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 "drmP.h"
  32 #include "drm.h"
  33 #include "intel_drv.h"
  34 #include "i915_drm.h"
  35 #include "i915_drv.h"
  36
  37 /* Intel GPIO access functions */
  38
  39 #define I2C_RISEFALL_TIME 20
  40
  41 static inline struct intel_gmbus *
  42 to_intel_gmbus(struct i2c_adapter *i2c)
  43 {
  44         return container_of(i2c, struct intel_gmbus, adapter);
  45 }
  46
  47 struct intel_gpio {
  48         struct i2c_adapter adapter;
  49         struct i2c_algo_bit_data algo;
  50         struct drm_i915_private *dev_priv;
  51         u32 reg;
  52 };
  53
  54 void
  55 intel_i2c_reset(struct drm_device *dev)
  56 {
  57         struct drm_i915_private *dev_priv = dev->dev_private;
  58         if (HAS_PCH_SPLIT(dev))
  59                 I915_WRITE(PCH_GMBUS0, 0);
  60         else
  61                 I915_WRITE(GMBUS0, 0);
  62 }
  63
  64 static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable)
  65 {
  66         u32 val;
  67
  68         /* When using bit bashing for I2C, this bit needs to be set to 1 */
  69         if (!IS_PINEVIEW(dev_priv->dev))
  70                 return;
  71
  72         val = I915_READ(DSPCLK_GATE_D);
  73         if (enable)
  74                 val |= DPCUNIT_CLOCK_GATE_DISABLE;
  75         else
  76                 val &= ~DPCUNIT_CLOCK_GATE_DISABLE;
  77         I915_WRITE(DSPCLK_GATE_D, val);
  78 }
  79
  80 static u32 get_reserved(struct intel_gpio *gpio)
  81 {
  82         struct drm_i915_private *dev_priv = gpio->dev_priv;
  83         struct drm_device *dev = dev_priv->dev;
  84         u32 reserved = 0;
  85
  86         /* On most chips, these bits must be preserved in software. */
  87         if (!IS_I830(dev) && !IS_845G(dev))
  88                 reserved = I915_READ_NOTRACE(gpio->reg) &
  89                                              (GPIO_DATA_PULLUP_DISABLE |
  90                                               GPIO_CLOCK_PULLUP_DISABLE);
  91
  92         return reserved;
  93 }
  94
  95 static int get_clock(void *data)
  96 {
  97         struct intel_gpio *gpio = data;
  98         struct drm_i915_private *dev_priv = gpio->dev_priv;
  99         u32 reserved = get_reserved(gpio);
 100         I915_WRITE_NOTRACE(gpio->reg, reserved | GPIO_CLOCK_DIR_MASK);
 101         I915_WRITE_NOTRACE(gpio->reg, reserved);
 102         return (I915_READ_NOTRACE(gpio->reg) & GPIO_CLOCK_VAL_IN) != 0;
 103 }
 104
 105 static int get_data(void *data)
 106 {
 107         struct intel_gpio *gpio = data;
 108         struct drm_i915_private *dev_priv = gpio->dev_priv;
 109         u32 reserved = get_reserved(gpio);
 110         I915_WRITE_NOTRACE(gpio->reg, reserved | GPIO_DATA_DIR_MASK);
 111         I915_WRITE_NOTRACE(gpio->reg, reserved);
 112         return (I915_READ_NOTRACE(gpio->reg) & GPIO_DATA_VAL_IN) != 0;
 113 }
 114
 115 static void set_clock(void *data, int state_high)
 116 {
 117         struct intel_gpio *gpio = data;
 118         struct drm_i915_private *dev_priv = gpio->dev_priv;
 119         u32 reserved = get_reserved(gpio);
 120         u32 clock_bits;
 121
 122         if (state_high)
 123                 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
 124         else
 125                 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
 126                         GPIO_CLOCK_VAL_MASK;
 127
 128         I915_WRITE_NOTRACE(gpio->reg, reserved | clock_bits);
 129         POSTING_READ(gpio->reg);
 130 }
 131
 132 static void set_data(void *data, int state_high)
 133 {
 134         struct intel_gpio *gpio = data;
 135         struct drm_i915_private *dev_priv = gpio->dev_priv;
 136         u32 reserved = get_reserved(gpio);
 137         u32 data_bits;
 138
 139         if (state_high)
