drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c

   1 /*
   2 * Copyright (C) 2012 Invensense, Inc.
   3 *
   4 * This software is licensed under the terms of the GNU General Public
   5 * License version 2, as published by the Free Software Foundation, and
   6 * may be copied, distributed, and modified under those terms.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14 #include <linux/acpi.h>
  15 #include <linux/delay.h>
  16 #include <linux/err.h>
  17 #include <linux/i2c.h>
  18 #include <linux/i2c-mux.h>
  19 #include <linux/iio/iio.h>
  20 #include <linux/module.h>
  21 #include "inv_mpu_iio.h"
  22
  23 static const struct regmap_config inv_mpu_regmap_config = {
  24         .reg_bits = 8,
  25         .val_bits = 8,
  26 };
  27
  28 /*
  29  * The i2c read/write needs to happen in unlocked mode. As the parent
  30  * adapter is common. If we use locked versions, it will fail as
  31  * the mux adapter will lock the parent i2c adapter, while calling
  32  * select/deselect functions.
  33  */
  34 static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
  35                                           u8 reg, u8 d)
  36 {
  37         int ret;
  38         u8 buf[2] = {reg, d};
  39         struct i2c_msg msg[1] = {
  40                 {
  41                         .addr = client->addr,
  42                         .flags = 0,
  43                         .len = sizeof(buf),
  44                         .buf = buf,
  45                 }
  46         };
  47
  48         ret = __i2c_transfer(client->adapter, msg, 1);
  49         if (ret != 1)
  50                 return ret;
  51
  52         return 0;
  53 }
  54
  55 static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
  56                                      u32 chan_id)
  57 {
  58         struct i2c_client *client = mux_priv;
  59         struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
  60         struct inv_mpu6050_state *st = iio_priv(indio_dev);
  61         int ret = 0;
  62
  63         /* Use the same mutex which was used everywhere to protect power-op */
  64         mutex_lock(&indio_dev->mlock);
  65         if (!st->powerup_count) {
  66                 ret = inv_mpu6050_write_reg_unlocked(client,
  67                                                      st->reg->pwr_mgmt_1, 0);
  68                 if (ret)
  69                         goto write_error;
  70
  71                 msleep(INV_MPU6050_REG_UP_TIME);
  72         }
  73         if (!ret) {
  74                 st->powerup_count++;
  75                 ret = inv_mpu6050_write_reg_unlocked(client,
  76                                                      st->reg->int_pin_cfg,
  77                                                      INV_MPU6050_INT_PIN_CFG |
  78                                                      INV_MPU6050_BIT_BYPASS_EN);
  79         }
  80 write_error:
  81         mutex_unlock(&indio_dev->mlock);
  82
  83         return ret;
  84 }
  85
  86 static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
  87                                        void *mux_priv, u32 chan_id)
  88 {
  89         struct i2c_client *client = mux_priv;
  90         struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
  91         struct inv_mpu6050_state *st = iio_priv(indio_dev);
  92
  93         mutex_lock(&indio_dev->mlock);
  94         /* It doesn't really mattter, if any of the calls fails */
  95         inv_mpu6050_write_reg_unlocked(client, st->reg->int_pin_cfg,
  96                                        INV_MPU6050_INT_PIN_CFG);
  97         st->powerup_count--;
  98         if (!st->powerup_count)
  99                 inv_mpu6050_write_reg_unlocked(client, st->reg->pwr_mgmt_1,
 100                                                INV_MPU6050_BIT_SLEEP);
 101         mutex_unlock(&indio_dev->mlock);
 102
 103         return 0;
 104 }
 105
 106 /**
 107  *  inv_mpu_probe() - probe function.
 108  *  @client:          i2c client.
 109  *  @id:              i2c device id.
 110  *
 111  *  Returns 0 on success, a negative error code otherwise.
 112  */
 113 static int inv_mpu_probe(struct i2c_client *client,
 114         const struct i2c_device_id *id)
 115 {
 116         struct inv_mpu6050_state *st;
 117         int result;
 118         const char *name = id ? id->name : NULL;
 119         struct regmap *regmap;
 120
 121         if (!i2c_check_functionality(client->adapter,
 122                                      I2C_FUNC_SMBUS_I2C_BLOCK))
 123                 return -ENOSYS;
 124
 125         regmap = devm_regmap_init_i2c(client, &inv_mpu_regmap_config);
 126         if (IS_ERR(regmap)) {
 127                 dev_err(&client->dev, "Failed to register i2c regmap %d\n",
 128                         (int)PTR_ERR(regmap));
 129                 return PTR_ERR(regmap);
 130         }
 131
 132         result = inv_mpu_core_probe(regmap, client->irq, name, NULL);
 133         if (result < 0)
 134                 return result;
 135
 136         st = iio_priv(dev_get_drvdata(&client->dev));
 137         st->mux_adapter = i2c_add_mux_adapter(client->adapter,
 138                                               &client->dev,
 139                                               client,
 140                                               0, 0, 0,
 141                                               inv_mpu6050_select_bypass,
 142                                               inv_mpu6050_deselect_bypass);
 143         if (!st->mux_adapter) {
 144                 result = -ENODEV;
 145                 goto out_unreg_device;
 146         }
 147
 148         result = inv_mpu_acpi_create_mux_client(client);
 149         if (result)
 150                 goto out_del_mux;
 151
 152         return 0;
 153
 154 out_del_mux:
 155         i2c_del_mux_adapter(st->mux_adapter);
 156 out_unreg_device:
 157         inv_mpu_core_remove(&client->dev);
 158         return result;
 159 }
 160
 161 static int inv_mpu_remove(struct i2c_client *client)
 162 {
 163         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 164         struct inv_mpu6050_state *st = iio_priv(indio_dev);
 165
 166         inv_mpu_acpi_delete_mux_client(client);
 167         i2c_del_mux_adapter(st->mux_adapter);
 168
 169         return inv_mpu_core_remove(&client->dev);
 170 }
 171
 172 /*
 173  * device id table is used to identify what device can be
 174  * supported by this driver
 175  */
 176 static const struct i2c_device_id inv_mpu_id[] = {
 177         {"mpu6050", INV_MPU6050},
 178         {"mpu6500", INV_MPU6500},
 179         {}
 180 };
 181
 182 MODULE_DEVICE_TABLE(i2c, inv_mpu_id);
 183
 184 static const struct acpi_device_id inv_acpi_match[] = {
 185         {"INVN6500", 0},
 186         { },
 187 };
 188
 189 MODULE_DEVICE_TABLE(acpi, inv_acpi_match);
 190
 191 static struct i2c_driver inv_mpu_driver = {
 192         .probe          =       inv_mpu_probe,
 193         .remove         =       inv_mpu_remove,
 194         .id_table       =       inv_mpu_id,
 195         .driver = {
 196                 .acpi_match_table = ACPI_PTR(inv_acpi_match),
 197                 .name   =       "inv-mpu6050-i2c",
 198                 .pm     =       &inv_mpu_pmops,
 199         },
 200 };
 201
 202 module_i2c_driver(inv_mpu_driver);
 203
 204 MODULE_AUTHOR("Invensense Corporation");
 205 MODULE_DESCRIPTION("Invensense device MPU6050 driver");
 206 MODULE_LICENSE("GPL");