Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0+
/* Realtek Simple Management Interface (SMI) driver
 * It can be discussed how "simple" this interface is.
 *
 * The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels
 * but the protocol is not MDIO at all. Instead it is a Realtek
 * pecularity that need to bit-bang the lines in a special way to
 * communicate with the switch.
 *
 * ASICs we intend to support with this driver:
 *
 * RTL8366   - The original version, apparently
 * RTL8369   - Similar enough to have the same datsheet as RTL8366
 * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
 *             different register layout from the other two
 * RTL8366S  - Is this "RTL8366 super"?
 * RTL8367   - Has an OpenWRT driver as well
 * RTL8368S  - Seems to be an alternative name for RTL8366RB
 * RTL8370   - Also uses SMI
 *
 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
 * Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com>
 * Copyright (C) 2010 Roman Yeryomin <roman@advem.lv>
 * Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com>
 * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
 */
 
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/bitops.h>
#include <linux/if_bridge.h>
 
#include "realtek-smi-core.h"
 
#define REALTEK_SMI_ACK_RETRY_COUNT		5
#define REALTEK_SMI_HW_STOP_DELAY		25	/* msecs */
#define REALTEK_SMI_HW_START_DELAY		100	/* msecs */
 
static inline void realtek_smi_clk_delay(struct realtek_smi *smi)
{
<------>ndelay(smi->clk_delay);
}
 
static void realtek_smi_start(struct realtek_smi *smi)
{
<------>/* Set GPIO pins to output mode, with initial state:
<------> * SCK = 0, SDA = 1
<------> */
<------>gpiod_direction_output(smi->mdc, 0);
<------>gpiod_direction_output(smi->mdio, 1);
<------>realtek_smi_clk_delay(smi);
 
<------>/* CLK 1: 0 -> 1, 1 -> 0 */
<------>gpiod_set_value(smi->mdc, 1);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 0);
<------>realtek_smi_clk_delay(smi);
 
<------>/* CLK 2: */
<------>gpiod_set_value(smi->mdc, 1);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdio, 0);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 0);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdio, 1);
}
 
static void realtek_smi_stop(struct realtek_smi *smi)
{
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdio, 0);
<------>gpiod_set_value(smi->mdc, 1);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdio, 1);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 1);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 0);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 1);
 
<------>/* Add a click */
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 0);
<------>realtek_smi_clk_delay(smi);
<------>gpiod_set_value(smi->mdc, 1);
 
<------>/* Set GPIO pins to input mode */
<------>gpiod_direction_input(smi->mdio);
<------>gpiod_direction_input(smi->mdc);
}
 
static void realtek_smi_write_bits(struct realtek_smi *smi, u32 data, u32 len)
{
<------>for (; len > 0; len--) {
<------><------>realtek_smi_clk_delay(smi);
 
<------><------>/* Prepare data */
<------><------>gpiod_set_value(smi->mdio, !!(data & (1 << (len - 1))));
<------><------>realtek_smi_clk_delay(smi);
 
<------><------>/* Clocking */
<------><------>gpiod_set_value(smi->mdc, 1);
<------><------>realtek_smi_clk_delay(smi);
<------><------>gpiod_set_value(smi->mdc, 0);
<------>}
}
 
static void realtek_smi_read_bits(struct realtek_smi *smi, u32 len, u32 *data)
{
<------>gpiod_direction_input(smi->mdio);
 
<------>for (*data = 0; len > 0; len--) {
<------><------>u32 u;
 
<------><------>realtek_smi_clk_delay(smi);
 
<------><------>/* Clocking */
<------><------>gpiod_set_value(smi->mdc, 1);
<------><------>realtek_smi_clk_delay(smi);
<------><------>u = !!gpiod_get_value(smi->mdio);
<------><------>gpiod_set_value(smi->mdc, 0);
 
<------><------>*data |= (u << (len - 1));
<------>}
 
<------>gpiod_direction_output(smi->mdio, 0);
}
 
static int realtek_smi_wait_for_ack(struct realtek_smi *smi)
{
<------>int retry_cnt;
 
<------>retry_cnt = 0;
<------>do {
<------><------>u32 ack;
 
