1 /** 2 * Freescale MMA7660FC 3-Axis Accelerometer 3 * 4 * Copyright (c) 2016, Intel Corporation. 5 * 6 * This file is subject to the terms and conditions of version 2 of 7 * the GNU General Public License. See the file COPYING in the main 8 * directory of this archive for more details. 9 * 10 * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c. 11 */ 12 13 #include <linux/acpi.h> 14 #include <linux/i2c.h> 15 #include <linux/module.h> 16 #include <linux/iio/iio.h> 17 #include <linux/iio/sysfs.h> 18 19 #define MMA7660_DRIVER_NAME "mma7660" 20 21 #define MMA7660_REG_XOUT 0x00 22 #define MMA7660_REG_YOUT 0x01 23 #define MMA7660_REG_ZOUT 0x02 24 #define MMA7660_REG_OUT_BIT_ALERT BIT(6) 25 26 #define MMA7660_REG_MODE 0x07 27 #define MMA7660_REG_MODE_BIT_MODE BIT(0) 28 #define MMA7660_REG_MODE_BIT_TON BIT(2) 29 30 #define MMA7660_I2C_READ_RETRIES 5 31 32 /* 33 * The accelerometer has one measurement range: 34 * 35 * -1.5g - +1.5g (6-bit, signed) 36 * 37 * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1) = 0.467142857 38 */ 39 40 #define MMA7660_SCALE_AVAIL "0.467142857" 41 42 const int mma7660_nscale = 467142857; 43 44 #define MMA7660_CHANNEL(reg, axis) { \ 45 .type = IIO_ACCEL, \ 46 .address = reg, \ 47 .modified = 1, \ 48 .channel2 = IIO_MOD_##axis, \ 49 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 50 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 51 } 52 53 static const struct iio_chan_spec mma7660_channels[] = { 54 MMA7660_CHANNEL(MMA7660_REG_XOUT, X), 55 MMA7660_CHANNEL(MMA7660_REG_YOUT, Y), 56 MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z), 57 }; 58 59 enum mma7660_mode { 60 MMA7660_MODE_STANDBY, 61 MMA7660_MODE_ACTIVE 62 }; 63 64 struct mma7660_data { 65 struct i2c_client *client; 66 struct mutex lock; 67 enum mma7660_mode mode; 68 }; 69 70 static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL); 71 72 static struct attribute *mma7660_attributes[] = { 73 &iio_const_attr_in_accel_scale_available.dev_attr.attr, 74 NULL, 75 }; 76 77 static const struct attribute_group mma7660_attribute_group = { 78 .attrs = mma7660_attributes 79 }; 80 81 static int mma7660_set_mode(struct mma7660_data *data, 82 enum mma7660_mode mode) 83 { 84 int ret; 85 struct i2c_client *client = data->client; 86 87 if (mode == data->mode) 88 return 0; 89 90 ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE); 91 if (ret < 0) { 92 dev_err(&client->dev, "failed to read sensor mode\n"); 93 return ret; 94 } 95 96 if (mode == MMA7660_MODE_ACTIVE) { 97 ret &= ~MMA7660_REG_MODE_BIT_TON; 98 ret |= MMA7660_REG_MODE_BIT_MODE; 99 } else { 100 ret &= ~MMA7660_REG_MODE_BIT_TON; 101 ret &= ~MMA7660_REG_MODE_BIT_MODE; 102 } 103 104 ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret); 105 if (ret < 0) { 106 dev_err(&client->dev, "failed to change sensor mode\n"); 107 return ret; 108 } 109 110 data->mode = mode; 111 112 return ret; 113 } 114 115 static int mma7660_read_accel(struct mma7660_data *data, u8 address) 116 { 117 int ret, retries = MMA7660_I2C_READ_RETRIES; 118 struct i2c_client *client = data->client; 119 120 /* 121 * Read data. If the Alert bit is set, the register was read at 122 * the same time as the device was attempting to update the content. 123 * The solution is to read the register again. Do this only 124 * MMA7660_I2C_READ_RETRIES times to avoid spending too much time 125 * in the kernel. 