[PATCH v1 2/8] usb: phy: tegra: Support waking up from a low power mode

From: Dmitry Osipenko
Date: Tue Dec 15 2020 - 15:23:32 EST

Support programming of waking up from a low power mode by implementing the
generic set_wakeup() callback of the USB PHY API.

Tested-by: Matt Merhar <mattmerhar@xxxxxxxxxxxxxx>
Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/usb/phy/phy-tegra-usb.c | 79 ++++++++++++++++++++++++++++---
include/linux/usb/tegra_usb_phy.h | 2 +
2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index cee9c9dbb775..ed5f6611b36a 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -45,6 +45,7 @@
#define TEGRA_PORTSC1_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC)

#define USB_SUSP_CTRL 0x400
+#define USB_WAKE_ON_RESUME_EN BIT(2)
#define USB_WAKE_ON_CNNT_EN_DEV BIT(3)
#define USB_WAKE_ON_DISCON_EN_DEV BIT(4)
#define USB_SUSP_CLR BIT(5)
@@ -56,6 +57,9 @@
#define USB_SUSP_SET BIT(14)
#define USB_WAKEUP_DEBOUNCE_COUNT(x) (((x) & 0x7) << 16)

+#define USB_PHY_VBUS_WAKEUP_ID 0x408
+#define VBUS_WAKEUP_WAKEUP_EN BIT(30)
+
#define USB1_LEGACY_CTRL 0x410
#define USB1_NO_LEGACY_MODE BIT(0)
#define USB1_VBUS_SENSE_CTL_MASK (3 << 1)
@@ -334,6 +338,11 @@ static int utmip_pad_power_on(struct tegra_usb_phy *phy)
writel_relaxed(val, base + UTMIP_BIAS_CFG0);
}

+ if (phy->pad_wakeup) {
+ phy->pad_wakeup = false;
+ utmip_pad_count--;
+ }
+
spin_unlock(&utmip_pad_lock);

clk_disable_unprepare(phy->pad_clk);
@@ -359,6 +368,17 @@ static int utmip_pad_power_off(struct tegra_usb_phy *phy)
goto ulock;
}

+ /*
+ * In accordance to TRM, OTG and Bias pad circuits could be turned off
+ * to save power if wake is enabled, but the VBUS-change detection
+ * method is board-specific and these circuits may need to be enabled
+ * to generate wakeup event, hence we will just keep them both enabled.
+ */
+ if (phy->wakeup_enabled) {
+ phy->pad_wakeup = true;
+ utmip_pad_count++;
+ }
+
if (--utmip_pad_count == 0) {
val = readl_relaxed(base + UTMIP_BIAS_CFG0);
val |= UTMIP_OTGPD | UTMIP_BIASPD;
@@ -503,11 +523,19 @@ static int utmi_phy_power_on(struct tegra_usb_phy *phy)
writel_relaxed(val, base + UTMIP_PLL_CFG1);
}

+ val = readl_relaxed(base + USB_SUSP_CTRL);
+ val &= ~USB_WAKE_ON_RESUME_EN;
+ writel_relaxed(val, base + USB_SUSP_CTRL);
+
if (phy->mode == USB_DR_MODE_PERIPHERAL) {
val = readl_relaxed(base + USB_SUSP_CTRL);
val &= ~(USB_WAKE_ON_CNNT_EN_DEV | USB_WAKE_ON_DISCON_EN_DEV);
writel_relaxed(val, base + USB_SUSP_CTRL);

+ val = readl_relaxed(base + USB_PHY_VBUS_WAKEUP_ID);
+ val &= ~VBUS_WAKEUP_WAKEUP_EN;
+ writel_relaxed(val, base + USB_PHY_VBUS_WAKEUP_ID);
+
val = readl_relaxed(base + UTMIP_BAT_CHRG_CFG0);
val &= ~UTMIP_PD_CHRG;
writel_relaxed(val, base + UTMIP_BAT_CHRG_CFG0);
@@ -605,31 +633,51 @@ static int utmi_phy_power_off(struct tegra_usb_phy *phy)

utmi_phy_clk_disable(phy);

- if (phy->mode == USB_DR_MODE_PERIPHERAL) {
- val = readl_relaxed(base + USB_SUSP_CTRL);
- val &= ~USB_WAKEUP_DEBOUNCE_COUNT(~0);
- val |= USB_WAKE_ON_CNNT_EN_DEV | USB_WAKEUP_DEBOUNCE_COUNT(5);
- writel_relaxed(val, base + USB_SUSP_CTRL);
- }
+ /* PHY won't resume if reset is asserted */
+ if (phy->wakeup_enabled)
+ goto chrg_cfg0;

val = readl_relaxed(base + USB_SUSP_CTRL);
val |= UTMIP_RESET;
writel_relaxed(val, base + USB_SUSP_CTRL);

