005 Character Device Drivers Development - EmbLogic

005.10.Sysfs. Giving Our Linux Driver, A Dashboard

pravjot — Mon, 11 May 2026 13:08:03 +0530

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005.10.Sysfs: Giving Our Linux Driver, A Dashboard

should be posted here.

04.Device-Operations-open-release-io/

pravjot — Wed, 25 Dec 2024 16:49:02 +0530

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04.Device-Operations-open-release-io/

should be posted here.

02.Building, Configuring kernel for Device Driver Development

spatlou — Mon, 15 Jun 2020 11:55:30 +0530

Go to /lib/modules/$(uname -r)/build

at this path you should have Makefile (atleast)

if not the follow. http://www.emblogic.com/members/document_view/1258

If you face any issue, error, dough or want any clarifications. Post it here.

lsmod

spatlou — Thu, 11 Nov 2021 17:49:49 +0530

what is this?

25.TimingMeasurements_DelaysTimersTasklets

spatlou — Thu, 15 Oct 2020 06:47:54 +0530

You are invited to put in all queries/resolutions/advice/articles/discussion related to

25.Timing Measurements_Delays Timers Tasklets

here...

005.08: Control Operations using ioctl

spatlou — Thu, 02 Jul 2020 08:29:56 +0530

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005.08: Control Operations using ioctl

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12, 13.Device Operations Seeking

spatlou — Wed, 19 Aug 2020 18:24:45 +0530

You are invited to put in all queries/resolutions/advice/articles/discussion related to

12, 13.Device Operations Seeking

here...

Character device driver completed till OPEN(scull_open)

ramandeepsingh900 — Thu, 13 Feb 2014 06:21:36 +0530

MODULE_AUTHOR("RAMANDEEP SINGH");

MODULE_DESCRIPTION("CHARACTER DRIVER");

head    1.3;
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@this is the header file this includes all the main headrers file .
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@this is the all descriptions file.
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@Initial revision
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@this is the initialization file init.c.
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@this is the cleanup file exit.c .
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@Initial revision
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text

03.Character-Device-Driver-Registration

spatlou — Sat, 05 Dec 2020 08:48:23 +0530

All queries, discussions, updates and clarifications related to

005.03.Start-Writing-Device-Driver

should be posted here.

01. An Introduction to Character Device Drivers

ramandeepsingh900 — Fri, 14 Mar 2014 05:39:06 +0530

In computing, a device driver (commonly referred to as simply a driver) is a computer program that operates or controls a particular type of device that is attached to a computer. A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details of the hardware being used.

A driver typically communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device. Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware-dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.

Applications

Because of the diversity of modern hardware and operating systems, drivers operate in many different environments. Drivers may interface with:
*    printers
*    video adapters
*    Network cards
*    Sound cards
*    Computer storage devices such as hard disk, CD-ROM, and floppy disk buses (ATA, SATA, SCSI)
*    Implementing support for different file systems
*    Image scanners
*    Digital cameras

insmod

spatlou — Thu, 11 Nov 2021 17:49:37 +0530

What is this?

modinfo

spatlou — Thu, 11 Nov 2021 17:49:10 +0530

What is This?

localmodconfig

spatlou — Thu, 11 Nov 2021 17:35:22 +0530

What is This?

03.Character Device Driver Architecture

spatlou — Mon, 25 Oct 2021 21:52:03 +0530

Trimming The SCULL in Character Device Driver Development

atifzaidi92 — Thu, 20 Mar 2014 15:53:04 +0530

RCS file: ./app.c,v

Working file: ./app.c

head: 1.1

branch:

locks: strict

root: 1.1

access list:

symbolic names:

keyword substitution: kv

total revisions: 1; selected revisions: 1

description:

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

revision 1.1 locked by: root;

date: 2014/03/20 08:20:27; author: root; state: Exp;

Initial revision

=============================================================================

RCS file: ./app1.c,v

Working file: ./app1.c

head: 1.1

branch:

locks: strict

root: 1.1

access list:

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keyword substitution: kv

total revisions: 1; selected revisions: 1

description:

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

revision 1.1 locked by: root;

date: 2014/03/20 08:20:28; author: root; state: Exp;

Initial revision

=============================================================================

RCS file: ./close.c,v

Working file: ./close.c

head: 1.1

branch:

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total revisions: 1; selected revisions: 1

description:

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

revision 1.1 locked by: root;

date: 2014/03/20 08:20:26; author: root; state: Exp;

