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/sched.h>
  28 #include <linux/errno.h>
  29 #include <linux/ioport.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/phy.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/of_platform.h>
  34
  35 #define DELAY 1
  36
  37 static void __iomem *gpio_regs;
  38
  39 struct gpio_priv {
  40         int mdc_pin;
  41         int mdio_pin;
  42 };
  43
  44 #define MDC_PIN(bus)    (((struct gpio_priv *)bus->priv)->mdc_pin)
  45 #define MDIO_PIN(bus)   (((struct gpio_priv *)bus->priv)->mdio_pin)
  46
  47 static inline void mdio_lo(struct mii_bus *bus)
  48 {
  49         out_le32(gpio_regs+0x10, 1 << MDIO_PIN(bus));
  50 }
  51
  52 static inline void mdio_hi(struct mii_bus *bus)
  53 {
  54         out_le32(gpio_regs, 1 << MDIO_PIN(bus));
  55 }
  56
  57 static inline void mdc_lo(struct mii_bus *bus)
  58 {
  59         out_le32(gpio_regs+0x10, 1 << MDC_PIN(bus));
  60 }
  61
  62 static inline void mdc_hi(struct mii_bus *bus)
  63 {
  64         out_le32(gpio_regs, 1 << MDC_PIN(bus));
  65 }
  66
  67 static inline void mdio_active(struct mii_bus *bus)
  68 {
  69         out_le32(gpio_regs+0x20, (1 << MDC_PIN(bus)) | (1 << MDIO_PIN(bus)));
  70 }
  71
  72 static inline void mdio_tristate(struct mii_bus *bus)
  73 {
  74         out_le32(gpio_regs+0x30, (1 << MDIO_PIN(bus)));
  75 }
  76
  77 static inline int mdio_read(struct mii_bus *bus)
  78 {
  79         return !!(in_le32(gpio_regs+0x40) & (1 << MDIO_PIN(bus)));
  80 }
  81
  82 static void clock_out(struct mii_bus *bus, int bit)
  83 {
  84         if (bit)
  85                 mdio_hi(bus);
  86         else
  87                 mdio_lo(bus);
  88         udelay(DELAY);
  89         mdc_hi(bus);
  90         udelay(DELAY);
  91         mdc_lo(bus);
  92 }
  93
  94 /* Utility to send the preamble, address, and register (common to read and write). */
  95 static void bitbang_pre(struct mii_bus *bus, int read, u8 addr, u8 reg)
  96 {
  97         int i;
  98
  99         /* CFE uses a really long preamble (40 bits). We'll do the same. */
 100         mdio_active(bus);
 101         for (i = 0; i < 40; i++) {
 102                 clock_out(bus, 1);
 103         }
 104
 105         /* send the start bit (01) and the read opcode (10) or write (10) */
 106         clock_out(bus, 0);
 107         clock_out(bus, 1);
 108
 109         clock_out(bus, read);
 110         clock_out(bus, !read);
 111
 112         /* send the PHY address */
 113         for (i = 0; i < 5; i++) {
 114                 clock_out(bus, (addr & 0x10) != 0);
 115                 addr <<= 1;
 116         }
 117
 118         /* send the register address */
 119         for (i = 0; i < 5; i++) {
 120                 clock_out(bus, (reg & 0x10) != 0);
 121                 reg <<= 1;
 122         }
 123 }
 124
 125 static int gpio_mdio_read(struct mii_bus *bus, int phy_id, int location)
 126 {
 127         u16 rdreg;
 128         int ret, i;
 129         u8 addr = phy_id & 0xff;
 130         u8 reg = location & 0xff;
 131
 132         bitbang_pre(bus, 1, addr, reg);
 133
 134         /* tri-state our MDIO I/O pin so we can read */
 135         mdio_tristate(bus);
 136         udelay(DELAY);
 137         mdc_hi(bus);
 138         udelay(DELAY);
 139         mdc_lo(bus);
 140
 141         /* read 16 bits of register data, MSB first */
 142         rdreg = 0;
 143         for (i = 0; i < 16; i++) {
 144                 mdc_lo(bus);
 145                 udelay(DELAY);
 146                 mdc_hi(bus);
 147                 udelay(DELAY);
 148                 mdc_lo(bus);
 149                 udelay(DELAY);
 150                 rdreg <<= 1;
 151                 rdreg |= mdio_read(bus);
 152         }
 153
 154         mdc_hi(bus);
 155         udelay(DELAY);
 156         mdc_lo(bus);
 157         udelay(DELAY);
 158
 159         ret = rdreg;
 160
 161         return ret;
 162 }
 163
 164 static int gpio_mdio_write(struct mii_bus *bus, int phy_id, int location, u16 val)
 165 {
 166         int i;
 167
 168         u8 addr = phy_id & 0xff;
 169         u8 reg = location & 0xff;
 170         u16 value = val & 0xffff;
 171
 172         bitbang_pre(bus, 0, addr, reg);
 173
 174         /* send the turnaround (10) */
 175         mdc_lo(bus);
 176         mdio_hi(bus);
 177         udelay(DELAY);
 178         mdc_hi(bus);
 179         udelay(DELAY);
 180         mdc_lo(bus);
 181         mdio_lo(bus);
 182         udelay(DELAY);
 183         mdc_hi(bus);
 184         udelay(DELAY);
 185
 186         /* write 16 bits of register data, MSB first */
 187         for (i = 0; i < 16; i++) {
 188                 mdc_lo(bus);
 189                 if (value & 0x8000)
 190                         mdio_hi(bus);
 191                 else
 192                         mdio_lo(bus);
 193                 udelay(DELAY);
 194                 mdc_hi(bus);
 195                 udelay(DELAY);
 196                 value <<= 1;
 197         }
 198
 199         /*
 200          * Tri-state the MDIO line.
