[PATCH v7 0/2] Fine tune USB 3.0 PHY on exynos5420

From: Vivek Gautam
Date: Fri Oct 31 2014 - 09:26:48 EST


This series is tested with V3 of Heikki's patches for simpliefied phy lookup table:
[PATCHv3 0/6] phy: simplified phy lookup [1] on 'usb-next' branch.
V4 of this series is giving some issue, which i have already pointed out in the
patch: [PATCHv4 2/6] phy: improved lookup method

Changes since v6:
- Dropped the changes for adding additional phy_calibrate() callback.
- Added phy_init() and phy_power_on() sequence in xhci-plat driver;
NOTE: both phy_init() and phy_power_on() will now require PHY's
'init_count' and 'power_count' to be reset to '0' so that
we can actually re-initialize the phy. Though this has already been
pointed out in discussion for the previous patch-series. [2]
- Refactored return codes and error handling in cr_port functions as pointed
out by Felipe.

Changes since v5:
- Assigned NULL to hcd->gen_phy in error path in xhci-plat.c, so that
we don't need to check for IS_ERR() while calibrating the PHYs in
core/hcd.c
- Removed extra empty lines in register definitions in exynos5-usbdrd
phy driver.
- Added write access for EXYNOS5_DRD_PHYREG0 register before any
crport_handshake() call as suggested by Jingoo Han.
- Renamed member 'calibrate' to 'phy_exynos_calibrate' of
struct exynos5_usbdrd_phy_drvdata.

Changes since v4:
- Rebased on latest patches by Heikki.
- Took care of handling -EPROBE_DEFER error number while getting PHY in
xhci plat.

Changes from v3:
- Modified error message as per review comments from Julius.

Changes since v2:
- Removed any check for DWC3 in xhci-plat for getting usb2-phy and usb3-phy,
in order to make it more generic.
- Moved the phy_calibration calls to core/hcd.c to enable a more generic
solution for issues of calibrating the PHYs.

Changes since v1:
- Using 'gen_phy' member of 'hcd' instead of declaring more variables
to hold phys.
- Added a check for compatible match for 'Synopsys-dwc3' controller,
since the 'gen_phy' member of 'hcd' already gets the 'usb' PHY
in core/hcd.c; but XHCI on Synopsys-dwc3 doesn't need that,
instead two separate PHYs for UTMI+ and PIPE3 for the two HCDs
(main hcd and shared hcd).
- Restructured the code in 'xhci_plat_setup()' and 'xhci_plat_resume()'
to use hcd->gen_phy directly. Also added the check for Synopsys's DWC3
controller while trying to calibrate the PHY.

Explanation for the need of this patch-series:
"The DWC3-exynos eXtensible host controller present on Exynos5420/5800
SoCs is quirky. The PHY serving this controller operates at High-Speed
by default, so it detects even Super-speed devices as high-speed ones.
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."

[1] https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg710094.html
[2] https://lkml.org/lkml/2014/9/2/170; (to be specific https://lkml.org/lkml/2014/9/10/132)

Vivek Gautam (2):
usb: host: xhci-plat: Get PHYs for xhci's hcds
phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800

drivers/phy/phy-exynos5-usbdrd.c | 219 +++++++++++++++++++++++++++++++++++---
drivers/usb/host/xhci-plat.c | 74 +++++++++++++
2 files changed, 277 insertions(+), 16 deletions(-)

--
1.7.10.4

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