drivers/media/i2c/ad5820.c

   1 /*
   2  * drivers/media/i2c/ad5820.c
   3  *
   4  * AD5820 DAC driver for camera voice coil focus.
   5  *
   6  * Copyright (C) 2008 Nokia Corporation
   7  * Copyright (C) 2007 Texas Instruments
   8  * Copyright (C) 2016 Pavel Machek <pavel@ucw.cz>
   9  *
  10  * Contact: Tuukka Toivonen <tuukkat76@gmail.com>
  11  *          Sakari Ailus <sakari.ailus@iki.fi>
  12  *
  13  * Based on af_d88.c by Texas Instruments.
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * version 2 as published by the Free Software Foundation.
  18  *
  19  * This program is distributed in the hope that it will be useful, but
  20  * WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  * General Public License for more details.
  23  */
  24
  25 #include <linux/errno.h>
  26 #include <linux/i2c.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/regulator/consumer.h>
  30
  31 #include <media/v4l2-ctrls.h>
  32 #include <media/v4l2-device.h>
  33 #include <media/v4l2-subdev.h>
  34
  35 #define AD5820_NAME             "ad5820"
  36
  37 /* Register definitions */
  38 #define AD5820_POWER_DOWN               (1 << 15)
  39 #define AD5820_DAC_SHIFT                4
  40 #define AD5820_RAMP_MODE_LINEAR         (0 << 3)
  41 #define AD5820_RAMP_MODE_64_16          (1 << 3)
  42
  43 #define CODE_TO_RAMP_US(s)      ((s) == 0 ? 0 : (1 << ((s) - 1)) * 50)
  44 #define RAMP_US_TO_CODE(c)      fls(((c) + ((c)>>1)) / 50)
  45
  46 #define to_ad5820_device(sd)    container_of(sd, struct ad5820_device, subdev)
  47
  48 struct ad5820_device {
  49         struct v4l2_subdev subdev;
  50         struct ad5820_platform_data *platform_data;
  51         struct regulator *vana;
  52
  53         struct v4l2_ctrl_handler ctrls;
  54         u32 focus_absolute;
  55         u32 focus_ramp_time;
  56         u32 focus_ramp_mode;
  57
  58         struct mutex power_lock;
  59         int power_count;
  60
  61         bool standby;
  62 };
  63
  64 static int ad5820_write(struct ad5820_device *coil, u16 data)
  65 {
  66         struct i2c_client *client = v4l2_get_subdevdata(&coil->subdev);
  67         struct i2c_msg msg;
  68         __be16 be_data;
  69         int r;
  70
  71         if (!client->adapter)
  72                 return -ENODEV;
  73
  74         be_data = cpu_to_be16(data);
  75         msg.addr  = client->addr;
  76         msg.flags = 0;
  77         msg.len   = 2;
  78         msg.buf   = (u8 *)&be_data;
  79
  80         r = i2c_transfer(client->adapter, &msg, 1);
  81         if (r < 0) {
  82                 dev_err(&client->dev, "write failed, error %d\n", r);
  83                 return r;
  84         }
  85
  86         return 0;
  87 }
  88
  89 /*
  90  * Calculate status word and write it to the device based on current
  91  * values of V4L2 controls. It is assumed that the stored V4L2 control
  92  * values are properly limited and rounded.
  93  */
  94 static int ad5820_update_hw(struct ad5820_device *coil)
  95 {
  96         u16 status;
  97
  98         status = RAMP_US_TO_CODE(coil->focus_ramp_time);
  99         status |= coil->focus_ramp_mode
 100                 ? AD5820_RAMP_MODE_64_16 : AD5820_RAMP_MODE_LINEAR;
 101         status |= coil->focus_absolute << AD5820_DAC_SHIFT;
 102
 103         if (coil->standby)
 104                 status |= AD5820_POWER_DOWN;
 105
 106         return ad5820_write(coil, status);
 107 }
 108
 109 /*
 110  * Power handling
 111  */
 112 static int ad5820_power_off(struct ad5820_device *coil, bool standby)
 113 {
 114         int ret = 0, ret2;
 115
 116         /*
 117          * Go to standby first as real power off my be denied by the hardware
 118          * (single power line control for both coil and sensor).