Initial revision

=============================================================================

RCS file: ./decelerations.h,v

Working file: ./decelerations.h

head: 1.1

branch:

locks: strict

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symbolic names:

keyword substitution: kv

total revisions: 1; selected revisions: 1

description:

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

revision 1.1 locked by: root;

date: 2014/03/20 08:20:22; author: root; state: Exp;

Initial revision

=============================================================================

work on character device driver

abhishek.jain — Sat, 15 Feb 2014 05:00:24 +0530

RCS file: init.c,v
Working file: init.c
head: 1.5
branch:
locks: strict
   root: 1.5
access list:
symbolic names:
keyword substitution: kv
total revisions: 5;   selected revisions: 5
description:
this is the kernel file to find the major and minor numbers.
----------------------------
revision 1.5   locked by: root;
date: 2014/02/13 12:11:07; author: root; state: Exp; lines: +13 -12
extern the file_operations fops.
----------------------------
revision 1.4
date: 2014/02/13 06:08:26; author: root; state: Exp; lines: +28 -18
create no. of device by a one drivers using for loop and give the value 5 to the macro NODE.
----------------------------
revision 1.3
date: 2014/02/12 16:08:36; author: root; state: Exp; lines: +1 -1
*** empty log message ***
----------------------------
revision 1.2
date: 2014/02/11 07:28:57; author: root; state: Exp; lines: +32 -24
allocate the memmory to the device ScullDev
----------------------------
revision 1.1
date: 2014/02/11 04:24:33; author: root; state: Exp;
Initial revision
=============================================================================

RCS file: exit.c,v
Working file: exit.c
head: 1.3
branch:
locks: strict
    root: 1.3
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keyword substitution: kv
total revisions: 3;    selected revisions: 3
description:
free the memmory of ScullDev
----------------------------
revision 1.3    locked by: root;
date: 2014/02/13 06:09:11; author: root; state: Exp; lines: +2 -1
*** empty log message ***
----------------------------
revision 1.2
date: 2014/02/12 16:08:44; author: root; state: Exp; lines: +1 -0
used cdev_del().
----------------------------
revision 1.1
date: 2014/02/11 07:35:06; author: root; state: Exp;
Initial revision
=============================================================================

RCS file: declare.h,v
Working file: declare.h
head: 1.4
branch:
locks: strict
    root: 1.4
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total revisions: 4;    selected revisions: 4
description:
Defi8ne the device struct ScullDev
----------------------------
revision 1.4    locked by: root;
date: 2014/02/13 12:12:31; author: root; state: Exp; lines: +8 -15
Remove the structre struct ScullDev .
Only declare the objects as sculldev and scull_local.
----------------------------
revision 1.3
date: 2014/02/13 06:09:15; author: root; state: Exp; lines: +4 -1
*** empty log message ***
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revision 1.2
date: 2014/02/12 16:08:59; author: root; state: Exp; lines: +4 -0
*** empty log message ***
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revision 1.1
date: 2014/02/11 07:36:10; author: root; state: Exp;
Initial revision
=============================================================================

RCS file: header.h,v
Working file: header.h
head: 1.4
branch:
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    root: 1.4
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total revisions: 4;    selected revisions: 4
description:
Declare the macros
----------------------------
revision 1.4    locked by: root;
date: 2014/02/13 12:11:39; author: root; state: Exp; lines: +11 -1
Replace the structure struct ScullDev from the declare.h
----------------------------
revision 1.3
date: 2014/02/13 06:09:15; author: root; state: Exp; lines: +1 -1
*** empty log message ***
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revision 1.2
date: 2014/02/12 16:08:56; author: root; state: Exp; lines: +1 -0
*** empty log message ***
----------------------------
revision 1.1
date: 2014/02/11 07:35:45; author: root; state: Exp;
Initial revision
=============================================================================

RCS file: RCS/open.c,v
Working file: open.c
head: 1.1
branch:
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    abhishek: 1.1
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total revisions: 1;    selected revisions: 1
description:
open function: to open the file.
----------------------------
revision 1.1    locked by: abhishek;
date: 2014/02/15 09:56:50; author: abhishek; state: Exp;
Initial revision
=============================================================================

RCS file: RCS/close.c,v
Working file: close.c
head:
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total revisions: 0
description:
close function
=============================================================================

