phy: sun4i-usb: Introduce port2 SIDDQ quirk

[ Upstream commit b45c6d8 ]

At least the Allwinner H616 SoC requires a weird quirk to make most
USB PHYs work: Only port2 works out of the box, but all other ports
need some help from this port2 to work correctly: The CLK_BUS_PHY2 and
RST_USB_PHY2 clock and reset need to be enabled, and the SIDDQ bit in
the PMU PHY control register needs to be cleared. For this register to
be accessible, CLK_BUS_ECHI2 needs to be ungated. Don't ask ....

Instead of disguising this as some generic feature, treat it more like
a quirk (what it really is):
If the quirk bit is set, and we initialise a PHY other than PHY2, ungate
this one special clock, and clear the SIDDQ bit. We also pick the clock
and reset from PHY2 and enable them as well.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20221031111358.3387297-4-andre.przywara@arm.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/phy/allwinner/phy-sun4i-usb.c

@@ -120,6 +120,7 @@ struct sun4i_usb_phy_cfg {
 	u8 phyctl_offset;
 	bool dedicated_clocks;
 	bool phy0_dual_route;
+	bool needs_phy2_siddq;
 	int missing_phys;
 };
 
@@ -289,6 +290,50 @@ static int sun4i_usb_phy_init(struct phy *_phy)
 		return ret;
 	}
 
+	/* Some PHYs on some SoCs need the help of PHY2 to work. */
+	if (data->cfg->needs_phy2_siddq && phy->index != 2) {
+		struct sun4i_usb_phy *phy2 = &data->phys[2];
+
+		ret = clk_prepare_enable(phy2->clk);
+		if (ret) {
+			reset_control_assert(phy->reset);
+			clk_disable_unprepare(phy->clk2);
+			clk_disable_unprepare(phy->clk);
+			return ret;
+		}
+
+		ret = reset_control_deassert(phy2->reset);
+		if (ret) {
+			clk_disable_unprepare(phy2->clk);
+			reset_control_assert(phy->reset);
+			clk_disable_unprepare(phy->clk2);
+			clk_disable_unprepare(phy->clk);
+			return ret;
+		}
+
+		/*
+		 * This extra clock is just needed to access the
+		 * REG_HCI_PHY_CTL PMU register for PHY2.
+		 */
+		ret = clk_prepare_enable(phy2->clk2);
+		if (ret) {
+			reset_control_assert(phy2->reset);
+			clk_disable_unprepare(phy2->clk);
+			reset_control_assert(phy->reset);
+			clk_disable_unprepare(phy->clk2);
+			clk_disable_unprepare(phy->clk);
+			return ret;
+		}
+
+		if (phy2->pmu && data->cfg->hci_phy_ctl_clear) {
+			val = readl(phy2->pmu + REG_HCI_PHY_CTL);
+			val &= ~data->cfg->hci_phy_ctl_clear;
+			writel(val, phy2->pmu + REG_HCI_PHY_CTL);
+		}
+
+		clk_disable_unprepare(phy->clk2);
+	}
+
 	if (phy->pmu && data->cfg->hci_phy_ctl_clear) {
 		val = readl(phy->pmu + REG_HCI_PHY_CTL);
 		val &= ~data->cfg->hci_phy_ctl_clear;
@@ -354,6 +399,13 @@ static int sun4i_usb_phy_exit(struct phy *_phy)
 		data->phy0_init = false;
 	}
 
+	if (data->cfg->needs_phy2_siddq && phy->index != 2) {
+		struct sun4i_usb_phy *phy2 = &data->phys[2];
+
+		clk_disable_unprepare(phy2->clk);
+		reset_control_assert(phy2->reset);
+	}
+
 	sun4i_usb_phy_passby(phy, 0);
 	reset_control_assert(phy->reset);
 	clk_disable_unprepare(phy->clk2);
@@ -785,6 +837,13 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev)
 				dev_err(dev, "failed to get clock %s\n", name);
 				return PTR_ERR(phy->clk2);
 			}
+		} else {
+			snprintf(name, sizeof(name), "pmu%d_clk", i);
+			phy->clk2 = devm_clk_get_optional(dev, name);
+			if (IS_ERR(phy->clk2)) {
+				dev_err(dev, "failed to get clock %s\n", name);
+				return PTR_ERR(phy->clk2);
+			}
 		}
 
 		snprintf(name, sizeof(name), "usb%d_reset", i);