drivers/net/dsa/microchip/ksz8863_smi.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Microchip KSZ8863 series register access through SMI
 *
 * Copyright (C) 2019 Pengutronix, Michael Grzeschik <kernel@pengutronix.de>
 */

#include <linux/property.h>

#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;
	int i, ret = 0;

	mdev = dev->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;
	int i, ret = 0;
	u32 reg;
	u8 *val;

	mdev = dev->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,
	},
	{
		.read = ksz8863_mdio_read,
		.write = ksz8863_mdio_write,
		.val_format_endian_default = REGMAP_ENDIAN_BIG,
	},
	{
		.read = ksz8863_mdio_read,
		.write = ksz8863_mdio_write,
		.val_format_endian_default = REGMAP_ENDIAN_BIG,
	}
};

static const struct regmap_config ksz8863_regmap_config[] = {
	{
		.name = "#8",
		.reg_bits = 8,
		.pad_bits = 24,
		.val_bits = 8,
		.cache_type = REGCACHE_NONE,
		.lock = ksz_regmap_lock,
		.unlock = ksz_regmap_unlock,
		.max_register = U8_MAX,
	},
	{
		.name = "#16",
		.reg_bits = 8,
		.pad_bits = 24,
		.val_bits = 16,
		.cache_type = REGCACHE_NONE,
		.lock = ksz_regmap_lock,
		.unlock = ksz_regmap_unlock,
		.max_register = U8_MAX,
	},
	{
		.name = "#32",
		.reg_bits = 8,
		.pad_bits = 24,
		.val_bits = 32,
		.cache_type = REGCACHE_NONE,
		.lock = ksz_regmap_lock,
		.unlock = ksz_regmap_unlock,
		.max_register = U8_MAX,
	}
};

static int ksz8863_smi_probe(struct mdio_device *mdiodev)
{
	struct device *ddev = &mdiodev->dev;
	const struct ksz_chip_data *chip;
	struct regmap_config rc;
	struct ksz_device *dev;
	int ret;
	int i;

	chip = device_get_match_data(ddev);
	if (!chip)
		return -EINVAL;

	dev = ksz_switch_alloc(&mdiodev->dev, chip, mdiodev);
	if (!dev)
		return -ENOMEM;

	for (i = 0; i < __KSZ_NUM_REGMAPS; i++) {
		rc = ksz8863_regmap_config[i];
		rc.lock_arg = &dev->regmap_mutex;
		rc.wr_table = chip->wr_table;
		rc.rd_table = chip->rd_table;
		dev->regmap[i] = devm_regmap_init(&mdiodev->dev,
						  &regmap_smi[i], dev,
						  &rc);
		if (IS_ERR(dev->regmap[i])) {
			return dev_err_probe(&mdiodev->dev,
					     PTR_ERR(dev->regmap[i]),
					     "Failed to initialize regmap%i\n",
					     ksz8863_regmap_config[i].val_bits);
		}
	}

	if (mdiodev->dev.platform_data)
		dev->pdata = mdiodev->dev.platform_data;

	ret = ksz_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 void ksz8863_smi_shutdown(struct mdio_device *mdiodev)
{
	struct ksz_device *dev = dev_get_drvdata(&mdiodev->dev);

	if (dev)
		dsa_switch_shutdown(dev->ds);

	dev_set_drvdata(&mdiodev->dev, NULL);
}

static const struct of_device_id ksz8863_dt_ids[] = {
	{
		.compatible = "microchip,ksz8863",
		.data = &ksz_switch_chips[KSZ88X3]
	},
	{
		.compatible = "microchip,ksz8873",
		.data = &ksz_switch_chips[KSZ88X3]
	},
	{ },
};
MODULE_DEVICE_TABLE(of, ksz8863_dt_ids);

static struct mdio_driver ksz8863_driver = {
	.probe	= ksz8863_smi_probe,
	.remove	= ksz8863_smi_remove,
	.shutdown = ksz8863_smi_shutdown,
	.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");