Makefile for Building Character Device Driver

spatlou — Sat, 05 Oct 2019 12:34:49 +0530

INSTALL_DIR=modules

ifneq (${KERNELRELEASE},)

obj-m := mycdd.o

mycdd-objs := initFunc.o cleanup.o

else

KERNELDIR ?= /lib/modules/4.13.12/build

# KERNELDIR ?= /lib/modules/$(shell uname -r)/build

PWD := $(shell pwd)

default:

$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

@rm -rf ${INSTALL_DIR}

@mkdir ${INSTALL_DIR}

@mv -f *.o *.ko *.mod.c .*.cmd ${INSTALL_DIR}

clean:

rm -rf ${INSTALL_DIR}

endif

Character Device Driver from Scratch

spatlou — Sun, 16 Nov 2014 14:54:52 +0530

HEADER FILE>

RCS file: header.h,v
Working file: header.h
head: 1.6
branch:
locks: strict
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keyword substitution: kv
total revisions: 6;	selected revisions: 6
description:
This si the base header file
----------------------------
revision 1.6
date: 2014/11/16 08:56:59;  author: root;  state: Exp;  lines: +1 -0
Included moduleparam.h
for module_param() macro.
----------------------------
revision 1.5
date: 2014/11/16 08:11:22;  author: root;  state: Exp;  lines: +2 -0
Includec cdev.h and slab.h for struct cdev and kmalloc()
----------------------------
revision 1.4
date: 2014/11/16 07:54:24;  author: root;  state: Exp;  lines: +8 -0
Defined the macros for MINORNO and NOD.
----------------------------
revision 1.3
date: 2014/11/09 10:26:03;  author: root;  state: Exp;  lines: +8 -0
Defined the Macreos
MAJORNO and DEVNAME
----------------------------
revision 1.2
date: 2014/11/09 10:01:54;  author: root;  state: Exp;  lines: +1 -0
Included fs.h
----------------------------
revision 1.1
date: 2014/11/09 09:36:05;  author: root;  state: Exp;
Initial revision
=============================================================================

DECELERATIONS File

RCS file: declerations.h,v
Working file: declerations.h
head: 1.7
branch:
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total revisions: 7;	selected revisions: 7
description:
This file would contsin all the decleration for our driver.
----------------------------
revision 1.7
date: 2014/11/16 09:06:43;  author: root;  state: Exp;  lines: +1 -1
declared new_dev for using with multiple devices.
----------------------------
revision 1.6
date: 2014/11/16 08:44:44;  author: root;  state: Exp;  lines: +1 -1
defined struct file_operations
----------------------------
revision 1.5
date: 2014/11/16 08:12:09;  author: root;  state: Exp;  lines: +13 -0
Gave the decleration for struct ScullDev and struct ScullQset.
----------------------------
revision 1.4
date: 2014/11/16 07:55:39;  author: root;  state: Exp;  lines: +4 -2
declared variables minorno, nod, dev.
removed the decleration of struct file_operations
----------------------------
revision 1.3
date: 2014/11/09 10:26:54;  author: root;  state: Exp;  lines: +3 -0
gave the prototype for initialization().
----------------------------
revision 1.2
date: 2014/11/09 10:17:58;  author: root;  state: Exp;  lines: +1 -1
declared exters struct file_operations
----------------------------
revision 1.1
date: 2014/11/09 10:10:26;  author: root;  state: Exp;
Initial revision
=============================================================================

