lkml.org 
[lkml]   [2016]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] regmap: add iopoll-like polling macro
From
Date
Hi Mark,

Am Freitag, den 08.07.2016, 18:26 +0200 schrieb Philipp Zabel:
> 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.

Any comments on this? If I can't convince you to keep the macro, I could
change it into a function:

int regmap_poll_bits_wait_timeout(struct regmap *map, unsigned int reg,
unsigned int mask, unsigned int val,
unsigned long sleep, u64 timeout);

With the changed name there would be no expectation for it to work the
same as readx_poll_wait_timeout, and the mask and val condition is in
the same place as mask and val for regmap_update_bits.

regards
Philipp

\
 
 \ /
  Last update: 2016-07-13 10:21    [W:0.111 / U:7.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site