<------><------>realtek_smi_read_bits(smi, 1, &ack);
<------><------>if (ack == 0)
<------><------><------>break;
 
<------><------>if (++retry_cnt > REALTEK_SMI_ACK_RETRY_COUNT) {
<------><------><------>dev_err(smi->dev, "ACK timeout\n");
<------><------><------>return -ETIMEDOUT;
<------><------>}
<------>} while (1);
 
<------>return 0;
}
 
static int realtek_smi_write_byte(struct realtek_smi *smi, u8 data)
{
<------>realtek_smi_write_bits(smi, data, 8);
<------>return realtek_smi_wait_for_ack(smi);
}
 
static int realtek_smi_write_byte_noack(struct realtek_smi *smi, u8 data)
{
<------>realtek_smi_write_bits(smi, data, 8);
<------>return 0;
}
 
static int realtek_smi_read_byte0(struct realtek_smi *smi, u8 *data)
{
<------>u32 t;
 
<------>/* Read data */
<------>realtek_smi_read_bits(smi, 8, &t);
<------>*data = (t & 0xff);
 
<------>/* Send an ACK */
<------>realtek_smi_write_bits(smi, 0x00, 1);
 
<------>return 0;
}
 
static int realtek_smi_read_byte1(struct realtek_smi *smi, u8 *data)
{
<------>u32 t;
 
<------>/* Read data */
<------>realtek_smi_read_bits(smi, 8, &t);
<------>*data = (t & 0xff);
 
<------>/* Send an ACK */
<------>realtek_smi_write_bits(smi, 0x01, 1);
 
<------>return 0;
}
 
static int realtek_smi_read_reg(struct realtek_smi *smi, u32 addr, u32 *data)
{
<------>unsigned long flags;
<------>u8 lo = 0;
<------>u8 hi = 0;
<------>int ret;
 
<------>spin_lock_irqsave(&smi->lock, flags);
 
<------>realtek_smi_start(smi);
 
<------>/* Send READ command */
<------>ret = realtek_smi_write_byte(smi, smi->cmd_read);
<------>if (ret)
<------><------>goto out;
 
<------>/* Set ADDR[7:0] */
<------>ret = realtek_smi_write_byte(smi, addr & 0xff);
<------>if (ret)
<------><------>goto out;
 
<------>/* Set ADDR[15:8] */
<------>ret = realtek_smi_write_byte(smi, addr >> 8);
<------>if (ret)
<------><------>goto out;
 
<------>/* Read DATA[7:0] */
<------>realtek_smi_read_byte0(smi, &lo);
<------>/* Read DATA[15:8] */
<------>realtek_smi_read_byte1(smi, &hi);
 
<------>*data = ((u32)lo) | (((u32)hi) << 8);
 
<------>ret = 0;
 
 out:
<------>realtek_smi_stop(smi);
<------>spin_unlock_irqrestore(&smi->lock, flags);
 
<------>return ret;
}
 
static int realtek_smi_write_reg(struct realtek_smi *smi,
<------><------><------><------> u32 addr, u32 data, bool ack)
{
<------>unsigned long flags;
<------>int ret;
 
<------>spin_lock_irqsave(&smi->lock, flags);
 
<------>realtek_smi_start(smi);
 
<------>/* Send WRITE command */
<------>ret = realtek_smi_write_byte(smi, smi->cmd_write);
<------>if (ret)
<------><------>goto out;
 
<------>/* Set ADDR[7:0] */
<------>ret = realtek_smi_write_byte(smi, addr & 0xff);
<------>if (ret)
<------><------>goto out;
 
<------>/* Set ADDR[15:8] */
<------>ret = realtek_smi_write_byte(smi, addr >> 8);
<------>if (ret)
<------><------>goto out;
 
<------>/* Write DATA[7:0] */
<------>ret = realtek_smi_write_byte(smi, data & 0xff);
<------>if (ret)
<------><------>goto out;
 
<------>/* Write DATA[15:8] */
<------>if (ack)
<------><------>ret = realtek_smi_write_byte(smi, data >> 8);
<------>else
<------><------>ret = realtek_smi_write_byte_noack(smi, data >> 8);
<------>if (ret)
<------><------>goto out;
 
