[PATCH v3 2/2] phy: intel-lgm-sdxc: Add support for SDXC PHY

[Ramuthevar,Vadivel MuruganX]

From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>

Add support for SDXC PHY on Intel's Lightning Mountain SoC.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
---
 drivers/phy/intel/Kconfig          |   6 ++
 drivers/phy/intel/Makefile         |   1 +
 drivers/phy/intel/phy-intel-sdxc.c | 144 +++++++++++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 drivers/phy/intel/phy-intel-sdxc.c

diff --git a/drivers/phy/intel/Kconfig b/drivers/phy/intel/Kconfig
index 4ea6a8897cd7..d6356c762a6b 100644
--- a/drivers/phy/intel/Kconfig
+++ b/drivers/phy/intel/Kconfig
@@ -7,3 +7,9 @@ config PHY_INTEL_EMMC
 	select GENERIC_PHY
 	help
 	  Enable this to support the Intel EMMC PHY
+
+config PHY_INTEL_SDXC
+       tristate "Intel SDXC PHY driver"
+       select GENERIC_PHY
+       help
+         Enable this to support the Intel SDXC PHY driver
diff --git a/drivers/phy/intel/Makefile b/drivers/phy/intel/Makefile
index 6b876a75599d..3c6e7523200c 100644
--- a/drivers/phy/intel/Makefile
+++ b/drivers/phy/intel/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_PHY_INTEL_EMMC)            += phy-intel-emmc.o
+obj-$(CONFIG_PHY_INTEL_SDXC)            += phy-intel-sdxc.o
diff --git a/drivers/phy/intel/phy-intel-sdxc.c b/drivers/phy/intel/phy-intel-sdxc.c
new file mode 100644
index 000000000000..7e13fd9ced5b
--- /dev/null
+++ b/drivers/phy/intel/phy-intel-sdxc.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel SDXC PHY driver
+ * Copyright (C) 2019 Intel, Corp.
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* SDXC PHY register definitions */
+#define SDXC_PHYCTRL_REG	0x88
+#define OTAPDLYENA_MASK		BIT(14)
+#define OTAPDLYSEL(x)		((x) << 10)
+#define OTAPDLYSEL_ALL		OTAPDLYSEL(GENMASK(3, 0))
+
+struct intel_sdxc_phy {
+	struct regmap *syscfg;
+	struct clk *sdxcclk;
+};
+
+static int intel_sdxc_phy_init(struct phy *phy)
+{
+	struct intel_sdxc_phy *priv = phy_get_drvdata(phy);
+
+	/*
+	 * We purposely get the clock here and not in probe to avoid the
+	 * circular dependency problem.  We expect:
+	 * - PHY driver to probe
+	 * - SDHCI driver to start probe
+	 * - SDHCI driver to register it's clock
+	 * - SDHCI driver to get the PHY
+	 * - SDHCI driver to init the PHY
+	 *
+	 * The clock is optional, so upon any error just return it like
+	 * any other error to user.
+	 */
+	priv->sdxcclk = clk_get_optional(&phy->dev, "sdxcclk");
+	if (IS_ERR(priv->sdxcclk)) {
+		dev_err(&phy->dev, "Error getting sdxcclk\n");
+		return PTR_ERR(priv->sdxcclk);
+	}
+
+	return 0;
+}
+
+static int intel_sdxc_phy_exit(struct phy *phy)
+{
+	struct intel_sdxc_phy *priv = phy_get_drvdata(phy);
+
+	clk_put(priv->sdxcclk);
+
+	return 0;
+}
+
+static int intel_sdxc_phy_power_on(struct phy *phy)
+{
+	struct intel_sdxc_phy *priv = phy_get_drvdata(phy);
+
+	/* Output tap delay: disable */
+	regmap_update_bits(priv->syscfg, SDXC_PHYCTRL_REG, OTAPDLYENA_MASK, 0);
+
+	/* Output tap delay */
+	regmap_update_bits(priv->syscfg, SDXC_PHYCTRL_REG, OTAPDLYSEL_ALL,
+			   OTAPDLYSEL_ALL);
+
+	return 0;
+}
+
+static int intel_sdxc_phy_power_off(struct phy *phy)
+{
+	/* Do nothing */
+	return 0;
+}
+
+static const struct phy_ops ops = {
+	.init		= intel_sdxc_phy_init,
+	.exit		= intel_sdxc_phy_exit,
+	.power_on	= intel_sdxc_phy_power_on,
+	.power_off	= intel_sdxc_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int intel_sdxc_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct intel_sdxc_phy *priv;
+	struct phy *generic_phy;
+	struct phy_provider *phy_provider;
+
+	if (!dev->parent || !dev->parent->of_node)
+		return -ENODEV;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/* Get SDXC phy (accessed via chiptop) regmap */
+	priv->syscfg = syscon_regmap_lookup_by_phandle(dev->of_node,
+						       "intel,syscon");
+	if (IS_ERR(priv->syscfg)) {
+		dev_err(dev, "No syscon phandle for chiptop\n");
+		return PTR_ERR(priv->syscfg);
+	}
+
+	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, priv);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id intel_sdxc_phy_dt_ids[] = {
+	{ .compatible = "intel,lgm-sdxc-phy" },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, intel_sdxc_phy_dt_ids);
+
+static struct platform_driver intel_sdxc_driver = {
+	.probe		= intel_sdxc_phy_probe,
+	.driver		= {
+		.name	= "intel-sdxc-phy",
+		.of_match_table = intel_sdxc_phy_dt_ids,
+	},
+};
+
+module_platform_driver(intel_sdxc_driver);
+
+MODULE_AUTHOR("Peter Harliman Liem <peter.harliman.liem@xxxxxxxxx>");
+MODULE_DESCRIPTION("Intel SDXC PHY driver");
+MODULE_LICENSE("GPL v2");
-- 
2.11.0