 140                 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
 141         else
 142                 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
 143                         GPIO_DATA_VAL_MASK;
 144
 145         I915_WRITE_NOTRACE(gpio->reg, reserved | data_bits);
 146         POSTING_READ(gpio->reg);
 147 }
 148
 149 static struct i2c_adapter *
 150 intel_gpio_create(struct drm_i915_private *dev_priv, u32 pin)
 151 {
 152         static const int map_pin_to_reg[] = {
 153                 0,
 154                 GPIOB,
 155                 GPIOA,
 156                 GPIOC,
 157                 GPIOD,
 158                 GPIOE,
 159                 0,
 160                 GPIOF,
 161         };
 162         struct intel_gpio *gpio;
 163
 164         if (pin >= ARRAY_SIZE(map_pin_to_reg) || !map_pin_to_reg[pin])
 165                 return NULL;
 166
 167         gpio = kzalloc(sizeof(struct intel_gpio), GFP_KERNEL);
 168         if (gpio == NULL)
 169                 return NULL;
 170
 171         gpio->reg = map_pin_to_reg[pin];
 172         if (HAS_PCH_SPLIT(dev_priv->dev))
 173                 gpio->reg += PCH_GPIOA - GPIOA;
 174         gpio->dev_priv = dev_priv;
 175
 176         snprintf(gpio->adapter.name, sizeof(gpio->adapter.name),
 177                  "i915 GPIO%c", "?BACDE?F"[pin]);
 178         gpio->adapter.owner = THIS_MODULE;
 179         gpio->adapter.algo_data = &gpio->algo;
 180         gpio->adapter.dev.parent = &dev_priv->dev->pdev->dev;
 181         gpio->algo.setsda = set_data;
 182         gpio->algo.setscl = set_clock;
 183         gpio->algo.getsda = get_data;
 184         gpio->algo.getscl = get_clock;
 185         gpio->algo.udelay = I2C_RISEFALL_TIME;
 186         gpio->algo.timeout = usecs_to_jiffies(2200);
 187         gpio->algo.data = gpio;
 188
 189         if (i2c_bit_add_bus(&gpio->adapter))
 190                 goto out_free;
 191
 192         return &gpio->adapter;
 193
 194 out_free:
 195         kfree(gpio);
 196         return NULL;
 197 }
 198
 199 static int
 200 intel_i2c_quirk_xfer(struct drm_i915_private *dev_priv,
 201                      struct i2c_adapter *adapter,
 202                      struct i2c_msg *msgs,
 203                      int num)
 204 {
 205         struct intel_gpio *gpio = container_of(adapter,
 206                                                struct intel_gpio,
 207                                                adapter);
 208         int ret;
 209
 210         intel_i2c_reset(dev_priv->dev);
 211
 212         intel_i2c_quirk_set(dev_priv, true);
 213         set_data(gpio, 1);
 214         set_clock(gpio, 1);
 215         udelay(I2C_RISEFALL_TIME);
 216
 217         ret = adapter->algo->master_xfer(adapter, msgs, num);
 218
 219         set_data(gpio, 1);
 220         set_clock(gpio, 1);
 221         intel_i2c_quirk_set(dev_priv, false);
 222
 223         return ret;
 224 }
 225
 226 static int
 227 gmbus_xfer(struct i2c_adapter *adapter,
 228            struct i2c_msg *msgs,
 229            int num)
 230 {
 231         struct intel_gmbus *bus = container_of(adapter,
 232                                                struct intel_gmbus,
 233                                                adapter);
 234         struct drm_i915_private *dev_priv = adapter->algo_data;
 235         int i, reg_offset;
 236
 237         if (bus->force_bit)
 238                 return intel_i2c_quirk_xfer(dev_priv,
 239                                             bus->force_bit, msgs, num);
 240
 241         reg_offset = HAS_PCH_SPLIT(dev_priv->dev) ? PCH_GMBUS0 - GMBUS0 : 0;
 242
 243         I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
 244
 245         for (i = 0; i < num; i++) {
 246                 u16 len = msgs[i].len;
