phy: add a driver for the Rockchip SoC internal PCIe PHY

This patch to add a generic PHY driver for rockchip PCIe PHY.
Access the PHY via registers provided by GRF (general register
files) module.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

3 files changed, 366 insertions, 0 deletions

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index f9bf9817e63f..46e5536c453e 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -388,6 +388,14 @@ config PHY_ROCKCHIP_DP
         help
           Enable this to support the Rockchip Display Port PHY.
 
+config PHY_ROCKCHIP_PCIE
+        tristate "Rockchip PCIe PHY Driver"
+        depends on (ARCH_ROCKCHIP && OF) || COMPILE_TEST
+        select GENERIC_PHY
+        select MFD_SYSCON
+        help
+          Enable this to support the Rockchip PCIe PHY.
+
 config PHY_ST_SPEAR1310_MIPHY
         tristate "ST SPEAR1310-MIPHY driver"
         select GENERIC_PHY
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 74b44ef5f0a5..ce0e526059dd 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
 obj-$(CONFIG_PHY_ROCKCHIP_USB) += phy-rockchip-usb.o
 obj-$(CONFIG_PHY_ROCKCHIP_INNO_USB2)    += phy-rockchip-inno-usb2.o
 obj-$(CONFIG_PHY_ROCKCHIP_EMMC) += phy-rockchip-emmc.o
+obj-$(CONFIG_PHY_ROCKCHIP_PCIE) += phy-rockchip-pcie.o
 obj-$(CONFIG_PHY_ROCKCHIP_DP)           += phy-rockchip-dp.o
 obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA)     += phy-qcom-ipq806x-sata.o
 obj-$(CONFIG_PHY_ST_SPEAR1310_MIPHY)    += phy-spear1310-miphy.o
diff --git a/drivers/phy/phy-rockchip-pcie.c b/drivers/phy/phy-rockchip-pcie.c
new file mode 100644
index 000000000000..a2b4c6b58aea
--- /dev/null
+++ b/drivers/phy/phy-rockchip-pcie.c
@@ -0,0 +1,357 @@
+/*
+ * Rockchip PCIe PHY driver
+ *
+ * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
+ * Copyright (C) 2016 ROCKCHIP, Inc.
+ *
+ * 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; either version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.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/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+/*
+ * The higher 16-bit of this register is used for write protection
+ * only if BIT(x + 16) set to 1 the BIT(x) can be written.
+ */
+#define HIWORD_UPDATE(val, mask, shift) \
+                ((val) << (shift) | (mask) << ((shift) + 16))
+
+#define PHY_MAX_LANE_NUM      4
+#define PHY_CFG_DATA_SHIFT    7
+#define PHY_CFG_ADDR_SHIFT    1
+#define PHY_CFG_DATA_MASK     0xf
+#define PHY_CFG_ADDR_MASK     0x3f
+#define PHY_CFG_RD_MASK       0x3ff
+#define PHY_CFG_WR_ENABLE     1
+#define PHY_CFG_WR_DISABLE    1
+#define PHY_CFG_WR_SHIFT      0
+#define PHY_CFG_WR_MASK       1
+#define PHY_CFG_PLL_LOCK      0x10
+#define PHY_CFG_CLK_TEST      0x10
+#define PHY_CFG_CLK_SCC       0x12
+#define PHY_CFG_SEPE_RATE     BIT(3)
+#define PHY_CFG_PLL_100M      BIT(3)
+#define PHY_PLL_LOCKED        BIT(9)
+#define PHY_PLL_OUTPUT        BIT(10)
+#define PHY_LANE_A_STATUS     0x30
+#define PHY_LANE_B_STATUS     0x31
+#define PHY_LANE_C_STATUS     0x32
+#define PHY_LANE_D_STATUS     0x33
+#define PHY_LANE_RX_DET_SHIFT 11
+#define PHY_LANE_RX_DET_TH    0x1
+#define PHY_LANE_IDLE_OFF     0x1
+#define PHY_LANE_IDLE_MASK    0x1
+#define PHY_LANE_IDLE_A_SHIFT 3
+#define PHY_LANE_IDLE_B_SHIFT 4
+#define PHY_LANE_IDLE_C_SHIFT 5
+#define PHY_LANE_IDLE_D_SHIFT 6
+
+struct rockchip_pcie_data {
+        unsigned int pcie_conf;
+        unsigned int pcie_status;
+        unsigned int pcie_laneoff;
+};
+
+struct rockchip_pcie_phy {
+        struct rockchip_pcie_data *phy_data;
+        struct regmap *reg_base;
+        struct reset_control *phy_rst;
+        struct clk *clk_pciephy_ref;
+};
+
+static inline void phy_wr_cfg(struct rockchip_pcie_phy *rk_phy,
+                              u32 addr, u32 data)
+{
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(data,
+                                   PHY_CFG_DATA_MASK,
+                                   PHY_CFG_DATA_SHIFT) |
+                     HIWORD_UPDATE(addr,
+                                   PHY_CFG_ADDR_MASK,
+                                   PHY_CFG_ADDR_SHIFT));
+        udelay(1);
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(PHY_CFG_WR_ENABLE,
