linux-kernel - [RFC v2 11/13] usb: port: Parse pwrseq phandle from Device Tree

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Date:	Thu, 05 May 2016 14:34:24 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-mmc@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-usb@...r.kernel.org,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Mark Brown <broonie@...nel.org>
Cc:	tjakobi@...h.uni-bielefeld.de, m.szyprowski@...sung.com,
	hverkuil@...all.nl, Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [RFC v2 11/13] usb: port: Parse pwrseq phandle from Device Tree

Parse usb-pwrseq property from Device Tree to get the phandle to pwrseq
device. The pwrseq device will be used by USB hub to cycle the power
before activating ports.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
---
 drivers/usb/core/hub.h  |  3 +++
 drivers/usb/core/port.c | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 34c1a7e22aae..68ca89780d26 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -24,6 +24,8 @@
 #include <linux/usb/hcd.h>
 #include "usb.h"
 
+struct pwrseq;
+
 struct usb_hub {
 	struct device		*intfdev;	/* the "interface" device */
 	struct usb_device	*hdev;
@@ -101,6 +103,7 @@ struct usb_port {
 	struct usb_dev_state *port_owner;
 	struct usb_port *peer;
 	struct dev_pm_qos_request *req;
+	struct pwrseq *pwrseq;
 	enum usb_port_connect_type connect_type;
 	usb_port_location_t location;
 	struct mutex status_lock;
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 14718a9ffcfb..a875bd342452 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -18,6 +18,8 @@
 
 #include <linux/slab.h>
 #include <linux/pm_qos.h>
+#include <linux/pwrseq.h>
+#include <linux/usb/of.h>
 
 #include "hub.h"
 
@@ -532,6 +534,14 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 		return retval;
 	}
 
+	port_dev->dev.of_node = usb_of_get_child_node(hub->hdev->dev.of_node, port1);
+	port_dev->pwrseq = pwrseq_alloc(&port_dev->dev);
+	if (IS_ERR(port_dev->pwrseq)) {
+		device_unregister(&port_dev->dev);
+		/* TODO: what about EPROBE_DEFER? */
+		return PTR_ERR(port_dev->pwrseq);
+	}
+
 	find_and_link_peer(hub, port1);
 
 	/*
@@ -573,8 +583,13 @@ void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 	struct usb_port *port_dev = hub->ports[port1 - 1];
 	struct usb_port *peer;
 
+	pwrseq_power_off(port_dev->pwrseq);
+
 	peer = port_dev->peer;
 	if (peer)
 		unlink_peers(port_dev, peer);
+
+	pwrseq_free(port_dev->pwrseq);
+	port_dev->pwrseq = NULL;
 	device_unregister(&port_dev->dev);
 }
-- 
1.9.1