phy: cygnus: pcie: Add Cygnus PCIe PHY support

This patch adds the PCIe PHY support for the Broadcom PCIe RC interface
on Cygnus

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Arun Parameswaran <aparames@broadcom.com>
Reviewed-by: JD (Jiandong) Zheng <jdzheng@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/Kconfig

@@ -380,4 +380,13 @@ config PHY_BRCMSTB_SATA
 	  Enable this to support the SATA3 PHY on 28nm Broadcom STB SoCs.
 	  Likely useful only with CONFIG_SATA_BRCMSTB enabled.
 
+config PHY_CYGNUS_PCIE
+	tristate "Broadcom Cygnus PCIe PHY driver"
+	depends on OF && (ARCH_BCM_CYGNUS || COMPILE_TEST)
+	select GENERIC_PHY
+	default ARCH_BCM_CYGNUS
+	help
+	  Enable this to support the Broadcom Cygnus PCIe PHY.
+	  If unsure, say N.
+
 endmenu

drivers/phy/Makefile

@@ -47,3 +47,4 @@ obj-$(CONFIG_PHY_QCOM_UFS) 	+= phy-qcom-ufs-qmp-14nm.o
 obj-$(CONFIG_PHY_TUSB1210)		+= phy-tusb1210.o
 obj-$(CONFIG_PHY_BRCMSTB_SATA)		+= phy-brcmstb-sata.o
 obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
+obj-$(CONFIG_PHY_CYGNUS_PCIE)		+= phy-bcm-cygnus-pcie.o

