linux-kernel - [PATCH v6 12/17] phy: sun4i-usb: Introduce port2 SIDDQ quirk

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Date:   Wed, 19 May 2021 11:41:47 +0100
From:   Andre Przywara <andre.przywara@....com>
To:     Maxime Ripard <mripard@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>
Cc:     Rob Herring <robh@...nel.org>, Icenowy Zheng <icenowy@...c.io>,
        Samuel Holland <samuel@...lland.org>,
        Ondrej Jirman <megous@...ous.com>,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...glegroups.com,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>, linux-phy@...ts.infradead.org,
        linux-usb@...r.kernel.org
Subject: [PATCH v6 12/17] phy: sun4i-usb: Introduce port2 SIDDQ quirk

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, do exactly that
in our PHY init:
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 can pull in the
other required clocks via the DT.

Signed-off-by: Andre Przywara <andre.przywara@....com>
---
 drivers/phy/allwinner/phy-sun4i-usb.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/phy/allwinner/phy-sun4i-usb.c b/drivers/phy/allwinner/phy-sun4i-usb.c
index 126ef74d013c..ed7b9cc5a424 100644
--- a/drivers/phy/allwinner/phy-sun4i-usb.c
+++ b/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;
 };
 
@@ -331,6 +332,27 @@ static int sun4i_usb_phy_init(struct phy *_phy)
 		queue_delayed_work(system_wq, &data->detect, 0);
 	}
 
+	/* 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];
+
+		/*
+		 * 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)
+			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);
+	}
+
 	return 0;
 }
 
@@ -785,6 +807,13 @@ 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);
-- 
2.17.5