### Board Setup Code Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/sh/new-machine.txt

Provides definitions for get_system_type() and platform_setup() required for board-specific setup code. This example demonstrates initializing a custom timer and starting up imaginary PCI devices.

```c
#include <linux/init.h>
#include <asm/rtc.h> /* for board_time_init() */

const char *get_system_type(void)
{
	return "FooTech Vaporboard";
}

int __init platform_setup(void)
{
  	/*
	 * If our hardware actually existed, we would do real
	 * setup here. Though it's also sane to leave this empty
	 * if there's no real init work that has to be done for
	 * this board.
	 */

  	/* 
	 * Presume all FooTech boards have the same broken timer,
	 * and also presume that we've defined foo_timer_init to
	 * do something useful.
	 */
  	board_time_init = foo_timer_init;

	/* Start-up imaginary PCI ... */

	/* And whatever else ... */

	return 0;
}

```

--------------------------------

### Start Espeakup (Manual Installation)

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/drivers/staging/speakup/spkguide.txt

Manually starts the Espeakup synthesizer binary after it has been built and installed from source.

```bash
/usr/bin/espeakup
```

--------------------------------

### Start Espeakup (Package Installation)

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/drivers/staging/speakup/spkguide.txt

Starts the Espeakup synthesizer daemon if it was installed as a system package. Replace 'init.d' with 'rc.d' if your system uses that directory structure.

```bash
/etc/init.d/espeakup start
```

--------------------------------

### LUKS Disk Encryption Setup Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/device-mapper/dm-crypt.txt

This is a basic shell script example demonstrating how to set up LUKS disk encryption using cryptsetup. It is intended as a starting point for users familiar with the cryptsetup utility.

```shell
#!/bin/sh

```

--------------------------------

### Example Boot Setup Command (LILO)

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/scsi/sym53c8xx_2.txt

Demonstrates how to pass driver configuration options via the LILO boot loader prompt. This example enables tagged commands, sets synchronous negotiation speed, and enables a specific debug flag.

```bash
lilo: linux root=/dev/sda2 sym53c8xx.cmd_per_lun=4 sym53c8xx.sync=10 sym53c8xx.debug=0x200
```

--------------------------------

### Initrd fstab Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/power/swsusp-dmcrypt.txt

An example /etc/fstab for an initrd, mounting necessary file systems like proc, sysfs, and the partition containing crypto setup keys. This defines how the initrd's temporary filesystem is structured.

```text
/dev/hda1   /mnt    ext3      ro                            0 0
none        /proc   proc      defaults,noatime,nodiratime   0 0
none        /sys    sysfs     defaults,noatime,nodiratime   0 0
```

--------------------------------

### V4L2 Capture Example Initialization and Setup

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/driver-api/80211/uapi/v4l/capture.c.md

This C code snippet demonstrates the initialization and setup for a V4L2 video capture application. It includes necessary headers, defines I/O methods, and structures for buffers. It also contains helper functions for error handling and I/O control.

```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include <getopt.h>             /* getopt_long() */

#include <fcntl.h>              /* low-level i/o */
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

#include <linux/videodev2.h>

#define CLEAR(x) memset(&(x), 0, sizeof(x))

enum io_method {
        IO_METHOD_READ,
        IO_METHOD_MMAP,
        IO_METHOD_USERPTR,
};

struct buffer {
        void   *start;
        size_t  length;
};

static char            *dev_name;
static enum io_method   io = IO_METHOD_MMAP;
static int              fd = -1;
struct buffer          *buffers;
static unsigned int     n_buffers;
static int              out_buf;
static int              force_format;
static int              frame_count = 70;

static void errno_exit(const char *s)
{
        fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno));
        exit(EXIT_FAILURE);
}

static int xioctl(int fh, int request, void *arg)
{
        int r;

        do {
                r = ioctl(fh, request, arg);
        } while (-1 == r && EINTR == errno);

        return r;
}

static void process_image(const void *p, int size)
{
        if (out_buf)
                fwrite(p, size, 1, stdout);

        fflush(stderr);
        fprintf(stderr, ".");
        fflush(stdout);
}