INITIALIZATION FILE

RCS file: init.c,v
Working file: init.c
head: 1.17
branch:
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keyword substitution: kv
total revisions: 17;	selected revisions: 17
description:
Initialization function.
----------------------------
revision 1.17
date: 2014/11/16 09:09:35;  author: root;  state: Exp;  lines: +2 -2
*** empty log message ***
----------------------------
revision 1.16
date: 2014/11/16 09:08:31;  author: root;  state: Exp;  lines: +1 -1
declared lv.
----------------------------
revision 1.15
date: 2014/11/16 09:07:07;  author: root;  state: Exp;  lines: +20 -15
Multiple devices.
registering, allocating, initializing and adding for all devices.
----------------------------
revision 1.14
date: 2014/11/16 08:58:47;  author: root;  state: Exp;  lines: +1 -0
Diaplaying nod.
----------------------------
revision 1.13
date: 2014/11/16 08:57:27;  author: root;  state: Exp;  lines: +4 -2
using macro module_param() for accepting module parameters.
accepting nod here.
----------------------------
revision 1.12
date: 2014/11/16 08:32:08;  author: root;  state: Exp;  lines: +6 -4
testing our driver using cdev.
fetching device id from cdev.
----------------------------
revision 1.11
date: 2014/11/16 08:25:40;  author: root;  state: Exp;  lines: +9 -0
initialized the device specific structure cdev.
also added it to the device table.
----------------------------
revision 1.10
date: 2014/11/16 08:13:07;  author: root;  state: Exp;  lines: +1 -0
defined ScullDev.
----------------------------
revision 1.9
date: 2014/11/16 08:11:39;  author: root;  state: Exp;  lines: +9 -2
Allocated space on the scull device for IO.
----------------------------
revision 1.8
date: 2014/11/16 07:54:46;  author: root;  state: Exp;  lines: +12 -4
registered the driver usig alloc_chrdev_region()
Fetched the majorno and minorno using macros MAJOR and MINOR respectively.
----------------------------
revision 1.7
date: 2014/11/09 10:27:38;  author: root;  state: Exp;  lines: +1 -0
*** empty log message ***
----------------------------
revision 1.6
date: 2014/11/09 10:26:21;  author: root;  state: Exp;  lines: +7 -3
Implemented initialization() that initializes all the variables to default values from Macros.
----------------------------
revision 1.5
date: 2014/11/09 10:17:46;  author: root;  state: Exp;  lines: +1 -2
Declared struct file_operations.
----------------------------
revision 1.4
date: 2014/11/09 10:09:05;  author: root;  state: Exp;  lines: +2 -1
*** empty log message ***
----------------------------
revision 1.3
date: 2014/11/09 10:03:49;  author: root;  state: Exp;  lines: +1 -0
Printing maojr no.
----------------------------
revision 1.2
date: 2014/11/09 10:02:06;  author: root;  state: Exp;  lines: +13 -0
Registering the driver with the kernel using register_chrdev().
Obtaining major no.
----------------------------
revision 1.1
date: 2014/11/09 09:36:05;  author: root;  state: Exp;
Initial revision
=============================================================================

20.Control Operations Ioctls

spatlou — Fri, 25 Sep 2020 06:55:17 +0530

All queries, discussions, updates and clarifications related to

20.Control Operations Ioctls

should be posted here.

005.09.Software Implemented Filesystem. /proc

spatlou — Fri, 22 Nov 2013 02:37:01 +0530

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005.09: Software Implemented Filesystem. /proc

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05.Concurrency, Races and Synchronization issues in device drivers

spatlou — Tue, 26 May 2020 08:44:07 +0530

Concurrency, Races and Synchronization issues in device drivers

20.02.53 Character Driver

spatlou — Tue, 25 Nov 2014 17:06:01 +0530

RCS file: header.h,v
Working file: header.h
head: 1.9
branch:
locks: strict
	root: 1.9
access list:
symbolic names:
keyword substitution: kv
total revisions: 9;	selected revisions: 9
description:
This is the base header file for our Character Device Driver.
Included init.h and module.h
Gave the License information.
----------------------------
revision 1.9	locked by: root;
date: 2014/11/25 10:52:56;  author: root;  state: Exp;  lines: +15 -0
defined macros
QUANTUM_SIZE, QSET_SIZE< DEVICE_SIZE and DATA_SIZE
----------------------------
revision 1.8
date: 2014/11/25 10:42:41;  author: root;  state: Exp;  lines: +3 -2
Included moduleparam.h
----------------------------
revision 1.7
date: 2014/11/25 10:22:55;  author: root;  state: Exp;  lines: +2 -2
*** empty log message ***
----------------------------
revision 1.6
date: 2014/11/25 10:21:41;  author: root;  state: Exp;  lines: +4 -0
*** empty log message ***
----------------------------
revision 1.5
date: 2014/11/25 10:16:06;  author: root;  state: Exp;  lines: +1 -0
Included slab.h
----------------------------
revision 1.4
date: 2014/11/25 09:33:05;  author: root;  state: Exp;  lines: +9 -0
Defined macros
MINORNO and NOD
----------------------------
revision 1.3
date: 2014/11/22 11:28:33;  author: root;  state: Exp;  lines: +1 -0
Included fs.h
----------------------------
revision 1.2
date: 2014/11/22 11:25:15;  author: root;  state: Exp;  lines: +15 -3
Aded the macros MAJORNO and DEVNAME.
----------------------------
revision 1.1
date: 2014/11/22 11:05:17;  author: root;  state: Exp;
Initial revision