linux-kernel - Re: [PATCH v2 2/2] extcon: intel-cht-wc: Ignore failure to detect charger-type on host mode exit

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Date:   Wed, 05 Apr 2017 10:08:09 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Hans de Goede <hdegoede@...hat.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] extcon: intel-cht-wc: Ignore failure to detect
 charger-type on host mode exit

On 2017년 04월 05일 07:04, Hans de Goede wrote:
> When we leave host-mode because the id-pin is no longer connected to
> ground, the 5v boost converter is normally still on, so we will see
> Vbus, but it is not from a charger (normally) so the charger-type
> detection will fail.
> 
> This commit silences the cht_wc_extcon_get_charger() false-positive
> errors when we're leaving host mode.
> 
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
> ---
>  drivers/extcon/extcon-intel-cht-wc.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/extcon/extcon-intel-cht-wc.c b/drivers/extcon/extcon-intel-cht-wc.c
> index e22df5f..5f37112 100644
> --- a/drivers/extcon/extcon-intel-cht-wc.c
> +++ b/drivers/extcon/extcon-intel-cht-wc.c
> @@ -96,6 +96,7 @@ struct cht_wc_extcon_data {
>  	struct regmap *regmap;
>  	struct extcon_dev *edev;
>  	unsigned int previous_cable;
> +	bool usb_host;
>  };
>  
>  static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts)
> @@ -112,7 +113,8 @@ static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts)
>  	return USB_ID_FLOAT;
>  }
>  
> -static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext)
> +static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext,
> +				     bool ignore_errors)
>  {
>  	int ret, usbsrc, status;
>  	unsigned long timeout;
> @@ -135,6 +137,9 @@ static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext)
>  	} while (time_before(jiffies, timeout));
>  
>  	if (status != CHT_WC_USBSRC_STS_SUCCESS) {
> +		if (ignore_errors)
> +			return EXTCON_CHG_USB_SDP; /* Save fallback */
> +
>  		if (status == CHT_WC_USBSRC_STS_FAIL)
>  			dev_warn(ext->dev, "Could not detect charger type\n");
>  		else
> @@ -203,6 +208,8 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
>  {
>  	int ret, pwrsrc_sts, id;
>  	unsigned int cable = EXTCON_NONE;
> +	/* Ignore errors in host mode, as the 5v boost converter is on then */
> +	bool ignore_get_charger_errors = ext->usb_host;
>  
>  	ret = regmap_read(ext->regmap, CHT_WC_PWRSRC_STS, &pwrsrc_sts);
>  	if (ret) {
> @@ -223,7 +230,7 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
>  		goto set_state;
>  	}
>  
> -	ret = cht_wc_extcon_get_charger(ext);
> +	ret = cht_wc_extcon_get_charger(ext, ignore_get_charger_errors);
>  	if (ret >= 0)
>  		cable = ret;
>  
> @@ -238,8 +245,8 @@ static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
>  		ext->previous_cable = cable;
>  	}
>  
> -	extcon_set_state_sync(ext->edev, EXTCON_USB_HOST,
> -			      id == USB_ID_GND || id == USB_RID_A);
> +	ext->usb_host = id == USB_ID_GND || id == USB_RID_A;

I'll modify it as following to improve the readability:
	ext->usb_host = ((id == USB_ID_GND) || (id == USB_RID_A));

> +	extcon_set_state_sync(ext->edev, EXTCON_USB_HOST, ext->usb_host);
>  }
>  
>  static irqreturn_t cht_wc_extcon_isr(int irq, void *data)
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics