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    SubjectRe: [PATCH v3 15/15] xhci: tegra: Enable ELPG for runtime/system PM
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    I will amend accordingly and submit new patch.

    Thanks for review.
    JC

    On 9/28/20 10:06 PM, Thierry Reding wrote:
    > On Wed, Sep 09, 2020 at 04:10:41PM +0800, JC Kuo wrote:
    >> This commit implements the complete programming sequence for ELPG
    >> entry and exit.
    >>
    >> 1. At ELPG entry, invokes tegra_xusb_padctl_enable_phy_sleepwalk()
    >> and tegra_xusb_padctl_enable_phy_wake() to configure XUSB PADCTL
    >> sleepwalk and wake detection circuits to maintain USB lines level
    >> and respond to wake events (wake-on-connect, wake-on-disconnect,
    >> device-initiated-wake).
    >>
    >> 2. At ELPG exit, invokes tegra_xusb_padctl_disable_phy_sleepwalk()
    >> and tegra_xusb_padctl_disable_phy_wake() to disarm sleepwalk and
    >> wake detection circuits.
    >>
    >> At runtime suspend, XUSB host controller can enter ELPG to reduce
    >> power consumption. When XUSB PADCTL wake detection circuit detects
    >> a wake event, an interrupt will be raised. xhci-tegra driver then
    >> will invoke pm_runtime_resume() for xhci-tegra.
    >>
    >> Runtime resume could also be triggered by protocol drivers, this is
    >> the host-initiated-wake event. At runtime resume, xhci-tegra driver
    >> brings XUSB host controller out of ELPG to handle the wake events.
    >>
    >> The same ELPG enter/exit procedure will be performed for system
    >> suspend/resume path so USB devices can remain connected across SC7.
    >>
    >> Signed-off-by: JC Kuo <jckuo@nvidia.com>
    >> ---
    >> v3:
    >> use 'unsigned int' for PHY index
    >> remove unnecessary 'else'
    >> drop IRQF_TRIGGER_HIGH when invokes devm_request_threaded_irq()
    >>
    >> drivers/usb/host/xhci-tegra.c | 389 +++++++++++++++++++++++++++++++---
    >> 1 file changed, 360 insertions(+), 29 deletions(-)
    >>
    >> diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
    >> index aabff8ee0bb3..ba3f40e78171 100644
    >> --- a/drivers/usb/host/xhci-tegra.c
    >> +++ b/drivers/usb/host/xhci-tegra.c
    >> @@ -15,9 +15,11 @@
    >> #include <linux/kernel.h>
    >> #include <linux/module.h>
    >> #include <linux/of_device.h>
    >> +#include <linux/of_irq.h>
    >> #include <linux/phy/phy.h>
    >> #include <linux/phy/tegra/xusb.h>
    >> #include <linux/platform_device.h>
    >> +#include <linux/usb/ch9.h>
    >> #include <linux/pm.h>
    >> #include <linux/pm_domain.h>
    >> #include <linux/pm_runtime.h>
    >> @@ -224,6 +226,7 @@ struct tegra_xusb {
    >>
    >> int xhci_irq;
    >> int mbox_irq;
    >> + int padctl_irq;
    >>
    >> void __iomem *ipfs_base;
    >> void __iomem *fpci_base;
    >> @@ -269,10 +272,13 @@ struct tegra_xusb {
    >> dma_addr_t phys;
    >> } fw;
    >>
    >> + bool suspended;
    >> struct tegra_xusb_context context;
    >> };
    >>
    >> static struct hc_driver __read_mostly tegra_xhci_hc_driver;
    >> +static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool runtime);
    >> +static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool runtime);
    >
    > Can we reshuffle the code to avoid these predeclarations? Looks like
    > they're only used in tegra_xusb_runtime_{suspend,resume}(), so perhaps
    > move the implementations right before those?
    >
    > Thierry
    >

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