drivers/gpu/drm/i915/intel_i2c.c

   1 /*
   2  * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
   3  * Copyright © 2006-2008,2010 Intel Corporation
   4  *   Jesse Barnes <jesse.barnes@intel.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *      Eric Anholt <eric@anholt.net>
  27  *      Chris Wilson <chris@chris-wilson.co.uk>
  28  */
  29 #include <linux/i2c.h>
  30 #include <linux/i2c-algo-bit.h>
  31 #include <linux/export.h>
  32 #include "drmP.h"
  33 #include "drm.h"
  34 #include "intel_drv.h"
  35 #include "i915_drm.h"
  36 #include "i915_drv.h"
  37
  38 /* Intel GPIO access functions */
  39
  40 #define I2C_RISEFALL_TIME 20
  41
  42 static inline struct intel_gmbus *
  43 to_intel_gmbus(struct i2c_adapter *i2c)
  44 {
  45         return container_of(i2c, struct intel_gmbus, adapter);
  46 }
  47
  48 struct intel_gpio {
  49         struct i2c_adapter adapter;
  50         struct i2c_algo_bit_data algo;
  51         struct drm_i915_private *dev_priv;
  52         u32 reg;
  53 };
  54
  55 void
  56 intel_i2c_reset(struct drm_device *dev)
  57 {
  58         struct drm_i915_private *dev_priv = dev->dev_private;
  59         if (HAS_PCH_SPLIT(dev))
  60                 I915_WRITE(PCH_GMBUS0, 0);
  61         else
  62                 I915_WRITE(GMBUS0, 0);
  63 }
  64
  65 static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable)
  66 {
  67         u32 val;
  68
  69         /* When using bit bashing for I2C, this bit needs to be set to 1 */
  70         if (!IS_PINEVIEW(dev_priv->dev))
  71                 return;
  72
  73         val = I915_READ(DSPCLK_GATE_D);
  74         if (enable)
  75                 val |= DPCUNIT_CLOCK_GATE_DISABLE;
  76         else
  77                 val &= ~DPCUNIT_CLOCK_GATE_DISABLE;
  78         I915_WRITE(DSPCLK_GATE_D, val);
  79 }
  80
  81 static u32 get_reserved(struct intel_gpio *gpio)
  82 {
  83         struct drm_i915_private *dev_priv = gpio->dev_priv;
  84         struct drm_device *dev = dev_priv->dev;
  85         u32 reserved = 0;
  86
  87         /* On most chips, these bits must be preserved in software. */
  88         if (!IS_I830(dev) && !IS_845G(dev))
  89                 reserved = I915_READ_NOTRACE(gpio->reg) &
  90                                              (GPIO_DATA_PULLUP_DISABLE |
  91                                               GPIO_CLOCK_PULLUP_DISABLE);
  92
  93         return reserved;
  94 }
  95
  96 static int get_clock(void *data)
  97 {
  98         struct intel_gpio *gpio = data;
  99         struct drm_i915_private *dev_priv = gpio->dev_priv;
 100         u32 reserved = get_reserved(gpio);
 101         I915_WRITE_NOTRACE(gpio->reg, reserved | GPIO_CLOCK_DIR_MASK);
 102         I915_WRITE_NOTRACE(gpio->reg, reserved);
 103         return (I915_READ_NOTRACE(gpio->reg) & GPIO_CLOCK_VAL_IN) != 0;
 104 }
 105
 106 static int get_data(void *data)
 107 {
 108         struct intel_gpio *gpio = data;
 109         struct drm_i915_private *dev_priv = gpio->dev_priv;
 110         u32 reserved = get_reserved(gpio);
 111         I915_WRITE_NOTRACE(gpio->reg, reserved | GPIO_DATA_DIR_MASK);
 112         I915_WRITE_NOTRACE(gpio->reg, reserved);
 113         return (I915_READ_NOTRACE(gpio->reg) & GPIO_DATA_VAL_IN) != 0;
 114 }
 115
 116 static void set_clock(void *data, int state_high)
 117 {
 118         struct intel_gpio *gpio = data;
 119         struct drm_i915_private *dev_priv = gpio->dev_priv;
 120         u32 reserved = get_reserved(gpio);
 121         u32 clock_bits;
 122
 123         if (state_high)
 124                 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
 125         else
 126                 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
 127                         GPIO_CLOCK_VAL_MASK;
 128
 129         I915_WRITE_NOTRACE(gpio->reg, reserved | clock_bits);
 130         POSTING_READ(gpio->reg);
 131 }
 132
