drivers/staging/iio/accel/sca3000.h

   1 /*
   2  * sca3000.c -- support VTI sca3000 series accelerometers
   3  *              via SPI
   4  *
   5  * Copyright (c) 2007 Jonathan Cameron <jic23@cam.ac.uk>
   6  *
   7  * Partly based upon tle62x0.c
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * Initial mode is direct measurement.
  14  *
  15  * Untested things
  16  *
  17  * Temperature reading (the e05 I'm testing with doesn't have a sensor)
  18  *
  19  * Free fall detection mode - supported but untested as I'm not droping my
  20  * dubious wire rig far enough to test it.
  21  *
  22  * Unsupported as yet
  23  *
  24  * Time stamping of data from ring. Various ideas on how to do this but none
  25  * are remotely simple. Suggestions welcome.
  26  *
  27  * Individual enabling disabling of channels going into ring buffer
  28  *
  29  * Overflow handling (this is signaled for all but 8 bit ring buffer mode.)
  30  *
  31  * Motion detector using AND combinations of signals.
  32  *
  33  * Note: Be very careful about not touching an register bytes marked
  34  * as reserved on the data sheet. They really mean it as changing convents of
  35  * some will cause the device to lock up.
  36  *
  37  * Known issues - on rare occasions the interrupts lock up. Not sure why as yet.
  38  * Can probably alleviate this by reading the interrupt register on start, but
  39  * that is really just brushing the problem under the carpet.
  40  */
  41 #define SCA3000_WRITE_REG(a) (((a) << 2) | 0x02)
  42 #define SCA3000_READ_REG(a) ((a) << 2)
  43
  44 #define SCA3000_REG_ADDR_REVID                  0x00
  45 #define SCA3000_REVID_MAJOR_MASK                0xf0
  46 #define SCA3000_REVID_MINOR_MASK                0x0f
  47
  48 #define SCA3000_REG_ADDR_STATUS                 0x02
  49 #define SCA3000_LOCKED                          0x20
  50 #define SCA3000_EEPROM_CS_ERROR                 0x02
  51 #define SCA3000_SPI_FRAME_ERROR                 0x01
  52
  53 /* All reads done using register decrement so no need to directly access LSBs */
  54 #define SCA3000_REG_ADDR_X_MSB                  0x05
  55 #define SCA3000_REG_ADDR_Y_MSB                  0x07
  56 #define SCA3000_REG_ADDR_Z_MSB                  0x09
  57
  58 #define SCA3000_REG_ADDR_RING_OUT               0x0f
  59
  60 /* Temp read untested - the e05 doesn't have the sensor */
  61 #define SCA3000_REG_ADDR_TEMP_MSB               0x13
  62
  63 #define SCA3000_REG_ADDR_MODE                   0x14
  64 #define SCA3000_MODE_PROT_MASK                  0x28
  65
  66 #define SCA3000_RING_BUF_ENABLE                 0x80
  67 #define SCA3000_RING_BUF_8BIT                   0x40
  68 /* Free fall detection triggers an interrupt if the acceleration
  69  * is below a threshold for equivalent of 25cm drop
  70  */
  71 #define SCA3000_FREE_FALL_DETECT                0x10
  72 #define SCA3000_MEAS_MODE_NORMAL                0x00
  73 #define SCA3000_MEAS_MODE_OP_1                  0x01
  74 #define SCA3000_MEAS_MODE_OP_2                  0x02
  75
  76 /* In motion detection mode the accelerations are band pass filtered
  77  * (aprox 1 - 25Hz) and then a programmable threshold used to trigger
  78  * and interrupt.
