net: dsa: microchip: Add Microchip KSZ8863 SMI based driver support

Add KSZ88X3 driver support. We add support for the KXZ88X3 three port
switches using the Microchip SMI Interface. They are supported using the
MDIO-Bitbang Interface.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 213 insertions, 0 deletions

diff --git a/drivers/net/dsa/microchip/ksz8863_smi.c b/drivers/net/dsa/microchip/ksz8863_smi.c
new file mode 100644
index 000000000000..30d97ea7a949
--- /dev/null
+++ b/drivers/net/dsa/microchip/ksz8863_smi.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip KSZ8863 series register access through SMI
+ *
+ * Copyright (C) 2019 Pengutronix, Michael Grzeschik <kernel@pengutronix.de>
+ */
+
+#include "ksz8.h"
+#include "ksz_common.h"
+
+/* Serial Management Interface (SMI) uses the following frame format:
+ *
+ *       preamble|start|Read/Write|  PHY   |  REG  |TA|   Data bits      | Idle
+ *               |frame| OP code  |address |address|  |                  |
+ * read | 32x1´s | 01  |    00    | 1xRRR  | RRRRR |Z0| 00000000DDDDDDDD |  Z
+ * write| 32x1´s | 01  |    00    | 0xRRR  | RRRRR |10| xxxxxxxxDDDDDDDD |  Z
+ *
+ */
+
+#define SMI_KSZ88XX_READ_PHY	BIT(4)
+
+static int ksz8863_mdio_read(void *ctx, const void *reg_buf, size_t reg_len,
+			     void *val_buf, size_t val_len)
+{
+	struct ksz_device *dev = ctx;
+	struct mdio_device *mdev;
+	u8 reg = *(u8 *)reg_buf;
+	u8 *val = val_buf;
+	struct ksz8 *ksz8;
+	int i, ret = 0;
+
+	ksz8 = dev->priv;
+	mdev = ksz8->priv;
+
+	mutex_lock_nested(&mdev->bus->mdio_lock, MDIO_MUTEX_NESTED);
+	for (i = 0; i < val_len; i++) {
+		int tmp = reg + i;
+
+		ret = __mdiobus_read(mdev->bus, ((tmp & 0xE0) >> 5) |
+				     SMI_KSZ88XX_READ_PHY, tmp);
+		if (ret < 0)
+			goto out;
+
+		val[i] = ret;
+	}
+	ret = 0;
+
+ out:
+	mutex_unlock(&mdev->bus->mdio_lock);
+
+	return ret;
+}
+
+static int ksz8863_mdio_write(void *ctx, const void *data, size_t count)
+{
+	struct ksz_device *dev = ctx;
+	struct mdio_device *mdev;
+	struct ksz8 *ksz8;
+	int i, ret = 0;
+	u32 reg;
+	u8 *val;
+
+	ksz8 = dev->priv;
+	mdev = ksz8->priv;
+
+	val = (u8 *)(data + 4);
+	reg = *(u32 *)data;
+
+	mutex_lock_nested(&mdev->bus->mdio_lock, MDIO_MUTEX_NESTED);
+	for (i = 0; i < (count - 4); i++) {
+		int tmp = reg + i;
+
+		ret = __mdiobus_write(mdev->bus, ((tmp & 0xE0) >> 5),
+				      tmp, val[i]);
+		if (ret < 0)
+			goto out;
+	}
+
+ out:
+	mutex_unlock(&mdev->bus->mdio_lock);
+
+	return ret;
+}
+
+static const struct regmap_bus regmap_smi[] = {
+	{
+		.read = ksz8863_mdio_read,
+		.write = ksz8863_mdio_write,
+		.max_raw_read = 1,
+		.max_raw_write = 1,
+	},
+	{
+		.read = ksz8863_mdio_read,
+		.write = ksz8863_mdio_write,
