Re: [PATCH v6 11/25] usb: chipidea: vbus event may exist before starting gadget

From: Peter Chen <hzpeterchen@gmail.com>
To: Stephen Boyd <stephen.boyd@linaro.org>
Cc: linux-usb@vger.kernel.org, Peter Chen <peter.chen@nxp.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Neil Armstrong <narmstrong@baylibre.com>,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andy Gross <andy.gross@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Felipe Balbi <balbi@kernel.org>
Subject: Re: [PATCH v6 11/25] usb: chipidea: vbus event may exist before starting gadget
Date: Tue, 3 Jan 2017 16:00:31 +0800	[thread overview]
Message-ID: <20170103080031.GC14542@b29397-desktop> (raw)
In-Reply-To: <20161228225711.698-12-stephen.boyd@linaro.org>

On Wed, Dec 28, 2016 at 02:56:57PM -0800, Stephen Boyd wrote:
> From: Peter Chen <peter.chen@nxp.com>
> 
> At some situations, the vbus may already be there before starting
> gadget. So we need to check vbus event after switch to gadget in
> order to handle missing vbus event. The typical use cases are plugging
> vbus cable before driver load or the vbus has already been there
> after stopping host but before starting gadget.
> 
> Signed-off-by: Peter Chen <peter.chen@nxp.com>
> Tested-by: Stephen Boyd <stephen.boyd@linaro.org>
> Reviewed-by: Stephen Boyd <stephen.boyd@linaro.org>
> [sboyd@codeaurora.org: Modify comment text per list discussion]
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
>  drivers/usb/chipidea/core.c |  4 ----
>  drivers/usb/chipidea/otg.c  | 14 +++++++++-----
>  drivers/usb/chipidea/udc.c  |  2 ++
>  3 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index 8a020ebbbe2f..37f888e31f10 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -979,10 +979,6 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>  	}
>  
>  	if (!ci_otg_is_fsm_mode(ci)) {
> -		/* only update vbus status for peripheral */
> -		if (ci->role == CI_ROLE_GADGET)
> -			ci_handle_vbus_change(ci);
> -
>  		ret = ci_role_start(ci, ci->role);
>  		if (ret) {
>  			dev_err(dev, "can't start %s role\n",
> diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
> index 695f3fe3ae21..c972ed23b8ec 100644
> --- a/drivers/usb/chipidea/otg.c
> +++ b/drivers/usb/chipidea/otg.c
> @@ -134,9 +134,9 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
>  	if (!ci->is_otg)
>  		return;
>  
> -	if (hw_read_otgsc(ci, OTGSC_BSV))
> +	if (hw_read_otgsc(ci, OTGSC_BSV) && !ci->vbus_active)
>  		usb_gadget_vbus_connect(&ci->gadget);
> -	else
> +	else if (!hw_read_otgsc(ci, OTGSC_BSV) && ci->vbus_active)
>  		usb_gadget_vbus_disconnect(&ci->gadget);
>  }
>  
> @@ -175,10 +175,14 @@ static void ci_handle_id_switch(struct ci_hdrc *ci)
>  
>  		ci_role_stop(ci);
>  
> -		if (role == CI_ROLE_GADGET)
> +		if (role == CI_ROLE_GADGET &&
> +				IS_ERR(ci->platdata->vbus_extcon.edev))
>  			/*
> -			 * wait vbus lower than OTGSC_BSV before connecting
> -			 * to host
> +			 * wait vbus lower than OTGSC_BSV before connecting to
> +			 * host. If connecting status is from an external
> +			 * connector instead of register, we don't need to care
> +			 * vbus on the board, since it will not affect external
> +			 * connector status.
>  			 */
>  			hw_wait_vbus_lower_bsv(ci);
>  
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index 732b281485de..0db56fb7e9e9 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -1961,6 +1961,8 @@ static int udc_id_switch_for_device(struct ci_hdrc *ci)
>  		/* Clear and enable BSV irq */
>  		hw_write_otgsc(ci, OTGSC_BSVIS | OTGSC_BSVIE,
>  					OTGSC_BSVIS | OTGSC_BSVIE);
> +	/* vbus change may has already been occurred */
> +	ci_handle_vbus_change(ci);
>  
>  	return 0;

After thinking more, the above change will affect OTG FSM which calls
this API too, but handle vbus change later, see ci_otg_start_host and
ci_otg_start_gadget. How about changing patch like below:

 drivers/usb/chipidea/otg.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index 695f3fe..10236fe 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -134,9 +134,9 @@ void ci_handle_vbus_change(struct ci_hdrc *ci)
 	if (!ci->is_otg)
 		return;
 
-	if (hw_read_otgsc(ci, OTGSC_BSV))
+	if (hw_read_otgsc(ci, OTGSC_BSV) && !ci->vbus_active)
 		usb_gadget_vbus_connect(&ci->gadget);
-	else
+	else if (!hw_read_otgsc(ci, OTGSC_BSV) && ci->vbus_active)
 		usb_gadget_vbus_disconnect(&ci->gadget);
 }
 
@@ -175,14 +175,21 @@ static void ci_handle_id_switch(struct ci_hdrc *ci)
 
 		ci_role_stop(ci);
 
-		if (role == CI_ROLE_GADGET)
+		if (role == CI_ROLE_GADGET &&
+				IS_ERR(ci->platdata->vbus_extcon.edev))
 			/*
-			 * wait vbus lower than OTGSC_BSV before connecting
-			 * to host
+			 * Wait vbus lower than OTGSC_BSV before connecting
+			 * to host. If connecting status is from an external
+			 * connector instead of register, we don't need to
+			 * care vbus on the board, since it will not affect
+			 * external connector status.
 			 */
 			hw_wait_vbus_lower_bsv(ci);
 
 		ci_role_start(ci, role);
+		/* vbus change may have already occurred */
+		if (role == CI_ROLE_GADGET)
+			ci_handle_vbus_change(ci);
 	}
 }
 /**
-- 
2.7.4

-- 

Best Regards,
Peter Chen