```

--------------------------------

### IIO Triggered Buffer Setup Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/core-api/iio/triggered-buffers.md

Demonstrates the setup of a triggered buffer, including buffer setup operations, poll function, and trigger handler. This is typically used within a device's probe function.

```c
const struct iio_buffer_setup_ops sensor_buffer_setup_ops = {
  .preenable    = sensor_buffer_preenable,
  .postenable   = sensor_buffer_postenable,
  .postdisable  = sensor_buffer_postdisable,
  .predisable   = sensor_buffer_predisable,
};

irqreturn_t sensor_iio_pollfunc(int irq, void *p)
{
    pf->timestamp = iio_get_time_ns((struct indio_dev *)p);
    return IRQ_WAKE_THREAD;
}

irqreturn_t sensor_trigger_handler(int irq, void *p)
{
    u16 buf[8];
    int i = 0;

    /* read data for each active channel */
    for_each_set_bit(bit, active_scan_mask, masklength)
        buf[i++] = sensor_get_data(bit)

    iio_push_to_buffers_with_timestamp(indio_dev, buf, timestamp);

    iio_trigger_notify_done(trigger);
    return IRQ_HANDLED;
}

/* setup triggered buffer, usually in probe function */
iio_triggered_buffer_setup(indio_dev, sensor_iio_polfunc,
                           sensor_trigger_handler,
                           sensor_buffer_setup_ops);
```

--------------------------------

### Setup and Monitor L3 Cache Occupancy (Example 1)

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/x86/intel_rdt_ui.txt

Demonstrates setting up resource control groups (p0, p1) and monitor groups (m11, m12) on a two-socket machine, then reading L3 cache occupancy data.

```bash
# mount -t resctrl resctrl /sys/fs/resctrl
# cd /sys/fs/resctrl
# mkdir p0 p1
# echo "L3:0=3;1=c" > /sys/fs/resctrl/p0/schemata
# echo "L3:0=3;1=3" > /sys/fs/resctrl/p1/schemata
# echo 5678 > p1/tasks
# echo 5679 > p1/tasks

# cd /sys/fs/resctrl/p1/mon_groups
# mkdir m11 m12
# echo 5678 > m11/tasks
# echo 5679 > m12/tasks

# cat m11/mon_data/mon_L3_00/llc_occupancy
16234000
# cat m11/mon_data/mon_L3_01/llc_occupancy
14789000
# cat m12/mon_data/mon_L3_00/llc_occupancy
16789000

# cat /sys/fs/resctrl/p1/mon_data/mon_l3_00/llc_occupancy
31234000
```

--------------------------------

### Example CPU Topology Strings

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/tools/perf/Documentation/perf.data-file-format.txt

Illustrative example of how CPU topology strings might appear.

```text
sibling cores   : 0-3
sibling threads : 0-1
sibling threads : 2-3
```

--------------------------------

### V4L Device Initialization and Capture Setup

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/crypto/uapi/v4l/capture.c.md

Initializes the video device, sets up capture parameters, and starts the capture process. This function is called after the device has been opened.

```c
static void init_device(void)
{
        struct v4l2_capability cap;
        struct v4l2_cropcap cropcap;
        struct v4l2_crop crop;
        struct v4l2_format fmt;
        unsigned int i;

        if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap))
                {
                if (EINVAL == errno)
                        {
                        fprintf(stderr, "%s is not a V4L2 device\n",
                                 dev_name);
                        exit(EXIT_FAILURE);
                        }
                else
                        errno_exit("VIDIOC_QUERYCAP");
                }

        if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
                {
                fprintf(stderr, "%s is not a video capture device\n",
                         dev_name);
                exit(EXIT_FAILURE);
                }

        switch (io) {
        case IO_METHOD_MMAP:
                if (!(cap.capabilities & V4L2_CAP_STREAMING))
                        {
                        fprintf(stderr, "%s does not support streaming i/o\n",
                                 dev_name);
                        exit(EXIT_FAILURE);
                        }
                break;

        case IO_METHOD_READ:
                if (!(cap.capabilities & V4L2_CAP_READWRITE))
                        {
                        fprintf(stderr, "%s does not support read i/o\n",
                                 dev_name);
                        exit(EXIT_FAILURE);
                        }
                break;

        case IO_METHOD_USERPTR:
                if (!(cap.capabilities & V4L2_CAP_STREAMING))
                        {
                        fprintf(stderr, "%s does not support streaming i/o\n",
                                 dev_name);
                        exit(EXIT_FAILURE);
                        }
                break;
        }


        CLEAR(cropcap);

        cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap.c)) {
                struct v4l2_crop crop;

                if (cropcap.defrect.type != V4L2_FIELD_ANY) {
                        crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
                        crop.c = cropcap.defrect;

                        if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop))
                                {
                                memset(&crop, 0, sizeof(crop));
                                } else {
                                        
                                        char value[PROPERTY_VALUE_MAX];
                                        property_get("debug.sf.latch_underrun", value, "0");
                                        if (strcmp(value, "1") == 0) {
                                                // This is a workaround for a bug in the driver
                                                // that causes underruns when the crop is set.
                                                // We disable the crop to avoid the underrun.
                                                memset(&crop, 0, sizeof(crop));
                                        }
                                }
                }
        }

        CLEAR(fmt);

        fmt.C.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        if (force_format)
                {
                fmt.C.pix.width = 640; 
                fmt.C.pix.height = 480;
                fmt.C.pix.pixelformat = V4L2_PIX_FMT_YUYV;
                fmt.C.pix.field = V4L2_FIELD_INTERLACED;

                if (-1 == xioctl(fd, VIDIOC_S_fmt, &fmt)) {
                        fprintf(stderr, "Failed to set format to 640x480 YUYV\n");
                        exit(EXIT_FAILURE);
                }
                }
        else
                {
                fmt.C.pix.width = 0; /* use largest size possible */
                fmt.C.pix.height = 0;
                fmt.C.pix.pixelformat = V4L2_PIX_FMT_MJPEG; 
                fmt.C.pix.field = V4L2_FIELD_ANY; 
                if (-1 == xioctl(fd, VIDIOC_S_fmt, &fmt)) {
                        fmt.C.pix.pixelformat = V4L2_PIX_FMT_YUYV;
                        if (-1 == xioctl(fd, VIDIOC_S_fmt, &fmt)) {
                                fprintf(stderr, "Failed to set format to YUYV\n");
                                exit(EXIT_FAILURE);
                        }
                }
                }

        /* Check the format */
        unsigned int min;
        if (xioctl(fd, VIDIOC_G_fmt, &fmt) < 0)
                errno_exit("VIDIOC_G_fmt");
        if (fmt.C.pix.pixelformat == V4L2_PIX_FMT_MJPEG)
                fprintf(stderr, "Using MJPEG format\n");
        else if (fmt.C.pix.pixelformat == V4L2_PIX_FMT_YUYV)
                fprintf(stderr, "Using YUYV format\n");
        else
                fprintf(stderr, "Unknown format 0x%X\n", fmt.C.pix.pixelformat);

        /* check the minimum buffer size */
        if (fmt.C.pix.sizeimage == 0) {
                /* this should not happen */
                fprintf(stderr, "Invalid sizeimage %u!\n", fmt.C.pix.sizeimage);
                exit(EXIT_FAILURE);
        }

        min = fmt.C.pix.sizeimage;

        switch (io) {
        case IO_METHOD_READ:
                init_read(fmt.C.pix.sizeimage);
                break;

        case IO_METHOD_MMAP:
                init_mmap();
                break;

        case IO_METHOD_USERPTR:
                init_userp(fmt.C.pix.sizeimage);
                break;
        }
}

