arch/powerpc/platforms/pasemi/gpio_mdio.c

   1 /*
   2  * Copyright (C) 2006-2007 PA Semi, Inc
   3  *
   4  * Author: Olof Johansson, PA Semi
   5  *
   6  * Maintained by: Olof Johansson <olof@lixom.net>
   7  *
   8  * Based on drivers/net/fs_enet/mii-bitbang.c.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  22  */
  23
  24 #include <linux/io.h>
  25 #include <linux/module.h>
  26 #include <linux/types.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/errno.h>
  30 #include <linux/ioport.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/phy.h>
  33 #include <linux/of_address.h>
  34 #include <linux/of_mdio.h>
  35 #include <linux/of_platform.h>
  36
  37 #define DELAY 1
  38
  39 static void __iomem *gpio_regs;
  40
  41 struct gpio_priv {
  42         int mdc_pin;
  43         int mdio_pin;
  44 };
  45
  46 #define MDC_PIN(bus)    (((struct gpio_priv *)bus->priv)->mdc_pin)
  47 #define MDIO_PIN(bus)   (((struct gpio_priv *)bus->priv)->mdio_pin)
  48
  49 static inline void mdio_lo(struct mii_bus *bus)
  50 {
  51         out_le32(gpio_regs+0x10, 1 << MDIO_PIN(bus));
  52 }
  53
  54 static inline void mdio_hi(struct mii_bus *bus)
  55 {
  56         out_le32(gpio_regs, 1 << MDIO_PIN(bus));
  57 }
  58
  59 static inline void mdc_lo(struct mii_bus *bus)
  60 {
  61         out_le32(gpio_regs+0x10, 1 << MDC_PIN(bus));
  62 }
  63
  64 static inline void mdc_hi(struct mii_bus *bus)
  65 {
  66         out_le32(gpio_regs, 1 << MDC_PIN(bus));
  67 }
  68
  69 static inline void mdio_active(struct mii_bus *bus)
  70 {
  71         out_le32(gpio_regs+0x20, (1 << MDC_PIN(bus)) | (1 << MDIO_PIN(bus)));
  72 }
  73
  74 static inline void mdio_tristate(struct mii_bus *bus)
  75 {
  76         out_le32(gpio_regs+0x30, (1 << MDIO_PIN(bus)));
  77 }
  78
  79 static inline int mdio_read(struct mii_bus *bus)
  80 {
  81         return !!(in_le32(gpio_regs+0x40) & (1 << MDIO_PIN(bus)));
  82 }
  83
  84 static void clock_out(struct mii_bus *bus, int bit)
  85 {
  86         if (bit)
  87                 mdio_hi(bus);
  88         else
  89                 mdio_lo(bus);
  90         udelay(DELAY);
  91         mdc_hi(bus);
  92         udelay(DELAY);
  93         mdc_lo(bus);
  94 }
  95
  96 /* Utility to send the preamble, address, and register (common to read and write). */
  97 static void bitbang_pre(struct mii_bus *bus, int read, u8 addr, u8 reg)
  98 {
  99         int i;
 100
 101         /* CFE uses a really long preamble (40 bits). We'll do the same. */
 102         mdio_active(bus);
 103         for (i = 0; i < 40; i++) {
 104                 clock_out(bus, 1);
 105         }
 106
 107         /* send the start bit (01) and the read opcode (10) or write (10) */
 108         clock_out(bus, 0);
 109         clock_out(bus, 1);
 110
 111         clock_out(bus, read);
 112         clock_out(bus, !read);
 113
 114         /* send the PHY address */
 115         for (i = 0; i < 5; i++) {
 116                 clock_out(bus, (addr & 0x10) != 0);
 117                 addr <<= 1;
 118         }
 119
 120         /* send the register address */
 121         for (i = 0; i < 5; i++) {
 122                 clock_out(bus, (reg & 0x10) != 0);
 123                 reg <<= 1;
 124         }
 125 }
 126
 127 static int gpio_mdio_read(struct mii_bus *bus, int phy_id, int location)
 128 {
 129         u16 rdreg;
 130         int ret, i;
 131         u8 addr = phy_id & 0xff;
 132         u8 reg = location & 0xff;
 133
 134         bitbang_pre(bus, 1, addr, reg);
 135
 136         /* tri-state our MDIO I/O pin so we can read */
 137         mdio_tristate(bus);
 138         udelay(DELAY);
 139         mdc_hi(bus);
 140         udelay(DELAY);
 141         mdc_lo(bus);
 142
 143         /* read 16 bits of register data, MSB first */
 144         rdreg = 0;
 145         for (i = 0; i < 16; i++) {
 146                 mdc_lo(bus);
 147                 udelay(DELAY);
 148                 mdc_hi(bus);
 149                 udelay(DELAY);
 150                 mdc_lo(bus);
 151                 udelay(DELAY);
 152                 rdreg <<= 1;
 153                 rdreg |= mdio_read(bus);
 154         }
 155
 156         mdc_hi(bus);
 157         udelay(DELAY);
 158         mdc_lo(bus);
 159         udelay(DELAY);
 160
 161         ret = rdreg;
 162
 163         return ret;
 164 }
 165
 166 static int gpio_mdio_write(struct mii_bus *bus, int phy_id, int location, u16 val)
 167 {
 168         int i;
 169
 170         u8 addr = phy_id & 0xff;
 171         u8 reg = location & 0xff;
 172         u16 value = val & 0xffff;
 173
 174         bitbang_pre(bus, 0, addr, reg);
 175
 176         /* send the turnaround (10) */
 177         mdc_lo(bus);
 178         mdio_hi(bus);
 179         udelay(DELAY);
 180         mdc_hi(bus);
 181         udelay(DELAY);
 182         mdc_lo(bus);
 183         mdio_lo(bus);
 184         udelay(DELAY);
 185         mdc_hi(bus);
 186         udelay(DELAY);
 187
 188         /* write 16 bits of register data, MSB first */
 189         for (i = 0; i < 16; i++) {
 190                 mdc_lo(bus);
 191                 if (value & 0x8000)
 192                         mdio_hi(bus);
 193                 else
 194                         mdio_lo(bus);
 195                 udelay(DELAY);
 196                 mdc_hi(bus);
 197                 udelay(DELAY);
 198                 value <<= 1;
 199         }
 200
 201         /*
 202          * Tri-state the MDIO line.
