[PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Yossi Mansharoff]

On the db410c 96boards platform we have a TC7USB40MU on the board
to mux the D+/D- lines coming from the controller between a micro
usb "device" port and a USB hub for "host" roles[1]. During a
role switch, we need to toggle this mux to forward the D+/D-
lines to either the port or the hub. Add the necessary code to do
the role switch in chipidea core via the generic mux framework.
Board configurations like on db410c are expected to change roles
via the sysfs API described in
Documentation/ABI/testing/sysfs-platform-chipidea-usb2.

[1] https://github.com/96boards/documentation/raw/master/ConsumerEdition/DragonBoard-410c/HardwareDocs/Schematics_DragonBoard.pdf

Cc: Peter Rosin <peda@axentia.se>
Cc: Peter Chen <peter.chen@nxp.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>

Signed-off-by: Yossi Mansharoff <yossim@codeaurora.org>
---
 drivers/usb/chipidea/Kconfig |  2 ++
 drivers/usb/chipidea/core.c  |  5 +++++
 drivers/usb/chipidea/host.c  |  7 +++++++
 drivers/usb/chipidea/udc.c   | 13 ++++++++++++-
 include/linux/usb/chipidea.h |  2 ++
 5 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/chipidea/Kconfig b/drivers/usb/chipidea/Kconfig
index 785f0ed..6a8e635 100644
--- a/drivers/usb/chipidea/Kconfig
+++ b/drivers/usb/chipidea/Kconfig
@@ -3,6 +3,8 @@ config USB_CHIPIDEA
 	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
 	select EXTCON
 	select RESET_CONTROLLER
+	select MULTIPLEXER
+	select MUX_GPIO
 	help
 	  Say Y here if your system has a dual role high speed USB
 	  controller based on ChipIdea silicon IP. It supports:
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 33ae87f..8fa0991 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -61,6 +61,7 @@
 #include <linux/of.h>
 #include <linux/regulator/consumer.h>
 #include <linux/usb/ehci_def.h>
+#include <linux/mux/consumer.h>
 
 #include "ci.h"
 #include "udc.h"
@@ -687,6 +688,10 @@ static int ci_get_platdata(struct device *dev,
 	if (of_find_property(dev->of_node, "non-zero-ttctrl-ttha", NULL))
 		platdata->flags |= CI_HDRC_SET_NON_ZERO_TTHA;
 
+	platdata->usb_switch = devm_mux_control_get_optional(dev, "usb_switch");
+	if (IS_ERR(platdata->usb_switch))
+		return PTR_ERR(platdata->usb_switch);
+
 	ext_id = ERR_PTR(-ENODEV);
 	ext_vbus = ERR_PTR(-ENODEV);
 	if (of_property_read_bool(dev->of_node, "extcon")) {
diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
index af45aa32..d9d2d00 100644
--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -13,6 +13,7 @@
 #include <linux/usb/hcd.h>
 #include <linux/usb/chipidea.h>
 #include <linux/regulator/consumer.h>
+#include <linux/mux/consumer.h>
 
 #include "../host/ehci.h"
 
@@ -161,6 +162,10 @@ static int host_start(struct ci_hdrc *ci)
 		if (ci_otg_is_fsm_mode(ci)) {
 			otg->host = &hcd->self;
 			hcd->self.otg_port = 1;
+		} else {
+			ret = mux_control_select(ci->platdata->usb_switch, 1);
+			if (ret)
+				goto disable_reg;
 		}
 	}
 
@@ -181,6 +186,8 @@ static void host_stop(struct ci_hdrc *ci)
 	struct usb_hcd *hcd = ci->hcd;
 
 	if (hcd) {
+		if (!ci_otg_is_fsm_mode(ci))
+			mux_control_deselect(ci->platdata->usb_switch);
 		if (ci->platdata->notify_event)
 			ci->platdata->notify_event(ci,
 				CI_HDRC_CONTROLLER_STOPPED_EVENT);
diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 9852ec5..209d3f6 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -19,6 +19,7 @@
 #include <linux/usb/gadget.h>
 #include <linux/usb/otg-fsm.h>
 #include <linux/usb/chipidea.h>
+#include <linux/mux/consumer.h>
 