```

--------------------------------

### Setup BTT Namespace with ndctl

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/nvdimm/btt.txt

Use the 'ndctl' utility to set up a BTT namespace on a disk. This example creates a namespace with a 4k sector size.

```bash
ndctl create-namespace -f -e namespace0.0 -m sector -l 4k
```

--------------------------------

### AX.25 Port Configuration Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/networking/z8530drv.txt

Example configuration for /etc/ax25/axports file, defining different AX.25 links with their parameters.

```text
9k6	 dl0tha-9  9600  255 4 9600 baud port (scc3)
axlink	 dl0tha-15 38400 255 4 Link to NOS
```

--------------------------------

### Creating and Testing a Simple Initramfs with 'hello world'

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/filesystems/ramfs-rootfs-initramfs.txt

This snippet demonstrates how to create a minimal C program, compile it statically, package it as a cpio.gz archive, and test it as an external initramfs using qemu. This is useful for initial setup and testing.

```c
#include <stdio.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
  printf("Hello world!\n");
  sleep(999999999);
}
```

```bash
gcc -static hello.c -o init
echo init | cpio -o -H newc | gzip > test.cpio.gz
# Testing external initramfs using the initrd loading mechanism.
qemu -kernel /boot/vmlinuz -initrd test.cpio.gz /dev/zero
```

--------------------------------

### Setting up and Monitoring Real-time Tasks

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/x86/intel_rdt_ui.txt

This example demonstrates setting up the resctrl filesystem, creating a new resource control group 'p1', and moving specific CPUs to this group to monitor their cache occupancy.

```bash
# mount -t resctrl resctrl /sys/fs/resctrl
# cd /sys/fs/resctrl
# mkdir p1

# Move the cpus 4-7 over to p1
# echo f0 > p0/cpus

# View the llc occupancy snapshot
# cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
11234000
```

--------------------------------

### ALSA Mixer Get Single Value Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/admin-guide/kernel-api/writing-an-alsa-driver.md

Example of retrieving register, shift, and mask values from private_value in an ALSA mixer get callback. Used for single-value controls.

```c
static int snd_sbmixer_get_single(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
{
        int reg = kcontrol->private_value & 0xff;
        int shift = (kcontrol->private_value >> 16) & 0xff;
        int mask = (kcontrol->private_value >> 24) & 0xff;
        ....
}
```

--------------------------------

### Renesas R-Car VIN Board Setup Example (Composite Video Input)

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/devicetree/bindings/media/rcar_vin.txt

Example of a board setup configuration for a composite video input using the rcar_vin driver and an ADV7180 video decoder.

```devicetree
&i2c2 {
        status = "ok";
        pinctrl-0 = <&i2c2_pins>;
        pinctrl-names = "default";

        adv7180@20 {
                compatible = "adi,adv7180";
                reg = <0x20>;
                remote = <&vin1>;

                port {
                        adv7180: endpoint {
                                bus-width = <8>;
                                remote-endpoint = <&vin1ep0>;
                        };
                };
        };
};

/* composite video input */
&vin1 {
        pinctrl-0 = <&vin1_pins>;
        pinctrl-names = "default";

        status = "ok";

        port {
                #address-cells = <1>;
                #size-cells = <0>;

                vin1ep0: endpoint {
                        remote-endpoint = <&adv7180>;
                        bus-width = <8>;
                };
        };
};
```

--------------------------------

### Install Sphinx in a Virtual Environment

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/admin-guide/sphinx.md

Install Sphinx and its dependencies within a virtual environment to avoid conflicts with system packages. This example installs Sphinx version 1.4.9.

```bash
$ virtualenv sphinx_1.4
$ . sphinx_1.4/bin/activate
(sphinx_1.4) $ pip install -r Documentation/sphinx/requirements.txt
```

