linux-kernel - Re: [PATCH] extcon: usbc-tusb320: make sure the state is initialized on probe

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Date:   Thu, 30 Jun 2022 04:54:33 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Peter Rosin <peda@...ntia.se>, linux-kernel@...r.kernel.org
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Michael Auchter <michael.auchter@...com>
Subject: Re: [PATCH] extcon: usbc-tusb320: make sure the state is initialized
 on probe

On 22. 6. 23. 20:21, Peter Rosin wrote:
> When the port is connected at boot, there is not necessarily
> an interrupt flagged in the interrupt status register, causing
> the IRQ handler to bail out early without reading the state when
> it is invoked directly from probe.
> 
> Add a flag that overrides the interrupt status register and reads
> the state regardless during probe.
> 
> Fixes: 06bc4ca115cd ("extcon: Add driver for TI TUSB320")
> Signed-off-by: Peter Rosin <peda@...ntia.se>
> ---
>  drivers/extcon/extcon-usbc-tusb320.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c
> index 6ba3d89b106d..bd3645ae0d52 100644
> --- a/drivers/extcon/extcon-usbc-tusb320.c
> +++ b/drivers/extcon/extcon-usbc-tusb320.c
> @@ -55,6 +55,7 @@ struct tusb320_priv {
>  	struct extcon_dev *edev;
>  	struct tusb320_ops *ops;
>  	enum tusb320_attached_state state;
> +	bool initialized;
>  };
>  
>  static const char * const tusb_attached_states[] = {
> @@ -195,7 +196,7 @@ static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
>  		return IRQ_NONE;
>  	}
>  
> -	if (!(reg & TUSB320_REG9_INTERRUPT_STATUS))
> +	if (priv->initialized && !(reg & TUSB320_REG9_INTERRUPT_STATUS))
>  		return IRQ_NONE;
>  
>  	state = (reg >> TUSB320_REG9_ATTACHED_STATE_SHIFT) &
> @@ -297,6 +298,8 @@ static int tusb320_extcon_probe(struct i2c_client *client,
>  		 */
>  		tusb320_irq_handler(client->irq, priv);
>  
> +	priv->initialized = true;
> +

After initializing as 'priv->initialized = true', 
tusb320_irq_handler() is not anymore detecting the external connector changes.

If external connector is detached after finished kernel boot,
how to change the state of external connector by using extcon_set_state()?

-- 
Best Regards,
Samsung Electronics
Chanwoo Choi