 #include "ci.h"
 #include "udc.h"
@@ -1965,16 +1966,26 @@ void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
 
 static int udc_id_switch_for_device(struct ci_hdrc *ci)
 {
+	int ret = 0;
+
 	if (ci->is_otg)
 		/* Clear and enable BSV irq */
 		hw_write_otgsc(ci, OTGSC_BSVIS | OTGSC_BSVIE,
 					OTGSC_BSVIS | OTGSC_BSVIE);
 
-	return 0;
+	if (!ci_otg_is_fsm_mode(ci))
+		ret = mux_control_select(ci->platdata->usb_switch, 0);
+
+	if (ci->is_otg && ret)
+		hw_write_otgsc(ci, OTGSC_BSVIE | OTGSC_BSVIS, OTGSC_BSVIS);
+
+	return ret;
 }
 
 static void udc_id_switch_for_host(struct ci_hdrc *ci)
 {
+	mux_control_deselect(ci->platdata->usb_switch);
+
 	/*
 	 * host doesn't care B_SESSION_VALID event
 	 * so clear and disbale BSV irq
diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h
index 07f9936..9ea55a1 100644
--- a/include/linux/usb/chipidea.h
+++ b/include/linux/usb/chipidea.h
@@ -10,6 +10,7 @@
 #include <linux/usb/otg.h>
 
 struct ci_hdrc;
+struct mux_control;
 
 /**
  * struct ci_hdrc_cable - structure for external connector cable state tracking
@@ -76,6 +77,7 @@ struct ci_hdrc_platform_data {
 	/* VBUS and ID signal state tracking, using extcon framework */
 	struct ci_hdrc_cable		vbus_extcon;
 	struct ci_hdrc_cable		id_extcon;
+	struct mux_control		*usb_switch;
 	u32			phy_clkgate_delay_us;
 };
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Peter Rosin]

On 2018-04-17 15:52, Yossi Mansharoff wrote:
> On the db410c 96boards platform we have a TC7USB40MU on the board
> to mux the D+/D- lines coming from the controller between a micro
> usb "device" port and a USB hub for "host" roles[1]. During a
> role switch, we need to toggle this mux to forward the D+/D-
> lines to either the port or the hub. Add the necessary code to do
> the role switch in chipidea core via the generic mux framework.
> Board configurations like on db410c are expected to change roles
> via the sysfs API described in
> Documentation/ABI/testing/sysfs-platform-chipidea-usb2.

Ok, so this is v2. Please describe what is different from v1.
I have told you before that this information helps.

> [1] https://github.com/96boards/documentation/raw/master/ConsumerEdition/DragonBoard-410c/HardwareDocs/Schematics_DragonBoard.pdf

This link returns 404 for me.

Cheers,
Peter

Re: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[yossim]

On 2018-04-17 17:11, Peter Rosin wrote:
> On 2018-04-17 15:52, Yossi Mansharoff wrote:
>> On the db410c 96boards platform we have a TC7USB40MU on the board
>> to mux the D+/D- lines coming from the controller between a micro
>> usb "device" port and a USB hub for "host" roles[1]. During a
>> role switch, we need to toggle this mux to forward the D+/D-
>> lines to either the port or the hub. Add the necessary code to do
>> the role switch in chipidea core via the generic mux framework.
>> Board configurations like on db410c are expected to change roles
>> via the sysfs API described in
>> Documentation/ABI/testing/sysfs-platform-chipidea-usb2.
> 
> Ok, so this is v2. Please describe what is different from v1.
> I have told you before that this information helps.
> 
>> [1] 
>> https://github.com/96boards/documentation/raw/master/ConsumerEdition/DragonBoard-410c/HardwareDocs/Schematics_DragonBoard.pdf
> 
> This link returns 404 for me.
> 
> Cheers,
> Peter


Hi,
This patch was split apart from the original patch into two patches
one for chipidea and the other for bindings.
this patch has no other changes two the code.