 133 static void set_data(void *data, int state_high)
 134 {
 135         struct intel_gpio *gpio = data;
 136         struct drm_i915_private *dev_priv = gpio->dev_priv;
 137         u32 reserved = get_reserved(gpio);
 138         u32 data_bits;
 139
 140         if (state_high)
 141                 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
 142         else
 143                 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
 144                         GPIO_DATA_VAL_MASK;
 145
 146         I915_WRITE_NOTRACE(gpio->reg, reserved | data_bits);
 147         POSTING_READ(gpio->reg);
 148 }
 149
 150 static struct i2c_adapter *
 151 intel_gpio_create(struct drm_i915_private *dev_priv, u32 pin)
 152 {
 153         static const int map_pin_to_reg[] = {
 154                 0,
 155                 GPIOB,
 156                 GPIOA,
 157                 GPIOC,
 158                 GPIOD,
 159                 GPIOE,
 160                 0,
 161                 GPIOF,
 162         };
 163         struct intel_gpio *gpio;
 164
 165         if (pin >= ARRAY_SIZE(map_pin_to_reg) || !map_pin_to_reg[pin])
 166                 return NULL;
 167
 168         gpio = kzalloc(sizeof(struct intel_gpio), GFP_KERNEL);
 169         if (gpio == NULL)
 170                 return NULL;
 171
 172         gpio->reg = map_pin_to_reg[pin];
 173         if (HAS_PCH_SPLIT(dev_priv->dev))
 174                 gpio->reg += PCH_GPIOA - GPIOA;
 175         gpio->dev_priv = dev_priv;
 176
 177         snprintf(gpio->adapter.name, sizeof(gpio->adapter.name),
 178                  "i915 GPIO%c", "?BACDE?F"[pin]);
 179         gpio->adapter.owner = THIS_MODULE;
 180         gpio->adapter.algo_data = &gpio->algo;
 181         gpio->adapter.dev.parent = &dev_priv->dev->pdev->dev;
 182         gpio->algo.setsda = set_data;
 183         gpio->algo.setscl = set_clock;
 184         gpio->algo.getsda = get_data;
 185         gpio->algo.getscl = get_clock;
 186         gpio->algo.udelay = I2C_RISEFALL_TIME;
 187         gpio->algo.timeout = usecs_to_jiffies(2200);
 188         gpio->algo.data = gpio;
 189
 190         if (i2c_bit_add_bus(&gpio->adapter))
 191                 goto out_free;
 192
 193         return &gpio->adapter;
 194
 195 out_free:
 196         kfree(gpio);
 197         return NULL;
 198 }
 199
 200 static int
 201 intel_i2c_quirk_xfer(struct drm_i915_private *dev_priv,
 202                      struct i2c_adapter *adapter,
 203                      struct i2c_msg *msgs,
 204                      int num)
 205 {
 206         struct intel_gpio *gpio = container_of(adapter,
 207                                                struct intel_gpio,
 208                                                adapter);
 209         int ret;
 210
 211         intel_i2c_reset(dev_priv->dev);
 212
 213         intel_i2c_quirk_set(dev_priv, true);
 214         set_data(gpio, 1);
 215         set_clock(gpio, 1);
 216         udelay(I2C_RISEFALL_TIME);
 217
 218         ret = adapter->algo->master_xfer(adapter, msgs, num);
 219
 220         set_data(gpio, 1);
 221         set_clock(gpio, 1);
 222         intel_i2c_quirk_set(dev_priv, false);
 223
 224         return ret;
 225 }
 226
 227 static int
 228 gmbus_xfer(struct i2c_adapter *adapter,
 229            struct i2c_msg *msgs,
 230            int num)
 231 {
 232         struct intel_gmbus *bus = container_of(adapter,
 233                                                struct intel_gmbus,
 234                                                adapter);
 235         struct drm_i915_private *dev_priv = adapter->algo_data;
 236         int i, reg_offset;
 237
 238         if (bus->force_bit)
 239                 return intel_i2c_quirk_xfer(dev_priv,
 240                                             bus->force_bit, msgs, num);
 241
 242         reg_offset = HAS_PCH_SPLIT(dev_priv->dev) ? PCH_GMBUS0 - GMBUS0 : 0;
 243