 203          */
 204         mdio_tristate(bus);
 205         mdc_lo(bus);
 206         udelay(DELAY);
 207         mdc_hi(bus);
 208         udelay(DELAY);
 209         return 0;
 210 }
 211
 212 static int gpio_mdio_reset(struct mii_bus *bus)
 213 {
 214         /*nothing here - dunno how to reset it*/
 215         return 0;
 216 }
 217
 218
 219 static int gpio_mdio_probe(struct platform_device *ofdev)
 220 {
 221         struct device *dev = &ofdev->dev;
 222         struct device_node *np = ofdev->dev.of_node;
 223         struct mii_bus *new_bus;
 224         struct gpio_priv *priv;
 225         const unsigned int *prop;
 226         int err;
 227
 228         err = -ENOMEM;
 229         priv = kzalloc(sizeof(struct gpio_priv), GFP_KERNEL);
 230         if (!priv)
 231                 goto out;
 232
 233         new_bus = mdiobus_alloc();
 234
 235         if (!new_bus)
 236                 goto out_free_priv;
 237
 238         new_bus->name = "pasemi gpio mdio bus";
 239         new_bus->read = &gpio_mdio_read;
 240         new_bus->write = &gpio_mdio_write;
 241         new_bus->reset = &gpio_mdio_reset;
 242
 243         prop = of_get_property(np, "reg", NULL);
 244         snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", *prop);
 245         new_bus->priv = priv;
 246
 247         prop = of_get_property(np, "mdc-pin", NULL);
 248         priv->mdc_pin = *prop;
 249
 250         prop = of_get_property(np, "mdio-pin", NULL);
 251         priv->mdio_pin = *prop;
 252
 253         new_bus->parent = dev;
 254         dev_set_drvdata(dev, new_bus);
 255
 256         err = of_mdiobus_register(new_bus, np);
 257
 258         if (err != 0) {
 259                 printk(KERN_ERR "%s: Cannot register as MDIO bus, err %d\n",
 260                                 new_bus->name, err);
 261                 goto out_free_irq;
 262         }
 263
 264         return 0;
 265
 266 out_free_irq:
 267         kfree(new_bus);
 268 out_free_priv:
 269         kfree(priv);
 270 out:
 271         return err;
 272 }
 273
 274
 275 static int gpio_mdio_remove(struct platform_device *dev)
 276 {
 277         struct mii_bus *bus = dev_get_drvdata(&dev->dev);
 278
 279         mdiobus_unregister(bus);
 280
 281         dev_set_drvdata(&dev->dev, NULL);
 282
 283         kfree(bus->priv);
 284         bus->priv = NULL;
 285         mdiobus_free(bus);
 286
 287         return 0;
 288 }
 289
 290 static const struct of_device_id gpio_mdio_match[] =
 291 {
 292         {
 293                 .compatible      = "gpio-mdio",
 294         },
 295         {},
 296 };
 297 MODULE_DEVICE_TABLE(of, gpio_mdio_match);
 298
 299 static struct platform_driver gpio_mdio_driver =
 300 {
 301         .probe          = gpio_mdio_probe,
 302         .remove         = gpio_mdio_remove,
 303         .driver = {
 304                 .name = "gpio-mdio-bitbang",
 305                 .of_match_table = gpio_mdio_match,
 306         },
 307 };
 308
 309 static int gpio_mdio_init(void)
 310 {
 311         struct device_node *np;
 312
 313         np = of_find_compatible_node(NULL, NULL, "1682m-gpio");
 314         if (!np)
 315                 np = of_find_compatible_node(NULL, NULL,
 316                                              "pasemi,pwrficient-gpio");
 317         if (!np)
 318                 return -ENODEV;
 319         gpio_regs = of_iomap(np, 0);
 320         of_node_put(np);
 321
 322         if (!gpio_regs)
 323                 return -ENODEV;
 324
 325         return platform_driver_register(&gpio_mdio_driver);
 326 }
 327 module_init(gpio_mdio_init);
 328
 329 static void gpio_mdio_exit(void)
 330 {
 331         platform_driver_unregister(&gpio_mdio_driver);
 332         if (gpio_regs)
 333                 iounmap(gpio_regs);
 334 }
 335 module_exit(gpio_mdio_exit);
 336
 337 MODULE_LICENSE("GPL");
 338 MODULE_AUTHOR("Olof Johansson <olof@lixom.net>");
 339 MODULE_DESCRIPTION("Driver for MDIO over GPIO on PA Semi PWRficient-based boards");