Thread (34 messages) 34 messages, 3 authors, 2020-01-29

Re: [Patch V3 07/18] phy: tegra: xusb: Add set_mode support for utmi phy on Tegra186

From: Thierry Reding <hidden>
Date: 2020-01-28 17:45:13
Also in: linux-tegra, linux-usb, lkml

On Mon, Dec 30, 2019 at 04:39:44PM +0530, Nagarjuna Kristam wrote:
Add support for set_mode on utmi phy. This allow XUSB host/device mode
drivers to configure the hardware to corresponding modes.
"utmi" -> "UTMI" in the subject and the commit message.
quoted hunk ↗ jump to hunk
Signed-off-by: Nagarjuna Kristam <redacted>
---
V2-V3:
 - No changes in this version
---
 drivers/phy/tegra/xusb-tegra186.c | 109 ++++++++++++++++++++++++++++++--------
 1 file changed, 87 insertions(+), 22 deletions(-)
diff --git a/drivers/phy/tegra/xusb-tegra186.c b/drivers/phy/tegra/xusb-tegra186.c
index 84c2739..9a45160 100644
--- a/drivers/phy/tegra/xusb-tegra186.c
+++ b/drivers/phy/tegra/xusb-tegra186.c
@@ -301,6 +301,92 @@ static void tegra_phy_xusb_utmi_pad_power_down(struct phy *phy)
 	tegra186_utmi_bias_pad_power_off(padctl);
 }
 
+static int tegra186_xusb_padctl_vbus_override(struct tegra_xusb_padctl *padctl,
+					       bool status)
+{
+	u32 value;
+
+	dev_dbg(padctl->dev, "%s vbus override\n", status ? "set" : "clear");
+
+	value = padctl_readl(padctl, USB2_VBUS_ID);
+
+	if (status) {
+		value |= VBUS_OVERRIDE;
+		value &= ~ID_OVERRIDE(~0);
+		value |= ID_OVERRIDE_FLOATING;
+	} else {
+		value &= ~VBUS_OVERRIDE;
+	}
+
+	padctl_writel(padctl, value, USB2_VBUS_ID);
+
+	return 0;
+}
+
+static int tegra186_xusb_padctl_id_override(struct tegra_xusb_padctl *padctl,
+					    bool status)
+{
+	u32 value;
+
+	dev_dbg(padctl->dev, "%s id override\n", status ? "set" : "clear");
+
+	value = padctl_readl(padctl, USB2_VBUS_ID);
+
+	if (status) {
+		if (value & VBUS_OVERRIDE) {
+			value &= ~VBUS_OVERRIDE;
+			padctl_writel(padctl, value, USB2_VBUS_ID);
+			usleep_range(1000, 2000);
+
+			value = padctl_readl(padctl, USB2_VBUS_ID);
+		}
+
+		value &= ~ID_OVERRIDE(~0);
+		value |= ID_OVERRIDE_GROUNDED;
+	} else {
+		value &= ~ID_OVERRIDE(~0);
+		value |= ID_OVERRIDE_FLOATING;
+	}
+
+	padctl_writel(padctl, value, USB2_VBUS_ID);
+
+	return 0;
+}
+
+static int tegra186_utmi_phy_set_mode(struct phy *phy, enum phy_mode mode,
+				      int submode)
+{
+	struct tegra_xusb_lane *lane = phy_get_drvdata(phy);
+	struct tegra_xusb_padctl *padctl = lane->pad->padctl;
+	struct tegra_xusb_usb2_port *port = tegra_xusb_find_usb2_port(padctl,
+								lane->index);
+	int err = 0;
+
+	mutex_lock(&padctl->lock);
+
+	dev_dbg(&port->base.dev, "%s: mode %d", __func__, mode);
+
+	if (mode == PHY_MODE_USB_OTG) {
+		if (submode == USB_ROLE_HOST) {
+			tegra186_xusb_padctl_id_override(padctl, true);
+
+			err = regulator_enable(port->supply);
+		} else if (submode == USB_ROLE_DEVICE) {
+			tegra186_xusb_padctl_vbus_override(padctl, true);
+		} else if (submode == USB_ROLE_NONE) {
+			if (regulator_is_enabled(port->supply))
I vaguely recall that we discussed this before, but I don't recall. Why
do we need to check that the regulator is enabled? Regulators are
reference-counted, so as long as the reference count is balanced, there
should be no need to check for this.

If there's really no way to avoid this check, perhaps add a comment that
points out exactly why this is needed?

With that fixed:

Acked-by: Thierry Reding <redacted>

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