// SPDX-License-Identifier: (GPL-2.0 OR MIT)
/*
* Driver for the MDIO interface of Microsemi network switches.
*
* Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
* Copyright (c) 2017 Microsemi Corporation
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/mdio/mdio-mscc-miim.h>
#include <linux/mfd/ocelot.h>
#include <linux/module.h>
#include <linux/of_mdio.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#define MSCC_MIIM_REG_STATUS 0x0
#define MSCC_MIIM_STATUS_STAT_PENDING BIT(2)
#define MSCC_MIIM_STATUS_STAT_BUSY BIT(3)
#define MSCC_MIIM_REG_CMD 0x8
#define MSCC_MIIM_CMD_OPR_WRITE BIT(1)
#define MSCC_MIIM_CMD_OPR_READ BIT(2)
#define MSCC_MIIM_CMD_WRDATA_SHIFT 4
#define MSCC_MIIM_CMD_REGAD_SHIFT 20
#define MSCC_MIIM_CMD_PHYAD_SHIFT 25
#define MSCC_MIIM_CMD_VLD BIT(31)
#define MSCC_MIIM_REG_DATA 0xC
#define MSCC_MIIM_DATA_ERROR (BIT(16) | BIT(17))
#define MSCC_MIIM_REG_CFG 0x10
#define MSCC_MIIM_CFG_PRESCALE_MASK GENMASK(7, 0)
#define MSCC_PHY_REG_PHY_CFG 0x0
#define PHY_CFG_PHY_ENA (BIT(0) | BIT(1) | BIT(2) | BIT(3))
#define PHY_CFG_PHY_COMMON_RESET BIT(4)
#define PHY_CFG_PHY_RESET (BIT(5) | BIT(6) | BIT(7) | BIT(8))
#define MSCC_PHY_REG_PHY_STATUS 0x4
#define LAN966X_CUPHY_COMMON_CFG 0x0
#define CUPHY_COMMON_CFG_RESET_N BIT(0)
struct mscc_miim_info {
unsigned int phy_reset_offset;
unsigned int phy_reset_bits;
};
struct mscc_miim_dev {
struct regmap *regs;
int mii_status_offset;
bool ignore_read_errors;
struct regmap *phy_regs;
const struct mscc_miim_info *info;
struct clk *clk;
u32 bus_freq;
};
/* When high resolution timers aren't built-in: we can't use usleep_range() as
* we would sleep way too long. Use udelay() instead.
*/
#define mscc_readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us)\
({ \
if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS)) \
readx_poll_timeout_atomic(op, addr, val, cond, delay_us, \
timeout_us); \
readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us); \
})
static int mscc_miim_status(struct mii_bus *bus)
{
struct mscc_miim_dev *miim = bus->priv;
int val, ret;
ret = regmap_read(miim->regs,
MSCC_MIIM_REG_STATUS + miim->mii_status_offset, &val);
if (ret < 0) {
WARN_ONCE(1, "mscc miim status read error %d\n", ret);
return ret;
}
return val;
}
static int mscc_miim_wait_ready(struct mii_bus *bus)
{
u32 val;
return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
!(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
10000);
}
static int mscc_miim_wait_pending(struct mii_bus *bus)
{
u32 val;
return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
!(val & MSCC_MIIM_STATUS_STAT_PENDING),
50, 10000);
}
static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
{
struct mscc_miim_dev *miim = bus->priv;
u32 val;
int ret;
ret = mscc_miim_wait_pending(bus);
if (ret)
goto out;
ret = regmap_write(miim->regs,
MSCC_MIIM_REG_CMD + miim->mii_status_offset,
MSCC_MIIM_CMD_VLD |
(mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
(regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
MSCC_MIIM_CMD_OPR_READ);
if (ret < 0) {
WARN_ONCE(1, "mscc miim write cmd reg error %d\n", ret);
goto out;
}
ret = mscc_miim_wait_ready(bus);
if (ret)
goto out;
ret = regmap_read(miim->regs,
MSCC_MIIM_REG_DATA + miim->mii_status_offset, &val);
if (ret < 0) {
WARN_ONCE(1, "mscc miim read data reg error %d\n", ret);
goto out;
}
if (!miim->ignore_read_errors && !!(val & MSCC_MIIM_DATA_ERROR)) {
ret = -EIO;
goto out;
}
ret = val & 0xFFFF;
out:
return ret;
}
static int mscc_miim_write(struct mii_bus *bus, int mii_id,
int regnum, u16 value)
{
struct mscc_miim_dev *miim = bus->priv;
int ret;
ret = mscc_miim_wait_pending(bus);
if (ret < 0)
goto out;
ret = regmap_write(miim->regs,
MSCC_MIIM_REG_CMD + miim->mii_status_offset,
MSCC_MIIM_CMD_VLD |
(mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
(regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
(value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
MSCC_MIIM_CMD_OPR_WRITE);
if (ret < 0)
WARN_ONCE(1, "mscc miim write error %d\n", ret);
out:
return ret;
}
static int mscc_miim_reset(struct mii_bus *bus)
{
struct mscc_miim_dev *miim = bus->priv;
unsigned int offset, bits;
int ret;
if (!miim->phy_regs)
return 0;
offset = miim->info->phy_reset_offset;
bits = miim->info->phy_reset_bits;
ret = regmap_update_bits(miim->phy_regs, offset, bits, 0);
