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From:   Marek Szyprowski <m.szyprowski@samsung.com>
To:     linux-usb@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Felipe Balbi <balbi@kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Jochen Sprickerhof <jochen@sprickerhof.de>,
        Anand Moon <linux.amoon@gmail.com>
Subject: [PATCH v2 1/2 RESEND] usb: core: phy: add support for PHY
 calibration
Date:   Thu, 29 Aug 2019 07:30:27 +0200
Message-Id: <20190829053028.32438-2-m.szyprowski@samsung.com>
In-Reply-To: <20190829053028.32438-1-m.szyprowski@samsung.com>
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <20190829053028.32438-1-m.szyprowski@samsung.com>
        <CGME20190829053048eucas1p1f6549a72d7374812b2aa3cf93862794e@eucas1p1.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Some PHYs (for example Exynos5 USB3.0 DRD PHY) require calibration to be
done after every USB HCD reset. Generic PHY framework has been already
extended with phy_calibrate() function in commit 36914111e682 ("drivers:
phy: add calibrate method"). This patch adds support for it to generic
PHY handling code in USB HCD core.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Tested-by: Jochen Sprickerhof <jochen@sprickerhof.de>
---
 drivers/usb/core/hcd.c |  7 +++++++
 drivers/usb/core/phy.c | 21 +++++++++++++++++++++
 drivers/usb/core/phy.h |  1 +
 3 files changed, 29 insertions(+)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 88533938ce19..b89936c1df23 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2291,6 +2291,9 @@ int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
 	hcd->state = HC_STATE_RESUMING;
 	status = hcd->driver->bus_resume(hcd);
 	clear_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
+	if (status == 0)
+		status = usb_phy_roothub_calibrate(hcd->phy_roothub);
+
 	if (status == 0) {
 		struct usb_device *udev;
 		int port1;
@@ -2864,6 +2867,10 @@ int usb_add_hcd(struct usb_hcd *hcd,
 	}
 	hcd->rh_pollable = 1;
 
+	retval = usb_phy_roothub_calibrate(hcd->phy_roothub);
+	if (retval)
+		goto err_hcd_driver_setup;
+
 	/* NOTE: root hub and controller capabilities may not be the same */
 	if (device_can_wakeup(hcd->self.controller)
 			&& device_can_wakeup(&hcd->self.root_hub->dev))
diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c
index 7580493b867a..fb1588e7c282 100644
--- a/drivers/usb/core/phy.c
+++ b/drivers/usb/core/phy.c
@@ -151,6 +151,27 @@ int usb_phy_roothub_set_mode(struct usb_phy_roothub *phy_roothub,
 }
 EXPORT_SYMBOL_GPL(usb_phy_roothub_set_mode);
 
+int usb_phy_roothub_calibrate(struct usb_phy_roothub *phy_roothub)
+{
+	struct usb_phy_roothub *roothub_entry;
+	struct list_head *head;
+	int err;
+
+	if (!phy_roothub)
+		return 0;
+
+	head = &phy_roothub->list;
+
+	list_for_each_entry(roothub_entry, head, list) {
+		err = phy_calibrate(roothub_entry->phy);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_phy_roothub_calibrate);
+
 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub)
 {
 	struct usb_phy_roothub *roothub_entry;
diff --git a/drivers/usb/core/phy.h b/drivers/usb/core/phy.h
index dad564e2d2d4..20a267cd986b 100644
--- a/drivers/usb/core/phy.h
+++ b/drivers/usb/core/phy.h
@@ -18,6 +18,7 @@ int usb_phy_roothub_exit(struct usb_phy_roothub *phy_roothub);
 
 int usb_phy_roothub_set_mode(struct usb_phy_roothub *phy_roothub,
 			     enum phy_mode mode);
+int usb_phy_roothub_calibrate(struct usb_phy_roothub *phy_roothub);
 int usb_phy_roothub_power_on(struct usb_phy_roothub *phy_roothub);
 void usb_phy_roothub_power_off(struct usb_phy_roothub *phy_roothub);
 
-- 
2.17.1