 201          */
 202         mdio_tristate(bus);
 203         mdc_lo(bus);
 204         udelay(DELAY);
 205         mdc_hi(bus);
 206         udelay(DELAY);
 207         return 0;
 208 }
 209
 210 static int gpio_mdio_reset(struct mii_bus *bus)
 211 {
 212         /*nothing here - dunno how to reset it*/
 213         return 0;
 214 }
 215
 216
 217 static int __devinit gpio_mdio_probe(struct of_device *ofdev,
 218                                      const struct of_device_id *match)
 219 {
 220         struct device *dev = &ofdev->dev;
 221         struct device_node *phy_dn, *np = ofdev->node;
 222         struct mii_bus *new_bus;
 223         struct gpio_priv *priv;
 224         const unsigned int *prop;
 225         int err;
 226         int i;
 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         new_bus->phy_mask = 0;
 248
 249         new_bus->irq = kmalloc(sizeof(int)*PHY_MAX_ADDR, GFP_KERNEL);
 250
 251         if (!new_bus->irq)
 252                 goto out_free_bus;
 253
 254         for (i = 0; i < PHY_MAX_ADDR; i++)
 255                 new_bus->irq[i] = NO_IRQ;
 256
 257         for (phy_dn = of_get_next_child(np, NULL);
 258              phy_dn != NULL;
 259              phy_dn = of_get_next_child(np, phy_dn)) {
 260                 const unsigned int *ip, *regp;
 261
 262                 ip = of_get_property(phy_dn, "interrupts", NULL);
 263                 regp = of_get_property(phy_dn, "reg", NULL);
 264                 if (!ip || !regp || *regp >= PHY_MAX_ADDR)
 265                         continue;
 266                 new_bus->irq[*regp] = irq_create_mapping(NULL, *ip);
 267         }
 268
 269         prop = of_get_property(np, "mdc-pin", NULL);
 270         priv->mdc_pin = *prop;
 271
 272         prop = of_get_property(np, "mdio-pin", NULL);
 273         priv->mdio_pin = *prop;
 274
 275         new_bus->parent = dev;
 276         dev_set_drvdata(dev, new_bus);
 277
 278         err = mdiobus_register(new_bus);
 279
 280         if (err != 0) {
 281                 printk(KERN_ERR "%s: Cannot register as MDIO bus, err %d\n",
 282                                 new_bus->name, err);
 283                 goto out_free_irq;
 284         }
 285
 286         return 0;
 287
 288 out_free_irq:
 289         kfree(new_bus->irq);
 290 out_free_bus:
 291         kfree(new_bus);
 292 out_free_priv:
 293         kfree(priv);
 294 out:
 295         return err;
 296 }
 297
 298
 299 static int gpio_mdio_remove(struct of_device *dev)
 300 {
 301         struct mii_bus *bus = dev_get_drvdata(&dev->dev);
 302
 303         mdiobus_unregister(bus);
 304
 305         dev_set_drvdata(&dev->dev, NULL);
 306
 307         kfree(bus->priv);
 308         bus->priv = NULL;
 309         mdiobus_free(bus);
 310
 311         return 0;
 312 }
 313
 314 static struct of_device_id gpio_mdio_match[] =
 315 {
 316         {
 317                 .compatible      = "gpio-mdio",
 318         },
 319         {},
 320 };
 321 MODULE_DEVICE_TABLE(of, gpio_mdio_match);
 322
 323 static struct of_platform_driver gpio_mdio_driver =
 324 {
 325         .match_table    = gpio_mdio_match,
 326         .probe          = gpio_mdio_probe,
 327         .remove         = gpio_mdio_remove,
 328         .driver         = {
 329                 .name   = "gpio-mdio-bitbang",
 330         },
 331 };
 332
 333 int gpio_mdio_init(void)
 334 {
 335         struct device_node *np;
 336
 337         np = of_find_compatible_node(NULL, NULL, "1682m-gpio");
 338         if (!np)
 339                 np = of_find_compatible_node(NULL, NULL,
 340                                              "pasemi,pwrficient-gpio");
 341         if (!np)
 342                 return -ENODEV;
 343         gpio_regs = of_iomap(np, 0);
 344         of_node_put(np);
 345
 346         if (!gpio_regs)
 347                 return -ENODEV;
 348
 349         return of_register_platform_driver(&gpio_mdio_driver);
 350 }
 351 module_init(gpio_mdio_init);
 352
 353 void gpio_mdio_exit(void)
 354 {
 355         of_unregister_platform_driver(&gpio_mdio_driver);
 356         if (gpio_regs)
 357                 iounmap(gpio_regs);
 358 }
 359 module_exit(gpio_mdio_exit);
 360
 361 MODULE_LICENSE("GPL");
 362 MODULE_AUTHOR("Olof Johansson <olof@lixom.net>");
 363 MODULE_DESCRIPTION("Driver for MDIO over GPIO on PA Semi PWRficient-based boards");