i.MX Processors中的主题 Re: sysfs entry for v4l2src?

sysfs entry for v4l2src?

gbiradar — Mon, 18 Jan 2016 07:15:49 GMT

Hi Guys,

I want to enable sysfs entry to my ov5640 camera. with sysfs i'm trying to control brightness,contrast values. i know about sysfs but adding support for camera i don't know if anyone has idea plaese share it.

regards,

Ganesh

Re: sysfs entry for v4l2src?

BrilliantovKiri — Mon, 18 Jan 2016 08:03:33 GMT

linux/sysfs.txt at master · torvalds/linux · GitHub

linux/debugfs.txt at master · torvalds/linux · GitHub

Re: sysfs entry for v4l2src?

alejandrolozan1 — Mon, 18 Jan 2016 18:32:14 GMT

Hi,

I think you can use as reference the code of drivers/media/platform/mxc/capture/mxc_v4l2_capture.c

There you can see the below example.

static ssize_t show_streaming(struct device *dev,

struct device_attribute *attr, char *buf)

{

struct video_device *video_dev = container_of(dev,

struct video_device, dev);

cam_data *cam = video_get_drvdata(video_dev);

if (cam->capture_on)

return sprintf(buf, "stream on\n");

else

return sprintf(buf, "stream off\n");

}

static DEVICE_ATTR(fsl_v4l2_capture_property, S_IRUGO, show_streaming, NULL);

Please take a look at that file. You may find it very helpful.

Best Regards,

Alejandro

Re: sysfs entry for v4l2src?

gbiradar — Tue, 19 Jan 2016 06:46:18 GMT

Hi alejandrolozano,

well i have actually able to create sysfs entry able to pass some value to desired brightness level but it is returning ov5640_write_reg fail.

Below is my code snippet check.

static struct kobject *ov5640_mipi_kobj;

static ssize_t ov5640_mipi_brightness_set(struct device *dev, struct device_attribute *attr, char *buf,size_t size)

{

int err;

unsigned long val;

if (strict_strtoul(buf, 10, &val))

return -EINVAL;

pr_info("GB : ov5640_mipi_brightness_set\n");

switch(val){

case 0 : ov5640_write_reg(0x5001, 0xff);

ov5640_write_reg(0x5587, 0x40);

ov5640_write_reg(0x5580, 0x04);

ov5640_write_reg(0x5588, 0x01);

break;

..................

}

static struct kobj_attribute brightness = __ATTR(brightness_ctrl, 0664, NULL, ov5640_mipi_brightness_set);

static struct attribute *attributes_ov5640_mipi[] = {

&brightness.attr,

NULL,

};

static struct attribute_group attr_group_ov5640_mipi = {

.attrs = attributes_ov5640_mipi,

};

static int create_sysfs_interfaces(struct device *dev)

{

int err;

ov5640_mipi_kobj = kobject_create_and_add("ov5640_mipi_sensor", &dev->kobj);

if(!ov5640_mipi_kobj)

return -ENOMEM;

err = sysfs_create_group(ov5640_mipi_kobj, &attr_group_ov5640_mipi);

if (err)

{

kobject_put(ov5640_mipi_kobj);

dev_err(dev, "%s:Unable to create interface\n", __func__);

return -1;

}

pr_info("GB : create_sysfs_interfaces\n");

return 0;

}

$ echo 0 > /sys/bus/i2c/../devices/ov5640_brightness_set/brightness_ctrl

GB : ov5640_mipi_brightness_set

ov5640_write_reg:write reg error:reg=5001,val=ff

ov5640_write_reg:write reg error:reg=5587,val=40

ov5640_write_reg:write reg error:reg=5580,val=4

ov5640_write_reg:write reg error:reg=5588,val=1

Re: sysfs entry for v4l2src?

gbiradar — Thu, 21 Jan 2016 13:27:29 GMT

update:

Camera will be powerdown mode so some application is run to allow the camera in active mode then the write error will not come