include/linux/iio/adc/ad_sigma_delta.h

   1 /*
   2  * Support code for Analog Devices Sigma-Delta ADCs
   3  *
   4  * Copyright 2012 Analog Devices Inc.
   5  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9 #ifndef __AD_SIGMA_DELTA_H__
  10 #define __AD_SIGMA_DELTA_H__
  11
  12 enum ad_sigma_delta_mode {
  13         AD_SD_MODE_CONTINUOUS = 0,
  14         AD_SD_MODE_SINGLE = 1,
  15         AD_SD_MODE_IDLE = 2,
  16         AD_SD_MODE_POWERDOWN = 3,
  17 };
  18
  19 /**
  20  * struct ad_sigma_delta_calib_data - Calibration data for Sigma Delta devices
  21  * @mode: Calibration mode.
  22  * @channel: Calibration channel.
  23  */
  24 struct ad_sd_calib_data {
  25         unsigned int mode;
  26         unsigned int channel;
  27 };
  28
  29 struct ad_sigma_delta;
  30 struct iio_dev;
  31
  32 /**
  33  * struct ad_sigma_delta_info - Sigma Delta driver specific callbacks and options
  34  * @set_channel: Will be called to select the current channel, may be NULL.
  35  * @set_mode: Will be called to select the current mode, may be NULL.
  36  * @postprocess_sample: Is called for each sampled data word, can be used to
  37  *              modify or drop the sample data, it, may be NULL.
  38  * @has_registers: true if the device has writable and readable registers, false
  39  *              if there is just one read-only sample data shift register.
  40  * @addr_shift: Shift of the register address in the communications register.
  41  * @read_mask: Mask for the communications register having the read bit set.
  42  */
  43 struct ad_sigma_delta_info {
  44         int (*set_channel)(struct ad_sigma_delta *, unsigned int channel);
  45         int (*set_mode)(struct ad_sigma_delta *, enum ad_sigma_delta_mode mode);
  46         int (*postprocess_sample)(struct ad_sigma_delta *, unsigned int raw_sample);
  47         bool has_registers;
  48         unsigned int addr_shift;
  49         unsigned int read_mask;
  50 };
  51
  52 /**
  53  * struct ad_sigma_delta - Sigma Delta device struct
  54  * @spi: The spi device associated with the Sigma Delta device.
  55  * @trig: The IIO trigger associated with the Sigma Delta device.
  56  *
  57  * Most of the fields are private to the sigma delta library code and should not
  58  * be accessed by individual drivers.
  59  */
  60 struct ad_sigma_delta {
  61         struct spi_device       *spi;
  62         struct iio_trigger      *trig;
  63
  64 /* private: */
  65         struct completion       completion;
  66         bool                    irq_dis;
  67
  68         bool                    bus_locked;
  69
  70         uint8_t                 comm;
  71
  72         const struct ad_sigma_delta_info *info;
  73
  74         /*
  75          * DMA (thus cache coherency maintenance) requires the
  76          * transfer buffers to live in their own cache lines.
  77          */
  78         uint8_t                         data[4] ____cacheline_aligned;
  79 };
  80
  81 static inline int ad_sigma_delta_set_channel(struct ad_sigma_delta *sd,
  82         unsigned int channel)
  83 {
  84         if (sd->info->set_channel)
  85                 return sd->info->set_channel(sd, channel);
  86
  87         return 0;
  88 }
  89
  90 static inline int ad_sigma_delta_set_mode(struct ad_sigma_delta *sd,
  91         unsigned int mode)
  92 {
  93         if (sd->info->set_mode)
  94                 return sd->info->set_mode(sd, mode);
  95
  96         return 0;
  97 }
  98
  99 static inline int ad_sigma_delta_postprocess_sample(struct ad_sigma_delta *sd,
 100         unsigned int raw_sample)
 101 {
 102         if (sd->info->postprocess_sample)
 103                 return sd->info->postprocess_sample(sd, raw_sample);
 104
 105         return 0;
 106 }
 107
 108 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm);
 109 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
 110         unsigned int size, unsigned int val);
 111 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
 112         unsigned int size, unsigned int *val);
 113
 114 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
 115         unsigned int reset_length);
 116
 117 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
 118         const struct iio_chan_spec *chan, int *val);
 119 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
 120         const struct ad_sd_calib_data *cd, unsigned int n);
 121 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
 122         struct spi_device *spi, const struct ad_sigma_delta_info *info);
 123
 124 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev);
 125 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev);
 126
 127 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig);
 128
 129 #define __AD_SD_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
 130         _storagebits, _shift, _extend_name, _type) \
 131         { \
 132                 .type = (_type), \
 133                 .differential = (_channel2 == -1 ? 0 : 1), \
 134                 .indexed = 1, \
 135                 .channel = (_channel1), \
 136                 .channel2 = (_channel2), \
 137                 .address = (_address), \
 138                 .extend_name = (_extend_name), \
 139                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 140                         BIT(IIO_CHAN_INFO_OFFSET), \
 141                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 142                 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
 143                 .scan_index = (_si), \
 144                 .scan_type = { \
 145                         .sign = 'u', \
 146                         .realbits = (_bits), \
 147                         .storagebits = (_storagebits), \
 148                         .shift = (_shift), \
 149                         .endianness = IIO_BE, \
 150                 }, \
 151         }
 152
 153 #define AD_SD_DIFF_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
 154         _storagebits, _shift) \
 155         __AD_SD_CHANNEL(_si, _channel1, _channel2, _address, _bits, \
 156                 _storagebits, _shift, NULL, IIO_VOLTAGE)
 157
 158 #define AD_SD_SHORTED_CHANNEL(_si, _channel, _address, _bits, \
 159         _storagebits, _shift) \
 160         __AD_SD_CHANNEL(_si, _channel, _channel, _address, _bits, \
 161                 _storagebits, _shift, "shorted", IIO_VOLTAGE)
 162
 163 #define AD_SD_CHANNEL(_si, _channel, _address, _bits, \
 164         _storagebits, _shift) \
 165         __AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \
 166                 _storagebits, _shift, NULL, IIO_VOLTAGE)
 167
 168 #define AD_SD_TEMP_CHANNEL(_si, _address, _bits, _storagebits, _shift) \
 169         __AD_SD_CHANNEL(_si, 0, -1, _address, _bits, \
 170                 _storagebits, _shift, NULL, IIO_TEMP)
 171
 172 #define AD_SD_SUPPLY_CHANNEL(_si, _channel, _address, _bits, _storagebits, \
 173         _shift) \
 174         __AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \
 175                 _storagebits, _shift, "supply", IIO_VOLTAGE)
 176
 177 #endif