126 */ 127 do { 128 ret = i2c_smbus_read_byte_data(client, address); 129 if (ret < 0) { 130 dev_err(&client->dev, "register read failed\n"); 131 return ret; 132 } 133 } while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT); 134 135 if (ret & MMA7660_REG_OUT_BIT_ALERT) { 136 dev_err(&client->dev, "all register read retries failed\n"); 137 return -ETIMEDOUT; 138 } 139 140 return ret; 141 } 142 143 static int mma7660_read_raw(struct iio_dev *indio_dev, 144 struct iio_chan_spec const *chan, 145 int *val, int *val2, long mask) 146 { 147 struct mma7660_data *data = iio_priv(indio_dev); 148 int ret; 149 150 switch (mask) { 151 case IIO_CHAN_INFO_RAW: 152 mutex_lock(&data->lock); 153 ret = mma7660_read_accel(data, chan->address); 154 mutex_unlock(&data->lock); 155 if (ret < 0) 156 return ret; 157 *val = sign_extend32(ret, 5); 158 return IIO_VAL_INT; 159 case IIO_CHAN_INFO_SCALE: 160 *val = 0; 161 *val2 = mma7660_nscale; 162 return IIO_VAL_INT_PLUS_NANO; 163 default: 164 return -EINVAL; 165 } 166 167 return -EINVAL; 168 } 169 170 static const struct iio_info mma7660_info = { 171 .driver_module = THIS_MODULE, 172 .read_raw = mma7660_read_raw, 173 .attrs = &mma7660_attribute_group, 174 }; 175 176 static int mma7660_probe(struct i2c_client *client, 177 const struct i2c_device_id *id) 178 { 179 int ret; 180 struct iio_dev *indio_dev; 181 struct mma7660_data *data; 182 183 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 184 if (!indio_dev) { 185 dev_err(&client->dev, "iio allocation failed!\n"); 186 return -ENOMEM; 187 } 188 189 data = iio_priv(indio_dev); 190 data->client = client; 191 i2c_set_clientdata(client, indio_dev); 192 mutex_init(&data->lock); 193 data->mode = MMA7660_MODE_STANDBY; 194 195 indio_dev->dev.parent = &client->dev; 196 indio_dev->info = &mma7660_info; 197 indio_dev->name = MMA7660_DRIVER_NAME; 198 indio_dev->modes = INDIO_DIRECT_MODE; 199 indio_dev->channels = mma7660_channels; 200 indio_dev->num_channels = ARRAY_SIZE(mma7660_channels); 201 202 ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE); 203 if (ret < 0) 204 return ret; 205 206 ret = iio_device_register(indio_dev); 207 if (ret < 0) { 208 dev_err(&client->dev, "device_register failed\n"); 209 mma7660_set_mode(data, MMA7660_MODE_STANDBY); 210 } 211 212 return ret; 213 } 214 215 static int mma7660_remove(struct i2c_client *client) 216 { 217 struct iio_dev *indio_dev = i2c_get_clientdata(client); 218 219 iio_device_unregister(indio_dev); 220 221 return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY); 222 } 223 224 #ifdef CONFIG_PM_SLEEP 225 static int mma7660_suspend(struct device *dev) 226 { 227 struct mma7660_data *data; 228 229 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); 230 231 return mma7660_set_mode(data, MMA7660_MODE_STANDBY); 232 } 233 234 static int mma7660_resume(struct device *dev) 235 { 236 struct mma7660_data *data; 237 238 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); 239 240 return mma7660_set_mode(data, MMA7660_MODE_ACTIVE); 241 } 242 243 static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume); 244 245 #define MMA7660_PM_OPS (&mma7660_pm_ops) 246 #else 247 #define MMA7660_PM_OPS NULL 248 #endif 249 250 static const struct i2c_device_id mma7660_i2c_id[] = { 251 {"mma7660", 0}, 252 {} 253 }; 254 255 static const struct acpi_device_id mma7660_acpi_id[] = { 256 {"MMA7660", 0}, 257 {} 258 }; 259 260 MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id); 261 262 static struct i2c_driver mma7660_driver = { 263 .driver = { 264 .name = "mma7660", 265 .pm = MMA7660_PM_OPS, 266 .acpi_match_table = ACPI_PTR(mma7660_acpi_id), 267 }, 268 .probe = mma7660_probe, 269 .remove = mma7660_remove, 270 .id_table = mma7660_i2c_id, 271 }; 272 273 module_i2c_driver(mma7660_driver); 274 275 MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>"); 276 MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver"); 277 MODULE_LICENSE("GPL v2"); 278