I will update the link.

thanks
Yossi

RE: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Peter Chen]

 
 
> --- a/drivers/usb/chipidea/Kconfig
> +++ b/drivers/usb/chipidea/Kconfig
> @@ -3,6 +3,8 @@ config USB_CHIPIDEA
>  	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD
> && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
>  	select EXTCON
>  	select RESET_CONTROLLER
> +	select MULTIPLEXER
> +	select MUX_GPIO

The above two configurations are only used at your specific platforms, please add
them at either your platform defconfig or the related hardware driver's Kconfig. 

>  	help
>  	  Say Y here if your system has a dual role high speed USB
>  	  controller based on ChipIdea silicon IP. It supports:
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c index
> 33ae87f..8fa0991 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -61,6 +61,7 @@
>  #include <linux/of.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/usb/ehci_def.h>
> +#include <linux/mux/consumer.h>
> 
>  #include "ci.h"
>  #include "udc.h"
> @@ -687,6 +688,10 @@ static int ci_get_platdata(struct device *dev,
>  	if (of_find_property(dev->of_node, "non-zero-ttctrl-ttha", NULL))
>  		platdata->flags |= CI_HDRC_SET_NON_ZERO_TTHA;
> 
> +	platdata->usb_switch = devm_mux_control_get_optional(dev, "usb_switch");
> +	if (IS_ERR(platdata->usb_switch))
> +		return PTR_ERR(platdata->usb_switch);
> +
>  	ext_id = ERR_PTR(-ENODEV);
>  	ext_vbus = ERR_PTR(-ENODEV);
>  	if (of_property_read_bool(dev->of_node, "extcon")) { diff --git
> a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c index af45aa32..d9d2d00
> 100644
> --- a/drivers/usb/chipidea/host.c
> +++ b/drivers/usb/chipidea/host.c
> @@ -13,6 +13,7 @@
>  #include <linux/usb/hcd.h>
>  #include <linux/usb/chipidea.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/mux/consumer.h>
> 
>  #include "../host/ehci.h"
> 
> @@ -161,6 +162,10 @@ static int host_start(struct ci_hdrc *ci)
>  		if (ci_otg_is_fsm_mode(ci)) {
>  			otg->host = &hcd->self;
>  			hcd->self.otg_port = 1;
> +		} else {
> +			ret = mux_control_select(ci->platdata->usb_switch, 1);
> +			if (ret)
> +				goto disable_reg;

What will happen if ci->platdata->usb_switch  is NULL?

>  		}
>  	}
> 
> @@ -181,6 +186,8 @@ static void host_stop(struct ci_hdrc *ci)
>  	struct usb_hcd *hcd = ci->hcd;
> 
>  	if (hcd) {
> +		if (!ci_otg_is_fsm_mode(ci))
> +			mux_control_deselect(ci->platdata->usb_switch);

Ditto.

>  		if (ci->platdata->notify_event)
>  			ci->platdata->notify_event(ci,
>  				CI_HDRC_CONTROLLER_STOPPED_EVENT);
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c index
> 9852ec5..209d3f6 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -19,6 +19,7 @@
>  #include <linux/usb/gadget.h>
>  #include <linux/usb/otg-fsm.h>
>  #include <linux/usb/chipidea.h>
> +#include <linux/mux/consumer.h>
> 
>  #include "ci.h"
>  #include "udc.h"
> @@ -1965,16 +1966,26 @@ void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
> 
>  static int udc_id_switch_for_device(struct ci_hdrc *ci)  {
> +	int ret = 0;
> +
>  	if (ci->is_otg)
>  		/* Clear and enable BSV irq */
>  		hw_write_otgsc(ci, OTGSC_BSVIS | OTGSC_BSVIE,
>  					OTGSC_BSVIS | OTGSC_BSVIE);
> 
> -	return 0;
> +	if (!ci_otg_is_fsm_mode(ci))
> +		ret = mux_control_select(ci->platdata->usb_switch, 0);
> +

