drivers/i2c/busses/i2c-amd-mp2-plat.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /*
   3  * AMD MP2 platform driver
   4  *
   5  * Setup the I2C adapters enumerated in the ACPI namespace.
   6  * MP2 controllers have 2 separate busses, up to 2 I2C adapters may be listed.
   7  *
   8  * Authors: Nehal Bakulchandra Shah <[email protected]>
   9  *          Elie Morisse <[email protected]>
  10  */
  11
  12 #include <linux/acpi.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/slab.h>
  17 #include <linux/types.h>
  18
  19 #include "i2c-amd-mp2.h"
  20
  21 #define AMD_MP2_I2C_MAX_RW_LENGTH ((1 << 12) - 1)
  22 #define AMD_I2C_TIMEOUT (msecs_to_jiffies(250))
  23
  24 /**
  25  * struct amd_i2c_dev - MP2 bus/i2c adapter context
  26  * @common: shared context with the MP2 PCI driver
  27  * @pdev: platform driver node
  28  * @adap: i2c adapter
  29  * @cmd_complete: xfer completion object
  30  */
  31 struct amd_i2c_dev {
  32         struct amd_i2c_common common;
  33         struct platform_device *pdev;
  34         struct i2c_adapter adap;
  35         struct completion cmd_complete;
  36 };
  37
  38 #define amd_i2c_dev_common(__common) \
  39         container_of(__common, struct amd_i2c_dev, common)
  40
  41 static int i2c_amd_dma_map(struct amd_i2c_common *i2c_common)
  42 {
  43         struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
  44         struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
  45         enum dma_data_direction dma_direction =
  46                         i2c_common->msg->flags & I2C_M_RD ?
  47                         DMA_FROM_DEVICE : DMA_TO_DEVICE;
  48
  49         i2c_common->dma_buf = i2c_get_dma_safe_msg_buf(i2c_common->msg, 0);
  50         i2c_common->dma_addr = dma_map_single(dev_pci, i2c_common->dma_buf,
  51                                               i2c_common->msg->len,
  52                                               dma_direction);
  53
  54         if (unlikely(dma_mapping_error(dev_pci, i2c_common->dma_addr))) {
  55                 dev_err(&i2c_dev->pdev->dev,
  56                         "Error while mapping dma buffer %p\n",
  57                         i2c_common->dma_buf);
  58                 return -EIO;
  59         }
  60
  61         return 0;
  62 }
  63
  64 static void i2c_amd_dma_unmap(struct amd_i2c_common *i2c_common)
  65 {
  66         struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
  67         enum dma_data_direction dma_direction =
  68                         i2c_common->msg->flags & I2C_M_RD ?
  69                         DMA_FROM_DEVICE : DMA_TO_DEVICE;
  70
  71         dma_unmap_single(dev_pci, i2c_common->dma_addr,
  72                          i2c_common->msg->len, dma_direction);
  73
  74         i2c_put_dma_safe_msg_buf(i2c_common->dma_buf, i2c_common->msg, true);
  75 }
  76
  77 static void i2c_amd_start_cmd(struct amd_i2c_dev *i2c_dev)
  78 {
  79         struct amd_i2c_common *i2c_common = &i2c_dev->common;
  80
  81         reinit_completion(&i2c_dev->cmd_complete);
  82         i2c_common->cmd_success = false;
  83 }
  84
  85 static void i2c_amd_cmd_completion(struct amd_i2c_common *i2c_common)
  86 {
  87         struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
  88         union i2c_event *event = &i2c_common->eventval;
  89
  90         if (event->r.status == i2c_readcomplete_event)
  91                 dev_dbg(&i2c_dev->pdev->dev, "readdata:%*ph\n", event->r.length,
  92                         i2c_common->msg->buf);
  93
  94         complete(&i2c_dev->cmd_complete);
  95 }
  96
  97 static int i2c_amd_check_cmd_completion(struct amd_i2c_dev *i2c_dev)
  98 {
  99         struct amd_i2c_common *i2c_common = &i2c_dev->common;
 100         unsigned long timeout;
 101
 102         timeout = wait_for_completion_timeout(&i2c_dev->cmd_complete,
 103                                               i2c_dev->adap.timeout);
 104
 105         if ((i2c_common->reqcmd == i2c_read ||
 106              i2c_common->reqcmd == i2c_write) &&
 107             i2c_common->msg->len > 32)
 108                 i2c_amd_dma_unmap(i2c_common);
 109
 110         if (timeout == 0) {
 111                 amd_mp2_rw_timeout(i2c_common);
 112                 return -ETIMEDOUT;
 113         }
 114
 115         amd_mp2_process_event(i2c_common);
 116
 117         if (!i2c_common->cmd_success)
 118                 return -EIO;
 119
 120         return 0;
 121 }
 122
 123 static int i2c_amd_enable_set(struct amd_i2c_dev *i2c_dev, bool enable)
 124 {
 125         struct amd_i2c_common *i2c_common = &i2c_dev->common;
