1/* 2 * kxsd9.c simple support for the Kionix KXSD9 3D 3 * accelerometer. 4 * 5 * Copyright (c) 2008-2009 Jonathan Cameron <jic23@cam.ac.uk> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * The i2c interface is very similar, so shouldn't be a problem once 12 * I have a suitable wire made up. 13 * 14 * TODO: Support the motion detector 15 * Uses register address incrementing so could have a 16 * heavily optimized ring buffer access function. 17 */ 18 19#include <linux/device.h> 20#include <linux/kernel.h> 21#include <linux/spi/spi.h> 22#include <linux/sysfs.h> 23#include <linux/slab.h> 24#include <linux/module.h> 25 26#include "../iio.h" 27#include "../sysfs.h" 28 29#define KXSD9_REG_X 0x00 30#define KXSD9_REG_Y 0x02 31#define KXSD9_REG_Z 0x04 32#define KXSD9_REG_AUX 0x06 33#define KXSD9_REG_RESET 0x0a 34#define KXSD9_REG_CTRL_C 0x0c 35 36#define KXSD9_FS_MASK 0x03 37 38#define KXSD9_REG_CTRL_B 0x0d 39#define KXSD9_REG_CTRL_A 0x0e 40 41#define KXSD9_READ(a) (0x80 | (a)) 42#define KXSD9_WRITE(a) (a) 43 44#define KXSD9_STATE_RX_SIZE 2 45#define KXSD9_STATE_TX_SIZE 2 46/** 47 * struct kxsd9_state - device related storage 48 * @buf_lock: protect the rx and tx buffers. 49 * @us: spi device 50 * @rx: single rx buffer storage 51 * @tx: single tx buffer storage 52 **/ 53struct kxsd9_state { 54 struct mutex buf_lock; 55 struct spi_device *us; 56 u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned; 57 u8 tx[KXSD9_STATE_TX_SIZE]; 58}; 59 60#define KXSD9_SCALE_2G "0.011978" 61#define KXSD9_SCALE_4G "0.023927" 62#define KXSD9_SCALE_6G "0.035934" 63#define KXSD9_SCALE_8G "0.047853" 64 65/* reverse order */ 66static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 }; 67 68static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro) 69{ 70 int ret, i; 71 struct kxsd9_state *st = iio_priv(indio_dev); 72 bool foundit = false; 73 74 for (i = 0; i < 4; i++) 75 if (micro == kxsd9_micro_scales[i]) { 76 foundit = true; 77 break; 78 } 79 if (!foundit) 80 return -EINVAL; 81 82 mutex_lock(&st->buf_lock); 83 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C)); 84 if (ret) 85 goto error_ret; 86 st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C); 87 st->tx[1] = (ret & ~KXSD9_FS_MASK) | i; 88 89 ret = spi_write(st->us, st->tx, 2); 90error_ret: 91 mutex_unlock(&st->buf_lock); 92 return ret; 93} 94 95static int kxsd9_read(struct iio_dev *indio_dev, u8 address) 96{ 97 struct spi_message msg; 98 int ret; 99 struct kxsd9_state *st = iio_priv(indio_dev); 100 struct spi_transfer xfers[] = { 101 { 102 .bits_per_word = 8, 103 .len = 1, 104 .delay_usecs = 200, 105 .tx_buf = st->tx, 106 }, { 107 .bits_per_word = 8, 108 .len = 2, 109 .rx_buf = st->rx, 110 }, 111 }; 112 113 mutex_lock(&st->buf_lock); 114 st->tx[0] = KXSD9_READ(address); 115 spi_message_init(&msg); 116 spi_message_add_tail(&xfers[0], &msg); 117 spi_message_add_tail(&xfers[1], &msg); 118 ret = spi_sync(st->us, &msg); 119 if (ret) 120 return ret; 121 return (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0); 122} 123 124static IIO_CONST_ATTR(accel_scale_available, 125 KXSD9_SCALE_2G " " 126 KXSD9_SCALE_4G " " 127 KXSD9_SCALE_6G " " 128 KXSD9_SCALE_8G); 129 130static struct attribute *kxsd9_attributes[] = { 131 &iio_const_attr_accel_scale_available.dev_attr.attr, 132 NULL, 133}; 134 135static int kxsd9_write_raw(struct iio_dev *indio_dev, 136 struct iio_chan_spec const *chan, 137 int val, 138 int val2, 139 long mask) 140{ 141 int ret = -EINVAL; 142 143 if (mask == IIO_CHAN_INFO_SCALE) { 144 /* Check no integer component */ 145 if (val) 146 return -EINVAL; 147 ret = kxsd9_write_scale(indio_dev, val2); 148 } 149 150 return ret; 151} 152 153static int kxsd9_read_raw(struct iio_dev *indio_dev, 154 struct iio_chan_spec const *chan, 155 int *val, int *val2, long mask) 156{ 157 int ret = -EINVAL; 158 struct kxsd9_state *st = iio_priv(indio_dev); 159 160 switch (mask) { 161 case 0: 162 ret = kxsd9_read(indio_dev, chan->address); 163 if (ret < 0) 164 goto error_ret; 165 *val = ret; 166 break; 167 case IIO_CHAN_INFO_SCALE: 168 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C)); 169 if (ret) 170 goto error_ret; 171 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK]; 172 ret = IIO_VAL_INT_PLUS_MICRO; 173 break; 174 }; 175 176error_ret: 177 return ret; 178}; 179#define KXSD9_ACCEL_CHAN(axis) \ 180 { \ 181 .type = IIO_ACCEL, \ 182 .modified = 1, \ 183 .channel2 = IIO_MOD_##axis, \ 184 .info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT, \ 185 .address = KXSD9_REG_##axis, \ 186 } 187 188static struct iio_chan_spec kxsd9_channels[] = { 189 KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z), 190 { 191 .type = IIO_VOLTAGE, 192 .indexed = 1, 193 .address = KXSD9_REG_AUX, 194 } 195}; 196 197static const struct attribute_group kxsd9_attribute_group = { 198 .attrs = kxsd9_attributes, 199}; 200 201static int __devinit kxsd9_power_up(struct kxsd9_state *st) 202{ 203 int ret; 204 205 st->tx[0] = 0x0d; 206 st->tx[1] = 0x40; 207 ret = spi_write(st->us, st->tx, 2); 208 if (ret) 209 return ret; 210 211 st->tx[0] = 0x0c; 212 st->tx[1] = 0x9b; 213 return spi_write(st->us, st->tx, 2); 214}; 215 216static const struct iio_info kxsd9_info = { 217 .read_raw = &kxsd9_read_raw, 218 .write_raw = &kxsd9_write_raw, 219 .attrs = &kxsd9_attribute_group, 220 .driver_module = THIS_MODULE, 221}; 222 223static int __devinit kxsd9_probe(struct spi_device *spi) 224{ 225 struct iio_dev *indio_dev; 226 struct kxsd9_state *st; 227 int ret = 0; 228 229 indio_dev = iio_allocate_device(sizeof(*st)); 230 if (indio_dev == NULL) { 231 ret = -ENOMEM; 232 goto error_ret; 233 } 234 st = iio_priv(indio_dev); 235 spi_set_drvdata(spi, indio_dev); 236 237 st->us = spi; 238 mutex_init(&st->buf_lock); 239 indio_dev->channels = kxsd9_channels; 240 indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels); 241 indio_dev->name = spi_get_device_id(spi)->name; 242 indio_dev->dev.parent = &spi->dev; 243 indio_dev->info = &kxsd9_info; 244 indio_dev->modes = INDIO_DIRECT_MODE; 245 246 ret = iio_device_register(indio_dev); 247 if (ret) 248 goto error_free_dev; 249 250 spi->mode = SPI_MODE_0; 251 spi_setup(spi); 252 kxsd9_power_up(st); 253 254 return 0; 255 256error_free_dev: 257 iio_free_device(indio_dev); 258error_ret: 259 return ret; 260} 261 262static int __devexit kxsd9_remove(struct spi_device *spi) 263{ 264 iio_device_unregister(spi_get_drvdata(spi)); 265 iio_free_device(spi_get_drvdata(spi)); 266 267 return 0; 268} 269 270static const struct spi_device_id kxsd9_id[] = { 271 {"kxsd9", 0}, 272 { }, 273}; 274MODULE_DEVICE_TABLE(spi, kxsd9_id); 275 276static struct spi_driver kxsd9_driver = { 277 .driver = { 278 .name = "kxsd9", 279 .owner = THIS_MODULE, 280 }, 281 .probe = kxsd9_probe, 282 .remove = __devexit_p(kxsd9_remove), 283 .id_table = kxsd9_id, 284}; 285module_spi_driver(kxsd9_driver); 286 287MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); 288MODULE_DESCRIPTION("Kionix KXSD9 SPI driver"); 289MODULE_LICENSE("GPL v2"); 290