Ditto

> +	if (ci->is_otg && ret)
> +		hw_write_otgsc(ci, OTGSC_BSVIE | OTGSC_BSVIS,
> OTGSC_BSVIS);
> +
> +	return ret;
>  }
> 
>  static void udc_id_switch_for_host(struct ci_hdrc *ci)  {
> +	mux_control_deselect(ci->platdata->usb_switch);
> +
>  	/*
>  	 * host doesn't care B_SESSION_VALID event
>  	 * so clear and disbale BSV irq
> diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h index
> 07f9936..9ea55a1 100644
> --- a/include/linux/usb/chipidea.h
> +++ b/include/linux/usb/chipidea.h
> @@ -10,6 +10,7 @@
>  #include <linux/usb/otg.h>
> 
>  struct ci_hdrc;
> +struct mux_control;
> 
>  /**
>   * struct ci_hdrc_cable - structure for external connector cable state tracking @@ -
> 76,6 +77,7 @@ struct ci_hdrc_platform_data {
>  	/* VBUS and ID signal state tracking, using extcon framework */
>  	struct ci_hdrc_cable		vbus_extcon;
>  	struct ci_hdrc_cable		id_extcon;
> +	struct mux_control		*usb_switch;
>  	u32			phy_clkgate_delay_us;
 
If CONFIG_USB_CHIPIDEA_HOST is not defined, it may cause build error

Peter
 

Re: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Peter Rosin]

On 2018-04-20 04:00, Peter Chen wrote:
>  
>  
>> --- a/drivers/usb/chipidea/Kconfig
>> +++ b/drivers/usb/chipidea/Kconfig
>> @@ -3,6 +3,8 @@ config USB_CHIPIDEA
>>  	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD
>> && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
>>  	select EXTCON
>>  	select RESET_CONTROLLER
>> +	select MULTIPLEXER
>> +	select MUX_GPIO
> 
> The above two configurations are only used at your specific platforms, please add
> them at either your platform defconfig or the related hardware driver's Kconfig. 

"select MUX_GPIO" is indeed questionable and should be somewhere else because
this driver will work with any other mux as well. It's simply something else
that requires it. If it was the case that MUX_GPIO is indeed required then the
whole use of the mux subsystem is questionable and the thing controlled might
as well be controlled directly with the GPIO line. The mux subsystem is good
when a single mux "controller" is shared between several unrelated drivers
utilizing different muxes controlled by that same mux "controller" (think
several muxes controlled by the same GPIO line/lines). The mux subsystem is
also useful when the driver does not want to handle/know how the specific mux
is controlled. That said, it's of course not wrong to use the mux subsystem
in cases like this either, but I think it might be much easier and direct to
just twiddle the single GPIO line directly here?

Or do you expect some future HW variant that will use some other means to
control this mux?

