CSI Camera Module 5MP OV5640 (Linux)

Applicable for

BSP Layers / Reference Images for Yocto (Linux) | TorizonCore (Linux)

Introduction

This article explains how to use the Toradex CSI Camera Module 5MP OV5640. It can be used with a combination of hardware and software:

Hardware

The following sub-sections describe the possible hardware combinations for out-of-the-box usage of the CSI Camera Module. In addition, it might be possible to add a converter IC to your carrier board, though we don't go through it in this article.

Apalis

Apalis Evaluation Board: via the first aka CSI_1_CSI-2/4x FFC receptacle available on the V2.0A versions of our module type-specific Apalis mezzanine boards.
Ixora Carrier Board V1.1A onwards: via the MIPI Camera Serial Interface 2 (MIPI CSI-2).

Colibri

Colibri iMX8X: directly on the SoM, via the X3 FFC connector.

Verdin

Verdin Development Board: via the MIPI CSI-2 connector X47.
Dahlia Carrier Board: via the MIPI CSI-2 connector X16.

Software

Device drivers are included out-of-the-box in our BSPs. On most SoMs they are loaded by default. On Apalis T30 and Apalis TK1 you need to load drivers manually and this is explained in their respective usage sections.

The following Embedded Linux offerings by Toradex allow you to use the CSI Camera Module:

TorizonCore

You can use Torizon to build a container with all userspace dependencies required, such as gstreamer:

How to use Gstreamer in a Docker Container with TorizonCore

BSP Layers and Reference Images for Yocto Project

You are recommended to always use the latest Toradex BSP Layers and Reference Images for Yocto Project. The CSI Camera Module is supported since its release on BSP 2.8.

BSP 2.8: works out-of-the-box with our pre-built binary images.
BSP 3.0: Toradex only provides console images, you need to add userspace multimedia packages to use the camera, such as v4l2 and Gstreamer.
BSP 4.0: works out-of-the-box with our pre-built Graphical Image.
BSP 5.0: works out-of-the-box with our pre-built Multimedia Reference Image.

Single Camera Use Case

Apalis iMX6

On Apalis iMX6 the kernel modules are included out-of-the-box and are loaded by default.

Note: You may need to load a device tree with the correct camera sensor node enabled e.g. for Ixora V1.1A doing setenv fdt_file imx6q-apalis-ixora-v1.1.dtb; saveenv from within U-Boot.

Camera preview:

# gst-launch-1.0 imxv4l2videosrc device=/dev/video2 ! imxipuvideosink use-vsync=true

# gst-launch-1.0 imxv4l2videosrc device=/dev/video2 imx-capture-mode=2 ! imxeglvivsink

Apalis iMX8

On Apalis iMX8 the kernel modules are included out-of-the-box and are loaded by default.

Camera preview:

# gst-launch-1.0 v4l2src device='/dev/video4' ! video/x-raw,format=RGB16,width=1920,height=1080,framerate=30/1 ! waylandsink -v

Example for the BSP 5

As an example for the BSP 5, you can enable the camera by editing the overlays.txt at the module boot partition, so it will have a content like showed below:

 overlays.txt
fdt_overlays=apalis-imx8_ov5640_overlay.dtbo

Note: If you also need other device tree overlays enabled, you need to list all of them after the fdt_overlays= in the overlays.txt file and every device tree overlay file nome must be separated by a space.

Apalis iMX8X

On Apalis iMX8X the kernel modules are included out-of-the-box and are loaded by default.

Camera preview:

# gst-launch-1.0 v4l2src device='/dev/video0' ! video/x-raw,format=RGB16,width=1920,height=1080,framerate=30/1 ! waylandsink -v

Apalis T30

Assert reset on the OV5640 camera sensor:

# echo low > /sys/class/gpio/gpio146/direction****

Power-up OV5640 camera sensor:

# echo low > /sys/class/gpio/gpio147/direction

Release reset on the OV5640 camera sensor:

# echo high > /sys/class/gpio/gpio146/direction

On Apalis T30 the kernel modules are included out-of-the-box. Load camera-related kernel modules in this order:

# modprobe videobuf2-memops
# modprobe videobuf2-dma-nvmap
# modprobe ov5640
# modprobe tegra_v4l2_camera

Camera preview:

# gst-launch -e v4l2src device="/dev/video0" ! 'video/x-raw-yuv, width=(int)640, height=(int)480, format=(fourcc)YUY2' ! nvvidconv ! 'video/x-nvrm-yuv, format=(fourcc)I420' ! nvxvimagesink

# gst-launch -e v4l2src device="/dev/video0" ! 'video/x-raw-yuv, width=(int)1920, height=(int)1088, format=(fourcc)YUY2' ! nvvidconv ! 'video/x-nvrm-yuv, format=(fourcc)I420' ! nvxvimagesink

Apalis TK1

Assert reset on the OV5640 camera sensor:

# echo 250 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio250/direction

Power-up OV5640 camera sensor:

# echo 248 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio248/direction

Release reset on the OV5640 camera sensor:

# echo high > /sys/class/gpio/gpio250/direction

On Apalis TK1 the kernel modules are included out-of-the-box. Load camera-related kernel modules in this order:

Note: When running NVIDIA's L4T aka Ubuntu ARM you may need to un-load aka rmmod the nvhost_vi Linux kernel module first which otherwise would conflict with tegra_camera.

