phy: samsung-ufs: add UFS PHY driver for samsung SoC

This patch introduces Samsung UFS PHY driver. This driver
supports to deal with phy calibration and power control
according to UFS host driver's behavior.

[Robot: -Wmissing-prototypes and -Wsometimes-uninitialized]
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Kiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: Seungwon Jeon <essuuj@gmail.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Tested-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Link: https://lore.kernel.org/r/20200716192217.35740-2-alim.akhtar@samsung.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 366 insertions, 0 deletions

diff --git a/drivers/phy/samsung/phy-samsung-ufs.c b/drivers/phy/samsung/phy-samsung-ufs.c
new file mode 100644
index 000000000000..43ef77d1d96c
--- /dev/null
+++ b/drivers/phy/samsung/phy-samsung-ufs.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * UFS PHY driver for Samsung SoC
+ *
+ * Copyright (C) 2020 Samsung Electronics Co., Ltd.
+ * Author: Seungwon Jeon <essuuj@gmail.com>
+ * Author: Alim Akhtar <alim.akhtar@samsung.com>
+ *
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "phy-samsung-ufs.h"
+
+#define for_each_phy_lane(phy, i) \
+	for (i = 0; i < (phy)->lane_cnt; i++)
+#define for_each_phy_cfg(cfg) \
+	for (; (cfg)->id; (cfg)++)
+
+#define PHY_DEF_LANE_CNT	1
+
+static void samsung_ufs_phy_config(struct samsung_ufs_phy *phy,
+				   const struct samsung_ufs_phy_cfg *cfg,
+				   u8 lane)
+{
+	enum {LANE_0, LANE_1}; /* lane index */
+
+	switch (lane) {
+	case LANE_0:
+		writel(cfg->val, (phy)->reg_pma + cfg->off_0);
+		break;
+	case LANE_1:
+		if (cfg->id == PHY_TRSV_BLK)
+			writel(cfg->val, (phy)->reg_pma + cfg->off_1);
+		break;
+	}
+}
+
+static int samsung_ufs_phy_wait_for_lock_acq(struct phy *phy)
+{
+	struct samsung_ufs_phy *ufs_phy = get_samsung_ufs_phy(phy);
+	const unsigned int timeout_us = 100000;
+	const unsigned int sleep_us = 10;
+	u32 val;
+	int err;
+
+	err = readl_poll_timeout(
+			ufs_phy->reg_pma + PHY_APB_ADDR(PHY_PLL_LOCK_STATUS),
+			val, (val & PHY_PLL_LOCK_BIT), sleep_us, timeout_us);
+	if (err) {
+		dev_err(ufs_phy->dev,
+			"failed to get phy pll lock acquisition %d\n", err);
+		goto out;
+	}
+
+	err = readl_poll_timeout(
+			ufs_phy->reg_pma + PHY_APB_ADDR(PHY_CDR_LOCK_STATUS),
+			val, (val & PHY_CDR_LOCK_BIT), sleep_us, timeout_us);
+	if (err)
+		dev_err(ufs_phy->dev,
+			"failed to get phy cdr lock acquisition %d\n", err);
+out:
+	return err;
+}
+
+static int samsung_ufs_phy_calibrate(struct phy *phy)
+{
+	struct samsung_ufs_phy *ufs_phy = get_samsung_ufs_phy(phy);
+	struct samsung_ufs_phy_cfg **cfgs = ufs_phy->cfg;
+	const struct samsung_ufs_phy_cfg *cfg;
+	int err = 0;
+	int i;
+
+	if (unlikely(ufs_phy->ufs_phy_state < CFG_PRE_INIT ||
+		     ufs_phy->ufs_phy_state >= CFG_TAG_MAX)) {
+		dev_err(ufs_phy->dev, "invalid phy config index %d\n", ufs_phy->ufs_phy_state);
+		return -EINVAL;
+	}
+
+	cfg = cfgs[ufs_phy->ufs_phy_state];
+	if (!cfg)
+		goto out;
+
+	for_each_phy_cfg(cfg) {
+		for_each_phy_lane(ufs_phy, i) {
+			samsung_ufs_phy_config(ufs_phy, cfg, i);
+		}
+	}
+
+	if (ufs_phy->ufs_phy_state == CFG_POST_PWR_HS)
+		err = samsung_ufs_phy_wait_for_lock_acq(phy);
+
+	/**
+	 * In Samsung ufshci, PHY need to be calibrated at different
+	 * stages / state mainly before Linkstartup, after Linkstartup,
+	 * before power mode change and after power mode change.
