* i2c transfers during interrupt context
[not found] <38b2ab8a0708300311x5479effn5999ba118221a47f@mail.gmail.com>
@ 2007-08-30 13:55 ` Francis Moreau
2007-08-30 15:32 ` Jean Delvare
0 siblings, 1 reply; 4+ messages in thread
From: Francis Moreau @ 2007-08-30 13:55 UTC (permalink / raw)
To: linux-kernel; +Cc: khali
Hello,
I have a very simple question about i2c transfers.
I'm wondering if I'm allowed to initiate some very short i2c transfers
in an interrupt handler.
Thanks for your answers.
--
Francis
--
Francis
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: i2c transfers during interrupt context
2007-08-30 13:55 ` i2c transfers during interrupt context Francis Moreau
@ 2007-08-30 15:32 ` Jean Delvare
2007-08-30 20:16 ` Francis Moreau
2007-08-30 20:47 ` Jean Delvare
0 siblings, 2 replies; 4+ messages in thread
From: Jean Delvare @ 2007-08-30 15:32 UTC (permalink / raw)
To: Francis Moreau; +Cc: linux-kernel
Bonjour Francis ;)
On Thu, 30 Aug 2007 15:55:49 +0200, Francis Moreau wrote:
> I have a very simple question about i2c transfers.
>
> I'm wondering if I'm allowed to initiate some very short i2c transfers
> in an interrupt handler.
Non. Tu n'as pas le droit de dormir dans un gestionnaire
d'interruption, et la majorité des pilotes I2C dorment pendant les
transferts.
Si tu as besoin de faire ce genre de chose il faut typiquement passer
par une workqueue.
--
Jean Delvare
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: i2c transfers during interrupt context
2007-08-30 15:32 ` Jean Delvare
@ 2007-08-30 20:16 ` Francis Moreau
2007-08-30 20:47 ` Jean Delvare
1 sibling, 0 replies; 4+ messages in thread
From: Francis Moreau @ 2007-08-30 20:16 UTC (permalink / raw)
To: Jean Delvare; +Cc: linux-kernel
Bonjour Jean !
On 8/30/07, Jean Delvare <khali@linux-fr.org> wrote:
> Non. Tu n'as pas le droit de dormir dans un gestionnaire
> d'interruption, et la majorité des pilotes I2C dorment pendant les
> transferts.
>
Ok, c'est ce que je voulais savoir. Peut etre que cette regle pourrait
etre renforce par un "might_sleep()" ajoute dans les fonctions de
transfert de l'i2c-core ?
D'ailleurs pourquoi certains pilotes i2c ne dorment pas pendant les
transferts ? Qu'ont ils de different ?
> Si tu as besoin de faire ce genre de chose il faut typiquement passer
> par une workqueue.
Malheureusement dans certains cas la workqueue est schedulee trop
tardivement et le message i2c n'arrive pas a temps au device.
Une autre question, j'espere que je n'abuse pas: Comment peut on
changer la frequence du bus i2c depuis un driver ?
Merci pour tes reponses.
--
Francis
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: i2c transfers during interrupt context
2007-08-30 15:32 ` Jean Delvare
2007-08-30 20:16 ` Francis Moreau
@ 2007-08-30 20:47 ` Jean Delvare
1 sibling, 0 replies; 4+ messages in thread
From: Jean Delvare @ 2007-08-30 20:47 UTC (permalink / raw)
To: linux-kernel
Oops, sorry for replying in French, I completely missed the fact that
the original post was on LKML and not private.
--
Jean Delvare
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2007-08-30 20:46 UTC | newest]
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[not found] <38b2ab8a0708300311x5479effn5999ba118221a47f@mail.gmail.com>
2007-08-30 13:55 ` i2c transfers during interrupt context Francis Moreau
2007-08-30 15:32 ` Jean Delvare
2007-08-30 20:16 ` Francis Moreau
2007-08-30 20:47 ` Jean Delvare
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