# modprobe videobuf2-dma-contig
# modprobe ov5640
# modprobe tegra_camera

Camera preview:

# gst-launch-0.10 v4l2src queue-size=1 ! 'video/x-raw-yuv,format=(fourcc)UYVY,width=640,height=480' ! xvimagesink

# gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,format={UYVY},width=640,height=480' ! xvimagesink

Colibri iMX8X

On Colibri iMX8X the kernel modules are included out-of-the-box and are loaded by default.

Camera preview:

# gst-launch-1.0 v4l2src device='/dev/video0' ! video/x-raw,format=RGB16,width=1920,height=1080,framerate=30/1 ! waylandsink -v

Verdin iMX8M Mini

On Verdin iMX8M Mini the kernel modules are included out-of-the-box starting at the BSP 5, for both TorizonCore and our Yocto Reference Images.

In order to have the OV5640 Camera working, you need to activate the verdin-imx8mm_ov5640_overlay.dtbo Device Tree Overlay for it.

If you are working with TorizonCore, please check the article Device Tree Overlays on Torizon to see how to do it.
If you are working with BSP 5, please check the article Device Tree Overlays (Linux) to see how to do it.

Example for the BSP 5

As an example for the BSP 5, you can enable the camera by editing the overlays.txt at the module boot partition, so it will have a content like showed below:

 overlays.txt
fdt_overlays=overlays/verdin-imx8mm_ov5640_overlay.dtbo

Note: If you also need to have the DSI to HDMI adapter working on Verdin, please make to sure to add the overlays/verdin-imx8mm_lt8912_overlay.dtbo (followed by a space) in the sequence of the fdt_overlays parameter at overlays.txt file. For the TorizonCore 5, will need to activate the same device tree as well.

Save the file and reboot the module.

After reboot, you will be able to check if the camera is working by executing the following command for Camera preview:

# gst-launch-1.0 v4l2src device='/dev/video0' ! video/x-raw,format=YUY2,width=1920,height=1080,framerate=30/1 ! waylandsink -v

Dual Camera Use Case

Apalis TK1

With the Apalis Evaluation Board and an Apalis TK1 Mezzanine V2.0A it is possible to have two cameras running simultaneously. This works by connecting one camera to the first aka CSI_1_CSI-2/4x FFC receptacle and a second one to the third aka CSI_3_CSI-2/4x FFC receptacle available on the Mezzanine.

Assert reset for both OV5640 camera sensors:

# echo 250 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio250/direction
# echo 195 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio195/direction

Power on both OV6540 camera sensors:

# echo 248 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio248/direction
# echo 234 > /sys/class/gpio/export
# echo low > /sys/class/gpio/gpio234/direction

Release reset for the second OV6540 camera sensor:

# echo high > /sys/class/gpio/gpio195/direction

Move the second OV6540 camera to a different I2C address with this userspace application:

 ov5640-sccb_id.c
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/i2c-dev.h>
 
#define OV5640_REG_SLAVE_ID       0x3100
 
int main(int argc, char* argv[])
{
    char buf[8] = {0};
    char filename[20] ={0};
    int file;
    int adapter_nr = 0; /* probably dynamically determined */ 
    int addr = 0x3C;    /* The I2C address */
    int slave_id = 0x3D;
 
    if (argc < 4) {
        printf("usage: %s [i2c-bus] [i2c-addr] [sccb-id]\n", argv[0]);
        printf("\twhere:\n");
        printf("\ti2c-bus: 2 for Apalis T30/TK1, 3 for Apalis iMX6\n");
        printf("\ti2c-addr: 0x3C\n");
        printf("\tsccb-id: typically other than 0x3C\n");
        return 1;
    } else {
        adapter_nr = atoi(argv[1]);
        sscanf(argv[2], "0x%x", &addr);
        sscanf(argv[3], "0x%x", &slave_id);
        buf[0] = OV5640_REG_SLAVE_ID >> 8;
        buf[1] = OV5640_REG_SLAVE_ID & 0xff;
        buf[2] = slave_id << 1;
    }
 
    printf("i2c-bus = %d, i2c-addr = 0x%02x, sccb-id = 0x%02x\n", adapter_nr, addr, slave_id);
 
    /* open the device file */
    snprintf(filename, 19, "/dev/i2c-%d", adapter_nr);
    file = open(filename, O_RDWR);
    if (file < 0) {
        /* ERROR HANDLING; you can check errno to see what went wrong */
        printf("ERROR HANDLING; you can check errno to see what went wrong\n");
        return 1;
    }
 
    /* specify device address to communicate */
    if (ioctl(file, I2C_SLAVE, addr) < 0) {
        /* ERROR HANDLING; you can check errno to see what went wrong */
        printf("ERROR HANDLING; you can check errno to see what went wrong\n");
        return 1;
    }
 