+                                   PHY_CFG_WR_MASK,
+                                   PHY_CFG_WR_SHIFT));
+        udelay(1);
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(PHY_CFG_WR_DISABLE,
+                                   PHY_CFG_WR_MASK,
+                                   PHY_CFG_WR_SHIFT));
+}
+
+static inline u32 phy_rd_cfg(struct rockchip_pcie_phy *rk_phy,
+                             u32 addr)
+{
+        u32 val;
+
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(addr,
+                                   PHY_CFG_RD_MASK,
+                                   PHY_CFG_ADDR_SHIFT));
+        regmap_read(rk_phy->reg_base,
+                    rk_phy->phy_data->pcie_status,
+                    &val);
+        return val;
+}
+
+static int rockchip_pcie_phy_power_off(struct phy *phy)
+{
+        struct rockchip_pcie_phy *rk_phy = phy_get_drvdata(phy);
+        int err = 0;
+
+        err = reset_control_assert(rk_phy->phy_rst);
+        if (err) {
+                dev_err(&phy->dev, "assert phy_rst err %d\n", err);
+                return err;
+        }
+
+        return 0;
+}
+
+static int rockchip_pcie_phy_power_on(struct phy *phy)
+{
+        struct rockchip_pcie_phy *rk_phy = phy_get_drvdata(phy);
+        int err = 0;
+        u32 status;
+        unsigned long timeout;
+
+        err = reset_control_deassert(rk_phy->phy_rst);
+        if (err) {
+                dev_err(&phy->dev, "deassert phy_rst err %d\n", err);
+                return err;
+        }
+
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(PHY_CFG_PLL_LOCK,
+                                   PHY_CFG_ADDR_MASK,
+                                   PHY_CFG_ADDR_SHIFT));
+
+        /*
+         * No documented timeout value for phy operation below,
+         * so we make it large enough here. And we use loop-break
+         * method which should not be harmful.
+         */
+        timeout = jiffies + msecs_to_jiffies(1000);
+
+        err = -EINVAL;
+        while (time_before(jiffies, timeout)) {
+                regmap_read(rk_phy->reg_base,
+                            rk_phy->phy_data->pcie_status,
+                            &status);
+                if (status & PHY_PLL_LOCKED) {
+                        dev_dbg(&phy->dev, "pll locked!\n");
+                        err = 0;
+                        break;
+                }
+                msleep(20);
+        }
+
+        if (err) {
+                dev_err(&phy->dev, "pll lock timeout!\n");
+                goto err_pll_lock;
+        }
+
+        phy_wr_cfg(rk_phy, PHY_CFG_CLK_TEST, PHY_CFG_SEPE_RATE);
+        phy_wr_cfg(rk_phy, PHY_CFG_CLK_SCC, PHY_CFG_PLL_100M);
+
+        err = -ETIMEDOUT;
+        while (time_before(jiffies, timeout)) {
+                regmap_read(rk_phy->reg_base,
+                            rk_phy->phy_data->pcie_status,
+                            &status);
+                if (!(status & PHY_PLL_OUTPUT)) {
+                        dev_dbg(&phy->dev, "pll output enable done!\n");
+                        err = 0;
+                        break;
+                }
+                msleep(20);
+        }
+
+        if (err) {
+                dev_err(&phy->dev, "pll output enable timeout!\n");
+                goto err_pll_lock;
+        }
+
+        regmap_write(rk_phy->reg_base, rk_phy->phy_data->pcie_conf,
+                     HIWORD_UPDATE(PHY_CFG_PLL_LOCK,
+                                   PHY_CFG_ADDR_MASK,
+                                   PHY_CFG_ADDR_SHIFT));
+        err = -EINVAL;
+        while (time_before(jiffies, timeout)) {
+                regmap_read(rk_phy->reg_base,
+                            rk_phy->phy_data->pcie_status,
+                            &status);
+                if (status & PHY_PLL_LOCKED) {
+                        dev_dbg(&phy->dev, "pll relocked!\n");
+                        err = 0;
+                        break;
+                }
+                msleep(20);
+        }
+
+        if (err) {
+                dev_err(&phy->dev, "pll relock timeout!\n");
+                goto err_pll_lock;
+        }
+
+        return 0;
+
+err_pll_lock:
