Reading a config file in a driver ....
Hi all ....
I am writing a LCD driver in which the default configuration for LCD would be loded at the Init . This default configuration if keep in the driver then for a change in default configuration we need to compile the driver which we never want . Hence we want a .config file in /etc/lcd.config dir which could be changed and the next boot will take this configuration as the default configuration.
I need to know How to read from the config file in the driver form the dir /etc/lcd.config. The driver would be installed at boot up
Please if any of you have an experience in this or could suggest something ,I would really appriciate ...
----Misbah <><
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Quoted 10 lines · Misbah khan
Hi all ....
I am writing a LCD driver in which the default configuration for LCD would be loded at the Init . This default configuration if keep in the driver then for a change in default configuration we need to compile the driver which we never want . Hence we want a .config file in
/etc/lcd.configdir which could be changed and the next boot will take this configuration as the default configuration.
Quoted 2 lines
I need to know How to read from the config file in the driver form the dir
/etc/lcd.config. The driver would be installed at boot up
The driver/kernel shouldn't read the file directly, if anything you should have a userspace tool that reads it and adjusts the driver via sysfs or similar. That tool can be run from some of the init scripts, or from the ramdisk in case you want to do it early.
-Olof
Quoted 11 lines · Olof Johansson
Quoted 9 lines · Misbah khan
Hi all ....
I am writing a LCD driver in which the default configuration for LCD would be loded at the Init . This default configuration if keep in the driver then for a change in default configuration we need to compile the driver which we never want . Hence we want a .config file in
/etc/lcd.configdir which could be changed and the next boot will take this configuration as the default configuration.
Quoted 9 lines
Quoted 3 lines
I need to know How to read from the config file in the driver form the dir
/etc/lcd.config. The driver would be installed at boot upThe driver/kernel shouldn't read the file directly, if anything you should have a userspace tool that reads it and adjusts the driver via sysfs or similar. That tool can be run from some of the init scripts, or from the ramdisk in case you want to do it early.
What I've done in the past is to use module_param() to define variables that get set when the module is loaded. Then all you need to do is edit the /etc/modules file and change the parameter value. However, this technique is only efficient if only a few parameters will ever change. If you need to change more than a few parameters, Olof's suggestion would be preferred.
Carlos
i appriciate your concept and i need to know this :-
The config should be in a structure or a bit mask . The user will have to change the value whenever he needs to change the default config. Where should i put that struct or bit field defination ???? He should know it preciesly before he change ????
Can you share with me your Implimentation so that i could get the exactly how you had done ...
----Misbah < ><
Quoted 41 lines · Carlos Munoz-2 wrote:
Quoted 20 lines · Olof Johansson
Quoted 13 lines · Misbah khan
Hi all ....
I am writing a LCD driver in which the default configuration for LCD would
be loded at the Init . This default configuration if keep in the driver then
for a change in default configuration we need to compile the driver which we
never want . Hence we want a .config file in/etc/lcd.configdir which could
be changed and the next boot will take this configuration as the default configuration.Quoted 4 lines
I need to know How to read from the config file in the driver form the dir
/etc/lcd.config. The driver would be installed at boot upQuoted 5 lines
The driver/kernel shouldn't read the file directly, if anything you should have a userspace tool that reads it and adjusts the driver via sysfs or similar. That tool can be run from some of the init scripts, or from the ramdisk in case you want to do it early.
What I've done in the past is to use
module_param()to define variables that get set when the module is loaded. Then all you need to do is edit the/etc/modulesfile and change the parameter value. However, this technique is only efficient if only a few parameters will ever change. If you need to change more than a few parameters, Olof's suggestion would be preferred.Carlos
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Control not branching to the instruction present at resetvec i.e 0xfffffffc
Hi All,
We have a custom target board based on PPC-EP405. We just got the
board from the hardware team .I connected the board to BDI200 and powered it on.
The control came to the resetvec address which is 0xfffffffc. I was able to read and write to flash. So I erased the flash and burnt the bootloader into flash from 0xfffc0000.
I verified that the instruction at 0xfffffffc is 4bfc2104 whicis actually a branch to 0xfffc2100. Also a memory dump of 0xfffc2100 shows the correct code. This proved that
the uboot bootloader was burnt properly.
Now when I reset the board the control never reaches 0xfffc2100 i.e for some reason the code at the resetvec is not getting executed. Any help or pointers to resolve this is greatly appreciated.
Thanks,
Ravishankar Govindarao
RFL Electronics Inc.
E-mail : [email protected]
Voice: 973.334.3100 Ext. 233
Fax: 973.334.3863
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Re: Control not branching to the instruction present at resetvec i.e 0xfffffffc
Hi Mr Ravi ...
I suggest you to post a new concern in a new thread ....
----Misbah
Quoted 39 lines · ravi.rao
Hi All,
We have a custom target board based on PPC-EP405. We just got the
board from the hardware team .I connected the board to BDI200 and powered it on.
The control came to the resetvec address which is0xfffffffc. I was able to read and write to flash. So I erased the flash and burnt the bootloader into flash from0xfffc0000.
I verified that the instruction at0xfffffffcis4bfc2104whicis actually a branch to0xfffc2100. Also a memory dump of0xfffc2100shows the correct code. This proved that
the uboot bootloader was burnt properly.
Now when I reset the board the control never reaches0xfffc2100i.e for some reason the code at the resetvec is not getting executed. Any help or pointers to resolve this is greatly appreciated.
Thanks,
Ravishankar Govindarao
RFL Electronics Inc.
E-mail : [email protected]
Voice: 973.334.3100 Ext. 233
Fax: 973.334.3863CONFIDENTIALITY NOTE
This e-mail, including any attachments, may contain confidential and/or legally privileged information. The Information is intended only for the use of the individual or entity named on this e-mail . If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or the taking of any action in reliance on the contents of this transmitted Information is strictly prohibited. Further, if you are not the intended recipient, please notify us by return e-mail and delete the Information promptly._______________________________________________
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Could you please let me know How in the driver i could be able to read the file present in sysfs ??? Using init script how should i creat and edit the file ????
I never had done these hence your suggession could be a better way for me to learn it .
---Misbah
Quoted 33 lines · Olof Johansson-2 wrote:
Quoted 14 lines · Misbah khan
Hi all ....
I am writing a LCD driver in which the default configuration for LCD would
be loded at the Init . This default configuration if keep in the driver then
for a change in default configuration we need to compile the driver which we
never want . Hence we want a .config file in/etc/lcd.configdir which could
be changed and the next boot will take this configuration as the default configuration.Quoted 3 lines
I need to know How to read from the config file in the driver form the dir
/etc/lcd.config. The driver would be installed at boot upThe driver/kernel shouldn't read the file directly, if anything you should have a userspace tool that reads it and adjusts the driver via sysfs or similar. That tool can be run from some of the init scripts, or from the ramdisk in case you want to do it early.
-Olof
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