drivers/input/misc/mma8450.c

   1 /*
   2  *  Driver for Freescale's 3-Axis Accelerometer MMA8450
   3  *
   4  *  Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/slab.h>
  24 #include <linux/delay.h>
  25 #include <linux/i2c.h>
  26 #include <linux/input-polldev.h>
  27 #include <linux/of_device.h>
  28
  29 #define MMA8450_DRV_NAME        "mma8450"
  30
  31 #define MODE_CHANGE_DELAY_MS    100
  32 #define POLL_INTERVAL           100
  33 #define POLL_INTERVAL_MAX       500
  34
  35 /* register definitions */
  36 #define MMA8450_STATUS          0x00
  37 #define MMA8450_STATUS_ZXYDR    0x08
  38
  39 #define MMA8450_OUT_X8          0x01
  40 #define MMA8450_OUT_Y8          0x02
  41 #define MMA8450_OUT_Z8          0x03
  42
  43 #define MMA8450_OUT_X_LSB       0x05
  44 #define MMA8450_OUT_X_MSB       0x06
  45 #define MMA8450_OUT_Y_LSB       0x07
  46 #define MMA8450_OUT_Y_MSB       0x08
  47 #define MMA8450_OUT_Z_LSB       0x09
  48 #define MMA8450_OUT_Z_MSB       0x0a
  49
  50 #define MMA8450_XYZ_DATA_CFG    0x16
  51
  52 #define MMA8450_CTRL_REG1       0x38
  53 #define MMA8450_CTRL_REG2       0x39
  54
  55 /* mma8450 status */
  56 struct mma8450 {
  57         struct i2c_client       *client;
  58         struct input_polled_dev *idev;
  59 };
  60
  61 static int mma8450_read(struct mma8450 *m, unsigned off)
  62 {
  63         struct i2c_client *c = m->client;
  64         int ret;
  65
  66         ret = i2c_smbus_read_byte_data(c, off);
  67         if (ret < 0)
  68                 dev_err(&c->dev,
  69                         "failed to read register 0x%02x, error %d\n",
  70                         off, ret);
  71
  72         return ret;
  73 }
  74
  75 static int mma8450_write(struct mma8450 *m, unsigned off, u8 v)
  76 {
  77         struct i2c_client *c = m->client;
  78         int error;
  79
  80         error = i2c_smbus_write_byte_data(c, off, v);
  81         if (error < 0) {
  82                 dev_err(&c->dev,
  83                         "failed to write to register 0x%02x, error %d\n",
  84                         off, error);
  85                 return error;
  86         }
  87
  88         return 0;
  89 }
  90
  91 static int mma8450_read_block(struct mma8450 *m, unsigned off,
  92                               u8 *buf, size_t size)
  93 {
  94         struct i2c_client *c = m->client;
  95         int err;
  96
  97         err = i2c_smbus_read_i2c_block_data(c, off, size, buf);
  98         if (err < 0) {
  99                 dev_err(&c->dev,
 100                         "failed to read block data at 0x%02x, error %d\n",
 101                         MMA8450_OUT_X_LSB, err);
 102                 return err;
 103         }
 104
 105         return 0;
 106 }
 107
 108 static void mma8450_poll(struct input_polled_dev *dev)
 109 {
 110         struct mma8450 *m = dev->private;
 111         int x, y, z;
 112         int ret;
 113         u8 buf[6];
 114
 115         ret = mma8450_read(m, MMA8450_STATUS);
 116         if (ret < 0)
 117                 return;
 118
 119         if (!(ret & MMA8450_STATUS_ZXYDR))
 120                 return;
 121
 122         ret = mma8450_read_block(m, MMA8450_OUT_X_LSB, buf, sizeof(buf));
 123         if (ret < 0)
 124                 return;
 125
 126         x = ((int)(s8)buf[1] << 4) | (buf[0] & 0xf);
 127         y = ((int)(s8)buf[3] << 4) | (buf[2] & 0xf);
 128         z = ((int)(s8)buf[5] << 4) | (buf[4] & 0xf);
 129
 130         input_report_abs(dev->input, ABS_X, x);
 131         input_report_abs(dev->input, ABS_Y, y);