+	 * Below state machine to make sure to calibrate PHY in each
+	 * state. Here after configuring PHY in a given state, will
+	 * change the state to next state so that next state phy
+	 * calibration value can be programed
+	 */
+out:
+	switch (ufs_phy->ufs_phy_state) {
+	case CFG_PRE_INIT:
+		ufs_phy->ufs_phy_state = CFG_POST_INIT;
+		break;
+	case CFG_POST_INIT:
+		ufs_phy->ufs_phy_state = CFG_PRE_PWR_HS;
+		break;
+	case CFG_PRE_PWR_HS:
+		ufs_phy->ufs_phy_state = CFG_POST_PWR_HS;
+		break;
+	case CFG_POST_PWR_HS:
+		/* Change back to INIT state */
+		ufs_phy->ufs_phy_state = CFG_PRE_INIT;
+		break;
+	default:
+		dev_err(ufs_phy->dev, "wrong state for phy calibration\n");
+	}
+
+	return err;
+}
+
+static int samsung_ufs_phy_symbol_clk_init(struct samsung_ufs_phy *phy)
+{
+	int ret;
+
+	phy->tx0_symbol_clk = devm_clk_get(phy->dev, "tx0_symbol_clk");
+	if (IS_ERR(phy->tx0_symbol_clk)) {
+		dev_err(phy->dev, "failed to get tx0_symbol_clk clock\n");
+		return PTR_ERR(phy->tx0_symbol_clk);
+	}
+
+	phy->rx0_symbol_clk = devm_clk_get(phy->dev, "rx0_symbol_clk");
+	if (IS_ERR(phy->rx0_symbol_clk)) {
+		dev_err(phy->dev, "failed to get rx0_symbol_clk clock\n");
+		return PTR_ERR(phy->rx0_symbol_clk);
+	}
+
+	phy->rx1_symbol_clk = devm_clk_get(phy->dev, "rx1_symbol_clk");
+	if (IS_ERR(phy->rx0_symbol_clk)) {
+		dev_err(phy->dev, "failed to get rx1_symbol_clk clock\n");
+		return PTR_ERR(phy->rx1_symbol_clk);
+	}
+
+	ret = clk_prepare_enable(phy->tx0_symbol_clk);
+	if (ret) {
+		dev_err(phy->dev, "%s: tx0_symbol_clk enable failed %d\n", __func__, ret);
+		goto out;
+	}
+
+	ret = clk_prepare_enable(phy->rx0_symbol_clk);
+	if (ret) {
+		dev_err(phy->dev, "%s: rx0_symbol_clk enable failed %d\n", __func__, ret);
+		goto out_disable_tx0_clk;
+	}
+
+	ret = clk_prepare_enable(phy->rx1_symbol_clk);
+	if (ret) {
+		dev_err(phy->dev, "%s: rx1_symbol_clk enable failed %d\n", __func__, ret);
+		goto out_disable_rx0_clk;
+	}
+
+	return 0;
+
+out_disable_rx0_clk:
+	clk_disable_unprepare(phy->rx0_symbol_clk);
+out_disable_tx0_clk:
+	clk_disable_unprepare(phy->tx0_symbol_clk);
+out:
+	return ret;
+}
+
+static int samsung_ufs_phy_clks_init(struct samsung_ufs_phy *phy)
+{
+	int ret;
+
+	phy->ref_clk = devm_clk_get(phy->dev, "ref_clk");
+	if (IS_ERR(phy->ref_clk))
+		dev_err(phy->dev, "failed to get ref_clk clock\n");
+
+	ret = clk_prepare_enable(phy->ref_clk);
+	if (ret) {
+		dev_err(phy->dev, "%s: ref_clk enable failed %d\n", __func__, ret);
+		return ret;
+	}
+
+	dev_dbg(phy->dev, "UFS MPHY ref_clk_rate = %ld\n", clk_get_rate(phy->ref_clk));
+
+	return 0;
+}
+
+static int samsung_ufs_phy_init(struct phy *phy)
+{
+	struct samsung_ufs_phy *ss_phy = get_samsung_ufs_phy(phy);
+	int ret;
+
+	ss_phy->lane_cnt = phy->attrs.bus_width;
+	ss_phy->ufs_phy_state = CFG_PRE_INIT;
+
+	if (ss_phy->drvdata->has_symbol_clk) {
+		ret = samsung_ufs_phy_symbol_clk_init(ss_phy);
+		if (ret)
+			dev_err(ss_phy->dev, "failed to set ufs phy symbol clocks\n");
+	}
+
+	ret = samsung_ufs_phy_clks_init(ss_phy);
+	if (ret)
+		dev_err(ss_phy->dev, "failed to set ufs phy clocks\n");
+
+	ret = samsung_ufs_phy_calibrate(phy);
+	if (ret)
+		dev_err(ss_phy->dev, "ufs phy calibration failed\n");
+
+	return ret;
+}
+
+static int samsung_ufs_phy_power_on(struct phy *phy)
+{
+	struct samsung_ufs_phy *ss_phy = get_samsung_ufs_phy(phy);
+
+	samsung_ufs_phy_ctrl_isol(ss_phy, false);
