[PATCH 2/3] usb: chipidea: Hook into mux framework to toggle usb switch

[Stephen Boyd]

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@xxxxxxxxxx>
Cc: Peter Chen <peter.chen@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: <devicetree@xxxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <stephen.boyd@xxxxxxxxxx>
---
 Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt |  8 ++++++++
 drivers/usb/chipidea/core.c                            | 17 +++++++++++++++++
 drivers/usb/chipidea/host.c                            | 10 ++++++++++
 drivers/usb/chipidea/udc.c                             | 11 +++++++++++
 include/linux/usb/chipidea.h                           | 14 ++++++++++++++
 5 files changed, 60 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
index 0e03344e2e8b..96ce81d975d5 100644
--- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
+++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
@@ -76,6 +76,11 @@ Optional properties:
   needs to make sure it does not send more than 90%
   maximum_periodic_data_per_frame. The use case is multiple transactions, but
   less frame rate.
+- mux-controls: The mux control for toggling host/device output of this
+  controller.
+- mux-control-names: Shall be "usb_switch" if mux-controls is specified.
+- usb-switch-states: Two u32's defining the state to set on the mux for the
+  host mode and device modes respectively.
 
 i.mx specific properties
 - fsl,usbmisc: phandler of non-core register device, with one
@@ -102,4 +107,7 @@ Example:
 		rx-burst-size-dword = <0x10>;
 		extcon = <0>, <&usb_id>;
 		phy-clkgate-delay-us = <400>;
+		mux-controls = <&usb_switch>;
+		mux-control-names = "usb_switch";
+		usb-switch-states = <0>, <1>;
 	};
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index b17ed3a9a304..6531d771f296 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -64,6 +64,7 @@
 #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"
@@ -606,6 +607,7 @@ static int ci_get_platdata(struct device *dev,
 {
 	struct extcon_dev *ext_vbus, *ext_id;
 	struct ci_hdrc_cable *cable;
+	struct ci_hdrc_switch *usb_switch;
 	int ret;
 
 	if (!platdata->phy_mode)
@@ -690,6 +692,21 @@ 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;
 
+	if (IS_ENABLED(CONFIG_MULTIPLEXER)) {
+		usb_switch = &platdata->usb_switch;
+		usb_switch->mux = devm_mux_control_get(dev, "usb_switch");
+		if (!IS_ERR(usb_switch->mux)) {
+			if (of_property_read_u32_index(dev->of_node,
+						       "usb-switch-states",
+						       0, &usb_switch->device))
+				return -EINVAL;
+			if (of_property_read_u32_index(dev->of_node,
+						       "usb-switch-states",
+						       1, &usb_switch->host))
+				return -EINVAL;
+		}
+	}
+
 	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 18cb8e46262d..9fd23ecc2da3 100644
--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -25,6 +25,7 @@
 #include <linux/usb/hcd.h>
 #include <linux/usb/chipidea.h>
 #include <linux/regulator/consumer.h>
+#include <linux/mux/consumer.h>
 
 #include "../host/ehci.h"
 
@@ -123,6 +124,13 @@ static int host_start(struct ci_hdrc *ci)
 	if (usb_disabled())
 		return -ENODEV;
 
+	if (!IS_ERR(ci->platdata->usb_switch.mux)) {
+		ret = mux_control_select(ci->platdata->usb_switch.mux,
+					 ci->platdata->usb_switch.host);
+		if (ret)
+			return ret;
+	}
+
 	hcd = __usb_create_hcd(&ci_ehci_hc_driver, ci->dev->parent,
 			       ci->dev, dev_name(ci->dev), NULL);
 	if (!hcd)
@@ -205,6 +213,8 @@ static void host_stop(struct ci_hdrc *ci)
 		if (ci->platdata->reg_vbus && !ci_otg_is_fsm_mode(ci) &&
 			(ci->platdata->flags & CI_HDRC_TURN_VBUS_EARLY_ON))
 				regulator_disable(ci->platdata->reg_vbus);
+		if (!IS_ERR(ci->platdata->usb_switch.mux))
+			mux_control_deselect(ci->platdata->usb_switch.mux);
 	}
 	ci->hcd = NULL;
 	ci->otg.host = NULL;
diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index d68b125796f9..ab3355905740 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -22,6 +22,7 @@
 #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"
@@ -1899,6 +1900,13 @@ static int udc_start(struct ci_hdrc *ci)
 	ci->gadget.name         = ci->platdata->name;
 	ci->gadget.otg_caps	= otg_caps;
 
+	if (!IS_ERR(ci->platdata->usb_switch.mux)) {
+		retval = mux_control_select(ci->platdata->usb_switch.mux,
+					    ci->platdata->usb_switch.device);
+		if (retval)
+			return retval;
+	}
+
 	if (ci->is_otg && (otg_caps->hnp_support || otg_caps->srp_support ||
 						otg_caps->adp_support))
 		ci->gadget.is_otg = 1;
@@ -1982,6 +1990,9 @@ static void udc_id_switch_for_host(struct ci_hdrc *ci)
 		hw_write_otgsc(ci, OTGSC_BSVIE | OTGSC_BSVIS, OTGSC_BSVIS);
 
 	ci->vbus_active = 0;
+
+	if (!IS_ERR(ci->platdata->usb_switch.mux))
+		mux_control_deselect(ci->platdata->usb_switch.mux);
 }
 
 /**
diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h
index c5fdfcf99828..559bd470b8c0 100644
--- a/include/linux/usb/chipidea.h
+++ b/include/linux/usb/chipidea.h
@@ -9,6 +9,7 @@
 #include <linux/usb/otg.h>
 
 struct ci_hdrc;
+struct mux_control;
 
 /**
  * struct ci_hdrc_cable - structure for external connector cable state tracking
@@ -29,6 +30,18 @@ struct ci_hdrc_cable {
 	struct notifier_block		nb;
 };
 
+/**
+ * struct ci_hdrc_switch - structure for usb mux control
+ * @mux: mux to set @host state or @device state on during role switch
+ * @host: Value to set for mux to connect D+/D- to host D+/D- lines
+ * @device: Value to set for mux to connect D+/D- to device D+/D- lines
+ */
+struct ci_hdrc_switch {
+	struct mux_control		*mux;
+	int				host;
+	int				device;
+};
+
 struct ci_hdrc_platform_data {
 	const char	*name;
 	/* offset of the capability registers */
@@ -74,6 +87,7 @@ 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 ci_hdrc_switch		usb_switch;
 	u32			phy_clkgate_delay_us;
 };
 
-- 
2.10.0.297.gf6727b0