drivers/phy/phy-bcm-cygnus-pcie.c

@@ -0,0 +1,213 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+#define PCIE_CFG_OFFSET         0x00
+#define PCIE1_PHY_IDDQ_SHIFT    10
+#define PCIE0_PHY_IDDQ_SHIFT    2
+
+enum cygnus_pcie_phy_id {
+	CYGNUS_PHY_PCIE0 = 0,
+	CYGNUS_PHY_PCIE1,
+	MAX_NUM_PHYS,
+};
+
+struct cygnus_pcie_phy_core;
+
+/**
+ * struct cygnus_pcie_phy - Cygnus PCIe PHY device
+ * @core: pointer to the Cygnus PCIe PHY core control
+ * @id: internal ID to identify the Cygnus PCIe PHY
+ * @phy: pointer to the kernel PHY device
+ */
+struct cygnus_pcie_phy {
+	struct cygnus_pcie_phy_core *core;
+	enum cygnus_pcie_phy_id id;
+	struct phy *phy;
+};
+
+/**
+ * struct cygnus_pcie_phy_core - Cygnus PCIe PHY core control
+ * @dev: pointer to device
+ * @base: base register
+ * @lock: mutex to protect access to individual PHYs
+ * @phys: pointer to Cygnus PHY device
+ */
+struct cygnus_pcie_phy_core {
+	struct device *dev;
+	void __iomem *base;
+	struct mutex lock;
+	struct cygnus_pcie_phy phys[MAX_NUM_PHYS];
+};
+
+static int cygnus_pcie_power_config(struct cygnus_pcie_phy *phy, bool enable)
+{
+	struct cygnus_pcie_phy_core *core = phy->core;
+	unsigned shift;
+	u32 val;
+
+	mutex_lock(&core->lock);
+
+	switch (phy->id) {
+	case CYGNUS_PHY_PCIE0:
+		shift = PCIE0_PHY_IDDQ_SHIFT;
+		break;
+
+	case CYGNUS_PHY_PCIE1:
+		shift = PCIE1_PHY_IDDQ_SHIFT;
+		break;
+
+	default:
+		mutex_unlock(&core->lock);
+		dev_err(core->dev, "PCIe PHY %d invalid\n", phy->id);
+		return -EINVAL;
+	}
+
+	if (enable) {
+		val = readl(core->base + PCIE_CFG_OFFSET);
+		val &= ~BIT(shift);
+		writel(val, core->base + PCIE_CFG_OFFSET);
+		/*
+		 * Wait 50 ms for the PCIe Serdes to stabilize after the analog
+		 * front end is brought up
+		 */
+		msleep(50);
+	} else {
+		val = readl(core->base + PCIE_CFG_OFFSET);
+		val |= BIT(shift);
+		writel(val, core->base + PCIE_CFG_OFFSET);
+	}
+
+	mutex_unlock(&core->lock);
+	dev_dbg(core->dev, "PCIe PHY %d %s\n", phy->id,
+		enable ? "enabled" : "disabled");
+	return 0;
+}
+
+static int cygnus_pcie_phy_power_on(struct phy *p)
+{
+	struct cygnus_pcie_phy *phy = phy_get_drvdata(p);
+
+	return cygnus_pcie_power_config(phy, true);
+}
+
+static int cygnus_pcie_phy_power_off(struct phy *p)
+{
+	struct cygnus_pcie_phy *phy = phy_get_drvdata(p);
+
+	return cygnus_pcie_power_config(phy, false);
+}
+
+static struct phy_ops cygnus_pcie_phy_ops = {
+	.power_on = cygnus_pcie_phy_power_on,
+	.power_off = cygnus_pcie_phy_power_off,
+	.owner = THIS_MODULE,
+};
+
+static int cygnus_pcie_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node, *child;
+	struct cygnus_pcie_phy_core *core;
+	struct phy_provider *provider;
+	struct resource *res;
+	unsigned cnt = 0;
+
+	if (of_get_child_count(node) == 0) {
+		dev_err(dev, "PHY no child node\n");
+		return -ENODEV;
+	}
+
+	core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
+	if (!core)
+		return -ENOMEM;
+
+	core->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	core->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(core->base))
+		return PTR_ERR(core->base);
+
+	mutex_init(&core->lock);
+
+	for_each_available_child_of_node(node, child) {
+		unsigned int id;
+		struct cygnus_pcie_phy *p;
+
+		if (of_property_read_u32(child, "reg", &id)) {
+			dev_err(dev, "missing reg property for %s\n",
+				child->name);
+			return -EINVAL;
+		}
+
+		if (id >= MAX_NUM_PHYS) {
+			dev_err(dev, "invalid PHY id: %u\n", id);
+			return -EINVAL;
+		}
+
+		if (core->phys[id].phy) {
+			dev_err(dev, "duplicated PHY id: %u\n", id);
+			return -EINVAL;
+		}
+
+		p = &core->phys[id];
+		p->phy = devm_phy_create(dev, child, &cygnus_pcie_phy_ops);
+		if (IS_ERR(p->phy)) {
+			dev_err(dev, "failed to create PHY\n");
+			return PTR_ERR(p->phy);
+		}
+
+		p->core = core;
+		p->id = id;
+		phy_set_drvdata(p->phy, p);
+		cnt++;
+	}
+
+	dev_set_drvdata(dev, core);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider)) {
+		dev_err(dev, "failed to register PHY provider\n");
+		return PTR_ERR(provider);
+	}
+
+	dev_dbg(dev, "registered %u PCIe PHY(s)\n", cnt);
+
+	return 0;
+}
+
+static const struct of_device_id cygnus_pcie_phy_match_table[] = {
+	{ .compatible = "brcm,cygnus-pcie-phy" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, cygnus_pcie_phy_match_table);
+
+static struct platform_driver cygnus_pcie_phy_driver = {
+	.driver = {
+		.name = "cygnus-pcie-phy",
+		.of_match_table = cygnus_pcie_phy_match_table,
+	},
+	.probe = cygnus_pcie_phy_probe,
+};
+module_platform_driver(cygnus_pcie_phy_driver);
+
+MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom Cygnus PCIe PHY driver");
+MODULE_LICENSE("GPL v2");