+	return 0;
+}
+
+static int samsung_ufs_phy_power_off(struct phy *phy)
+{
+	struct samsung_ufs_phy *ss_phy = get_samsung_ufs_phy(phy);
+
+	samsung_ufs_phy_ctrl_isol(ss_phy, true);
+	return 0;
+}
+
+static int samsung_ufs_phy_set_mode(struct phy *generic_phy,
+				    enum phy_mode mode, int submode)
+{
+	struct samsung_ufs_phy *ss_phy = get_samsung_ufs_phy(generic_phy);
+
+	ss_phy->mode = PHY_MODE_INVALID;
+
+	if (mode > 0)
+		ss_phy->mode = mode;
+
+	return 0;
+}
+
+static int samsung_ufs_phy_exit(struct phy *phy)
+{
+	struct samsung_ufs_phy *ss_phy = get_samsung_ufs_phy(phy);
+
+	clk_disable_unprepare(ss_phy->ref_clk);
+
+	if (ss_phy->drvdata->has_symbol_clk) {
+		clk_disable_unprepare(ss_phy->tx0_symbol_clk);
+		clk_disable_unprepare(ss_phy->rx0_symbol_clk);
+		clk_disable_unprepare(ss_phy->rx1_symbol_clk);
+	}
+
+	return 0;
+}
+
+static struct phy_ops samsung_ufs_phy_ops = {
+	.init		= samsung_ufs_phy_init,
+	.exit		= samsung_ufs_phy_exit,
+	.power_on	= samsung_ufs_phy_power_on,
+	.power_off	= samsung_ufs_phy_power_off,
+	.calibrate	= samsung_ufs_phy_calibrate,
+	.set_mode	= samsung_ufs_phy_set_mode,
+	.owner          = THIS_MODULE,
+};
+
+static const struct of_device_id samsung_ufs_phy_match[];
+
+static int samsung_ufs_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *match;
+	struct samsung_ufs_phy *phy;
+	struct phy *gen_phy;
+	struct phy_provider *phy_provider;
+	const struct samsung_ufs_phy_drvdata *drvdata;
+	int err = 0;
+
+	match = of_match_node(samsung_ufs_phy_match, dev->of_node);
+	if (!match) {
+		err = -EINVAL;
+		dev_err(dev, "failed to get match_node\n");
+		goto out;
+	}
+
+	phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
+	if (!phy) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	phy->reg_pma = devm_platform_ioremap_resource_byname(pdev, "phy-pma");
+	if (IS_ERR(phy->reg_pma)) {
+		err = PTR_ERR(phy->reg_pma);
+		goto out;
+	}
+
+	phy->reg_pmu = syscon_regmap_lookup_by_phandle(
+				dev->of_node, "samsung,pmu-syscon");
+	if (IS_ERR(phy->reg_pmu)) {
+		err = PTR_ERR(phy->reg_pmu);
+		dev_err(dev, "failed syscon remap for pmu\n");
+		goto out;
+	}
+
+	gen_phy = devm_phy_create(dev, NULL, &samsung_ufs_phy_ops);
+	if (IS_ERR(gen_phy)) {
+		err = PTR_ERR(gen_phy);
+		dev_err(dev, "failed to create PHY for ufs-phy\n");
+		goto out;
+	}
+
+	drvdata = match->data;
+	phy->dev = dev;
+	phy->drvdata = drvdata;
+	phy->cfg = (struct samsung_ufs_phy_cfg **)drvdata->cfg;
+	phy->isol = &drvdata->isol;
+	phy->lane_cnt = PHY_DEF_LANE_CNT;
+
+	phy_set_drvdata(gen_phy, phy);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(phy_provider)) {
+		err = PTR_ERR(phy_provider);
+		dev_err(dev, "failed to register phy-provider\n");
+		goto out;
+	}
+out:
+	return err;
+}
+
+static const struct of_device_id samsung_ufs_phy_match[] = {
+	{
+		.compatible = "samsung,exynos7-ufs-phy",
+		.data = &exynos7_ufs_phy,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, samsung_ufs_phy_match);
+
+static struct platform_driver samsung_ufs_phy_driver = {
+	.probe  = samsung_ufs_phy_probe,
+	.driver = {
+		.name = "samsung-ufs-phy",
+		.of_match_table = samsung_ufs_phy_match,
+	},
+};
+module_platform_driver(samsung_ufs_phy_driver);
+MODULE_DESCRIPTION("Samsung SoC UFS PHY Driver");
+MODULE_AUTHOR("Seungwon Jeon <essuuj@gmail.com>");
+MODULE_AUTHOR("Alim Akhtar <alim.akhtar@samsung.com>");
+MODULE_LICENSE("GPL v2");