 247                 u8 *buf = msgs[i].buf;
 248
 249                 if (msgs[i].flags & I2C_M_RD) {
 250                         I915_WRITE(GMBUS1 + reg_offset,
 251                                    GMBUS_CYCLE_WAIT | (i + 1 == num ? GMBUS_CYCLE_STOP : 0) |
 252                                    (len << GMBUS_BYTE_COUNT_SHIFT) |
 253                                    (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
 254                                    GMBUS_SLAVE_READ | GMBUS_SW_RDY);
 255                         POSTING_READ(GMBUS2+reg_offset);
 256                         do {
 257                                 u32 val, loop = 0;
 258
 259                                 if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 260                                         goto timeout;
 261                                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 262                                         goto clear_err;
 263
 264                                 val = I915_READ(GMBUS3 + reg_offset);
 265                                 do {
 266                                         *buf++ = val & 0xff;
 267                                         val >>= 8;
 268                                 } while (--len && ++loop < 4);
 269                         } while (len);
 270                 } else {
 271                         u32 val, loop;
 272
 273                         val = loop = 0;
 274                         do {
 275                                 val |= *buf++ << (8 * loop);
 276                         } while (--len && ++loop < 4);
 277
 278                         I915_WRITE(GMBUS3 + reg_offset, val);
 279                         I915_WRITE(GMBUS1 + reg_offset,
 280                                    (i + 1 == num ? GMBUS_CYCLE_STOP : GMBUS_CYCLE_WAIT) |
 281                                    (msgs[i].len << GMBUS_BYTE_COUNT_SHIFT) |
 282                                    (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
 283                                    GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
 284                         POSTING_READ(GMBUS2+reg_offset);
 285
 286                         while (len) {
 287                                 if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 288                                         goto timeout;
 289                                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 290                                         goto clear_err;
 291
 292                                 val = loop = 0;
 293                                 do {
 294                                         val |= *buf++ << (8 * loop);
 295                                 } while (--len && ++loop < 4);
 296
 297                                 I915_WRITE(GMBUS3 + reg_offset, val);
 298                                 POSTING_READ(GMBUS2+reg_offset);
 299                         }
 300                 }
 301
 302                 if (i + 1 < num && wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50))
 303                         goto timeout;
 304                 if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
 305                         goto clear_err;
 306         }
 307
 308         goto done;
 309
 310 clear_err:
 311         /* Toggle the Software Clear Interrupt bit. This has the effect
 312          * of resetting the GMBUS controller and so clearing the
 313          * BUS_ERROR raised by the slave's NAK.
 314          */
 315         I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT);
 316         I915_WRITE(GMBUS1 + reg_offset, 0);
 317
 318 done:
 319         /* Mark the GMBUS interface as disabled. We will re-enable it at the
 320          * start of the next xfer, till then let it sleep.
