[PATCH V3 2/4] phy: phy-exynos-pcie: Add support for Exynos PCIe phy

[Jaehoon Chung]

This patch adds support for Generic PHY framework about Exynos SoCs.
Current Exynos PCIe driver doesn't use the PHY framework.
It's making a difficult to upstream the other Exynos variants because of
different PHY registers.

Move the codes relevant to PHY from Exnyos PCIe driver to PHY Exynos PCIe
driver.

Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
Acked-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Reviewed-by: Jingoo Han <jingoohan1@xxxxxxxxx>
Reviewed-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
---
Changelog on V3:
- Remove the dependency abot PCI_EXYNOS
- Adds a depends on COMPILE_TEST
- Use the readl_poll_timeout() instead of while()
- Fixes const type
- Adds MODULE_DESCRIPTION()/LICENCSE()/AUTHOR()
- Changes commit message

Changelog on V2:
- Not include the codes relevant to pci-exynos.
- Remove the getting child node.

 drivers/phy/Kconfig           |   8 ++
 drivers/phy/Makefile          |   1 +
 drivers/phy/phy-exynos-pcie.c | 285 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 294 insertions(+)
 create mode 100644 drivers/phy/phy-exynos-pcie.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index e8eb7f2..8659f38 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -331,6 +331,14 @@ config PHY_EXYNOS5_USBDRD
 	  This driver provides PHY interface for USB 3.0 DRD controller
 	  present on Exynos5 SoC series.
 