    /* Using I2C Write */
    if (write(file, buf, 3) != 3) {
        /* ERROR HANDLING: i2c transaction failed */
        printf("ERROR HANDLING: i2c transaction failed\n");
        return 1;
    }
# 
    return 0;
}

Compile with:

$ {CROSS_COMPILE}gcc ov5640-sccb_id.c -o ov5640-sccb_id

Execute this on the module:

# ./ov5640-sccb_id 2 0x3C 0x3D

Release reset on the first OV6540 camera sensor:

# echo high > /sys/class/gpio/gpio250/direction

Load the camera-related kernel modules as described above e.g. as follows:

# modprobe videobuf2-dma-contig
# modprobe ov5640
# modprobe tegra_camera

Camera preview Camera 1:

# gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,format={UYVY},width=640,height=480' ! xvimagesink

Camera perview Camera 2:

# gst-launch-1.0 v4l2src device=/dev/video1 ! 'video/x-raw,format={UYVY},width=640,height=480' ! xvimagesink

Disable Clock on V1.1 Camera Modules

On the hardware revision V1.1 of the OV5640 camera module general improvements were made. These improvements include a dedicated clock generation on the camera module itself. Because of these changes, the CAM1_MCLK is no longer needed. For EMI improvements, CAM1_MCLK may be turned off.

The general approach is to declare the corresponding pad as a GPIO. This will internally switch the multiplexer. As a result, the clock will not be able to leave the SoC. This approach is chosen because CAM1_MCLK is in every processor generated from a clock that is needed in other internal IPs.

Note: The following patches apply for the hardware relevant branches for our BSP 2.8b3.111-20180627.

Apalis iMX6

 arch/arm/boot/dts/imx6qdl-apalis-eval.dtsi
diff --git a/arch/arm/boot/dts/imx6qdl-apalis-eval.dtsi b/arch/arm/boot/dts/imx6qdl-apalis-eval.dtsi
index c06171783e60..3326488dafb1 100644
--- a/arch/arm/boot/dts/imx6qdl-apalis-eval.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-apalis-eval.dtsi
@@ -246,6 +246,8 @@
 	ov5640_mipi@3c {
 		compatible = "ovti,ov564x_mipi";
 		reg = <0x3c>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_cam_mclk_stash>;
 		clocks = <&clks 147>;
 		clock-names = "csi_mclk";
 		DOVDD-supply = <&reg_1p8v>;
diff --git a/arch/arm/boot/dts/imx6qdl-apalis.dtsi b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
index 26c94bd64e51..779a069cedb1 100644
--- a/arch/arm/boot/dts/imx6qdl-apalis.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-apalis.dtsi
@@ -823,6 +823,13 @@
 		>;
 	};
 
+	pinctrl_cam_mclk_stash: cammclkstashgrp {
+		fsl,pins = <
+			/* CAM sys_mclk */
+			MX6QDL_PAD_NANDF_CS2__GPIO6_IO15 0x0000
+		>;
+	};
+
 	pinctrl_ecspi1: ecspi1grp {
 		fsl,pins = <
 			MX6QDL_PAD_CSI0_DAT6__ECSPI1_MISO 0x100b1

Note: On this SoC it is possible to only shutdown the clock CCM_CLKO2 (that will generate CAM1_MCLK). Please note that this clock is also used in the audio subsystem. Turning it off will disable the audio functionality.

Apalis T30

 arch/arm/mach-tegra/board-apalis_t30-pinmux.c
diff --git a/arch/arm/mach-tegra/board-apalis_t30-pinmux.c b/arch/arm/mach-tegra/board-apalis_t30-pinmux.c
index ae5e82fbedd5..27a2fc0d9ca9 100644
--- a/arch/arm/mach-tegra/board-apalis_t30-pinmux.c
+++ b/arch/arm/mach-tegra/board-apalis_t30-pinmux.c
@@ -476,6 +476,7 @@ static __initdata struct tegra_pingroup_config apalis_t30_pinmux[] = {
        }
 
 static struct gpio_init_pin_info apalis_t30_init_gpio_mode[] = {
+       GPIO_INIT_PIN_MODE(TEGRA_GPIO_PCC0, true, 0),
 };
 
 static void __init apalis_t30_gpio_init_configure(void)

Apalis TK1

 arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-gpio.dtsi
diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-gpio.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-gpio.dtsi
index e67f79a3c5dd..fc1eb2c1fa00 100644
--- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-gpio.dtsi
+++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-gpio.dtsi
@@ -23,6 +23,7 @@
                                TEGRA_GPIO(W, 5)  /* 152 MMC1_D5 */
                                TEGRA_GPIO(BB, 0) /*  96 USBH_OC# */
                                TEGRA_GPIO(BB, 4) /* 262 USBO1_OC# */
+                               TEGRA_GPIO(CC, 0) /* 224 CAM_MCLK */
                                TEGRA_GPIO(CC, 5) /* 148 MMC1_D4 */
                                TEGRA_GPIO(DD, 1) /*  15 Apalis GPIO7 */
                                TEGRA_GPIO(DD, 2) /*  17 Apalis GPIO8 */

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