<------>ret = 0;
 
 out:
<------>realtek_smi_stop(smi);
<------>spin_unlock_irqrestore(&smi->lock, flags);
 
<------>return ret;
}
 
/* There is one single case when we need to use this accessor and that
 * is when issueing soft reset. Since the device reset as soon as we write
 * that bit, no ACK will come back for natural reasons.
 */
int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr,
<------><------><------><------>u32 data)
{
<------>return realtek_smi_write_reg(smi, addr, data, false);
}
EXPORT_SYMBOL_GPL(realtek_smi_write_reg_noack);
 
/* Regmap accessors */
 
static int realtek_smi_write(void *ctx, u32 reg, u32 val)
{
<------>struct realtek_smi *smi = ctx;
 
<------>return realtek_smi_write_reg(smi, reg, val, true);
}
 
static int realtek_smi_read(void *ctx, u32 reg, u32 *val)
{
<------>struct realtek_smi *smi = ctx;
 
<------>return realtek_smi_read_reg(smi, reg, val);
}
 
static const struct regmap_config realtek_smi_mdio_regmap_config = {
<------>.reg_bits = 10, /* A4..A0 R4..R0 */
<------>.val_bits = 16,
<------>.reg_stride = 1,
<------>/* PHY regs are at 0x8000 */
<------>.max_register = 0xffff,
<------>.reg_format_endian = REGMAP_ENDIAN_BIG,
<------>.reg_read = realtek_smi_read,
<------>.reg_write = realtek_smi_write,
<------>.cache_type = REGCACHE_NONE,
};
 
static int realtek_smi_mdio_read(struct mii_bus *bus, int addr, int regnum)
{
<------>struct realtek_smi *smi = bus->priv;
 
<------>return smi->ops->phy_read(smi, addr, regnum);
}
 
static int realtek_smi_mdio_write(struct mii_bus *bus, int addr, int regnum,
<------><------><------><------>  u16 val)
{
<------>struct realtek_smi *smi = bus->priv;
 
<------>return smi->ops->phy_write(smi, addr, regnum, val);
}
 
int realtek_smi_setup_mdio(struct realtek_smi *smi)
{
<------>struct device_node *mdio_np;
<------>int ret;
 
<------>mdio_np = of_get_compatible_child(smi->dev->of_node, "realtek,smi-mdio");
<------>if (!mdio_np) {
<------><------>dev_err(smi->dev, "no MDIO bus node\n");
<------><------>return -ENODEV;
<------>}
 
<------>smi->slave_mii_bus = devm_mdiobus_alloc(smi->dev);
<------>if (!smi->slave_mii_bus) {
<------><------>ret = -ENOMEM;
<------><------>goto err_put_node;
<------>}
<------>smi->slave_mii_bus->priv = smi;
<------>smi->slave_mii_bus->name = "SMI slave MII";
<------>smi->slave_mii_bus->read = realtek_smi_mdio_read;
<------>smi->slave_mii_bus->write = realtek_smi_mdio_write;
<------>snprintf(smi->slave_mii_bus->id, MII_BUS_ID_SIZE, "SMI-%d",
<------><------> smi->ds->index);
<------>smi->slave_mii_bus->dev.of_node = mdio_np;
<------>smi->slave_mii_bus->parent = smi->dev;
<------>smi->ds->slave_mii_bus = smi->slave_mii_bus;
 
<------>ret = devm_of_mdiobus_register(smi->dev, smi->slave_mii_bus, mdio_np);
<------>if (ret) {
<------><------>dev_err(smi->dev, "unable to register MDIO bus %s\n",
<------><------><------>smi->slave_mii_bus->id);
<------><------>goto err_put_node;
<------>}
 
<------>return 0;
 
err_put_node:
<------>of_node_put(mdio_np);
 
<------>return ret;
}
 
static int realtek_smi_probe(struct platform_device *pdev)
{
<------>const struct realtek_smi_variant *var;
<------>struct device *dev = &pdev->dev;
<------>struct realtek_smi *smi;
<------>struct device_node *np;
<------>int ret;
 
