net: dsa: microchip: add KSZ9477 I2C driver

Add KSZ9477 I2C driver support.  The code ksz9477.c and ksz_common.c are
used together to generate the I2C driver.

Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
[george.mccollister@gmail.com: bring up to date, use ksz_common regmap macros]
Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/microchip/Kconfig

@@ -9,6 +9,13 @@ menuconfig NET_DSA_MICROCHIP_KSZ9477
 	help
 	  This driver adds support for Microchip KSZ9477 switch chips.
 
+config NET_DSA_MICROCHIP_KSZ9477_I2C
+	tristate "KSZ9477 series I2C connected switch driver"
+	depends on NET_DSA_MICROCHIP_KSZ9477 && I2C
+	select REGMAP_I2C
+	help
+	  Select to enable support for registering switches configured through I2C.
+
 config NET_DSA_MICROCHIP_KSZ9477_SPI
 	tristate "KSZ9477 series SPI connected switch driver"
 	depends on NET_DSA_MICROCHIP_KSZ9477 && SPI

drivers/net/dsa/microchip/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON)	+= ksz_common.o
 obj-$(CONFIG_NET_DSA_MICROCHIP_KSZ9477)		+= ksz9477.o
+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

drivers/net/dsa/microchip/ksz9477_i2c.c

@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip KSZ9477 series register access through I2C
+ *
+ * Copyright (C) 2018-2019 Microchip Technology Inc.
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "ksz_common.h"
+
+KSZ_REGMAP_TABLE(ksz9477, not_used, 16, 0, 0);
+
+static int ksz9477_i2c_probe(struct i2c_client *i2c,
+			     const struct i2c_device_id *i2c_id)
+{
+	struct ksz_device *dev;
+	int i, ret;
+
+	dev = ksz_switch_alloc(&i2c->dev, i2c);
+	if (!dev)
+		return -ENOMEM;
+
+	for (i = 0; i < ARRAY_SIZE(ksz9477_regmap_config); i++) {
+		dev->regmap[i] = devm_regmap_init_i2c(i2c,
+					&ksz9477_regmap_config[i]);
+		if (IS_ERR(dev->regmap[i])) {
+			ret = PTR_ERR(dev->regmap[i]);
+			dev_err(&i2c->dev,
+				"Failed to initialize regmap%i: %d\n",
+				ksz9477_regmap_config[i].val_bits, ret);
+			return ret;
+		}
+	}
+
+	if (i2c->dev.platform_data)
+		dev->pdata = i2c->dev.platform_data;
+
+	ret = ksz9477_switch_register(dev);
+
+	/* Main DSA driver may not be started yet. */
+	if (ret)
+		return ret;
+
+	i2c_set_clientdata(i2c, dev);
+
+	return 0;
+}
+
+static int ksz9477_i2c_remove(struct i2c_client *i2c)
+{
+	struct ksz_device *dev = i2c_get_clientdata(i2c);
+
+	ksz_switch_remove(dev);
+
+	return 0;
+}
+
+static void ksz9477_i2c_shutdown(struct i2c_client *i2c)
+{
+	struct ksz_device *dev = i2c_get_clientdata(i2c);
+
+	if (dev && dev->dev_ops->shutdown)
+		dev->dev_ops->shutdown(dev);
+}
+
+static const struct i2c_device_id ksz9477_i2c_id[] = {
+	{ "ksz9477-switch", 0 },
+	{},
+};
+
+MODULE_DEVICE_TABLE(i2c, ksz9477_i2c_id);
+
+static const struct of_device_id ksz9477_dt_ids[] = {
+	{ .compatible = "microchip,ksz9477" },
+	{ .compatible = "microchip,ksz9897" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ksz9477_dt_ids);
+
+static struct i2c_driver ksz9477_i2c_driver = {
+	.driver = {
+		.name	= "ksz9477-switch",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ksz9477_dt_ids),
+	},
+	.probe	= ksz9477_i2c_probe,
+	.remove	= ksz9477_i2c_remove,
+	.shutdown = ksz9477_i2c_shutdown,
+	.id_table = ksz9477_i2c_id,
+};
+
+module_i2c_driver(ksz9477_i2c_driver);
+
+MODULE_AUTHOR("Tristram Ha <Tristram.Ha@microchip.com>");
+MODULE_DESCRIPTION("Microchip KSZ9477 Series Switch I2C access Driver");
+MODULE_LICENSE("GPL v2");

drivers/net/dsa/microchip/ksz_common.h

@@ -294,6 +294,8 @@ static inline void ksz_pwrite32(struct ksz_device *dev, int port, int offset,
 #define KSZ_SPI_OP_RD		3
 #define KSZ_SPI_OP_WR		2
 
+#define swabnot_used(x)		0
+
 #define KSZ_SPI_OP_FLAG_MASK(opcode, swp, regbits, regpad)		\
 	swab##swp((opcode) << ((regbits) + (regpad)))