+chrg_cfg0:
val = readl_relaxed(base + UTMIP_BAT_CHRG_CFG0);
val |= UTMIP_PD_CHRG;
writel_relaxed(val, base + UTMIP_BAT_CHRG_CFG0);

+ if (phy->wakeup_enabled)
+ goto xcvr_cfg1;
+
val = readl_relaxed(base + UTMIP_XCVR_CFG0);
val |= UTMIP_FORCE_PD_POWERDOWN | UTMIP_FORCE_PD2_POWERDOWN |
UTMIP_FORCE_PDZI_POWERDOWN;
writel_relaxed(val, base + UTMIP_XCVR_CFG0);

+xcvr_cfg1:
val = readl_relaxed(base + UTMIP_XCVR_CFG1);
val |= UTMIP_FORCE_PDDISC_POWERDOWN | UTMIP_FORCE_PDCHRP_POWERDOWN |
UTMIP_FORCE_PDDR_POWERDOWN;
writel_relaxed(val, base + UTMIP_XCVR_CFG1);

+ if (phy->wakeup_enabled) {
+ val = readl_relaxed(base + USB_SUSP_CTRL);
+ val &= ~USB_WAKEUP_DEBOUNCE_COUNT(~0);
+ val |= USB_WAKEUP_DEBOUNCE_COUNT(5);
+ val |= USB_WAKE_ON_RESUME_EN;
+ writel_relaxed(val, base + USB_SUSP_CTRL);
+
+ /*
+ * Ask VBUS sensor to generate wake event once cable is
+ * connected.
+ */
+ if (phy->mode == USB_DR_MODE_PERIPHERAL) {
+ val = readl_relaxed(base + USB_PHY_VBUS_WAKEUP_ID);
+ val |= VBUS_WAKEUP_WAKEUP_EN;
+ writel_relaxed(val, base + USB_PHY_VBUS_WAKEUP_ID);
+ }
+ }
+
return utmip_pad_power_off(phy);
}

@@ -765,6 +813,15 @@ static int ulpi_phy_power_off(struct tegra_usb_phy *phy)
usleep_range(5000, 6000);
clk_disable_unprepare(phy->clk);

+ /*
+ * Wakeup currently unimplemented for ULPI, thus PHY needs to be
+ * force-resumed.
+ */
+ if (WARN_ON_ONCE(phy->wakeup_enabled)) {
+ ulpi_phy_power_on(phy);
+ return -EOPNOTSUPP;
+ }
+
return 0;
}

@@ -827,6 +884,15 @@ static void tegra_usb_phy_shutdown(struct usb_phy *u_phy)
phy->freq = NULL;
}

+static int tegra_usb_phy_set_wakeup(struct usb_phy *u_phy, bool enable)
+{
+ struct tegra_usb_phy *phy = to_tegra_usb_phy(u_phy);
+
+ phy->wakeup_enabled = enable;
+
+ return 0;
+}
+
static int tegra_usb_phy_set_suspend(struct usb_phy *u_phy, int suspend)
{
struct tegra_usb_phy *phy = to_tegra_usb_phy(u_phy);
@@ -1198,6 +1264,7 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
tegra_phy->u_phy.dev = &pdev->dev;
tegra_phy->u_phy.init = tegra_usb_phy_init;
tegra_phy->u_phy.shutdown = tegra_usb_phy_shutdown;
+ tegra_phy->u_phy.set_wakeup = tegra_usb_phy_set_wakeup;
tegra_phy->u_phy.set_suspend = tegra_usb_phy_set_suspend;

platform_set_drvdata(pdev, tegra_phy);
diff --git a/include/linux/usb/tegra_usb_phy.h b/include/linux/usb/tegra_usb_phy.h
index c29d1b4c9381..fd1c9f6a4e37 100644
--- a/include/linux/usb/tegra_usb_phy.h
+++ b/include/linux/usb/tegra_usb_phy.h
@@ -79,6 +79,8 @@ struct tegra_usb_phy {
bool is_ulpi_phy;
struct gpio_desc *reset_gpio;
struct reset_control *pad_rst;
+ bool wakeup_enabled;
+ bool pad_wakeup;
bool powered_on;
};

--
2.29.2