--------------------------------

### MDIO Managed Mode Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/devicetree/bindings/net/dsa/lan9303.txt

Example DeviceTree configuration for the LAN9303 in MDIO managed mode. Includes phy-handle and MDIO bus setup.

```dts
master: masterdevice@X {
	phy-handle = <&switch>;

	mdio {
		#address-cells = <1>;
		#size-cells = <0>;

		switch: switch-phy@0 {
			compatible = "smsc,lan9303-mdio";
			reg = <0>;
			reset-gpios = <&gpio7 6 GPIO_ACTIVE_LOW>;
			reset-duration = <100>;

			ports {
				#address-cells = <1>;
				#size-cells = <0>;

				port@0 {
					reg = <0>;
					label = "cpu";
				
ethernet = <&master>;
				};

				port@1 { /* external port 1 */
					reg = <1>;
					label = "lan1;
				};

				port@2 { /* external port 2 */
					reg = <2>;
					label = "lan2";
				};
			};
		};
	};
};
```

--------------------------------

### Example Defconfig

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/sh/new-machine.txt

Provide a default configuration file for the new board, allowing others to easily build for it.

```text
arch/sh/configs/vapor_defconfig
```

--------------------------------

### I2C Managed Mode Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/devicetree/bindings/net/dsa/lan9303.txt

Example DeviceTree configuration for the LAN9303 in I2C managed mode. Includes fixed-link setup and port definitions.

```dts
master: masterdevice@X {

	fixed-link { /* RMII fixed link to LAN9303 */
		speed = <100>;
		full-duplex;
	};
};

switch: switch@a {
		compatible = "smsc,lan9303-i2c";
		reg = <0xa>;
		reset-gpios = <&gpio7 6 GPIO_ACTIVE_LOW>;
		reset-duration = <200>;

		ports {
			#address-cells = <1>;
			#size-cells = <0>;

			port@0 { /* RMII fixed link to master */
				reg = <0>;
				label = "cpu";
			
ethernet = <&master>;
			};

			port@1 { /* external port 1 */
				reg = <1>;
				label = "lan1;
			};

			port@2 { /* external port 2 */
				reg = <2>;
				label = "lan2";
			};
		};
	};
```

--------------------------------

### Unbindable Mount Use Case - Initial Setup

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/filesystems/sharedsubtree.txt

Demonstrates the initial setup for replicating a mount tree using bind mounts and shared subtrees, before introducing unbindable mounts.

```bash
mount --bind /root /root
mount --make-shared /root
mkdir -p /tmp/m1
mount --rbind /root /tmp/m1
```

--------------------------------

### Kernel Command Line Example with dyndbg

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/admin-guide/dynamic-debug-howto.md

Illustrates complex dyndbg configurations using kernel command line arguments, including comments and multiple settings.

```text
Kernel command line: ...
  // see whats going on in dyndbg=value processing
  dynamic_debug.verbose=1
  // enable pr_debugs in 2 builtins, #cmt is stripped
  dyndbg="module params +p #cmt ; module sys +p"
  // enable pr_debugs in 2 functions in a module loaded later
  pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p"
```

--------------------------------

### TI Composite Divider Clock Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/devicetree/bindings/clock/ti/composite.txt

Example of a composite divider clock. It includes properties for bit shifting, maximum division, and index starting.

```devicetree
usb_l4_div_ick: usb_l4_div_ick {
	#clock-cells = <0>;
	compatible = "ti,composite-divider-clock";
	clocks = <&l4_ick>;
	ti,bit-shift = <4>;
	ti,max-div = <1>;
	reg = <0x0a40>;
	ti,index-starts-at-one;
};
```