  79  */
  80 #define SCA3000_MEAS_MODE_MOT_DET               0x03
  81
  82 #define SCA3000_REG_ADDR_BUF_COUNT              0x15
  83
  84 #define SCA3000_REG_ADDR_INT_STATUS             0x16
  85
  86 #define SCA3000_INT_STATUS_THREE_QUARTERS       0x80
  87 #define SCA3000_INT_STATUS_HALF                 0x40
  88
  89 #define SCA3000_INT_STATUS_FREE_FALL            0x08
  90 #define SCA3000_INT_STATUS_Y_TRIGGER            0x04
  91 #define SCA3000_INT_STATUS_X_TRIGGER            0x02
  92 #define SCA3000_INT_STATUS_Z_TRIGGER            0x01
  93
  94 /* Used to allow accesss to multiplexed registers */
  95 #define SCA3000_REG_ADDR_CTRL_SEL               0x18
  96 /* Only available for SCA3000-D03 and SCA3000-D01 */
  97 #define SCA3000_REG_CTRL_SEL_I2C_DISABLE        0x01
  98 #define SCA3000_REG_CTRL_SEL_MD_CTRL            0x02
  99 #define SCA3000_REG_CTRL_SEL_MD_Y_TH            0x03
 100 #define SCA3000_REG_CTRL_SEL_MD_X_TH            0x04
 101 #define SCA3000_REG_CTRL_SEL_MD_Z_TH            0x05
 102 /* BE VERY CAREFUL WITH THIS, IF 3 BITS ARE NOT SET the device
 103    will not function */
 104 #define SCA3000_REG_CTRL_SEL_OUT_CTRL           0x0B
 105 #define SCA3000_OUT_CTRL_PROT_MASK              0xE0
 106 #define SCA3000_OUT_CTRL_BUF_X_EN               0x10
 107 #define SCA3000_OUT_CTRL_BUF_Y_EN               0x08
 108 #define SCA3000_OUT_CTRL_BUF_Z_EN               0x04
 109 #define SCA3000_OUT_CTRL_BUF_DIV_4              0x02
 110 #define SCA3000_OUT_CTRL_BUF_DIV_2              0x01
 111
 112 /* Control which motion detector interrupts are on.
 113  * For now only OR combinations are supported.x
 114  */
 115 #define SCA3000_MD_CTRL_PROT_MASK               0xC0
 116 #define SCA3000_MD_CTRL_OR_Y                    0x01
 117 #define SCA3000_MD_CTRL_OR_X                    0x02
 118 #define SCA3000_MD_CTRL_OR_Z                    0x04
 119 /* Currently unsupported */
 120 #define SCA3000_MD_CTRL_AND_Y                   0x08
 121 #define SCA3000_MD_CTRL_AND_X                   0x10
 122 #define SAC3000_MD_CTRL_AND_Z                   0x20
 123
 124 /* Some control registers of complex access methods requiring this register to
 125  * be used to remove a lock.
 126  */
 127 #define SCA3000_REG_ADDR_UNLOCK                 0x1e
 128
 129 #define SCA3000_REG_ADDR_INT_MASK               0x21
 130 #define SCA3000_INT_MASK_PROT_MASK              0x1C
 131
 132 #define SCA3000_INT_MASK_RING_THREE_QUARTER     0x80
 133 #define SCA3000_INT_MASK_RING_HALF              0x40
 134
 135 #define SCA3000_INT_MASK_ALL_INTS               0x02
 136 #define SCA3000_INT_MASK_ACTIVE_HIGH            0x01
 137 #define SCA3000_INT_MASK_ACTIVE_LOW             0x00
 138
 139 /* Values of mulipexed registers (write to ctrl_data after select) */
 140 #define SCA3000_REG_ADDR_CTRL_DATA              0x22
 141
 142 /* Measurement modes available on some sca3000 series chips. Code assumes others
 143  * may become available in the future.
 144  *
 145  * Bypass - Bypass the low-pass filter in the signal channel so as to increase
 146  *          signal bandwidth.
 147  *
 148  * Narrow - Narrow low-pass filtering of the signal channel and half output
 149  *          data rate by decimation.
 150  *
 151  * Wide - Widen low-pass filtering of signal channel to increase bandwidth
 152  */
 153 #define SCA3000_OP_MODE_BYPASS                  0x01
 154 #define SCA3000_OP_MODE_NARROW                  0x02
 155 #define SCA3000_OP_MODE_WIDE                    0x04
 156 #define SCA3000_MAX_TX 6
 157 #define SCA3000_MAX_RX 2
 158
 159 /**
 160  * struct sca3000_state - device instance state information
 161  * @us:                         the associated spi device
 162  * @info:                       chip variant information
 163  * @indio_dev:                  device information used by the IIO core
 164  * @interrupt_handler_ws:       event interrupt handler for all events
 165  * @last_timestamp:             the timestamp of the last event
 166  * @mo_det_use_count:           reference counter for the motion detection unit
 167  * @lock:                       lock used to protect elements of sca3000_state
 168  *                              and the underlying device state.
