diff options
Diffstat (limited to 'arch/powerpc/platforms/pasemi/gpio_mdio.c')
| -rw-r--r-- | arch/powerpc/platforms/pasemi/gpio_mdio.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pasemi/gpio_mdio.c b/arch/powerpc/platforms/pasemi/gpio_mdio.c new file mode 100644 index 000000000..fd130fe7a --- /dev/null +++ b/arch/powerpc/platforms/pasemi/gpio_mdio.c @@ -0,0 +1,327 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2006-2007 PA Semi, Inc + * + * Author: Olof Johansson, PA Semi + * + * Maintained by: Olof Johansson <olof@lixom.net> + * + * Based on drivers/net/fs_enet/mii-bitbang.c. + */ + +#include <linux/io.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/phy.h> +#include <linux/of_address.h> +#include <linux/of_mdio.h> +#include <linux/platform_device.h> + +#define DELAY 1 + +static void __iomem *gpio_regs; + +struct gpio_priv { + int mdc_pin; + int mdio_pin; +}; + +#define MDC_PIN(bus) (((struct gpio_priv *)bus->priv)->mdc_pin) +#define MDIO_PIN(bus) (((struct gpio_priv *)bus->priv)->mdio_pin) + +static inline void mdio_lo(struct mii_bus *bus) +{ + out_le32(gpio_regs+0x10, 1 << MDIO_PIN(bus)); +} + +static inline void mdio_hi(struct mii_bus *bus) +{ + out_le32(gpio_regs, 1 << MDIO_PIN(bus)); +} + +static inline void mdc_lo(struct mii_bus *bus) +{ + out_le32(gpio_regs+0x10, 1 << MDC_PIN(bus)); +} + +static inline void mdc_hi(struct mii_bus *bus) +{ + out_le32(gpio_regs, 1 << MDC_PIN(bus)); +} + +static inline void mdio_active(struct mii_bus *bus) +{ + out_le32(gpio_regs+0x20, (1 << MDC_PIN(bus)) | (1 << MDIO_PIN(bus))); +} + +static inline void mdio_tristate(struct mii_bus *bus) +{ + out_le32(gpio_regs+0x30, (1 << MDIO_PIN(bus))); +} + +static inline int mdio_read(struct mii_bus *bus) +{ + return !!(in_le32(gpio_regs+0x40) & (1 << MDIO_PIN(bus))); +} + +static void clock_out(struct mii_bus *bus, int bit) +{ + if (bit) + mdio_hi(bus); + else + mdio_lo(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + mdc_lo(bus); +} + +/* Utility to send the preamble, address, and register (common to read and write). */ +static void bitbang_pre(struct mii_bus *bus, int read, u8 addr, u8 reg) +{ + int i; + + /* CFE uses a really long preamble (40 bits). We'll do the same. */ + mdio_active(bus); + for (i = 0; i < 40; i++) { + clock_out(bus, 1); + } + + /* send the start bit (01) and the read opcode (10) or write (10) */ + clock_out(bus, 0); + clock_out(bus, 1); + + clock_out(bus, read); + clock_out(bus, !read); + + /* send the PHY address */ + for (i = 0; i < 5; i++) { + clock_out(bus, (addr & 0x10) != 0); + addr <<= 1; + } + + /* send the register address */ + for (i = 0; i < 5; i++) { + clock_out(bus, (reg & 0x10) != 0); + reg <<= 1; + } +} + +static int gpio_mdio_read(struct mii_bus *bus, int phy_id, int location) +{ + u16 rdreg; + int ret, i; + u8 addr = phy_id & 0xff; + u8 reg = location & 0xff; + + bitbang_pre(bus, 1, addr, reg); + + /* tri-state our MDIO I/O pin so we can read */ + mdio_tristate(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + mdc_lo(bus); + + /* read 16 bits of register data, MSB first */ + rdreg = 0; + for (i = 0; i < 16; i++) { + mdc_lo(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + mdc_lo(bus); + udelay(DELAY); + rdreg <<= 1; + rdreg |= mdio_read(bus); + } + + mdc_hi(bus); + udelay(DELAY); + mdc_lo(bus); + udelay(DELAY); + + ret = rdreg; + + return ret; +} + +static int gpio_mdio_write(struct mii_bus *bus, int phy_id, int location, u16 val) +{ + int i; + + u8 addr = phy_id & 0xff; + u8 reg = location & 0xff; + u16 value = val & 0xffff; + + bitbang_pre(bus, 0, addr, reg); + + /* send the turnaround (10) */ + mdc_lo(bus); + mdio_hi(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + mdc_lo(bus); + mdio_lo(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + + /* write 16 bits of register data, MSB first */ + for (i = 0; i < 16; i++) { + mdc_lo(bus); + if (value & 0x8000) + mdio_hi(bus); + else + mdio_lo(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + value <<= 1; + } + + /* + * Tri-state the MDIO line. + */ + mdio_tristate(bus); + mdc_lo(bus); + udelay(DELAY); + mdc_hi(bus); + udelay(DELAY); + return 0; +} + +static int gpio_mdio_reset(struct mii_bus *bus) +{ + /*nothing here - dunno how to reset it*/ + return 0; +} + + +static int gpio_mdio_probe(struct platform_device *ofdev) +{ + struct device *dev = &ofdev->dev; + struct device_node *np = ofdev->dev.of_node; + struct mii_bus *new_bus; + struct gpio_priv *priv; + const unsigned int *prop; + int err; + + err = -ENOMEM; + priv = kzalloc(sizeof(struct gpio_priv), GFP_KERNEL); + if (!priv) + goto out; + + new_bus = mdiobus_alloc(); + + if (!new_bus) + goto out_free_priv; + + new_bus->name = "pasemi gpio mdio bus"; + new_bus->read = &gpio_mdio_read; + new_bus->write = &gpio_mdio_write; + new_bus->reset = &gpio_mdio_reset; + + prop = of_get_property(np, "reg", NULL); + snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", *prop); + new_bus->priv = priv; + + prop = of_get_property(np, "mdc-pin", NULL); + priv->mdc_pin = *prop; + + prop = of_get_property(np, "mdio-pin", NULL); + priv->mdio_pin = *prop; + + new_bus->parent = dev; + dev_set_drvdata(dev, new_bus); + + err = of_mdiobus_register(new_bus, np); + + if (err != 0) { + pr_err("%s: Cannot register as MDIO bus, err %d\n", + new_bus->name, err); + goto out_free_irq; + } + + return 0; + +out_free_irq: + kfree(new_bus); +out_free_priv: + kfree(priv); +out: + return err; +} + + +static int gpio_mdio_remove(struct platform_device *dev) +{ + struct mii_bus *bus = dev_get_drvdata(&dev->dev); + + mdiobus_unregister(bus); + + dev_set_drvdata(&dev->dev, NULL); + + kfree(bus->priv); + bus->priv = NULL; + mdiobus_free(bus); + + return 0; +} + +static const struct of_device_id gpio_mdio_match[] = +{ + { + .compatible = "gpio-mdio", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, gpio_mdio_match); + +static struct platform_driver gpio_mdio_driver = +{ + .probe = gpio_mdio_probe, + .remove = gpio_mdio_remove, + .driver = { + .name = "gpio-mdio-bitbang", + .of_match_table = gpio_mdio_match, + }, +}; + +static int __init gpio_mdio_init(void) +{ + struct device_node *np; + + np = of_find_compatible_node(NULL, NULL, "1682m-gpio"); + if (!np) + np = of_find_compatible_node(NULL, NULL, + "pasemi,pwrficient-gpio"); + if (!np) + return -ENODEV; + gpio_regs = of_iomap(np, 0); + of_node_put(np); + + if (!gpio_regs) + return -ENODEV; + + return platform_driver_register(&gpio_mdio_driver); +} +module_init(gpio_mdio_init); + +static void __exit gpio_mdio_exit(void) +{ + platform_driver_unregister(&gpio_mdio_driver); + if (gpio_regs) + iounmap(gpio_regs); +} +module_exit(gpio_mdio_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Olof Johansson <olof@lixom.net>"); +MODULE_DESCRIPTION("Driver for MDIO over GPIO on PA Semi PWRficient-based boards"); |