--------------------------------

### Client Driver Demonstration

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/mailbox.txt

Demonstrates the setup and usage of both asynchronous and synchronous mailbox clients. It shows how to request channels, send messages, and wait for completion. Requires platform device initialization.

```c
static void client_demo(struct platform_device *pdev)
{
	struct demo_client *dc_sync, *dc_async;
	/* The controller already knows async_pkt and sync_pkt */
	struct async_pkt ap;
	struct sync_pkt sp;

	dc_sync = kzalloc(sizeof(*dc_sync), GFP_KERNEL);
	dc_async = kzalloc(sizeof(*dc_async), GFP_KERNEL);

	/* Populate non-blocking mode client */
	dc_async->cl.dev = &pdev->dev;
	dc_async->cl.rx_callback = message_from_remote;
	dc_async->cl.tx_done = sample_sent;
	dc_async->cl.tx_block = false;
	dc_async->cl.tx_tout = 0; /* doesn't matter here */
	dc_async->cl.knows_txdone = false; /* depending upon protocol */
	dc_async->async = true;
	init_completion(&dc_async->c);

	/* Populate blocking mode client */
	dc_sync->cl.dev = &pdev->dev;
	dc_sync->cl.rx_callback = message_from_remote;
	dc_sync->cl.tx_done = NULL; /* operate in blocking mode */
	dc_sync->cl.tx_block = true;
	dc_sync->cl.tx_tout = 500; /* by half a second */
	dc_sync->cl.knows_txdone = false; /* depending upon protocol */
	dc_sync->async = false;

	/* ASync mailbox is listed second in 'mboxes' property */
	dc_async->mbox = mbox_request_channel(&dc_async->cl, 1);
	/* Populate data packet */
	/* ap.xxx = 123; etc */
	/* Send async message to remote */
	mbox_send_message(dc_async->mbox, &ap);

	/* Sync mailbox is listed first in 'mboxes' property */
	dc_sync->mbox = mbox_request_channel(&dc_sync->cl, 0);
	/* Populate data packet */
	/* sp.abc = 123; etc */
	/* Send message to remote in blocking mode */
	mbox_send_message(dc_sync->mbox, &sp);
	/* At this point 'sp' has been sent */

	/* Now wait for async chan to be done */
	wait_for_completion(&dc_async->c);
}
```

--------------------------------

### Starting CAN Device with Bitrate

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/networking/can.txt

Start a CAN network device after defining proper bit-timing parameters to avoid error-prone default settings. This example sets the bitrate.

```bash
$ ip link set canX up type can bitrate 125000
```

--------------------------------

### Driver Initialization Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/admin-guide/drm-internals.md

Demonstrates the typical steps for initializing a DRM driver: allocating a device instance, initializing it, and registering it with the kernel.

```c
struct drm_device *dev;
int ret;

dev = drm_dev_alloc(&my_driver, sizeof(struct my_driver_private));
if (IS_ERR(dev)) {
    return PTR_ERR(dev);
}

ret = my_driver_init(dev);
if (ret) {
    drm_dev_put(dev);
    return ret;
}

ret = drm_dev_register(dev, 0);
if (ret)) {
    drm_dev_put(dev);
    return ret;
}

// Device is now registered and accessible from userspace.
```

--------------------------------

### RK805 PMIC Devicetree Node Example

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/Documentation/devicetree/bindings/pinctrl/pinctrl-rk805.txt

Example Devicetree node for the RK805 PMIC, demonstrating GPIO controller setup and pinmux configuration for the default state.

```devicetree
rk805: rk805@18 {
	compatible = "rockchip,rk805";
	...
	gpio-controller;
	#gpio-cells = <2>;

	pinctrl-names = "default";
	pinctrl-0 = <&pmic_int_l>, <&rk805_default>;

	rk805_default: pinmux {
		gpio01 {
			pins = "gpio0", "gpio1";
			function = "gpio";
			output-high;
		};
	};
};
```

--------------------------------

### Example of help format configuration

Source: https://github.com/cirruslogic/linux-drivers/blob/v4.14-madera/tools/perf/Documentation/perf-config.txt

This configuration specifies the format for displaying help information. Options include 'man', 'info', 'web', or 'html'.

```ini
[help]
	format = man
```