 132         input_report_abs(dev->input, ABS_Z, z);
 133         input_sync(dev->input);
 134 }
 135
 136 /* Initialize the MMA8450 chip */
 137 static void mma8450_open(struct input_polled_dev *dev)
 138 {
 139         struct mma8450 *m = dev->private;
 140         int err;
 141
 142         /* enable all events from X/Y/Z, no FIFO */
 143         err = mma8450_write(m, MMA8450_XYZ_DATA_CFG, 0x07);
 144         if (err)
 145                 return;
 146
 147         /*
 148          * Sleep mode poll rate - 50Hz
 149          * System output data rate - 400Hz
 150          * Full scale selection - Active, +/- 2G
 151          */
 152         err = mma8450_write(m, MMA8450_CTRL_REG1, 0x01);
 153         if (err < 0)
 154                 return;
 155
 156         msleep(MODE_CHANGE_DELAY_MS);
 157 }
 158
 159 static void mma8450_close(struct input_polled_dev *dev)
 160 {
 161         struct mma8450 *m = dev->private;
 162
 163         mma8450_write(m, MMA8450_CTRL_REG1, 0x00);
 164         mma8450_write(m, MMA8450_CTRL_REG2, 0x01);
 165 }
 166
 167 /*
 168  * I2C init/probing/exit functions
 169  */
 170 static int mma8450_probe(struct i2c_client *c,
 171                          const struct i2c_device_id *id)
 172 {
 173         struct input_polled_dev *idev;
 174         struct mma8450 *m;
 175         int err;
 176
 177         m = devm_kzalloc(&c->dev, sizeof(*m), GFP_KERNEL);
 178         if (!m)
 179                 return -ENOMEM;
 180
 181         idev = devm_input_allocate_polled_device(&c->dev);
 182         if (!idev)
 183                 return -ENOMEM;
 184
 185         m->client = c;
 186         m->idev = idev;
 187
 188         idev->private           = m;
 189         idev->input->name       = MMA8450_DRV_NAME;
 190         idev->input->id.bustype = BUS_I2C;
 191         idev->poll              = mma8450_poll;
 192         idev->poll_interval     = POLL_INTERVAL;
 193         idev->poll_interval_max = POLL_INTERVAL_MAX;
 194         idev->open              = mma8450_open;
 195         idev->close             = mma8450_close;
 196
 197         __set_bit(EV_ABS, idev->input->evbit);
 198         input_set_abs_params(idev->input, ABS_X, -2048, 2047, 32, 32);
 199         input_set_abs_params(idev->input, ABS_Y, -2048, 2047, 32, 32);
 200         input_set_abs_params(idev->input, ABS_Z, -2048, 2047, 32, 32);
 201
 202         err = input_register_polled_device(idev);
 203         if (err) {
 204                 dev_err(&c->dev, "failed to register polled input device\n");
 205                 return err;
 206         }
 207
 208         i2c_set_clientdata(c, m);
 209
 210         return 0;
 211 }
 212
 213 static const struct i2c_device_id mma8450_id[] = {
 214         { MMA8450_DRV_NAME, 0 },
 215         { },
 216 };
 217 MODULE_DEVICE_TABLE(i2c, mma8450_id);
 218
 219 static const struct of_device_id mma8450_dt_ids[] = {
 220         { .compatible = "fsl,mma8450", },
 221         { /* sentinel */ }
 222 };
 223 MODULE_DEVICE_TABLE(of, mma8450_dt_ids);
 224
 225 static struct i2c_driver mma8450_driver = {
 226         .driver = {
 227                 .name   = MMA8450_DRV_NAME,
 228                 .of_match_table = mma8450_dt_ids,
 229         },
 230         .probe          = mma8450_probe,
 231         .id_table       = mma8450_id,
 232 };
 233
 234 module_i2c_driver(mma8450_driver);
 235
 236 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
 237 MODULE_DESCRIPTION("MMA8450 3-Axis Accelerometer Driver");
 238 MODULE_LICENSE("GPL");