drivers/iio/dac/ti-dac5571.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ti-dac5571.c - Texas Instruments 8/10/12-bit 1/4-channel DAC driver
   4  *
   5  * Copyright (C) 2018 Prevas A/S
   6  *
   7  * https://www.ti.com/lit/ds/symlink/dac5571.pdf
   8  * https://www.ti.com/lit/ds/symlink/dac6571.pdf
   9  * https://www.ti.com/lit/ds/symlink/dac7571.pdf
  10  * https://www.ti.com/lit/ds/symlink/dac5574.pdf
  11  * https://www.ti.com/lit/ds/symlink/dac6574.pdf
  12  * https://www.ti.com/lit/ds/symlink/dac7574.pdf
  13  * https://www.ti.com/lit/ds/symlink/dac5573.pdf
  14  * https://www.ti.com/lit/ds/symlink/dac6573.pdf
  15  * https://www.ti.com/lit/ds/symlink/dac7573.pdf
  16  */
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/i2c.h>
  20 #include <linux/module.h>
  21 #include <linux/mod_devicetable.h>
  22 #include <linux/regulator/consumer.h>
  23
  24 enum chip_id {
  25         single_8bit, single_10bit, single_12bit,
  26         quad_8bit, quad_10bit, quad_12bit
  27 };
  28
  29 struct dac5571_spec {
  30         u8 num_channels;
  31         u8 resolution;
  32 };
  33
  34 static const struct dac5571_spec dac5571_spec[] = {
  35         [single_8bit]  = {.num_channels = 1, .resolution =  8},
  36         [single_10bit] = {.num_channels = 1, .resolution = 10},
  37         [single_12bit] = {.num_channels = 1, .resolution = 12},
  38         [quad_8bit]    = {.num_channels = 4, .resolution =  8},
  39         [quad_10bit]   = {.num_channels = 4, .resolution = 10},
  40         [quad_12bit]   = {.num_channels = 4, .resolution = 12},
  41 };
  42
  43 struct dac5571_data {
  44         struct i2c_client *client;
  45         int id;
  46         struct mutex lock;
  47         struct regulator *vref;
  48         u16 val[4];
  49         bool powerdown[4];
  50         u8 powerdown_mode[4];
  51         struct dac5571_spec const *spec;
  52         int (*dac5571_cmd)(struct dac5571_data *data, int channel, u16 val);
  53         int (*dac5571_pwrdwn)(struct dac5571_data *data, int channel, u8 pwrdwn);
  54         u8 buf[3] ____cacheline_aligned;
  55 };
  56
  57 #define DAC5571_POWERDOWN(mode)         ((mode) + 1)
  58 #define DAC5571_POWERDOWN_FLAG          BIT(0)
  59 #define DAC5571_CHANNEL_SELECT          1
  60 #define DAC5571_LOADMODE_DIRECT         BIT(4)
  61 #define DAC5571_SINGLE_PWRDWN_BITS      4
  62 #define DAC5571_QUAD_PWRDWN_BITS        6
  63
  64 static int dac5571_cmd_single(struct dac5571_data *data, int channel, u16 val)
  65 {
  66         unsigned int shift;
  67
  68         shift = 12 - data->spec->resolution;
  69         data->buf[1] = val << shift;
  70         data->buf[0] = val >> (8 - shift);
  71
  72         if (i2c_master_send(data->client, data->buf, 2) != 2)
  73                 return -EIO;
  74
  75         return 0;
  76 }
  77
  78 static int dac5571_cmd_quad(struct dac5571_data *data, int channel, u16 val)
  79 {
  80         unsigned int shift;
  81
  82         shift = 16 - data->spec->resolution;
  83         data->buf[2] = val << shift;
  84         data->buf[1] = (val >> (8 - shift));
  85         data->buf[0] = (channel << DAC5571_CHANNEL_SELECT) |
  86                        DAC5571_LOADMODE_DIRECT;
  87
  88         if (i2c_master_send(data->client, data->buf, 3) != 3)
  89                 return -EIO;
  90
  91         return 0;
  92 }
  93
  94 static int dac5571_pwrdwn_single(struct dac5571_data *data, int channel, u8 pwrdwn)
  95 {
  96         data->buf[1] = 0;
  97         data->buf[0] = pwrdwn << DAC5571_SINGLE_PWRDWN_BITS;
  98
  99         if (i2c_master_send(data->client, data->buf, 2) != 2)
 100                 return -EIO;
 101
 102         return 0;
 103 }
 104
 105 static int dac5571_pwrdwn_quad(struct dac5571_data *data, int channel, u8 pwrdwn)
 106 {
 107         data->buf[2] = 0;
 108         data->buf[1] = pwrdwn << DAC5571_QUAD_PWRDWN_BITS;
 109         data->buf[0] = (channel << DAC5571_CHANNEL_SELECT) |
 110                        DAC5571_LOADMODE_DIRECT | DAC5571_POWERDOWN_FLAG;
 111
 112         if (i2c_master_send(data->client, data->buf, 3) != 3)
 113                 return -EIO;
 114
 115         return 0;
 116 }
 117
 118 static const char *const dac5571_powerdown_modes[] = {
 119         "1kohm_to_gnd", "100kohm_to_gnd", "three_state",
 120 };
 121
 122 static int dac5571_get_powerdown_mode(struct iio_dev *indio_dev,
 123                                       const struct iio_chan_spec *chan)
 124 {
 125         struct dac5571_data *data = iio_priv(indio_dev);
 126
 127         return data->powerdown_mode[chan->channel];
 128 }
 129
 130 static int dac5571_set_powerdown_mode(struct iio_dev *indio_dev,
 131                                       const struct iio_chan_spec *chan,
 132                                       unsigned int mode)
 133 {
 134         struct dac5571_data *data = iio_priv(indio_dev);
 135         int ret = 0;
 136
 137         if (data->powerdown_mode[chan->channel] == mode)
 138                 return 0;
 139
 140         mutex_lock(&data->lock);
 141         if (data->powerdown[chan->channel]) {
 142                 ret = data->dac5571_pwrdwn(data, chan->channel,
 143                                            DAC5571_POWERDOWN(mode));
 144                 if (ret)
 145                         goto out;
 146         }
 147         data->powerdown_mode[chan->channel] = mode;
 148
 149  out:
 150         mutex_unlock(&data->lock);
 151
 152         return ret;
 153 }
 154
 155 static const struct iio_enum dac5571_powerdown_mode = {