 244         I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
 245
 246         for (i = 0; i < num; i++) {
 247                 u16 len = msgs[i].len;
 248                 u8 *buf = msgs[i].buf;
 249
 250                 if (msgs[i].flags & I2C_M_RD) {
 251                         I915_WRITE(GMBUS1 + reg_offset,
 252                                    GMBUS_CYCLE_WAIT | (i + 1 == num ? GMBUS_CYCLE_STOP : 0) |
 253                                    (len << GMBUS_BYTE_COUNT_SHIFT) |
 254                                    (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
 255                                    GMBUS_SLAVE_READ | GMBUS_SW_RDY);
 256                         POSTING_READ(GMBUS2+reg_offset);
 257                         do {
 258                                 u32 val, loop = 0;
 259
 260                                 if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 261                                         goto timeout;
 262                                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 263                                         goto clear_err;
 264
 265                                 val = I915_READ(GMBUS3 + reg_offset);
 266                                 do {
 267                                         *buf++ = val & 0xff;
 268                                         val >>= 8;
 269                                 } while (--len && ++loop < 4);
 270                         } while (len);
 271                 } else {
 272                         u32 val, loop;
 273
 274                         val = loop = 0;
 275                         do {
 276                                 val |= *buf++ << (8 * loop);
 277                         } while (--len && ++loop < 4);
 278
 279                         I915_WRITE(GMBUS3 + reg_offset, val);
 280                         I915_WRITE(GMBUS1 + reg_offset,
 281                                    (i + 1 == num ? GMBUS_CYCLE_STOP : GMBUS_CYCLE_WAIT) |
 282                                    (msgs[i].len << GMBUS_BYTE_COUNT_SHIFT) |
 283                                    (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
 284                                    GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
 285                         POSTING_READ(GMBUS2+reg_offset);
 286
 287                         while (len) {
 288                                 if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 289                                         goto timeout;
 290                                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 291                                         goto clear_err;
 292
 293                                 val = loop = 0;
 294                                 do {
 295                                         val |= *buf++ << (8 * loop);
 296                                 } while (--len && ++loop < 4);
 297
 298                                 I915_WRITE(GMBUS3 + reg_offset, val);
 299                                 POSTING_READ(GMBUS2+reg_offset);
 300                         }
 301                 }
 302
 303                 if (i + 1 < num && wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50))
 304                         goto timeout;
 305                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 306                         goto clear_err;
 307         }
 308
 309         goto done;
 310
 311 clear_err:
 312         /* Toggle the Software Clear Interrupt bit. This has the effect
 313          * of resetting the GMBUS controller and so clearing the
 314          * BUS_ERROR raised by the slave's NAK.
 315          */
 316         I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT);
 317         I915_WRITE(GMBUS1 + reg_offset, 0);
 318
 319 done:
 320         /* Mark the GMBUS interface as disabled. We will re-enable it at the
 321          * start of the next xfer, till then let it sleep.
