Re: [PATCH v2 9/9] media: i2c: tw9910: Remove soc_camera dependencies

From: Fabio Estevam
Date: Wed Jan 03 2018 - 12:27:59 EST


Hi Jacopo,

On Wed, Jan 3, 2018 at 3:13 PM, jacopo mondi <jacopo@xxxxxxxxxx> wrote:

> That would be true if I would have declared the GPIO to be ACTIVE_LOW.
> See patch [5/9] in this series and search for "rstb". The GPIO (which
> is shared between two devices) is said to be active high...

Just looked at your patch 5/9 and it seems it only works because you
made two inversions :-)

Initially the rest GPIO was doing:

- gpio_set_value(GPIO_PTT3, 0);
- mdelay(10);
- gpio_set_value(GPIO_PTT3, 1);
- mdelay(10); /* wait to let chip come out of reset */

So this is an active low reset.

So you should have converted it to:

GPIO_LOOKUP("sh7722_pfc", GPIO_PTT3, "rstb", GPIO_ACTIVE_LOW),

and then in this patch you should do as I said earlier:

gpiod_set_value(priv->rstb_gpio, 1);
usleep_range(500, 1000);
gpiod_set_value(priv->rstb_gpio, 0);