<------>var = of_device_get_match_data(dev);
<------>np = dev->of_node;
 
<------>smi = devm_kzalloc(dev, sizeof(*smi) + var->chip_data_sz, GFP_KERNEL);
<------>if (!smi)
<------><------>return -ENOMEM;
<------>smi->chip_data = (void *)smi + sizeof(*smi);
<------>smi->map = devm_regmap_init(dev, NULL, smi,
<------><------><------><------>    &realtek_smi_mdio_regmap_config);
<------>if (IS_ERR(smi->map)) {
<------><------>ret = PTR_ERR(smi->map);
<------><------>dev_err(dev, "regmap init failed: %d\n", ret);
<------><------>return ret;
<------>}
 
<------>/* Link forward and backward */
<------>smi->dev = dev;
<------>smi->clk_delay = var->clk_delay;
<------>smi->cmd_read = var->cmd_read;
<------>smi->cmd_write = var->cmd_write;
<------>smi->ops = var->ops;
 
<------>dev_set_drvdata(dev, smi);
<------>spin_lock_init(&smi->lock);
 
<------>/* TODO: if power is software controlled, set up any regulators here */
 
<------>/* Assert then deassert RESET */
<------>smi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
<------>if (IS_ERR(smi->reset)) {
<------><------>dev_err(dev, "failed to get RESET GPIO\n");
<------><------>return PTR_ERR(smi->reset);
<------>}
<------>msleep(REALTEK_SMI_HW_STOP_DELAY);
<------>gpiod_set_value(smi->reset, 0);
<------>msleep(REALTEK_SMI_HW_START_DELAY);
<------>dev_info(dev, "deasserted RESET\n");
 
<------>/* Fetch MDIO pins */
<------>smi->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
<------>if (IS_ERR(smi->mdc))
<------><------>return PTR_ERR(smi->mdc);
<------>smi->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW);
<------>if (IS_ERR(smi->mdio))
<------><------>return PTR_ERR(smi->mdio);
 
<------>smi->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");
 
<------>ret = smi->ops->detect(smi);
<------>if (ret) {
<------><------>dev_err(dev, "unable to detect switch\n");
<------><------>return ret;
<------>}
 
<------>smi->ds = devm_kzalloc(dev, sizeof(*smi->ds), GFP_KERNEL);
<------>if (!smi->ds)
<------><------>return -ENOMEM;
 
<------>smi->ds->dev = dev;
<------>smi->ds->num_ports = smi->num_ports;
<------>smi->ds->priv = smi;
 
<------>smi->ds->ops = var->ds_ops;
<------>ret = dsa_register_switch(smi->ds);
<------>if (ret) {
<------><------>dev_err(dev, "unable to register switch ret = %d\n", ret);
<------><------>return ret;
<------>}
<------>return 0;
}
 
static int realtek_smi_remove(struct platform_device *pdev)
{
<------>struct realtek_smi *smi = dev_get_drvdata(&pdev->dev);
 
<------>dsa_unregister_switch(smi->ds);
<------>if (smi->slave_mii_bus)
<------><------>of_node_put(smi->slave_mii_bus->dev.of_node);
<------>gpiod_set_value(smi->reset, 1);
 
<------>return 0;
}
 
static const struct of_device_id realtek_smi_of_match[] = {
<------>{
<------><------>.compatible = "realtek,rtl8366rb",
<------><------>.data = &rtl8366rb_variant,
<------>},
<------>{
<------><------>/* FIXME: add support for RTL8366S and more */
<------><------>.compatible = "realtek,rtl8366s",
<------><------>.data = NULL,
<------>},
<------>{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, realtek_smi_of_match);
 
static struct platform_driver realtek_smi_driver = {
<------>.driver = {
<------><------>.name = "realtek-smi",
<------><------>.of_match_table = of_match_ptr(realtek_smi_of_match),
<------>},
<------>.probe  = realtek_smi_probe,
<------>.remove = realtek_smi_remove,
};
module_platform_driver(realtek_smi_driver);
 
MODULE_LICENSE("GPL");