path: root/drivers/phy
diff options
authorAndrzej Pietrasiewicz <andrzej.p@samsung.com>2017-10-09 14:00:50 +0200
committerKishon Vijay Abraham I <kishon@ti.com>2017-10-23 11:19:28 +0530
commit36914111e6829be36b23d1109214250b5ee1ee9c (patch)
treeef05bb6df6624fdf44ee4d54c30caff9f58c6581 /drivers/phy
parent052553af6a31b459adfdc6fd1eebced75de332fc (diff)
drivers: phy: add calibrate method
Some quirky UDCs (like dwc3 on Exynos) need to have their phys calibrated e.g. for using super speed. This patch adds a new phy_calibrate() method. When the calibration should be used is dependent on actual chip. In case of dwc3 on Exynos the calibration must happen after usb_add_hcd() (while in host mode), because certain phy parameters like Tx LOS levels and boost levels need to be calibrated further post initialization of xHCI controller, to get SuperSpeed operations working. But an hcd must be prepared first in order to pass it to usb_add_hcd(), so, in particular, dwc3 registers must be available first, and in order for the latter to happen the phys must be initialized. This poses a chicken and egg problem if the calibration were to be performed in phy_init(). To break the circular dependency a separate method is added which can be called at a desired moment after phy intialization. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Diffstat (limited to 'drivers/phy')
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index a268f4d6f3e9..b4964b067aec 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -372,6 +372,21 @@ int phy_reset(struct phy *phy)
+int phy_calibrate(struct phy *phy)
+ int ret;
+ if (!phy || !phy->ops->calibrate)
+ return 0;
+ mutex_lock(&phy->mutex);
+ ret = phy->ops->calibrate(phy);
+ mutex_unlock(&phy->mutex);
+ return ret;
* _of_phy_get() - lookup and obtain a reference to a phy by phandle
* @np: device_node for which to get the phy

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