1 /* 2 * kxsd9.c simple support for the Kionix KXSD9 3D 3 * accelerometer. 4 * 5 * Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org> 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 <linux/iio/iio.h> 27 #include <linux/iio/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 **/ 53 struct 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 */ 66 static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 }; 67 68 static 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); 90 error_ret: 91 mutex_unlock(&st->buf_lock); 92 return ret; 93 } 94 95 static int kxsd9_read(struct iio_dev *indio_dev, u8 address) 96 { 97 int ret; 98 struct kxsd9_state *st = iio_priv(indio_dev); 99 struct spi_transfer xfers[] = { 100 { 101 .bits_per_word = 8, 102 .len = 1, 103 .delay_usecs = 200, 104 .tx_buf = st->tx, 105 }, { 106 .bits_per_word = 8, 107 .len = 2, 108 .rx_buf = st->rx, 109 }, 110 }; 111 112 mutex_lock(&st->buf_lock); 113 st->tx[0] = KXSD9_READ(address); 114 ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers)); 115 if (ret) 116 return ret; 117 return (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0); 118 } 119 120 static IIO_CONST_ATTR(accel_scale_available, 121 KXSD9_SCALE_2G " " 122 KXSD9_SCALE_4G " " 123 KXSD9_SCALE_6G " " 124 KXSD9_SCALE_8G); 125 126 static struct attribute *kxsd9_attributes[] = { 127 &iio_const_attr_accel_scale_available.dev_attr.attr, 128 NULL, 129 }; 130 131 static int kxsd9_write_raw(struct iio_dev *indio_dev, 132 struct iio_chan_spec const *chan, 133 int val, 134 int val2, 135 long mask) 136 { 137 int ret = -EINVAL; 138 139 if (mask == IIO_CHAN_INFO_SCALE) { 140 /* Check no integer component */ 141 if (val) 142 return -EINVAL; 143 ret = kxsd9_write_scale(indio_dev, val2); 144 } 145 146 return ret; 147 } 148 149 static int kxsd9_read_raw(struct iio_dev *indio_dev, 150 struct iio_chan_spec const *chan, 151 int *val, int *val2, long mask) 152 { 153 int ret = -EINVAL; 154 struct kxsd9_state *st = iio_priv(indio_dev); 155 156 switch (mask) { 157 case IIO_CHAN_INFO_RAW: 158 ret = kxsd9_read(indio_dev, chan->address); 159 if (ret < 0) 160 goto error_ret; 161 *val = ret; 162 break; 163 case IIO_CHAN_INFO_SCALE: 164 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C)); 165 if (ret) 166 goto error_ret; 167 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK]; 168 ret = IIO_VAL_INT_PLUS_MICRO; 169 break; 170 } 171 172 error_ret: 173 return ret; 174 }; 175 #define KXSD9_ACCEL_CHAN(axis) \ 176 { \ 177 .type = IIO_ACCEL, \ 178 .modified = 1, \ 179 .channel2 = IIO_MOD_##axis, \ 180 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 181 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 182 .address = KXSD9_REG_##axis, \ 183 } 184 185 static const struct iio_chan_spec kxsd9_channels[] = { 186 KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z), 187 { 188 .type = IIO_VOLTAGE, 189 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 190 .indexed = 1, 191 .address = KXSD9_REG_AUX, 192 } 193 }; 194 195 static const struct attribute_group kxsd9_attribute_group = { 196 .attrs = kxsd9_attributes, 197 }; 198 199 static int kxsd9_power_up(struct kxsd9_state *st) 200 { 201 int ret; 202 203 st->tx[0] = 0x0d; 204 st->tx[1] = 0x40; 205 ret = spi_write(st->us, st->tx, 2); 206 if (ret) 207 return ret; 208 209 st->tx[0] = 0x0c; 210 st->tx[1] = 0x9b; 211 return spi_write(st->us, st->tx, 2); 212 }; 213 214 static const struct iio_info kxsd9_info = { 215 .read_raw = &kxsd9_read_raw, 216 .write_raw = &kxsd9_write_raw, 217 .attrs = &kxsd9_attribute_group, 218 .driver_module = THIS_MODULE, 219 }; 220 221 static int kxsd9_probe(struct spi_device *spi) 222 { 223 struct iio_dev *indio_dev; 224 struct kxsd9_state *st; 225 int ret; 226 227 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 228 if (!indio_dev) 229 return -ENOMEM; 230 231 st = iio_priv(indio_dev); 232 spi_set_drvdata(spi, indio_dev); 233 234 st->us = spi; 235 mutex_init(&st->buf_lock); 236 indio_dev->channels = kxsd9_channels; 237 indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels); 238 indio_dev->name = spi_get_device_id(spi)->name; 239 indio_dev->dev.parent = &spi->dev; 240 indio_dev->info = &kxsd9_info; 241 indio_dev->modes = INDIO_DIRECT_MODE; 242 243 spi->mode = SPI_MODE_0; 244 spi_setup(spi); 245 kxsd9_power_up(st); 246 247 ret = iio_device_register(indio_dev); 248 if (ret) 249 return ret; 250 251 return 0; 252 } 253 254 static int kxsd9_remove(struct spi_device *spi) 255 { 256 iio_device_unregister(spi_get_drvdata(spi)); 257 258 return 0; 259 } 260 261 static const struct spi_device_id kxsd9_id[] = { 262 {"kxsd9", 0}, 263 { }, 264 }; 265 MODULE_DEVICE_TABLE(spi, kxsd9_id); 266 267 static struct spi_driver kxsd9_driver = { 268 .driver = { 269 .name = "kxsd9", 270 .owner = THIS_MODULE, 271 }, 272 .probe = kxsd9_probe, 273 .remove = kxsd9_remove, 274 .id_table = kxsd9_id, 275 }; 276 module_spi_driver(kxsd9_driver); 277 278 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 279 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver"); 280 MODULE_LICENSE("GPL v2"); 281