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 ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0); 117 mutex_unlock(&st->buf_lock); 118 return ret; 119 } 120 121 static IIO_CONST_ATTR(accel_scale_available, 122 KXSD9_SCALE_2G " " 123 KXSD9_SCALE_4G " " 124 KXSD9_SCALE_6G " " 125 KXSD9_SCALE_8G); 126 127 static struct attribute *kxsd9_attributes[] = { 128 &iio_const_attr_accel_scale_available.dev_attr.attr, 129 NULL, 130 }; 131 132 static int kxsd9_write_raw(struct iio_dev *indio_dev, 133 struct iio_chan_spec const *chan, 134 int val, 135 int val2, 136 long mask) 137 { 138 int ret = -EINVAL; 139 140 if (mask == IIO_CHAN_INFO_SCALE) { 141 /* Check no integer component */ 142 if (val) 143 return -EINVAL; 144 ret = kxsd9_write_scale(indio_dev, val2); 145 } 146 147 return ret; 148 } 149 150 static int kxsd9_read_raw(struct iio_dev *indio_dev, 151 struct iio_chan_spec const *chan, 152 int *val, int *val2, long mask) 153 { 154 int ret = -EINVAL; 155 struct kxsd9_state *st = iio_priv(indio_dev); 156 157 switch (mask) { 158 case IIO_CHAN_INFO_RAW: 159 ret = kxsd9_read(indio_dev, chan->address); 160 if (ret < 0) 161 goto error_ret; 162 *val = ret; 163 break; 164 case IIO_CHAN_INFO_SCALE: 165 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C)); 166 if (ret) 167 goto error_ret; 168 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK]; 169 ret = IIO_VAL_INT_PLUS_MICRO; 170 break; 171 } 172 173 error_ret: 174 return ret; 175 }; 176 #define KXSD9_ACCEL_CHAN(axis) \ 177 { \ 178 .type = IIO_ACCEL, \ 179 .modified = 1, \ 180 .channel2 = IIO_MOD_##axis, \ 181 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 182 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 183 .address = KXSD9_REG_##axis, \ 184 } 185 186 static const struct iio_chan_spec kxsd9_channels[] = { 187 KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z), 188 { 189 .type = IIO_VOLTAGE, 190 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 191 .indexed = 1, 192 .address = KXSD9_REG_AUX, 193 } 194 }; 195 196 static const struct attribute_group kxsd9_attribute_group = { 197 .attrs = kxsd9_attributes, 198 }; 199 200 static int kxsd9_power_up(struct kxsd9_state *st) 201 { 202 int ret; 203 204 st->tx[0] = 0x0d; 205 st->tx[1] = 0x40; 206 ret = spi_write(st->us, st->tx, 2); 207 if (ret) 208 return ret; 209 210 st->tx[0] = 0x0c; 211 st->tx[1] = 0x9b; 212 return spi_write(st->us, st->tx, 2); 213 }; 214 215 static const struct iio_info kxsd9_info = { 216 .read_raw = &kxsd9_read_raw, 217 .write_raw = &kxsd9_write_raw, 218 .attrs = &kxsd9_attribute_group, 219 .driver_module = THIS_MODULE, 220 }; 221 222 static int kxsd9_probe(struct spi_device *spi) 223 { 224 struct iio_dev *indio_dev; 225 struct kxsd9_state *st; 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 return iio_device_register(indio_dev); 248 } 249 250 static int kxsd9_remove(struct spi_device *spi) 251 { 252 iio_device_unregister(spi_get_drvdata(spi)); 253 254 return 0; 255 } 256 257 static const struct spi_device_id kxsd9_id[] = { 258 {"kxsd9", 0}, 259 { }, 260 }; 261 MODULE_DEVICE_TABLE(spi, kxsd9_id); 262 263 static struct spi_driver kxsd9_driver = { 264 .driver = { 265 .name = "kxsd9", 266 .owner = THIS_MODULE, 267 }, 268 .probe = kxsd9_probe, 269 .remove = kxsd9_remove, 270 .id_table = kxsd9_id, 271 }; 272 module_spi_driver(kxsd9_driver); 273 274 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 275 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver"); 276 MODULE_LICENSE("GPL v2"); 277