if (ret < 0) {
WARN_ONCE(1, "mscc reset set error %d\n", ret);
return ret;
}
ret = regmap_update_bits(miim->phy_regs, offset, bits, bits);
if (ret < 0) {
WARN_ONCE(1, "mscc reset clear error %d\n", ret);
return ret;
}
mdelay(500);
return 0;
}
static const struct regmap_config mscc_miim_regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
};
static const struct regmap_config mscc_miim_phy_regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
.name = "phy",
};
int mscc_miim_setup(struct device *dev, struct mii_bus **pbus, const char *name,
struct regmap *mii_regmap, int status_offset,
bool ignore_read_errors)
{
struct mscc_miim_dev *miim;
struct mii_bus *bus;
bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
if (!bus)
return -ENOMEM;
bus->name = name;
bus->read = mscc_miim_read;
bus->write = mscc_miim_write;
bus->reset = mscc_miim_reset;
snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
bus->parent = dev;
miim = bus->priv;
*pbus = bus;
miim->regs = mii_regmap;
miim->mii_status_offset = status_offset;
miim->ignore_read_errors = ignore_read_errors;
*pbus = bus;
return 0;
}
EXPORT_SYMBOL(mscc_miim_setup);
static int mscc_miim_clk_set(struct mii_bus *bus)
{
struct mscc_miim_dev *miim = bus->priv;
unsigned long rate;
u32 div;
/* Keep the current settings */
if (!miim->bus_freq)
return 0;
rate = clk_get_rate(miim->clk);
div = DIV_ROUND_UP(rate, 2 * miim->bus_freq) - 1;
if (div == 0 || div & ~MSCC_MIIM_CFG_PRESCALE_MASK) {
dev_err(&bus->dev, "Incorrect MDIO clock frequency\n");
return -EINVAL;
}
return regmap_update_bits(miim->regs, MSCC_MIIM_REG_CFG,
MSCC_MIIM_CFG_PRESCALE_MASK, div);
}
static int mscc_miim_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct regmap *mii_regmap, *phy_regmap;
struct device *dev = &pdev->dev;
struct mscc_miim_dev *miim;
struct mii_bus *bus;
int ret;
mii_regmap = ocelot_regmap_from_resource(pdev, 0,
&mscc_miim_regmap_config);
if (IS_ERR(mii_regmap))
return dev_err_probe(dev, PTR_ERR(mii_regmap),
"Unable to create MIIM regmap\n");
/* This resource is optional */
phy_regmap = ocelot_regmap_from_resource_optional(pdev, 1,
&mscc_miim_phy_regmap_config);
if (IS_ERR(phy_regmap))
return dev_err_probe(dev, PTR_ERR(phy_regmap),
"Unable to create phy register regmap\n");
ret = mscc_miim_setup(dev, &bus, "mscc_miim", mii_regmap, 0, false);
if (ret < 0) {
dev_err(dev, "Unable to setup the MDIO bus\n");
return ret;
}
miim = bus->priv;
miim->phy_regs = phy_regmap;
miim->info = device_get_match_data(dev);
if (!miim->info)
return -EINVAL;
miim->clk = devm_clk_get_optional(dev, NULL);
if (IS_ERR(miim->clk))
return PTR_ERR(miim->clk);
of_property_read_u32(np, "clock-frequency", &miim->bus_freq);
if (miim->bus_freq && !miim->clk) {
dev_err(dev, "cannot use clock-frequency without a clock\n");
return -EINVAL;
}
ret = clk_prepare_enable(miim->clk);
if (ret)
return ret;
ret = mscc_miim_clk_set(bus);
if (ret)
goto out_disable_clk;
ret = of_mdiobus_register(bus, np);
if (ret < 0) {
dev_err(dev, "Cannot register MDIO bus (%d)\n", ret);
goto out_disable_clk;
}
platform_set_drvdata(pdev, bus);
return 0;
out_disable_clk:
clk_disable_unprepare(miim->clk);
return ret;
}
static int mscc_miim_remove(struct platform_device *pdev)
{
struct mii_bus *bus = platform_get_drvdata(pdev);
struct mscc_miim_dev *miim = bus->priv;
clk_disable_unprepare(miim->clk);
mdiobus_unregister(bus);
return 0;
}
static const struct mscc_miim_info mscc_ocelot_miim_info = {
.phy_reset_offset = MSCC_PHY_REG_PHY_CFG,
.phy_reset_bits = PHY_CFG_PHY_ENA | PHY_CFG_PHY_COMMON_RESET |
PHY_CFG_PHY_RESET,
};
static const struct mscc_miim_info microchip_lan966x_miim_info = {
.phy_reset_offset = LAN966X_CUPHY_COMMON_CFG,
.phy_reset_bits = CUPHY_COMMON_CFG_RESET_N,
};
static const struct of_device_id mscc_miim_match[] = {
{
.compatible = "mscc,ocelot-miim",
.data = &mscc_ocelot_miim_info
}, {
.compatible = "microchip,lan966x-miim",
.data = µchip_lan966x_miim_info
},
{ }
};
MODULE_DEVICE_TABLE(of, mscc_miim_match);
static struct platform_driver mscc_miim_driver = {
.probe = mscc_miim_probe,
.remove = mscc_miim_remove,
.driver = {
.name = "mscc-miim",
.of_match_table = mscc_miim_match,
},
};
module_platform_driver(mscc_miim_driver);
MODULE_DESCRIPTION("Microsemi MIIM driver");
MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
MODULE_LICENSE("Dual MIT/GPL");