 321          */
 322         I915_WRITE(GMBUS0 + reg_offset, 0);
 323         return i;
 324
 325 timeout:
 326         DRM_INFO("GMBUS timed out, falling back to bit banging on pin %d [%s]\n",
 327                  bus->reg0 & 0xff, bus->adapter.name);
 328         I915_WRITE(GMBUS0 + reg_offset, 0);
 329
 330         /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
 331         bus->force_bit = intel_gpio_create(dev_priv, bus->reg0 & 0xff);
 332         if (!bus->force_bit)
 333                 return -ENOMEM;
 334
 335         return intel_i2c_quirk_xfer(dev_priv, bus->force_bit, msgs, num);
 336 }
 337
 338 static u32 gmbus_func(struct i2c_adapter *adapter)
 339 {
 340         struct intel_gmbus *bus = container_of(adapter,
 341                                                struct intel_gmbus,
 342                                                adapter);
 343
 344         if (bus->force_bit)
 345                 bus->force_bit->algo->functionality(bus->force_bit);
 346
 347         return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 348                 /* I2C_FUNC_10BIT_ADDR | */
 349                 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 350                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
 351 }
 352
 353 static const struct i2c_algorithm gmbus_algorithm = {
 354         .master_xfer    = gmbus_xfer,
 355         .functionality  = gmbus_func
 356 };
 357
 358 /**
 359  * intel_gmbus_setup - instantiate all Intel i2c GMBuses
 360  * @dev: DRM device
 361  */
 362 int intel_setup_gmbus(struct drm_device *dev)
 363 {
 364         static const char *names[GMBUS_NUM_PORTS] = {
 365                 "disabled",
 366                 "ssc",
 367                 "vga",
 368                 "panel",
 369                 "dpc",
 370                 "dpb",
 371                 "reserved",
 372                 "dpd",
 373         };
 374         struct drm_i915_private *dev_priv = dev->dev_private;
 375         int ret, i;
 376
 377         dev_priv->gmbus = kcalloc(sizeof(struct intel_gmbus), GMBUS_NUM_PORTS,
 378                                   GFP_KERNEL);
 379         if (dev_priv->gmbus == NULL)
 380                 return -ENOMEM;
 381
 382         for (i = 0; i < GMBUS_NUM_PORTS; i++) {
 383                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 384
 385                 bus->adapter.owner = THIS_MODULE;
 386                 bus->adapter.class = I2C_CLASS_DDC;
 387                 snprintf(bus->adapter.name,
 388                          sizeof(bus->adapter.name),
 389                          "i915 gmbus %s",
 390                          names[i]);
 391
 392                 bus->adapter.dev.parent = &dev->pdev->dev;
 393                 bus->adapter.algo_data  = dev_priv;
 394
 395                 bus->adapter.algo = &gmbus_algorithm;
 396                 ret = i2c_add_adapter(&bus->adapter);
 397                 if (ret)
 398                         goto err;
 399
 400                 /* By default use a conservative clock rate */
 401                 bus->reg0 = i | GMBUS_RATE_100KHZ;
 402
 403                 /* XXX force bit banging until GMBUS is fully debugged */
 404                 bus->force_bit = intel_gpio_create(dev_priv, i);
 405         }
 406
 407         intel_i2c_reset(dev_priv->dev);
 408
 409         return 0;
 410
 411 err:
 412         while (--i) {
 413                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 414                 i2c_del_adapter(&bus->adapter);
 415         }
 416         kfree(dev_priv->gmbus);
 417         dev_priv->gmbus = NULL;
 418         return ret;
 419 }
 420
 421 void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
 422 {
 423         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 424
 425         /* speed:
 426          * 0x0 = 100 KHz
 427          * 0x1 = 50 KHz
 428          * 0x2 = 400 KHz
 429          * 0x3 = 1000 Khz
 430          */
 431         bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | (speed << 8);
 432 }
 433
 434 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
 435 {
 436         struct intel_gmbus *bus = to_intel_gmbus(adapter);
 437
 438         if (force_bit) {
 439                 if (bus->force_bit == NULL) {
 440                         struct drm_i915_private *dev_priv = adapter->algo_data;
 441                         bus->force_bit = intel_gpio_create(dev_priv,
 442                                                            bus->reg0 & 0xff);
 443                 }
 444         } else {
 445                 if (bus->force_bit) {
 446                         i2c_del_adapter(bus->force_bit);
 447                         kfree(bus->force_bit);
 448                         bus->force_bit = NULL;
 449                 }
 450         }
 451 }
 452
 453 void intel_teardown_gmbus(struct drm_device *dev)
 454 {
 455         struct drm_i915_private *dev_priv = dev->dev_private;
 456         int i;
 457
 458         if (dev_priv->gmbus == NULL)
 459                 return;
 460
 461         for (i = 0; i < GMBUS_NUM_PORTS; i++) {
 462                 struct intel_gmbus *bus = &dev_priv->gmbus[i];
 463                 if (bus->force_bit) {
 464                         i2c_del_adapter(bus->force_bit);
 465                         kfree(bus->force_bit);
 466                 }
 467                 i2c_del_adapter(&bus->adapter);
 468         }
 469
 470         kfree(dev_priv->gmbus);
 471         dev_priv->gmbus = NULL;
 472 }