+config PHY_EXYNOS_PCIE
+	bool "Exynos PCIe PHY driver"
+	depends on (ARCH_EXYNOS && OF) || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable PCIe PHY support for Exynos SoC series.
+	  This driver provides PHY interface for Exynos PCIe controller.
+
 config PHY_PISTACHIO_USB
 	tristate "IMG Pistachio USB2.0 PHY driver"
 	depends on MACH_PISTACHIO
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 65eb2f4..081aeb4 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -37,6 +37,7 @@ phy-exynos-usb2-$(CONFIG_PHY_EXYNOS4X12_USB2)	+= phy-exynos4x12-usb2.o
 phy-exynos-usb2-$(CONFIG_PHY_EXYNOS5250_USB2)	+= phy-exynos5250-usb2.o
 phy-exynos-usb2-$(CONFIG_PHY_S5PV210_USB2)	+= phy-s5pv210-usb2.o
 obj-$(CONFIG_PHY_EXYNOS5_USBDRD)	+= phy-exynos5-usbdrd.o
+obj-$(CONFIG_PHY_EXYNOS_PCIE)	+= phy-exynos-pcie.o
 obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
 obj-$(CONFIG_PHY_ROCKCHIP_USB) += phy-rockchip-usb.o
 obj-$(CONFIG_PHY_ROCKCHIP_INNO_USB2)	+= phy-rockchip-inno-usb2.o
diff --git a/drivers/phy/phy-exynos-pcie.c b/drivers/phy/phy-exynos-pcie.c
new file mode 100644
index 0000000..9ec1855
--- /dev/null
+++ b/drivers/phy/phy-exynos-pcie.c
@@ -0,0 +1,285 @@
+/*
+ * Samsung EXYNOS SoC series PCIe PHY driver
+ *
+ * Phy provider for PCIe controller on Exynos SoC series
+ *
+ * Copyright (C) 2016 Samsung Electronics Co., Ltd.
+ * Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+
+/* PCIe Purple registers */
+#define PCIE_PHY_GLOBAL_RESET		0x000
+#define PCIE_PHY_COMMON_RESET		0x004
+#define PCIE_PHY_CMN_REG		0x008
+#define PCIE_PHY_MAC_RESET		0x00c
+#define PCIE_PHY_PLL_LOCKED		0x010
+#define PCIE_PHY_TRSVREG_RESET		0x020
+#define PCIE_PHY_TRSV_RESET		0x024
+
+/* PCIe PHY registers */
+#define PCIE_PHY_IMPEDANCE		0x004
+#define PCIE_PHY_PLL_DIV_0		0x008
+#define PCIE_PHY_PLL_BIAS		0x00c
+#define PCIE_PHY_DCC_FEEDBACK		0x014
+#define PCIE_PHY_PLL_DIV_1		0x05c
+#define PCIE_PHY_COMMON_POWER		0x064
+#define PCIE_PHY_COMMON_PD_CMN		BIT(3)
+#define PCIE_PHY_TRSV0_EMP_LVL		0x084
+#define PCIE_PHY_TRSV0_DRV_LVL		0x088
+#define PCIE_PHY_TRSV0_RXCDR		0x0ac
+#define PCIE_PHY_TRSV0_POWER		0x0c4
+#define PCIE_PHY_TRSV0_PD_TSV		BIT(7)
+#define PCIE_PHY_TRSV0_LVCC		0x0dc
+#define PCIE_PHY_TRSV1_EMP_LVL		0x144
+#define PCIE_PHY_TRSV1_RXCDR		0x16c
+#define PCIE_PHY_TRSV1_POWER		0x184
+#define PCIE_PHY_TRSV1_PD_TSV		BIT(7)
+#define PCIE_PHY_TRSV1_LVCC		0x19c
+#define PCIE_PHY_TRSV2_EMP_LVL		0x204
+#define PCIE_PHY_TRSV2_RXCDR		0x22c
+#define PCIE_PHY_TRSV2_POWER		0x244
+#define PCIE_PHY_TRSV2_PD_TSV		BIT(7)
+#define PCIE_PHY_TRSV2_LVCC		0x25c
+#define PCIE_PHY_TRSV3_EMP_LVL		0x2c4
+#define PCIE_PHY_TRSV3_RXCDR		0x2ec
+#define PCIE_PHY_TRSV3_POWER		0x304
+#define PCIE_PHY_TRSV3_PD_TSV		BIT(7)
+#define PCIE_PHY_TRSV3_LVCC		0x31c
+
+struct exynos_pcie_phy_data {
+	const struct phy_ops	*ops;
+};
+
+/* For Exynos pcie phy */
+struct exynos_pcie_phy {
+	const struct exynos_pcie_phy_data *drv_data;
+	void __iomem *phy_base;
+	void __iomem *blk_base; /* For exynos5440 */
+};
+
+static void exynos_pcie_phy_writel(void __iomem *base, u32 val, u32 offset)
+{
+	writel(val, base + offset);
+}
+
+static u32 exynos_pcie_phy_readl(void __iomem *base, u32 offset)
+{
+	return readl(base + offset);
+}
+
+/* For Exynos5440 specific functions */
+static int exynos5440_pcie_phy_init(struct phy *phy)
+{
+	struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
+
+	/* DCC feedback control off */
+	exynos_pcie_phy_writel(ep->phy_base, 0x29, PCIE_PHY_DCC_FEEDBACK);
+
+	/* set TX/RX impedance */
+	exynos_pcie_phy_writel(ep->phy_base, 0xd5, PCIE_PHY_IMPEDANCE);
+
+	/* set 50Mhz PHY clock */
+	exynos_pcie_phy_writel(ep->phy_base, 0x14, PCIE_PHY_PLL_DIV_0);
+	exynos_pcie_phy_writel(ep->phy_base, 0x12, PCIE_PHY_PLL_DIV_1);
+
+	/* set TX Differential output for lane 0 */
+	exynos_pcie_phy_writel(ep->phy_base, 0x7f, PCIE_PHY_TRSV0_DRV_LVL);
+
+	/* set TX Pre-emphasis Level Control for lane 0 to minimum */
+	exynos_pcie_phy_writel(ep->phy_base, 0x0, PCIE_PHY_TRSV0_EMP_LVL);
+
+	/* set RX clock and data recovery bandwidth */
+	exynos_pcie_phy_writel(ep->phy_base, 0xe7, PCIE_PHY_PLL_BIAS);
+	exynos_pcie_phy_writel(ep->phy_base, 0x82, PCIE_PHY_TRSV0_RXCDR);
+	exynos_pcie_phy_writel(ep->phy_base, 0x82, PCIE_PHY_TRSV1_RXCDR);
+	exynos_pcie_phy_writel(ep->phy_base, 0x82, PCIE_PHY_TRSV2_RXCDR);
+	exynos_pcie_phy_writel(ep->phy_base, 0x82, PCIE_PHY_TRSV3_RXCDR);
+
+	/* change TX Pre-emphasis Level Control for lanes */
+	exynos_pcie_phy_writel(ep->phy_base, 0x39, PCIE_PHY_TRSV0_EMP_LVL);
+	exynos_pcie_phy_writel(ep->phy_base, 0x39, PCIE_PHY_TRSV1_EMP_LVL);
+	exynos_pcie_phy_writel(ep->phy_base, 0x39, PCIE_PHY_TRSV2_EMP_LVL);
+	exynos_pcie_phy_writel(ep->phy_base, 0x39, PCIE_PHY_TRSV3_EMP_LVL);
+
+	/* set LVCC */
+	exynos_pcie_phy_writel(ep->phy_base, 0x20, PCIE_PHY_TRSV0_LVCC);
+	exynos_pcie_phy_writel(ep->phy_base, 0xa0, PCIE_PHY_TRSV1_LVCC);
+	exynos_pcie_phy_writel(ep->phy_base, 0xa0, PCIE_PHY_TRSV2_LVCC);