 126
 127         i2c_amd_start_cmd(i2c_dev);
 128         amd_mp2_bus_enable_set(i2c_common, enable);
 129
 130         return i2c_amd_check_cmd_completion(i2c_dev);
 131 }
 132
 133 static int i2c_amd_xfer_msg(struct amd_i2c_dev *i2c_dev, struct i2c_msg *pmsg)
 134 {
 135         struct amd_i2c_common *i2c_common = &i2c_dev->common;
 136
 137         i2c_amd_start_cmd(i2c_dev);
 138         i2c_common->msg = pmsg;
 139
 140         if (pmsg->len > 32)
 141                 if (i2c_amd_dma_map(i2c_common))
 142                         return -EIO;
 143
 144         if (pmsg->flags & I2C_M_RD)
 145                 amd_mp2_rw(i2c_common, i2c_read);
 146         else
 147                 amd_mp2_rw(i2c_common, i2c_write);
 148
 149         return i2c_amd_check_cmd_completion(i2c_dev);
 150 }
 151
 152 static int i2c_amd_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 153 {
 154         struct amd_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 155         int i;
 156         struct i2c_msg *pmsg;
 157         int err = 0;
 158
 159         /* the adapter might have been deleted while waiting for the bus lock */
 160         if (unlikely(!i2c_dev->common.mp2_dev))
 161                 return -EINVAL;
 162
 163         amd_mp2_pm_runtime_get(i2c_dev->common.mp2_dev);
 164
 165         for (i = 0; i < num; i++) {
 166                 pmsg = &msgs[i];
 167                 err = i2c_amd_xfer_msg(i2c_dev, pmsg);
 168                 if (err)
 169                         break;
 170         }
 171
 172         amd_mp2_pm_runtime_put(i2c_dev->common.mp2_dev);
 173         return err ? err : num;
 174 }
 175
 176 static u32 i2c_amd_func(struct i2c_adapter *a)
 177 {
 178         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 179 }
 180
 181 static const struct i2c_algorithm i2c_amd_algorithm = {
 182         .master_xfer = i2c_amd_xfer,
 183         .functionality = i2c_amd_func,
 184 };
 185
 186 #ifdef CONFIG_PM
 187 static int i2c_amd_suspend(struct amd_i2c_common *i2c_common)
 188 {
 189         struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
 190
 191         i2c_amd_enable_set(i2c_dev, false);
 192         return 0;
 193 }
 194
 195 static int i2c_amd_resume(struct amd_i2c_common *i2c_common)
 196 {
 197         struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
 198
 199         return i2c_amd_enable_set(i2c_dev, true);
 200 }
 201 #endif
 202
 203 static const u32 supported_speeds[] = {
 204         I2C_MAX_HIGH_SPEED_MODE_FREQ,
 205         I2C_MAX_TURBO_MODE_FREQ,
 206         I2C_MAX_FAST_MODE_PLUS_FREQ,
 207         I2C_MAX_FAST_MODE_FREQ,
 208         I2C_MAX_STANDARD_MODE_FREQ,
 209 };
 210
 211 static enum speed_enum i2c_amd_get_bus_speed(struct platform_device *pdev)
 212 {
 213         u32 acpi_speed;
 214         int i;
 215
 216         acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
 217         /* round down to the lowest standard speed */
 218         for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
 219                 if (acpi_speed >= supported_speeds[i])
 220                         break;
 221         }
 222         acpi_speed = i < ARRAY_SIZE(supported_speeds) ? supported_speeds[i] : 0;
 223
 224         switch (acpi_speed) {
 225         case I2C_MAX_STANDARD_MODE_FREQ:
 226                 return speed100k;
 227         case I2C_MAX_FAST_MODE_FREQ:
 228                 return speed400k;
 229         case I2C_MAX_FAST_MODE_PLUS_FREQ:
 230                 return speed1000k;
 231         case I2C_MAX_TURBO_MODE_FREQ:
 232                 return speed1400k;
 233         case I2C_MAX_HIGH_SPEED_MODE_FREQ:
 234                 return speed3400k;
 235         default:
 236                 return speed400k;
 237         }
 238 }
 239
 240 static const struct i2c_adapter_quirks amd_i2c_dev_quirks = {
 241         .max_read_len = AMD_MP2_I2C_MAX_RW_LENGTH,
 242         .max_write_len = AMD_MP2_I2C_MAX_RW_LENGTH,
 243 };
 244
 245 static int i2c_amd_probe(struct platform_device *pdev)
 246 {
 247         int ret;
 248         struct amd_i2c_dev *i2c_dev;
 249         acpi_handle handle = ACPI_HANDLE(&pdev->dev);
 250         struct acpi_device *adev;
 251         struct amd_mp2_dev *mp2_dev;
 252         const char *uid;
 253
 254         if (acpi_bus_get_device(handle, &adev))
 255                 return -ENODEV;
 256
 257         /* The ACPI namespace doesn't contain information about which MP2 PCI
 258          * device an AMDI0011 ACPI device is related to, so assume that there's
 259          * only one MP2 PCI device per system.
