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From:   Frank Wunderlich <linux@fw-web.de>
To:     linux-rockchip@lists.infradead.org
Cc:     Frank Wunderlich <frank-w@public-files.de>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Vinod Koul <vkoul@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Johan Jonker <jbx6244@gmail.com>,
        Peter Geis <pgwipeout@gmail.com>,
        Michael Riesch <michael.riesch@wolfvision.net>,
        linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-phy@lists.infradead.org
Subject: [RFC/RFT v2 06/11] PCI: rockchip-dwc: add PCIe bifurcation
Date:   Tue, 26 Apr 2022 15:21:34 +0200
Message-Id: <20220426132139.26761-7-linux@fw-web.de>
In-Reply-To: <20220426132139.26761-1-linux@fw-web.de>
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From: Frank Wunderlich <frank-w@public-files.de>

PCIe Lanes can be split to 2 slots with bifurcation.
Add support for this in existing PCIe driver that can be enabled
by new "bifurcation" devicetree property.

Co-developed-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>

---
changes in v2:
- change rockchip,bifurcation to vendor unspecific bifurcation
---
 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index b00832d653ea..79e909df241c 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
+#include <linux/phy/pcie.h>
 
 #include "pcie-designware.h"
 
@@ -58,6 +59,7 @@ struct rockchip_pcie {
 	struct gpio_desc		*rst_gpio;
 	struct regulator                *vpcie3v3;
 	struct irq_domain		*irq_domain;
+	bool				bifurcation;
 };
 
 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
@@ -259,6 +261,12 @@ static int rockchip_pcie_phy_init(struct rockchip_pcie *rockchip)
 		return dev_err_probe(dev, PTR_ERR(rockchip->phy),
 				     "missing PHY\n");
 
+	if (rockchip->bifurcation) {
+		ret = phy_set_mode_ext(rockchip->phy, PHY_MODE_PCIE, PHY_MODE_PCIE_BIFURCATION);
+		if (ret)
+			return ret;
+	}
+
 	ret = phy_init(rockchip->phy);
 	if (ret < 0)
 		return ret;
@@ -319,6 +327,9 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (device_property_read_bool(dev, "bifurcation"))
+		rockchip->bifurcation = true;
+
 	ret = rockchip_pcie_phy_init(rockchip);
 	if (ret)
 		goto disable_regulator;
-- 
2.25.1