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 < 0) 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 ret = IIO_VAL_INT; 164 break; 165 case IIO_CHAN_INFO_SCALE: 166 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C)); 167 if (ret < 0) 168 goto error_ret; 169 *val = 0; 170 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK]; 171 ret = IIO_VAL_INT_PLUS_MICRO; 172 break; 173 } 174 175 error_ret: 176 return ret; 177 }; 178 #define KXSD9_ACCEL_CHAN(axis) \ 179 { \ 180 .type = IIO_ACCEL, \ 181 .modified = 1, \ 182 .channel2 = IIO_MOD_##axis, \ 183 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 184 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 185 .address = KXSD9_REG_##axis, \ 186 } 187 188 static const 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 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 193 .indexed = 1, 194 .address = KXSD9_REG_AUX, 195 } 196 }; 197 198 static const struct attribute_group kxsd9_attribute_group = { 199 .attrs = kxsd9_attributes, 200 }; 201 202 static int kxsd9_power_up(struct kxsd9_state *st) 203 { 204 int ret; 205 206 st->tx[0] = 0x0d; 207 st->tx[1] = 0x40; 208 ret = spi_write(st->us, st->tx, 2); 209 if (ret) 210 return ret; 211 212 st->tx[0] = 0x0c; 213 st->tx[1] = 0x9b; 214 return spi_write(st->us, st->tx, 2); 215 }; 216 217 static const struct iio_info kxsd9_info = { 218 .read_raw = &kxsd9_read_raw, 219 .write_raw = &kxsd9_write_raw, 220 .attrs = &kxsd9_attribute_group, 221 .driver_module = THIS_MODULE, 222 }; 223 224 static int kxsd9_probe(struct spi_device *spi) 225 { 226 struct iio_dev *indio_dev; 227 struct kxsd9_state *st; 228 229 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 230 if (!indio_dev) 231 return -ENOMEM; 232 233 st = iio_priv(indio_dev); 234 spi_set_drvdata(spi, indio_dev); 235 236 st->us = spi; 237 mutex_init(&st->buf_lock); 238 indio_dev->channels = kxsd9_channels; 239 indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels); 240 indio_dev->name = spi_get_device_id(spi)->name; 241 indio_dev->dev.parent = &spi->dev; 242 indio_dev->info = &kxsd9_info; 243 indio_dev->modes = INDIO_DIRECT_MODE; 244 245 spi->mode = SPI_MODE_0; 246 spi_setup(spi); 247 kxsd9_power_up(st); 248 249 return iio_device_register(indio_dev); 250 } 251 252 static int kxsd9_remove(struct spi_device *spi) 253 { 254 iio_device_unregister(spi_get_drvdata(spi)); 255 256 return 0; 257 } 258 259 static const struct spi_device_id kxsd9_id[] = { 260 {"kxsd9", 0}, 261 { }, 262 }; 263 MODULE_DEVICE_TABLE(spi, kxsd9_id); 264 265 static struct spi_driver kxsd9_driver = { 266 .driver = { 267 .name = "kxsd9", 268 }, 269 .probe = kxsd9_probe, 270 .remove = kxsd9_remove, 271 .id_table = kxsd9_id, 272 }; 273 module_spi_driver(kxsd9_driver); 274 275 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); 276 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver"); 277 MODULE_LICENSE("GPL v2"); 278