__, ret);
>> goto free_dev;
>> }
>> @@ -1982,7 +1983,7 @@ static int bcm2835_mmal_probe(struct platform_device *pdev)
>> return ret;
>> }
>>
>> -static void bcm2835_mmal_remove(struct platform_device *pdev)
>> +static void bcm2835_mmal_remove(struct vchiq_device *device)
>> {
>> int camera;
>> struct vchiq_mmal_instance *instance = gdev[0]->instance;
>> @@ -1994,17 +1995,17 @@ static void bcm2835_mmal_remove(struct platform_device *pdev)
>> vchiq_mmal_finalise(instance);
>> }
>>
>> -static struct platform_driver bcm2835_camera_driver = {
>> +static struct vchiq_driver bcm2835_camera_driver = {
>> .probe = bcm2835_mmal_probe,
>> - .remove_new = bcm2835_mmal_remove,
>> + .remove = bcm2835_mmal_remove,
>> .driver = {
>> .name = "bcm2835-camera",
>> },
>> };
>>
>> -module_platform_driver(bcm2835_camera_driver)
>> +module_vchiq_driver(bcm2835_camera_driver)
>>
>> MODULE_DESCRIPTION("Broadcom 2835 MMAL video capture");
>> MODULE_AUTHOR("Vincent Sanders");
>> MODULE_LICENSE("GPL");
>> -MODULE_ALIAS("platform:bcm2835-camera");
>> +MODULE_ALIAS("bcm2835-camera");
> Now that you are on your own bus, why do you need the MODULE_ALIAS()
> line at all?

Because it breaks the module auto-loading support...

If you look at the vchiq_bus patch (3/6) in this series, there is
vchiq_bus_uevent() which sends a event that includes the MODALIAS.
>
> thanks,
>
> greg k-h