 322          */
 323         I915_WRITE(GMBUS0 + reg_offset, 0);
 324         return i;
 325
 326 timeout:
 327         DRM_INFO("GMBUS timed out, falling back to bit banging on pin %d [%s]\n",
 328                  bus->reg0 & 0xff, bus->adapter.name);
 329         I915_WRITE(GMBUS0 + reg_offset, 0);
 330
 331         /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
 332         bus->force_bit = intel_gpio_create(dev_priv, bus->reg0 & 0xff);
 333         if (!bus->force_bit)
 334                 return -ENOMEM;
 335
 336         return intel_i2c_quirk_xfer(dev_priv, bus->force_bit, msgs, num);
 337 }
 338
 339 static u32 gmbus_func(struct i2c_adapter *adapter)
 340 {
 341         struct intel_gmbus *bus = container_of(adapter,
 342                                                struct intel_gmbus,
 343                                                adapter);
 344
 345         if (bus->force_bit)
 346                 bus->force_bit->algo->functionality(bus->force_bit);
 347
 348         return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 349                 /* I2C_FUNC_10BIT_ADDR | */
 350                 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 351                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
 352 }
 353
 354 static const struct i2c_algorithm gmbus_algorithm = {
 355         .master_xfer    = gmbus_xfer,
 356         .functionality  = gmbus_func
 357 };
 358
 359 /**
 360  * intel_gmbus_setup - instantiate all Intel i2c GMBuses
 361  * @dev: DRM device
 362  */
 363 int intel_setup_gmbus(struct drm_device *dev)
 364 {
 365         static const char *names[GMBUS_NUM_PORTS] = {
 366                 "disabled",
 367                 "ssc",
 368                 "vga",
 369                 "panel",
 370                 "dpc",
 371                 "dpb",
 372                 "reserved",
 373                 "dpd",
 374         };
 375         struct drm_i915_private *dev_priv = dev->dev_private;
 376         int ret, i;
 377
 378         dev_priv->gmbus = kcalloc(sizeof(struct intel_gmbus), GMBUS_NUM_PORTS,
 379                                   GFP_KERNEL);
 380         if (dev_priv->gmbus == NULL)
 381                 return -ENOMEM;
 382
 383         for (i = 0; i < GMBUS_NUM_PORTS; i++) {
 384                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 385
 386                 bus->adapter.owner = THIS_MODULE;
 387                 bus->adapter.class = I2C_CLASS_DDC;
 388                 snprintf(bus->adapter.name,
 389                          sizeof(bus->adapter.name),
 390                          "i915 gmbus %s",
 391                          names[i]);
 392
 393                 bus->adapter.dev.parent = &dev->pdev->dev;
 394                 bus->adapter.algo_data  = dev_priv;
 395
 396                 bus->adapter.algo = &gmbus_algorithm;
 397                 ret = i2c_add_adapter(&bus->adapter);
 398                 if (ret)
 399                         goto err;
 400
 401                 /* By default use a conservative clock rate */
 402                 bus->reg0 = i | GMBUS_RATE_100KHZ;
 403
 404                 /* XXX force bit banging until GMBUS is fully debugged */
 405                 bus->force_bit = intel_gpio_create(dev_priv, i);
 406         }
 407
 408         intel_i2c_reset(dev_priv->dev);
 409
 410         return 0;
 411
 412 err:
 413         while (--i) {
 414                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 415                 i2c_del_adapter(&bus->adapter);
 416         }
 417         kfree(dev_priv->gmbus);
 418         dev_priv->gmbus = NULL;
 419         return ret;
 420 }
 421
 422 void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
 423 {
 424         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 425
 426         bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
 427 }
 428
 429 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
 430 {
 431         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 432
 433         if (force_bit) {
 434                 if (bus->force_bit == NULL) {
 435                         struct drm_i915_private *dev_priv = adapter->algo_data;
 436                         bus->force_bit = intel_gpio_create(dev_priv,
 437                                                            bus->reg0 & 0xff);
 438                 }
 439         } else {
 440                 if (bus->force_bit) {
 441                         i2c_del_adapter(bus->force_bit);
 442                         kfree(bus->force_bit);
 443                         bus->force_bit = NULL;
 444                 }
 445         }
 446 }
 447
 448 void intel_teardown_gmbus(struct drm_device *dev)
 449 {
 450         struct drm_i915_private *dev_priv = dev->dev_private;
 451         int i;
 452
 453         if (dev_priv->gmbus == NULL)
 454                 return;
 455
 456         for (i = 0; i < GMBUS_NUM_PORTS; i++) {
 457                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 458                 if (bus->force_bit) {
 459                         i2c_del_adapter(bus->force_bit);
 460                         kfree(bus->force_bit);
 461                 }
 462                 i2c_del_adapter(&bus->adapter);
 463         }
 464
 465         kfree(dev_priv->gmbus);
 466         dev_priv->gmbus = NULL;
 467 }