From: "ZHANG Xu (BST/ESA3.1)" <Xu.Zhang@cn.bosch.com>
To: Aniroop Mathur <a.mathur@samsung.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        "linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC: Aniroop Mathur <aniroop.mathur@gmail.com>,
        "s.samuel@samsung.com" <s.samuel@samsung.com>,
        "r.mahale@samsung.com" <r.mahale@samsung.com>
Subject: RE: [PATCH] Input: Change msleep to usleep_range for small msecs
Thread-Topic: [PATCH] Input: Change msleep to usleep_range for small msecs
Thread-Index: AQHSSZV4XtYR0VupXkSyAW8IOUH0A6Dykd1g
Date: Thu, 1 Dec 2016 05:49:19 +0000
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Hello Aniroop Mathur

Thank you for your mail.

We have used the  usleep_range() function in our new product's driver and the verification result  is working.
Your patch for bma150 is definitely working for sure. 

Just one question need your answer.
To replace the msleep(2),   is  usleep_range(2000, 2100)  better  than usleep_range(2000, 2000)  ?

Best regards

Albert (Xu) ZHANG
BST/ESA3.1  


-----Original Message-----
From: mathur.aniroop@gmail.com [mailto:mathur.aniroop@gmail.com] On Behalf Of Aniroop Mathur
Sent: Tuesday, November 29, 2016 12:36 AM
To: ZHANG Xu (BST/ESA3.1) <Xu.Zhang@cn.bosch.com>; Dmitry Torokhov <dmitry.torokhov@gmail.com>; linux-input@vger.kernel.org; linux-kernel@vger.kernel.org
Cc: Aniroop Mathur <aniroop.mathur@gmail.com>; s.samuel@samsung.com; r.mahale@samsung.com; Aniroop Mathur <a.mathur@samsung.com>
Subject: Re: [PATCH] Input: Change msleep to usleep_range for small msecs

Hello Mr. Albert Zhang,

I am Aniroop Mathur from Samsung R&D Institute, India.

I have submitted one patch as below for review to Linux Open Source.
The problem is that we do not have the hardware available with us to
test it and we would like to test it before actually applying it.
As you are the author of this driver, so I would like to request
you if you could help to test this patch or provide us the contact points
of individuals who could support to get this patch tested?

Thank you!

BR,
Aniroop Mathur


On Thu, Nov 24, 2016 at 9:33 PM, Aniroop Mathur <a.mathur@samsung.com> wrote:
> msleep(1~20) may not do what the caller intends, and will often sleep longer.
> (~20 ms actual sleep for any value given in the 1~20ms range)
> This is not the desired behaviour for many cases like device resume time,
> device suspend time, device enable time, etc.
> Thus, change msleep to usleep_range for precise wakeups.
>
> Signed-off-by: Aniroop Mathur <a.mathur@samsung.com>
> ---
>  drivers/input/misc/bma150.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/misc/bma150.c b/drivers/input/misc/bma150.c
> index 2124390..1fa8537 100644
> --- a/drivers/input/misc/bma150.c
> +++ b/drivers/input/misc/bma150.c
> @@ -207,7 +207,7 @@ static int bma150_set_mode(struct bma150_data *bma150, u8 mode)
>                 return error;
>
>         if (mode == BMA150_MODE_NORMAL)
> -               msleep(2);
> +               usleep_range(2000, 2100);
>
>         bma150->mode = mode;
>         return 0;
> @@ -222,7 +222,7 @@ static int bma150_soft_reset(struct bma150_data *bma150)
>         if (error)
>                 return error;
>
> -       msleep(2);
> +       usleep_range(2000, 2100);
>         return 0;
>  }
>
> --
> 2.6.2
>