 169  * @bpse:                       number of bits per scan element
 170  * @tx:                         dma-able transmit buffer
 171  * @rx:                         dma-able receive buffer
 172  **/
 173 struct sca3000_state {
 174         struct spi_device               *us;
 175         const struct sca3000_chip_info  *info;
 176         struct iio_dev                  *indio_dev;
 177         struct work_struct              interrupt_handler_ws;
 178         s64                             last_timestamp;
 179         int                             mo_det_use_count;
 180         struct mutex                    lock;
 181         int                             bpse;
 182         u8                              *tx;
 183         /* not used during a ring buffer read */
 184         u8                              *rx;
 185 };
 186
 187 /**
 188  * struct sca3000_chip_info - model dependant parameters
 189  * @name:                       model identification
 190  * @scale:                      string containing floating point scale factor
 191  * @temp_output:                some devices have temperature sensors.
 192  * @measurement_mode_freq:      normal mode sampling frequency
 193  * @option_mode_1:              first optional mode. Not all models have one
 194  * @option_mode_1_freq:         option mode 1 sampling frequency
 195  * @option_mode_2:              second optional mode. Not all chips have one
 196  * @option_mode_2_freq:         option mode 2 sampling frequency
 197  *
 198  * This structure is used to hold information about the functionality of a given
 199  * sca3000 variant.
 200  **/
 201 struct sca3000_chip_info {
 202         const char              *name;
 203         const char              *scale;
 204         bool                    temp_output;
 205         int                     measurement_mode_freq;
 206         int                     option_mode_1;
 207         int                     option_mode_1_freq;
 208         int                     option_mode_2;
 209         int                     option_mode_2_freq;
 210 };
 211
 212 /**
 213  * sca3000_read_data() read a series of values from the device
 214  * @dev:                device
 215  * @reg_address_high:   start address (decremented read)
 216  * @rx:                 pointer where recieved data is placed. Callee
 217  *                      responsible for freeing this.
 218  * @len:                number of bytes to read
 219  *
 220  * The main lock must be held.
 221  **/
 222 int sca3000_read_data(struct sca3000_state *st,
 223                       u8 reg_address_high,
 224                       u8 **rx_p,
 225                       int len);
 226
 227 /**
 228  * sca3000_write_reg() write a single register
 229  * @address:    address of register on chip
 230  * @val:        value to be written to register
 231  *
 232  * The main lock must be held.
 233  **/
 234 int sca3000_write_reg(struct sca3000_state *st, u8 address, u8 val);
 235
 236 /* Conversion function for use with the ring buffer when in 11bit mode */
 237 static inline int sca3000_11bit_convert(uint8_t msb, uint8_t lsb)
 238 {
 239         int16_t val;
 240
 241         val = ((lsb >> 3) & 0x1C) | (msb << 5);
 242         val |= (val & (1 << 12)) ? 0xE000 : 0;
 243
 244         return val;
 245 };
 246
 247 static inline int sca3000_13bit_convert(uint8_t msb, uint8_t lsb)
 248 {
 249         s16 val;
 250
 251         val = ((lsb >> 3) & 0x1F) | (msb << 5);
 252         /* sign fill */
 253         val |= (val & (1 << 12)) ? 0xE000 : 0;
 254
 255         return val;
 256 };
 257
 258
 259 #ifdef CONFIG_IIO_RING_BUFFER
 260 /**
 261  * sca3000_register_ring_funcs() setup the ring state change functions
 262  **/
 263 void sca3000_register_ring_funcs(struct iio_dev *indio_dev);
 264
 265 /**
 266  * sca3000_configure_ring() - allocate and configure ring buffer
 267  * @indio_dev: iio-core device whose ring is to be configured
 268  *
 269  * The hardware ring buffer needs far fewer ring buffer functions than
 270  * a software one as a lot of things are handled automatically.
 271  * This function also tells the iio core that our device supports a
 272  * hardware ring buffer mode.
 273  **/
 274 int sca3000_configure_ring(struct iio_dev *indio_dev);
 275
 276 /**
 277  * sca3000_unconfigure_ring() - deallocate the ring buffer
 278  * @indio_dev: iio-core device whose ring we are freeing
 279  **/
 280 void sca3000_unconfigure_ring(struct iio_dev *indio_dev);
 281
 282 /**
 283  * sca3000_ring_int_process() handles ring related event pushing and escalation
 284  * @val:        the event code
 285  **/
 286 void sca3000_ring_int_process(u8 val, struct iio_ring_buffer *ring);
 287
 288 #else
 289 static inline void sca3000_register_ring_funcs(struct iio_dev *indio_dev) {};
 290
 291 static inline
 292 int sca3000_register_ring_access_and_init(struct iio_dev *indio_dev)
 293 {
 294         return 0;
 295 };
 296
 297 static inline void sca3000_ring_int_process(u8 val, void *ring) {};
 298
 299 #endif
 300