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Category Archives: Character Driver

Module code to show how to perform read operation in multiple quantums.

Posted on March 4, 2014 by deepak.jain

RCS file: readf.c,v Working file: readf.c head: 1.14 branch: locks: strict access list: symbolic names: keyword substitution: kv total revisions: 14;    selected revisions: 14 description: chardev_read() function reside here which is responsible for performing the read operation. —————————- revision 1.14 … Continue reading →

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Module code showing how to read data in a single quantum using copy_to_user() function.

Posted on March 4, 2014 by deepak.jain

RCS file: readf.c,v Working file: readf.c head: 1.11 branch: locks: strict root: 1.11 access list: symbolic names: keyword substitution: kv total revisions: 11;    selected revisions: 11 description: chardev_read() function is implemented here in this file. —————————- revision 1.11    locked by: … Continue reading →

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Module code showing how to write data in multiple quantums from a user application.

Posted on March 4, 2014 by deepak.jain

RCS file: writef.c,v Working file: writef.c head: 1.19 branch: locks: strict root: 1.19 access list: symbolic names: keyword substitution: kv total revisions: 19;    selected revisions: 19 description: chardev_write() function reside here. —————————- revision 1.19    locked by: root; date: 2014/03/03 19:00:50;  … Continue reading →

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Module code showing how to write data in multiple qset arrays from a user application.

Posted on March 4, 2014 by deepak.jain

RCS file: writef.c,v Working file: writef.c head: 1.37 branch: locks: strict root: 1.37 access list: symbolic names: keyword substitution: kv total revisions: 37;    selected revisions: 37 description: chardev_write() function reside here. —————————- revision 1.37    locked by: root; date: 2014/03/04 18:55:04;  … Continue reading →

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Module code to show how to perform “trim” operation by calling chardev_trim() before the device is opened for writing.

Posted on March 2, 2014 by deepak.jain

RCS file: openf.c,v Working file: openf.c head: 1.14 branch: locks: strict root: 1.14 access list: symbolic names: keyword substitution: kv total revisions: 14;    selected revisions: 14 description: The functionality of chardev_open() is implemented here inside this file.Whenever the application calls … Continue reading →

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Module code to show how to write data in a single quantum using copy_from_user() function.

Posted on March 1, 2014 by deepak.jain

RCS file: writef.c,v Working file: writef.c head: 1.15 branch: locks: strict root: 1.15 access list: symbolic names: keyword substitution: kv total revisions: 15;    selected revisions: 15 description: chardev_write() function reside here. —————————- revision 1.15    locked by: root; date: 2014/03/01 11:19:07;  … Continue reading →

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Module code to show how to use container_of() macro inside driver’s open function and storing the return value of container_of() inside filep->private_data.

Posted on March 1, 2014 by deepak.jain

RCS file: openf.c,v Working file: openf.c head: 1.6 branch: locks: strict root: 1.6 access list: symbolic names: keyword substitution: kv total revisions: 6;    selected revisions: 6 description: The functionality of chardev_open() is implemented here inside this file.Whenever the application calls … Continue reading →

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module code to show how to perform an open and release operation, when an application issues open() and close() system call.

Posted on February 28, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.16 branch: locks: strict root: 1.16 access list: symbolic names: keyword substitution: kv total revisions: 16;    selected revisions: 16 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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module code to show how an open operation is performed on the device file when an application calls ” open() function”.

Posted on February 28, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.16 branch: locks: strict root: 1.16 access list: symbolic names: keyword substitution: kv total revisions: 16;    selected revisions: 16 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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module code to show how to initialize a cdev data structure with cdev_init() and tell the kernel about it with cdev_add().

Posted on February 28, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.16 branch: locks: strict root: 1.16 access list: symbolic names: keyword substitution: kv total revisions: 16;    selected revisions: 16 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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Module code to show how to allocate and deallocate memory using kmalloc() and kfree() functions for Sculldev (i.e the data structure used to hold device information)respectively.

Posted on February 28, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.14 branch: locks: strict root: 1.14 access list: symbolic names: keyword substitution: kv total revisions: 14;    selected revisions: 14 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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Module code to show how parameters can be passed to a module while loading it with the help of macro called module_param().

Posted on February 27, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.8 branch: locks: strict root: 1.8 access list: symbolic names: keyword substitution: kv total revisions: 8;    selected revisions: 8 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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Module code to show how device numbers are allocated and deallocated using alloc_chrdev_region() and unregister_chrdev_region().

Posted on February 27, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.7 branch: locks: strict root: 1.7 access list: symbolic names: keyword substitution: kv total revisions: 7;    selected revisions: 7 description: Base header file that includes the definitions of all the macros,structures and contains … Continue reading →

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Simplest driver module code to understand the macros module_init() and module_exit().

Posted on February 26, 2014 by deepak.jain

RCS file: header.h,v Working file: header.h head: 1.5 branch: locks: strict root: 1.5 access list: symbolic names: keyword substitution: kv total revisions: 5;    selected revisions: 5 description: Base header file that includes the definitions of all the macros,structure definitions and … Continue reading →

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character driver

Posted on February 23, 2014 by Atif hasnain Zaidi

Finally i completed the writing in multiple quantum. Description of my Character driver- step-1-> registered the driver by alloc_chrdev_region() and unregistered in exit function by unregister_chrdev_region(). After registering the driver you have major number that is given by by kernel. step-2->Now … Continue reading →

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