Messages in this thread Patch in this message | | | From | Jonghwan Choi <> | Subject | [PATCH] regulator: core: Reduce busy-wait looping | Date | Fri, 21 Mar 2014 11:31:25 +0900 |
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Commit 5df529d440("regulator: core: Reduce busy-wait looping") can also be used in regulator_do_set_voltage.
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com> --- drivers/regulator/core.c | 39 +++++++++++++++++++++++++++++++++------ 1 file changed, 33 insertions(+), 6 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index afca1bc..c375bfb 100644 --- a/drivers/regulator/core.c +++ b/d728099474rivers/regulator/core.c @@ -2355,12 +2355,39 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev, delay = 0; } - /* Insert any necessary delays */ - if (delay >= 1000) { - mdelay(delay / 1000); - udelay(delay % 1000); - } else if (delay) { - udelay(delay); + /* + * Delay for the requested amount of time as per the guidelines in: + * + * Documentation/timers/timers-howto.txt + * + * The assumption here is that regulators will never set the voltage in + * atomic context and therefore sleeping functions can be used. + */ + if (delay) { + unsigned int ms = delay / 1000; + unsigned int us = delay % 1000; + + if (ms > 0) { + /* + * For small enough values, handle super-millisecond + * delays in the usleep_range() call below. + */ + if (ms < 20) + us += ms * 1000; + else + msleep(ms); + } + + /* + * Give the scheduler some room to coalesce with any other + * wakeup sources. For delays shorter than 10 us, don't even + * bother setting up high-resolution timers and just busy- + * loop. + */ + if (us >= 10) + usleep_range(us, us + 100); + else + udelay(us); } } -- 1.7.10.4
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