[PATCH 4/8] phy: econet: Add PCIe PHY driver for EcoNet EN751221 and EN7528 SoCs.

[Caleb James DeLisle <cjd@cjdns.fr>]

Introduce support for EcoNet PCIe PHY controllers found in EN751221
and EN7528 SoCs, these SoCs are not identical but are similar, each
having one Gen1 port, and one Gen1/Gen2 port.

Co-developed-by: Ahmed Naseef <naseefkm@gmail.com>
Signed-off-by: Ahmed Naseef <naseefkm@gmail.com>
[cjd@cjdns.fr: add EN751221 support and refactor for clarity]
Co-developed-by: Caleb James DeLisle <cjd@cjdns.fr>
Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr>
---
 MAINTAINERS                   |   1 +
 drivers/phy/Kconfig           |  12 +++
 drivers/phy/Makefile          |   1 +
 drivers/phy/phy-econet-pcie.c | 180 ++++++++++++++++++++++++++++++++++
 4 files changed, 194 insertions(+)
 create mode 100644 drivers/phy/phy-econet-pcie.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ae053b1f174f..5d4544590069 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9128,6 +9128,7 @@ M:	Caleb James DeLisle <cjd@cjdns.fr>
 L:	linux-mips@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/phy/econet,en751221-pcie-phy.yaml
+F:	drivers/phy/phy-econet-pcie.c
 
 ECRYPT FILE SYSTEM
 M:	Tyler Hicks <code@tyhicks.com>
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 02467dfd4fb0..60efc37f6eb0 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -123,6 +123,18 @@ config PHY_AIROHA_PCIE
 	  This driver create the basic PHY instance and provides initialize
 	  callback for PCIe GEN3 port.
 
