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 return 0; 209 } 210 211 static const struct i2c_device_id mma8450_id[] = { 212 { MMA8450_DRV_NAME, 0 }, 213 { }, 214 }; 215 MODULE_DEVICE_TABLE(i2c, mma8450_id); 216 217 static const struct of_device_id mma8450_dt_ids[] = { 218 { .compatible = "fsl,mma8450", }, 219 { /* sentinel */ } 220 }; 221 MODULE_DEVICE_TABLE(of, mma8450_dt_ids); 222 223 static struct i2c_driver mma8450_driver = { 224 .driver = { 225 .name = MMA8450_DRV_NAME, 226 .of_match_table = mma8450_dt_ids, 227 }, 228 .probe = mma8450_probe, 229 .id_table = mma8450_id, 230 }; 231 232 module_i2c_driver(mma8450_driver); 233 234 MODULE_AUTHOR("Freescale Semiconductor, Inc."); 235 MODULE_DESCRIPTION("MMA8450 3-Axis Accelerometer Driver"); 236 MODULE_LICENSE("GPL"); 237