>>  	help
>>  	  Say Y here if your system has a dual role high speed USB
>>  	  controller based on ChipIdea silicon IP. It supports:
>> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c index
>> 33ae87f..8fa0991 100644
>> --- a/drivers/usb/chipidea/core.c
>> +++ b/drivers/usb/chipidea/core.c
>> @@ -61,6 +61,7 @@
>>  #include <linux/of.h>
>>  #include <linux/regulator/consumer.h>
>>  #include <linux/usb/ehci_def.h>
>> +#include <linux/mux/consumer.h>
>>
>>  #include "ci.h"
>>  #include "udc.h"
>> @@ -687,6 +688,10 @@ static int ci_get_platdata(struct device *dev,
>>  	if (of_find_property(dev->of_node, "non-zero-ttctrl-ttha", NULL))
>>  		platdata->flags |= CI_HDRC_SET_NON_ZERO_TTHA;
>>
>> +	platdata->usb_switch = devm_mux_control_get_optional(dev, "usb_switch");
>> +	if (IS_ERR(platdata->usb_switch))
>> +		return PTR_ERR(platdata->usb_switch);
>> +
>>  	ext_id = ERR_PTR(-ENODEV);
>>  	ext_vbus = ERR_PTR(-ENODEV);
>>  	if (of_property_read_bool(dev->of_node, "extcon")) { diff --git
>> a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c index af45aa32..d9d2d00
>> 100644
>> --- a/drivers/usb/chipidea/host.c
>> +++ b/drivers/usb/chipidea/host.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/usb/hcd.h>
>>  #include <linux/usb/chipidea.h>
>>  #include <linux/regulator/consumer.h>
>> +#include <linux/mux/consumer.h>
>>
>>  #include "../host/ehci.h"
>>
>> @@ -161,6 +162,10 @@ static int host_start(struct ci_hdrc *ci)
>>  		if (ci_otg_is_fsm_mode(ci)) {
>>  			otg->host = &hcd->self;
>>  			hcd->self.otg_port = 1;
>> +		} else {
>> +			ret = mux_control_select(ci->platdata->usb_switch, 1);
>> +			if (ret)
>> +				goto disable_reg;
> 
> What will happen if ci->platdata->usb_switch  is NULL?

What has not been mentioned in this patch is that it depends on another
patch which is not yet upstream. You can google for

mux: add mux_control_get_optional() API

to get an idea (it's also in linux-next). Anyway, with that patch this
is not a problem.

>>  		}
>>  	}
>>
>> @@ -181,6 +186,8 @@ static void host_stop(struct ci_hdrc *ci)
>>  	struct usb_hcd *hcd = ci->hcd;
>>
>>  	if (hcd) {
>> +		if (!ci_otg_is_fsm_mode(ci))
>> +			mux_control_deselect(ci->platdata->usb_switch);
> 
> Ditto.
> 
>>  		if (ci->platdata->notify_event)
>>  			ci->platdata->notify_event(ci,
>>  				CI_HDRC_CONTROLLER_STOPPED_EVENT);
>> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c index
>> 9852ec5..209d3f6 100644
>> --- a/drivers/usb/chipidea/udc.c
>> +++ b/drivers/usb/chipidea/udc.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/usb/gadget.h>
>>  #include <linux/usb/otg-fsm.h>
>>  #include <linux/usb/chipidea.h>
>> +#include <linux/mux/consumer.h>
>>
>>  #include "ci.h"
>>  #include "udc.h"
>> @@ -1965,16 +1966,26 @@ void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
>>
>>  static int udc_id_switch_for_device(struct ci_hdrc *ci)  {
>> +	int ret = 0;
>> +
>>  	if (ci->is_otg)
>>  		/* Clear and enable BSV irq */
>>  		hw_write_otgsc(ci, OTGSC_BSVIS | OTGSC_BSVIE,
>>  					OTGSC_BSVIS | OTGSC_BSVIE);
>>
>> -	return 0;
>> +	if (!ci_otg_is_fsm_mode(ci))
>> +		ret = mux_control_select(ci->platdata->usb_switch, 0);
>> +
> 
> Ditto
> 
>> +	if (ci->is_otg && ret)
>> +		hw_write_otgsc(ci, OTGSC_BSVIE | OTGSC_BSVIS,
>> OTGSC_BSVIS);
>> +
>> +	return ret;
>>  }
>>
>>  static void udc_id_switch_for_host(struct ci_hdrc *ci)  {
>> +	mux_control_deselect(ci->platdata->usb_switch);
>> +
>>  	/*
>>  	 * host doesn't care B_SESSION_VALID event
>>  	 * so clear and disbale BSV irq
>> diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h index
>> 07f9936..9ea55a1 100644
>> --- a/include/linux/usb/chipidea.h
>> +++ b/include/linux/usb/chipidea.h
>> @@ -10,6 +10,7 @@
>>  #include <linux/usb/otg.h>
>>
>>  struct ci_hdrc;
>> +struct mux_control;
>>
>>  /**
>>   * struct ci_hdrc_cable - structure for external connector cable state tracking @@ -
>> 76,6 +77,7 @@ struct ci_hdrc_platform_data {
>>  	/* VBUS and ID signal state tracking, using extcon framework */
>>  	struct ci_hdrc_cable		vbus_extcon;
>>  	struct ci_hdrc_cable		id_extcon;
>> +	struct mux_control		*usb_switch;
>>  	u32			phy_clkgate_delay_us;
>  
> If CONFIG_USB_CHIPIDEA_HOST is not defined, it may cause build error