 260          */
 261         mp2_dev = amd_mp2_find_device();
 262         if (!mp2_dev || !mp2_dev->probed)
 263                 /* The MP2 PCI device should get probed later */
 264                 return -EPROBE_DEFER;
 265
 266         i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
 267         if (!i2c_dev)
 268                 return -ENOMEM;
 269
 270         i2c_dev->common.mp2_dev = mp2_dev;
 271         i2c_dev->pdev = pdev;
 272         platform_set_drvdata(pdev, i2c_dev);
 273
 274         i2c_dev->common.cmd_completion = &i2c_amd_cmd_completion;
 275 #ifdef CONFIG_PM
 276         i2c_dev->common.suspend = &i2c_amd_suspend;
 277         i2c_dev->common.resume = &i2c_amd_resume;
 278 #endif
 279
 280         uid = adev->pnp.unique_id;
 281         if (!uid) {
 282                 dev_err(&pdev->dev, "missing UID/bus id!\n");
 283                 return -EINVAL;
 284         } else if (strcmp(uid, "0") == 0) {
 285                 i2c_dev->common.bus_id = 0;
 286         } else if (strcmp(uid, "1") == 0) {
 287                 i2c_dev->common.bus_id = 1;
 288         } else {
 289                 dev_err(&pdev->dev, "incorrect UID/bus id \"%s\"!\n", uid);
 290                 return -EINVAL;
 291         }
 292         dev_dbg(&pdev->dev, "bus id is %u\n", i2c_dev->common.bus_id);
 293
 294         /* Register the adapter */
 295         amd_mp2_pm_runtime_get(mp2_dev);
 296
 297         i2c_dev->common.reqcmd = i2c_none;
 298         if (amd_mp2_register_cb(&i2c_dev->common))
 299                 return -EINVAL;
 300         device_link_add(&i2c_dev->pdev->dev, &mp2_dev->pci_dev->dev,
 301                         DL_FLAG_AUTOREMOVE_CONSUMER);
 302
 303         i2c_dev->common.i2c_speed = i2c_amd_get_bus_speed(pdev);
 304
 305         /* Setup i2c adapter description */
 306         i2c_dev->adap.owner = THIS_MODULE;
 307         i2c_dev->adap.algo = &i2c_amd_algorithm;
 308         i2c_dev->adap.quirks = &amd_i2c_dev_quirks;
 309         i2c_dev->adap.dev.parent = &pdev->dev;
 310         i2c_dev->adap.algo_data = i2c_dev;
 311         i2c_dev->adap.timeout = AMD_I2C_TIMEOUT;
 312         ACPI_COMPANION_SET(&i2c_dev->adap.dev, ACPI_COMPANION(&pdev->dev));
 313         i2c_dev->adap.dev.of_node = pdev->dev.of_node;
 314         snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
 315                  "AMD MP2 i2c bus %u", i2c_dev->common.bus_id);
 316         i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
 317
 318         init_completion(&i2c_dev->cmd_complete);
 319
 320         /* Enable the bus */
 321         if (i2c_amd_enable_set(i2c_dev, true))
 322                 dev_err(&pdev->dev, "initial bus enable failed\n");
 323
 324         /* Attach to the i2c layer */
 325         ret = i2c_add_adapter(&i2c_dev->adap);
 326
 327         amd_mp2_pm_runtime_put(mp2_dev);
 328
 329         if (ret < 0)
 330                 dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);
 331
 332         return ret;
 333 }
 334
 335 static int i2c_amd_remove(struct platform_device *pdev)
 336 {
 337         struct amd_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 338         struct amd_i2c_common *i2c_common = &i2c_dev->common;
 339
 340         i2c_lock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);
 341
 342         i2c_amd_enable_set(i2c_dev, false);
 343         amd_mp2_unregister_cb(i2c_common);
 344         i2c_common->mp2_dev = NULL;
 345
 346         i2c_unlock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);
 347
 348         i2c_del_adapter(&i2c_dev->adap);
 349         return 0;
 350 }
 351
 352 static const struct acpi_device_id i2c_amd_acpi_match[] = {
 353         { "AMDI0011" },
 354         { },
 355 };
 356 MODULE_DEVICE_TABLE(acpi, i2c_amd_acpi_match);
 357
 358 static struct platform_driver i2c_amd_plat_driver = {
 359         .probe = i2c_amd_probe,
 360         .remove = i2c_amd_remove,
 361         .driver = {
 362                 .name = "i2c_amd_mp2",
 363                 .acpi_match_table = ACPI_PTR(i2c_amd_acpi_match),
 364         },
 365 };
 366 module_platform_driver(i2c_amd_plat_driver);
 367
 368 MODULE_DESCRIPTION("AMD(R) MP2 I2C Platform Driver");
 369 MODULE_AUTHOR("Nehal Shah <[email protected]>");
 370 MODULE_AUTHOR("Elie Morisse <[email protected]>");
 371 MODULE_LICENSE("Dual BSD/GPL");