+		.val_format_endian_default = REGMAP_ENDIAN_BIG,
+		.max_raw_read = 2,
+		.max_raw_write = 2,
+	},
+	{
+		.read = ksz8863_mdio_read,
+		.write = ksz8863_mdio_write,
+		.val_format_endian_default = REGMAP_ENDIAN_BIG,
+		.max_raw_read = 4,
+		.max_raw_write = 4,
+	}
+};
+
+static const struct regmap_config ksz8863_regmap_config[] = {
+	{
+		.name = "#8",
+		.reg_bits = 8,
+		.pad_bits = 24,
+		.val_bits = 8,
+		.cache_type = REGCACHE_NONE,
+		.use_single_read = 1,
+		.lock = ksz_regmap_lock,
+		.unlock = ksz_regmap_unlock,
+	},
+	{
+		.name = "#16",
+		.reg_bits = 8,
+		.pad_bits = 24,
+		.val_bits = 16,
+		.cache_type = REGCACHE_NONE,
+		.use_single_read = 1,
+		.lock = ksz_regmap_lock,
+		.unlock = ksz_regmap_unlock,
+	},
+	{
+		.name = "#32",
+		.reg_bits = 8,
+		.pad_bits = 24,
+		.val_bits = 32,
+		.cache_type = REGCACHE_NONE,
+		.use_single_read = 1,
+		.lock = ksz_regmap_lock,
+		.unlock = ksz_regmap_unlock,
+	}
+};
+
+static int ksz8863_smi_probe(struct mdio_device *mdiodev)
+{
+	struct regmap_config rc;
+	struct ksz_device *dev;
+	struct ksz8 *ksz8;
+	int ret;
+	int i;
+
+	ksz8 = devm_kzalloc(&mdiodev->dev, sizeof(struct ksz8), GFP_KERNEL);
+	ksz8->priv = mdiodev;
+
+	dev = ksz_switch_alloc(&mdiodev->dev, ksz8);
+	if (!dev)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(ksz8863_regmap_config); i++) {
+		rc = ksz8863_regmap_config[i];
+		rc.lock_arg = &dev->regmap_mutex;
+		dev->regmap[i] = devm_regmap_init(&mdiodev->dev,
+						  &regmap_smi[i], dev,
+						  &rc);
+		if (IS_ERR(dev->regmap[i])) {
+			ret = PTR_ERR(dev->regmap[i]);
+			dev_err(&mdiodev->dev,
+				"Failed to initialize regmap%i: %d\n",
+				ksz8863_regmap_config[i].val_bits, ret);
+			return ret;
+		}
+	}
+
+	if (mdiodev->dev.platform_data)
+		dev->pdata = mdiodev->dev.platform_data;
+
+	ret = ksz8_switch_register(dev);
+
+	/* Main DSA driver may not be started yet. */
+	if (ret)
+		return ret;
+
+	dev_set_drvdata(&mdiodev->dev, dev);
+
+	return 0;
+}
+
+static void ksz8863_smi_remove(struct mdio_device *mdiodev)
+{
+	struct ksz_device *dev = dev_get_drvdata(&mdiodev->dev);
+
+	if (dev)
+		ksz_switch_remove(dev);
+}
+
+static const struct of_device_id ksz8863_dt_ids[] = {
+	{ .compatible = "microchip,ksz8863" },
+	{ .compatible = "microchip,ksz8873" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ksz8863_dt_ids);
+
+static struct mdio_driver ksz8863_driver = {
+	.probe	= ksz8863_smi_probe,
+	.remove	= ksz8863_smi_remove,
+	.mdiodrv.driver = {
+		.name	= "ksz8863-switch",
+		.of_match_table = ksz8863_dt_ids,
+	},
+};
+
+mdio_module_driver(ksz8863_driver);
+
+MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
+MODULE_DESCRIPTION("Microchip KSZ8863 SMI Switch driver");
+MODULE_LICENSE("GPL v2");