+config PHY_ECONET_PCIE
+	tristate "EcoNet PCIe-PHY Driver"
+	depends on ECONET || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Say Y here to add support for EcoNet PCIe PHY driver.
+	  This driver create the basic PHY instance and provides initialize
+	  callback for PCIe GEN1 and GEN2 ports. This PHY is found on
+	  EcoNet SoCs including EN751221 and EN7528.
+
 config PHY_NXP_PTN3222
 	tristate "NXP PTN3222 1-port eUSB2 to USB2 redriver"
 	depends on I2C
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index a648c2e02a83..a77f182ee8f3 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
 obj-$(CONFIG_PHY_SNPS_EUSB2)		+= phy-snps-eusb2.o
 obj-$(CONFIG_USB_LGM_PHY)		+= phy-lgm-usb.o
 obj-$(CONFIG_PHY_AIROHA_PCIE)		+= phy-airoha-pcie.o
+obj-$(CONFIG_PHY_ECONET_PCIE)		+= phy-econet-pcie.o
 obj-$(CONFIG_PHY_NXP_PTN3222)		+= phy-nxp-ptn3222.o
 obj-$(CONFIG_PHY_SPACEMIT_K1_PCIE)	+= phy-spacemit-k1-pcie.o
 obj-$(CONFIG_GENERIC_PHY)		+= allwinner/	\
diff --git a/drivers/phy/phy-econet-pcie.c b/drivers/phy/phy-econet-pcie.c
new file mode 100644
index 000000000000..f9d6d061f54a
--- /dev/null
+++ b/drivers/phy/phy-econet-pcie.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Author: Caleb James DeLisle <cjd@cjdns.fr>
+ *	   Ahmed Naseef <naseefkm@gmail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* Rx detection timing for EN751221: 16*8 clock cycles  */
+#define EN751221_RXDET_VAL		16
+
+/* Rx detection timing when in power mode 3 */
+#define EN75_RXDET_P3_REG		0xa28
+#define EN75_RXDET_P3_MASK		GENMASK(17, 9)
+
+/* Rx detection timing when in power mode 2 */
+#define EN75_RXDET_P2_REG		0xa2c
+#define EN75_RXDET_P2_MASK		GENMASK(8, 0)
+
+/* Rx impedance */
+#define EN75_RX_IMPEDANCE_REG		0xb2c
+#define EN75_RX_IMPEDANCE_MASK		GENMASK(13, 12)
+enum en75_rx_impedance {
+	EN75_RX_IMPEDANCE_100_OHM	= 0,
+	EN75_RX_IMPEDANCE_95_OHM	= 1,
+	EN75_RX_IMPEDANCE_90_OHM	= 2,
+};
+
+/* PLL Invert clock */
+#define EN75_PLL_PH_INV_REG		0x4a0
+#define EN75_PLL_PH_INV_MASK		BIT(5)
+
+struct en75_phy_op {
+	u32 reg;
+	u32 mask;
+	u32 val;
+};
+
+struct en7528_pcie_phy {
+	struct regmap *regmap;
+	const struct en75_phy_op *data;
+};
+
+/* Port 0 PHY: set LCDDS_CLK_PH_INV for PLL operation */
+static const struct en75_phy_op en7528_phy_port0[] = {
+	{
+		.reg = EN75_PLL_PH_INV_REG,
+		.mask = EN75_PLL_PH_INV_MASK,
+		.val = 1,
+	},
+	{ /* sentinel */ }
+};
+
+/* EN7528 Port 1 PHY: Rx impedance tuning, target R -5 Ohm */
+static const struct en75_phy_op en7528_phy_port1[] = {
+	{
+		.reg = EN75_RX_IMPEDANCE_REG,
+		.mask = EN75_RX_IMPEDANCE_MASK,
+		.val = EN75_RX_IMPEDANCE_95_OHM,
+	},
+	{ /* sentinel */ }
+};
+
+/* EN751221 Port 1 PHY, set RX detect to 16*8 clock cycles */
+static const struct en75_phy_op en751221_phy_port1[] = {
+	{
+		.reg = EN75_RXDET_P3_REG,
+		.mask = EN75_RXDET_P3_MASK,
+		.val = EN751221_RXDET_VAL,
+	},
+	{
+		.reg = EN75_RXDET_P2_REG,
+		.mask = EN75_RXDET_P2_MASK,
+		.val = EN751221_RXDET_VAL,
+	},
+	{ /* sentinel */ }
+};
+
+static int en75_pcie_phy_init(struct phy *phy)
+{
+	struct en7528_pcie_phy *ephy = phy_get_drvdata(phy);
+	const struct en75_phy_op *data = ephy->data;
+	int i, ret;
+	u32 val;
+
+	for (i = 0; data[i].mask || data[i].val; i++) {
+		if (i)
+			usleep_range(1000, 2000);
+
+		val = field_prep(data[i].mask, data[i].val);
+
+		ret = regmap_update_bits(ephy->regmap, data[i].reg,
+					 data[i].mask, val);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct phy_ops en75_pcie_phy_ops = {
+	.init	= en75_pcie_phy_init,
+	.owner	= THIS_MODULE,
+};
+
+static int en75_pcie_phy_probe(struct platform_device *pdev)
+{
+	struct regmap_config regmap_config = {
+		.reg_bits = 32,
+		.val_bits = 32,
+		.reg_stride = 4,
+	};
+	struct device *dev = &pdev->dev;
+	const struct en75_phy_op *data;
+	struct phy_provider *provider;
+	struct en7528_pcie_phy *ephy;
+	void __iomem *base;
+	struct phy *phy;
+	int i;
+
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return -EINVAL;
+
+	ephy = devm_kzalloc(dev, sizeof(*ephy), GFP_KERNEL);
+	if (!ephy)
+		return -ENOMEM;
+
+	ephy->data = data;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	/* Set max_register to highest used register */
+	for (i = 0; data[i].mask || data[i].val; i++)
+		if (data[i].reg > regmap_config.max_register)
+			regmap_config.max_register = data[i].reg;
+
+	ephy->regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(ephy->regmap))
+		return PTR_ERR(ephy->regmap);
+
+	phy = devm_phy_create(dev, dev->of_node, &en75_pcie_phy_ops);
+	if (IS_ERR(phy))
+		return PTR_ERR(phy);
+
+	phy_set_drvdata(phy, ephy);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(provider);
+}
+
+static const struct of_device_id en75_pcie_phy_ids[] = {
+	{ .compatible = "econet,en7528-pcie-phy0", .data = en7528_phy_port0 },
+	{ .compatible = "econet,en7528-pcie-phy1", .data = en7528_phy_port1 },
+	{ .compatible = "econet,en751221-pcie-phy0", .data = en7528_phy_port0 },
+	{ .compatible = "econet,en751221-pcie-phy1", .data = en751221_phy_port1 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, en75_pcie_phy_ids);
+
+static struct platform_driver en75_pcie_phy_driver = {
+	.probe = en75_pcie_phy_probe,
+	.driver = {
+		.name = "econet-pcie-phy",
+		.of_match_table = en75_pcie_phy_ids,
+	},
+};
+module_platform_driver(en75_pcie_phy_driver);
+
+MODULE_AUTHOR("Caleb James DeLisle <cjd@cjdns.fr>");
+MODULE_DESCRIPTION("EcoNet PCIe PHY driver");
+MODULE_LICENSE("GPL");
-- 
2.39.5