Messages in this thread | | | Subject | Re: [PATCH] regmap: add iopoll-like polling macro | From | Philipp Zabel <> | Date | Fri, 08 Jul 2016 18:26:22 +0200 |
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Am Freitag, den 08.07.2016, 16:39 +0200 schrieb Mark Brown: > On Thu, Jul 07, 2016 at 12:01:43PM +0200, Philipp Zabel wrote: > > Am Donnerstag, den 07.07.2016, 11:42 +0200 schrieb Mark Brown: > > > On Wed, Jul 06, 2016 at 04:19:41PM +0200, Philipp Zabel wrote: > > > > > This patch adds a macro regmap_read_poll_timeout that works similar > > > > to the readx_poll_timeout defined in linux/iopoll.h, except that this > > > > can also return the error value returned by a failed regmap_read. > > > > Please make this a proper function. > > > I can't, the condition has to be evaluated inside the loop. This is > > basically a poor man's function template. > > Given that the condition is always going to be essentially the same one > checking that (read & mask) == value we could just parameterize it > couldn't we?
The iopoll macros also allow comparisons like < > !=, more complicated expressions, or even function calls.
Granted, the only existing example I am aware of is drivers/dma/qcom/hidma_ll.c, which calls a static function in readl_poll_wait_timeout, that evaluates to ((read == 1) || (read == 2)).
There's a similar condition in rt5659_headset_detect, although that may be dismissed as it's using snd_soc_read and variable delays: while (i < 5) { msleep(sleep_time[i]); val = snd_soc_read(codec, RT5659_EJD_CTRL_2) & 0x0003; i++; if (val == 0x1 || val == 0x2 || val == 0x3) break; }
A potential user for an inequality condition is drivers/media/tuners/it913x.c, which has a loop where the condition is (read != 0): #define TIMEOUT 50 timeout = jiffies + msecs_to_jiffies(TIMEOUT); while (!time_after(jiffies, timeout)) { ret = regmap_read(dev->regmap, 0x80ec82, &utmp); if (ret) goto err;
if (utmp) break; }
Even if by far the most common cases can be covered as you suggest, I would find it useful to keep this the same as the other readx_poll_wait_timeout variants.
regards Philipp
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