 119          */
 120         if (standby) {
 121                 coil->standby = true;
 122                 ret = ad5820_update_hw(coil);
 123         }
 124
 125         ret2 = regulator_disable(coil->vana);
 126         if (ret)
 127                 return ret;
 128         return ret2;
 129 }
 130
 131 static int ad5820_power_on(struct ad5820_device *coil, bool restore)
 132 {
 133         int ret;
 134
 135         ret = regulator_enable(coil->vana);
 136         if (ret < 0)
 137                 return ret;
 138
 139         if (restore) {
 140                 /* Restore the hardware settings. */
 141                 coil->standby = false;
 142                 ret = ad5820_update_hw(coil);
 143                 if (ret)
 144                         goto fail;
 145         }
 146         return 0;
 147
 148 fail:
 149         coil->standby = true;
 150         regulator_disable(coil->vana);
 151
 152         return ret;
 153 }
 154
 155 /*
 156  * V4L2 controls
 157  */
 158 static int ad5820_set_ctrl(struct v4l2_ctrl *ctrl)
 159 {
 160         struct ad5820_device *coil =
 161                 container_of(ctrl->handler, struct ad5820_device, ctrls);
 162
 163         switch (ctrl->id) {
 164         case V4L2_CID_FOCUS_ABSOLUTE:
 165                 coil->focus_absolute = ctrl->val;
 166                 return ad5820_update_hw(coil);
 167         }
 168
 169         return 0;
 170 }
 171
 172 static const struct v4l2_ctrl_ops ad5820_ctrl_ops = {
 173         .s_ctrl = ad5820_set_ctrl,
 174 };
 175
 176
 177 static int ad5820_init_controls(struct ad5820_device *coil)
 178 {
 179         v4l2_ctrl_handler_init(&coil->ctrls, 1);
 180
 181         /*
 182          * V4L2_CID_FOCUS_ABSOLUTE
 183          *
 184          * Minimum current is 0 mA, maximum is 100 mA. Thus, 1 code is
 185          * equivalent to 100/1023 = 0.0978 mA. Nevertheless, we do not use [mA]
 186          * for focus position, because it is meaningless for user. Meaningful
 187          * would be to use focus distance or even its inverse, but since the
 188          * driver doesn't have sufficiently knowledge to do the conversion, we
 189          * will just use abstract codes here. In any case, smaller value = focus
 190          * position farther from camera. The default zero value means focus at
 191          * infinity, and also least current consumption.
 192          */
 193         v4l2_ctrl_new_std(&coil->ctrls, &ad5820_ctrl_ops,
 194                           V4L2_CID_FOCUS_ABSOLUTE, 0, 1023, 1, 0);
 195
 196         if (coil->ctrls.error)
 197                 return coil->ctrls.error;
 198
 199         coil->focus_absolute = 0;
 200         coil->focus_ramp_time = 0;
 201         coil->focus_ramp_mode = 0;
 202
 203         coil->subdev.ctrl_handler = &coil->ctrls;
 204
 205         return 0;
 206 }
 207
 208 /*
 209  * V4L2 subdev operations
 210  */
 211 static int ad5820_registered(struct v4l2_subdev *subdev)
 212 {
 213         struct ad5820_device *coil = to_ad5820_device(subdev);
 214
 215         return ad5820_init_controls(coil);
 216 }
 217
 218 static int
 219 ad5820_set_power(struct v4l2_subdev *subdev, int on)
 220 {
 221         struct ad5820_device *coil = to_ad5820_device(subdev);
 222         int ret = 0;
 223
 224         mutex_lock(&coil->power_lock);
 225
 226         /*
 227          * If the power count is modified from 0 to != 0 or from != 0 to 0,
 228          * update the power state.
