[PATCH] input: touchscreen: add delay time to device power on

[PATCH] input: touchscreen: add delay time to device power on

[crag0715]

From: "Crag.Wang" <crag.wang@dell.com>

Delay time for MELFAS MIP4 controller is required at power on stage
regardless the existence of GPIO consumer lookup from devicetree or
ACPI device table.

There is an issue if GPIO ce is undefined in the ACPI results no delay
time for deive power on, the controller ended up in an abnormal state.

TEST=echo i2c-MLFS0000:00 > /sys/bus/i2c/drivers/mip4_ts/unbind
     verify the touch function is off

     echo i2c-MLFS0000:00 > /sys/bus/i2c/drivers/mip4_ts/bind
     verify the touch function is on

Signed-off-by: Crag.Wang <crag.wang@dell.com>
---
 drivers/input/touchscreen/melfas_mip4.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/melfas_mip4.c b/drivers/input/touchscreen/melfas_mip4.c
index 430a2bc5f7ca..8e803658fb43 100644
--- a/drivers/input/touchscreen/melfas_mip4.c
+++ b/drivers/input/touchscreen/melfas_mip4.c
@@ -374,12 +374,11 @@ static int mip4_query_device(struct mip4_ts *ts)
 
 static int mip4_power_on(struct mip4_ts *ts)
 {
-	if (ts->gpio_ce) {
+	if (ts->gpio_ce)
 		gpiod_set_value_cansleep(ts->gpio_ce, 1);
 
-		/* Booting delay : 200~300ms */
-		usleep_range(200 * 1000, 300 * 1000);
-	}
+	/* Booting delay : 200~300ms */
+	usleep_range(200 * 1000, 300 * 1000);
 
 	return 0;
 }
-- 
2.20.1

Re: [PATCH] input: touchscreen: add delay time to device power on

[Crag Wang]

Adding more

On Wed, Jul 10, 2019 at 10:59 AM <crag0715@gmail.com> wrote:
>
> From: "Crag.Wang" <crag.wang@dell.com>
>
> Delay time for MELFAS MIP4 controller is required at power on stage
> regardless the existence of GPIO consumer lookup from devicetree or
> ACPI device table.
>
> There is an issue if GPIO ce is undefined in the ACPI results no delay
> time for deive power on, the controller ended up in an abnormal state.
>
> TEST=echo i2c-MLFS0000:00 > /sys/bus/i2c/drivers/mip4_ts/unbind
>      verify the touch function is off
>
>      echo i2c-MLFS0000:00 > /sys/bus/i2c/drivers/mip4_ts/bind
>      verify the touch function is on
>
> Signed-off-by: Crag.Wang <crag.wang@dell.com>
> ---
>  drivers/input/touchscreen/melfas_mip4.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/touchscreen/melfas_mip4.c b/drivers/input/touchscreen/melfas_mip4.c
> index 430a2bc5f7ca..8e803658fb43 100644
> --- a/drivers/input/touchscreen/melfas_mip4.c
> +++ b/drivers/input/touchscreen/melfas_mip4.c
> @@ -374,12 +374,11 @@ static int mip4_query_device(struct mip4_ts *ts)
>
>  static int mip4_power_on(struct mip4_ts *ts)
>  {
> -       if (ts->gpio_ce) {
> +       if (ts->gpio_ce)
>                 gpiod_set_value_cansleep(ts->gpio_ce, 1);
>
> -               /* Booting delay : 200~300ms */
> -               usleep_range(200 * 1000, 300 * 1000);
> -       }
> +       /* Booting delay : 200~300ms */
> +       usleep_range(200 * 1000, 300 * 1000);
>
>         return 0;
>  }
> --
> 2.20.1
>

Re: [PATCH] input: touchscreen: add delay time to device power on

[Dmitry Torokhov]

Hi Crag,

On Wed, Jul 10, 2019 at 04:58:40PM +0800, Crag Wang wrote:
> Adding more
> 
> On Wed, Jul 10, 2019 at 10:59 AM <crag0715@gmail.com> wrote:
> >
> > From: "Crag.Wang" <crag.wang@dell.com>
> >
> > Delay time for MELFAS MIP4 controller is required at power on stage
> > regardless the existence of GPIO consumer lookup from devicetree or
> > ACPI device table.
> >
> > There is an issue if GPIO ce is undefined in the ACPI results no delay
> > time for deive power on, the controller ended up in an abnormal state.
> >

If kernel does not reset the controller it should not have to wait for
reset to complete either. Since your firmware resets the controller it
also has to conform to the timing requirements.

Thanks.

-- 
Dmitry