How is that related? There is a forward declaration above?

Cheers,
peda

RE: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Peter Chen]

 
> >> @@ -3,6 +3,8 @@ config USB_CHIPIDEA
> >>  	depends on ((USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD &&
> >> !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)) && HAS_DMA
> >>  	select EXTCON
> >>  	select RESET_CONTROLLER
> >> +	select MULTIPLEXER
> >> +	select MUX_GPIO
> >
> > The above two configurations are only used at your specific platforms,
> > please add them at either your platform defconfig or the related hardware driver's
> Kconfig.
> 
> "select MUX_GPIO" is indeed questionable and should be somewhere else because
> this driver will work with any other mux as well. It's simply something else that
> requires it. If it was the case that MUX_GPIO is indeed required then the whole use
> of the mux subsystem is questionable and the thing controlled might as well be
> controlled directly with the GPIO line. The mux subsystem is good when a single mux
> "controller" is shared between several unrelated drivers utilizing different muxes
> controlled by that same mux "controller" (think several muxes controlled by the same
> GPIO line/lines). The mux subsystem is also useful when the driver does not want to
> handle/know how the specific mux is controlled. That said, it's of course not wrong to
> use the mux subsystem in cases like this either, but I think it might be much easier
> and direct to just twiddle the single GPIO line directly here?
> 
> Or do you expect some future HW variant that will use some other means to control
> this mux?
> 

No, this mux is only used at Yossi's boards, I expect these two configurations is under
MUX's hardware driver Kconfig if it is existed, or under its platform defconfig. Someone
has already complained too many selects increase the code size:

