poller: Allow to call functions asynchronously
Sometimes execution of a function has to be delayed, for example when a backlight can only be turned on when the picture has stabilized. To help in such situations add a convenience function around the poller stuff to call a function after a delay. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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@ -11,24 +11,82 @@
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#include <module.h>
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#include <param.h>
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#include <poller.h>
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#include <clock.h>
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static LIST_HEAD(poller_list);
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static int poller_active;
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int poller_register(struct poller_struct *poller)
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{
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if (poller->registered)
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return -EBUSY;
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list_add_tail(&poller->list, &poller_list);
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poller->registered = 1;
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return 0;
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}
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int poller_unregister(struct poller_struct *poller)
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{
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if (!poller->registered)
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return -ENODEV;
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list_del(&poller->list);
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poller->registered = 0;
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return 0;
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}
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static void poller_async_callback(struct poller_struct *poller)
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{
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struct poller_async *pa = container_of(poller, struct poller_async, poller);
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if (get_time_ns() < pa->end)
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return;
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pa->fn(pa->ctx);
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pa->fn = NULL;
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poller_unregister(&pa->poller);
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}
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/*
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* Cancel an outstanding asynchronous function call
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*
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* @pa the poller that has been scheduled
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*
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* Cancel an outstanding function call. Returns 0 if the call
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* has actually been cancelled or -ENODEV when the call wasn't
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* scheduled.
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*
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*/
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int poller_async_cancel(struct poller_async *pa)
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{
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return poller_unregister(&pa->poller);
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}
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/*
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* Call a function asynchronously
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*
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* @pa the poller to be used
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* @delay The delay in nanoseconds
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* @fn The function to call
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* @ctx context pointer passed to the function
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*
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* This calls the passed function after a delay of delay_ns. Returns
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* a pointer which can be used as a cookie to cancel a scheduled call.
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*/
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int poller_call_async(struct poller_async *pa, uint64_t delay_ns,
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void (*fn)(void *), void *ctx)
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{
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pa->ctx = ctx;
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pa->poller.func = poller_async_callback;
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pa->end = get_time_ns() + delay_ns;
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pa->fn = fn;
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return poller_register(&pa->poller);
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}
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void poller_call(void)
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{
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struct poller_struct *poller, *tmp;
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@ -12,13 +12,25 @@
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struct poller_struct {
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void (*func)(struct poller_struct *poller);
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int registered;
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struct list_head list;
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};
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int poller_register(struct poller_struct *poller);
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int poller_unregister(struct poller_struct *poller);
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struct poller_async;
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struct poller_async {
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struct poller_struct poller;
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void (*fn)(void *);
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void *ctx;
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uint64_t end;
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};
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int poller_call_async(struct poller_async *pa, uint64_t delay_ns,
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void (*fn)(void *), void *ctx);
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int poller_async_cancel(struct poller_async *pa);
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#ifdef CONFIG_POLLER
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void poller_call(void);
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