 229          */
 230         if (coil->power_count == !on) {
 231                 ret = on ? ad5820_power_on(coil, true) :
 232                         ad5820_power_off(coil, true);
 233                 if (ret < 0)
 234                         goto done;
 235         }
 236
 237         /* Update the power count. */
 238         coil->power_count += on ? 1 : -1;
 239         WARN_ON(coil->power_count < 0);
 240
 241 done:
 242         mutex_unlock(&coil->power_lock);
 243         return ret;
 244 }
 245
 246 static int ad5820_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
 247 {
 248         return ad5820_set_power(sd, 1);
 249 }
 250
 251 static int ad5820_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
 252 {
 253         return ad5820_set_power(sd, 0);
 254 }
 255
 256 static const struct v4l2_subdev_core_ops ad5820_core_ops = {
 257         .s_power = ad5820_set_power,
 258 };
 259
 260 static const struct v4l2_subdev_ops ad5820_ops = {
 261         .core = &ad5820_core_ops,
 262 };
 263
 264 static const struct v4l2_subdev_internal_ops ad5820_internal_ops = {
 265         .registered = ad5820_registered,
 266         .open = ad5820_open,
 267         .close = ad5820_close,
 268 };
 269
 270 /*
 271  * I2C driver
 272  */
 273 static int __maybe_unused ad5820_suspend(struct device *dev)
 274 {
 275         struct i2c_client *client = container_of(dev, struct i2c_client, dev);
 276         struct v4l2_subdev *subdev = i2c_get_clientdata(client);
 277         struct ad5820_device *coil = to_ad5820_device(subdev);
 278
 279         if (!coil->power_count)
 280                 return 0;
 281
 282         return ad5820_power_off(coil, false);
 283 }
 284
 285 static int __maybe_unused ad5820_resume(struct device *dev)
 286 {
 287         struct i2c_client *client = container_of(dev, struct i2c_client, dev);
 288         struct v4l2_subdev *subdev = i2c_get_clientdata(client);
 289         struct ad5820_device *coil = to_ad5820_device(subdev);
 290
 291         if (!coil->power_count)
 292                 return 0;
 293
 294         return ad5820_power_on(coil, true);
 295 }
 296
 297 static int ad5820_probe(struct i2c_client *client,
 298                         const struct i2c_device_id *devid)
 299 {
 300         struct ad5820_device *coil;
 301         int ret;
 302
 303         coil = devm_kzalloc(&client->dev, sizeof(*coil), GFP_KERNEL);
 304         if (!coil)
 305                 return -ENOMEM;
 306
 307         coil->vana = devm_regulator_get(&client->dev, "VANA");
 308         if (IS_ERR(coil->vana)) {
 309                 ret = PTR_ERR(coil->vana);
 310                 if (ret != -EPROBE_DEFER)
 311                         dev_err(&client->dev, "could not get regulator for vana\n");
 312                 return ret;
 313         }
 314
 315         mutex_init(&coil->power_lock);
 316
 317         v4l2_i2c_subdev_init(&coil->subdev, client, &ad5820_ops);
 318         coil->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
 319         coil->subdev.internal_ops = &ad5820_internal_ops;
 320         strcpy(coil->subdev.name, "ad5820 focus");
 321
 322         ret = media_entity_pads_init(&coil->subdev.entity, 0, NULL);
 323         if (ret < 0)
 324                 goto cleanup2;
 325
 326         ret = v4l2_async_register_subdev(&coil->subdev);
 327         if (ret < 0)
 328                 goto cleanup;
 329
 330         return ret;
 331
 332 cleanup2:
 333         mutex_destroy(&coil->power_lock);
 334 cleanup:
 335         media_entity_cleanup(&coil->subdev.entity);
 336         return ret;
 337 }
 338
 339 static int __exit ad5820_remove(struct i2c_client *client)
 340 {
 341         struct v4l2_subdev *subdev = i2c_get_clientdata(client);
 342         struct ad5820_device *coil = to_ad5820_device(subdev);
 343
 344         v4l2_device_unregister_subdev(&coil->subdev);
 345         v4l2_ctrl_handler_free(&coil->ctrls);
 346         media_entity_cleanup(&coil->subdev.entity);
 347         mutex_destroy(&coil->power_lock);
 348         return 0;
 349 }
 350
 351 static const struct i2c_device_id ad5820_id_table[] = {
 352         { AD5820_NAME, 0 },
 353         { }
 354 };
 355 MODULE_DEVICE_TABLE(i2c, ad5820_id_table);
 356
 357 static SIMPLE_DEV_PM_OPS(ad5820_pm, ad5820_suspend, ad5820_resume);
 358
 359 static struct i2c_driver ad5820_i2c_driver = {
 360         .driver         = {
 361                 .name   = AD5820_NAME,
 362                 .pm     = &ad5820_pm,
 363         },
 364         .probe          = ad5820_probe,
 365         .remove         = __exit_p(ad5820_remove),
 366         .id_table       = ad5820_id_table,
 367 };
 368
 369 module_i2c_driver(ad5820_i2c_driver);
 370
 371 MODULE_AUTHOR("Tuukka Toivonen");
 372 MODULE_DESCRIPTION("AD5820 camera lens driver");
 373 MODULE_LICENSE("GPL");