https://patchwork.kernel.org/patch/10349293/

> >>  	help
> >>  	  Say Y here if your system has a dual role high speed USB
> >>  	  controller based on ChipIdea silicon IP. It supports:
> >> diff --git a/drivers/usb/chipidea/core.c
> >> b/drivers/usb/chipidea/core.c index
> >> 33ae87f..8fa0991 100644
> >> --- a/drivers/usb/chipidea/core.c
> >> +++ b/drivers/usb/chipidea/core.c
> >> @@ -61,6 +61,7 @@
> >>  #include <linux/of.h>
> >>  #include <linux/regulator/consumer.h>  #include
> >> <linux/usb/ehci_def.h>
> >> +#include <linux/mux/consumer.h>
> >>
> >>  #include "ci.h"
> >>  #include "udc.h"
> >> @@ -687,6 +688,10 @@ static int ci_get_platdata(struct device *dev,
> >>  	if (of_find_property(dev->of_node, "non-zero-ttctrl-ttha", NULL))
> >>  		platdata->flags |= CI_HDRC_SET_NON_ZERO_TTHA;
> >>
> >> +	platdata->usb_switch = devm_mux_control_get_optional(dev, "usb_switch");
> >> +	if (IS_ERR(platdata->usb_switch))
> >> +		return PTR_ERR(platdata->usb_switch);
> >> +
> >>  	ext_id = ERR_PTR(-ENODEV);
> >>  	ext_vbus = ERR_PTR(-ENODEV);
> >>  	if (of_property_read_bool(dev->of_node, "extcon")) { diff --git
> >> a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c index
> >> af45aa32..d9d2d00
> >> 100644
> >> --- a/drivers/usb/chipidea/host.c
> >> +++ b/drivers/usb/chipidea/host.c
> >> @@ -13,6 +13,7 @@
> >>  #include <linux/usb/hcd.h>
> >>  #include <linux/usb/chipidea.h>
> >>  #include <linux/regulator/consumer.h>
> >> +#include <linux/mux/consumer.h>
> >>
> >>  #include "../host/ehci.h"
> >>
> >> @@ -161,6 +162,10 @@ static int host_start(struct ci_hdrc *ci)
> >>  		if (ci_otg_is_fsm_mode(ci)) {
> >>  			otg->host = &hcd->self;
> >>  			hcd->self.otg_port = 1;
> >> +		} else {
> >> +			ret = mux_control_select(ci->platdata->usb_switch, 1);
> >> +			if (ret)
> >> +				goto disable_reg;
> >
> > What will happen if ci->platdata->usb_switch  is NULL?
> 
> What has not been mentioned in this patch is that it depends on another patch which
> is not yet upstream. You can google for
> 
> mux: add mux_control_get_optional() API
> 
> to get an idea (it's also in linux-next). Anyway, with that patch this is not a problem.
> 

Thanks, I see it judges NULL pointer, then it is OK.

 
> >>  /**
> >>   * struct ci_hdrc_cable - structure for external connector cable
> >> state tracking @@ -
> >> 76,6 +77,7 @@ struct ci_hdrc_platform_data {
> >>  	/* VBUS and ID signal state tracking, using extcon framework */
> >>  	struct ci_hdrc_cable		vbus_extcon;
> >>  	struct ci_hdrc_cable		id_extcon;
> >> +	struct mux_control		*usb_switch;
> >>  	u32			phy_clkgate_delay_us;
> >
> > If CONFIG_USB_CHIPIDEA_HOST is not defined, it may cause build error
> 
> How is that related? There is a forward declaration above?
> 

Sorry, I did not notice drivers/usb/chipidea/core.c also includes <linux/mux/consumer.h>.

Peter

Re: [PATCH v2] usb: chipidea: Hook into mux framework to toggle usb switch

[Peter Rosin]

On 2018-04-18 07:48, yossim@codeaurora.org wrote:
> On 2018-04-17 17:11, Peter Rosin wrote:
>> On 2018-04-17 15:52, Yossi Mansharoff wrote:
>>> On the db410c 96boards platform we have a TC7USB40MU on the board
>>> to mux the D+/D- lines coming from the controller between a micro
>>> usb "device" port and a USB hub for "host" roles[1]. During a
>>> role switch, we need to toggle this mux to forward the D+/D-
>>> lines to either the port or the hub. Add the necessary code to do
>>> the role switch in chipidea core via the generic mux framework.
>>> Board configurations like on db410c are expected to change roles
>>> via the sysfs API described in
>>> Documentation/ABI/testing/sysfs-platform-chipidea-usb2.
>>
>> Ok, so this is v2. Please describe what is different from v1.
>> I have told you before that this information helps.
>>
>>> [1] 
>>> https://github.com/96boards/documentation/raw/master/ConsumerEdition/DragonBoard-410c/HardwareDocs/Schematics_DragonBoard.pdf
>>
>> This link returns 404 for me.
>>
>> Cheers,
>> Peter
> 
> 
> Hi,
> This patch was split apart from the original patch into two patches
> one for chipidea and the other for bindings.
> this patch has no other changes two the code.
> 
> I will update the link.

Just a note: I will not feed the mux_control_get_optional patch upstream
until I feel confident that this patch is going also heading upstream.

Cheers,
Peter