+        reset_control_assert(rk_phy->phy_rst);
+        return err;
+}
+
+static int rockchip_pcie_phy_init(struct phy *phy)
+{
+        struct rockchip_pcie_phy *rk_phy = phy_get_drvdata(phy);
+        int err = 0;
+
+        err = clk_prepare_enable(rk_phy->clk_pciephy_ref);
+        if (err) {
+                dev_err(&phy->dev, "Fail to enable pcie ref clock.\n");
+                goto err_refclk;
+        }
+
+        err = reset_control_assert(rk_phy->phy_rst);
+        if (err) {
+                dev_err(&phy->dev, "assert phy_rst err %d\n", err);
+                goto err_reset;
+        }
+
+        return err;
+
+err_reset:
+        clk_disable_unprepare(rk_phy->clk_pciephy_ref);
+err_refclk:
+        return err;
+}
+
+static int rockchip_pcie_phy_exit(struct phy *phy)
+{
+        struct rockchip_pcie_phy *rk_phy = phy_get_drvdata(phy);
+        int err = 0;
+
+        clk_disable_unprepare(rk_phy->clk_pciephy_ref);
+
+        err = reset_control_deassert(rk_phy->phy_rst);
+        if (err) {
+                dev_err(&phy->dev, "deassert phy_rst err %d\n", err);
+                goto err_reset;
+        }
+
+        return err;
+
+err_reset:
+        clk_prepare_enable(rk_phy->clk_pciephy_ref);
+        return err;
+}
+
+static const struct phy_ops ops = {
+        .init           = rockchip_pcie_phy_init,
+        .exit           = rockchip_pcie_phy_exit,
+        .power_on       = rockchip_pcie_phy_power_on,
+        .power_off      = rockchip_pcie_phy_power_off,
+        .owner          = THIS_MODULE,
+};
+
+static const struct rockchip_pcie_data rk3399_pcie_data = {
+        .pcie_conf = 0xe220,
+        .pcie_status = 0xe2a4,
+        .pcie_laneoff = 0xe214,
+};
+
+static const struct of_device_id rockchip_pcie_phy_dt_ids[] = {
+        {
+                .compatible = "rockchip,rk3399-pcie-phy",
+                .data = &rk3399_pcie_data,
+        },
+        {}
+};
+
+MODULE_DEVICE_TABLE(of, rockchip_pcie_phy_dt_ids);
+
+static int rockchip_pcie_phy_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct rockchip_pcie_phy *rk_phy;
+        struct phy *generic_phy;
+        struct phy_provider *phy_provider;
+        struct regmap *grf;
+        const struct of_device_id *of_id;
+
+        grf = syscon_node_to_regmap(dev->parent->of_node);
+        if (IS_ERR(grf)) {
+                dev_err(dev, "Cannot find GRF syscon\n");
+                return PTR_ERR(grf);
+        }
+
+        rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
+        if (!rk_phy)
+                return -ENOMEM;
+
+        of_id = of_match_device(rockchip_pcie_phy_dt_ids, &pdev->dev);
+        if (!of_id)
+                return -EINVAL;
+
+        rk_phy->phy_data = (struct rockchip_pcie_data *)of_id->data;
+        rk_phy->reg_base = grf;
+
+        rk_phy->phy_rst = devm_reset_control_get(dev, "phy");
+        if (IS_ERR(rk_phy->phy_rst)) {
+                if (PTR_ERR(rk_phy->phy_rst) != -EPROBE_DEFER)
+                        dev_err(dev,
+                                "missing phy property for reset controller\n");
+                return PTR_ERR(rk_phy->phy_rst);
+        }
+
+        rk_phy->clk_pciephy_ref = devm_clk_get(dev, "refclk");
+        if (IS_ERR(rk_phy->clk_pciephy_ref)) {
+                dev_err(dev, "refclk not found.\n");
+                return PTR_ERR(rk_phy->clk_pciephy_ref);
+        }
+
+        generic_phy = devm_phy_create(dev, dev->of_node, &ops);
+        if (IS_ERR(generic_phy)) {
+                dev_err(dev, "failed to create PHY\n");
+                return PTR_ERR(generic_phy);
+        }
+
+        phy_set_drvdata(generic_phy, rk_phy);
+        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+        return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct platform_driver rockchip_pcie_driver = {
+        .probe          = rockchip_pcie_phy_probe,
+        .driver         = {
+                .name   = "rockchip-pcie-phy",
+                .of_match_table = rockchip_pcie_phy_dt_ids,
+        },
+};
+
+module_platform_driver(rockchip_pcie_driver);
+
+MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
+MODULE_DESCRIPTION("Rockchip PCIe PHY driver");
+MODULE_LICENSE("GPL v2");