+	exynos_pcie_phy_writel(ep->phy_base, 0xa0, PCIE_PHY_TRSV3_LVCC);
+
+	/* pulse for common reset */
+	exynos_pcie_phy_writel(ep->blk_base, 1, PCIE_PHY_COMMON_RESET);
+	udelay(500);
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_COMMON_RESET);
+
+	return 0;
+}
+
+static int exynos5440_pcie_phy_power_on(struct phy *phy)
+{
+	struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
+	u32 val;
+
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_COMMON_RESET);
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_CMN_REG);
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_TRSVREG_RESET);
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_TRSV_RESET);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_COMMON_POWER);
+	val &= ~PCIE_PHY_COMMON_PD_CMN;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_COMMON_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV0_POWER);
+	val &= ~PCIE_PHY_TRSV0_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV0_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV1_POWER);
+	val &= ~PCIE_PHY_TRSV1_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV1_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV2_POWER);
+	val &= ~PCIE_PHY_TRSV2_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV2_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV3_POWER);
+	val &= ~PCIE_PHY_TRSV3_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV3_POWER);
+
+	return 0;
+}
+
+static int exynos5440_pcie_phy_power_off(struct phy *phy)
+{
+	struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
+	u32 val;
+
+	if (readl_poll_timeout(ep->phy_base + PCIE_PHY_PLL_LOCKED, val,
+				(val != 0), 1, 500)) {
+		dev_err(&phy->dev, "PLL Locked: 0x%x\n", val);
+		return -ETIMEDOUT;
+	}
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_COMMON_POWER);
+	val |= PCIE_PHY_COMMON_PD_CMN;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_COMMON_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV0_POWER);
+	val |= PCIE_PHY_TRSV0_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV0_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV1_POWER);
+	val |= PCIE_PHY_TRSV1_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV1_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV2_POWER);
+	val |= PCIE_PHY_TRSV2_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV2_POWER);
+
+	val = exynos_pcie_phy_readl(ep->phy_base, PCIE_PHY_TRSV3_POWER);
+	val |= PCIE_PHY_TRSV3_PD_TSV;
+	exynos_pcie_phy_writel(ep->phy_base, val, PCIE_PHY_TRSV3_POWER);
+
+	return 0;
+}
+
+static int exynos5440_pcie_phy_reset(struct phy *phy)
+{
+	struct exynos_pcie_phy *ep = phy_get_drvdata(phy);
+
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_MAC_RESET);
+	exynos_pcie_phy_writel(ep->blk_base, 1, PCIE_PHY_GLOBAL_RESET);
+	exynos_pcie_phy_writel(ep->blk_base, 0, PCIE_PHY_GLOBAL_RESET);
+
+	return 0;
+}
+
+static const struct phy_ops exynos5440_phy_ops = {
+	.init		= exynos5440_pcie_phy_init,
+	.power_on	= exynos5440_pcie_phy_power_on,
+	.power_off	= exynos5440_pcie_phy_power_off,
+	.reset		= exynos5440_pcie_phy_reset,
+	.owner		= THIS_MODULE,
+};
+
+static const struct exynos_pcie_phy_data exynos5440_pcie_phy_data = {
+	.ops		= &exynos5440_phy_ops,
+};
+
+static const struct of_device_id exynos_pcie_phy_match[] = {
+	{
+		.compatible = "samsung,exynos5440-pcie-phy",
+		.data = &exynos5440_pcie_phy_data,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, exynos_pcie_phy_match);
+
+static int exynos_pcie_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct exynos_pcie_phy *exynos_phy;
+	struct phy *generic_phy;
+	struct phy_provider *phy_provider;
+	struct resource *res;
+	const struct exynos_pcie_phy_data *drv_data;
+
+	drv_data = of_device_get_match_data(dev);
+	if (!drv_data)
+		return -ENODEV;
+
+	exynos_phy = devm_kzalloc(dev, sizeof(*exynos_phy), GFP_KERNEL);
+	if (!exynos_phy)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	exynos_phy->phy_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(exynos_phy->phy_base))
+		return PTR_ERR(exynos_phy->phy_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	exynos_phy->blk_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(exynos_phy->phy_base))
+		return PTR_ERR(exynos_phy->phy_base);
+
+	exynos_phy->drv_data = drv_data;
+
+	generic_phy = devm_phy_create(dev, dev->of_node, drv_data->ops);
+	if (IS_ERR(generic_phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(generic_phy);
+	}
+
+	phy_set_drvdata(generic_phy, exynos_phy);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct platform_driver exynos_pcie_phy_driver = {
+	.probe	= exynos_pcie_phy_probe,
+	.driver = {
+		.of_match_table	= exynos_pcie_phy_match,
+		.name		= "exynos_pcie_phy",
+	}
+};
+module_platform_driver(exynos_pcie_phy_driver);
+
+MODULE_DESCRIPTION("Samsung S5P/EXYNOS SoC PCIe PHY driver");
+MODULE_AUTHOR("Jaehoon Chung <jh80.chung@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.10.2