[PATCH net-next v8 8/9] net: dsa: microchip: Add Microchip KSZ8863 SMI based driver support

From: Oleksij Rempel
Date: Tue Apr 27 2021 - 03:10:25 EST

From: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>

---
v1 -> v2: - this code was part of previuos patch
v2 -> v3: - this code was part of previuos patch
v3 -> v4: - moved this glue code so separate patch
- fixed locking in regmap and mdio_read/mdio_write
v4 -> v5: - removed extra default y in Kconfig
- fixed capitalization in Kconfig description
- removed unnecessary cast
- added back the define for READ operation
- added KSZ88x3 to help text for KSZ8795 Kconfig entry
---
drivers/net/dsa/microchip/Kconfig | 10 +-
drivers/net/dsa/microchip/Makefile | 1 +
drivers/net/dsa/microchip/ksz8863_smi.c | 213 ++++++++++++++++++++++++
3 files changed, 223 insertions(+), 1 deletion(-)
create mode 100644 drivers/net/dsa/microchip/ksz8863_smi.c

diff --git a/drivers/net/dsa/microchip/Kconfig b/drivers/net/dsa/microchip/Kconfig
index 4ec6a47b7f72..c9e2a8989556 100644
--- a/drivers/net/dsa/microchip/Kconfig
+++ b/drivers/net/dsa/microchip/Kconfig
@@ -29,7 +29,7 @@ menuconfig NET_DSA_MICROCHIP_KSZ8795
depends on NET_DSA
select NET_DSA_MICROCHIP_KSZ_COMMON
help
- This driver adds support for Microchip KSZ8795 switch chips.
+ This driver adds support for Microchip KSZ8795/KSZ88X3 switch chips.

config NET_DSA_MICROCHIP_KSZ8795_SPI
tristate "KSZ8795 series SPI connected switch driver"
@@ -40,3 +40,11 @@ config NET_DSA_MICROCHIP_KSZ8795_SPI

It is required to use the KSZ8795 switch driver as the only access
is through SPI.
+
+config NET_DSA_MICROCHIP_KSZ8863_SMI
+ tristate "KSZ series SMI connected switch driver"
+ depends on NET_DSA_MICROCHIP_KSZ8795
+ select MDIO_BITBANG
+ help
+ Select to enable support for registering switches configured through
+ Microchip SMI. It supports the KSZ8863 and KSZ8873 switch.
diff --git a/drivers/net/dsa/microchip/Makefile b/drivers/net/dsa/microchip/Makefile
index 929caa81e782..2a03b21a3386 100644
--- a/drivers/net/dsa/microchip/Makefile
+++ b/drivers/net/dsa/microchip/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_I2C) += ksz9477_i2c.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477_SPI) += ksz9477_spi.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ8795) += ksz8795.o
obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ8795_SPI) += ksz8795_spi.o
+obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ8863_SMI) += ksz8863_smi.o
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@xxxxxxxxxxxxxx>
+ */
+
+#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@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Microchip KSZ8863 SMI Switch driver");
+MODULE_LICENSE("GPL v2");
--
2.29.2