drivers/iio/dac/ad5592r.c

   1 /*
   2  * AD5592R Digital <-> Analog converters driver
   3  *
   4  * Copyright 2015-2016 Analog Devices Inc.
   5  * Author: Paul Cercueil <paul.cercueil@analog.com>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include "ad5592r-base.h"
  11
  12 #include <linux/bitops.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/spi/spi.h>
  16
  17 #define AD5592R_GPIO_READBACK_EN        BIT(10)
  18 #define AD5592R_LDAC_READBACK_EN        BIT(6)
  19
  20 static int ad5592r_spi_wnop_r16(struct ad5592r_state *st, u16 *buf)
  21 {
  22         struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
  23         struct spi_transfer t = {
  24                         .tx_buf = &st->spi_msg_nop,
  25                         .rx_buf = buf,
  26                         .len = 2
  27                 };
  28
  29         st->spi_msg_nop = 0; /* NOP */
  30
  31         return spi_sync_transfer(spi, &t, 1);
  32 }
  33
  34 static int ad5592r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)
  35 {
  36         struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
  37
  38         st->spi_msg = cpu_to_be16(BIT(15) | (chan << 12) | value);
  39
  40         return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
  41 }
  42
  43 static int ad5592r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)
  44 {
  45         struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
  46         int ret;
  47
  48         st->spi_msg = cpu_to_be16((AD5592R_REG_ADC_SEQ << 11) | BIT(chan));
  49
  50         ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
  51         if (ret)
  52                 return ret;
  53
  54         /*
  55          * Invalid data:
  56          * See Figure 40. Single-Channel ADC Conversion Sequence
  57          */
  58         ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
  59         if (ret)
  60                 return ret;
  61
  62         ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
  63         if (ret)
  64                 return ret;
  65
  66         *value = be16_to_cpu(st->spi_msg);
  67
  68         return 0;
  69 }
  70
  71 static int ad5592r_reg_write(struct ad5592r_state *st, u8 reg, u16 value)
  72 {
  73         struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
  74
  75         st->spi_msg = cpu_to_be16((reg << 11) | value);
  76
  77         return spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
  78 }
  79
  80 static int ad5592r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value)
  81 {
  82         struct spi_device *spi = container_of(st->dev, struct spi_device, dev);
  83         int ret;
  84
  85         st->spi_msg = cpu_to_be16((AD5592R_REG_LDAC << 11) |
  86                                    AD5592R_LDAC_READBACK_EN | (reg << 2));
  87
  88         ret = spi_write(spi, &st->spi_msg, sizeof(st->spi_msg));
  89         if (ret)
  90                 return ret;
  91
  92         ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
  93         if (ret)
  94                 return ret;
  95
  96         *value = be16_to_cpu(st->spi_msg);
  97
  98         return 0;
  99 }
 100
 101 static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value)
 102 {
 103         int ret;
 104
 105         ret = ad5592r_reg_write(st, AD5592R_REG_GPIO_IN_EN,
 106                                 AD5592R_GPIO_READBACK_EN | st->gpio_in);
 107         if (ret)
 108                 return ret;
 109
 110         ret = ad5592r_spi_wnop_r16(st, &st->spi_msg);
 111         if (ret)
 112                 return ret;
 113
 114         *value = (u8) be16_to_cpu(st->spi_msg);
 115
 116         return 0;
 117 }
 118
 119 static const struct ad5592r_rw_ops ad5592r_rw_ops = {
 120         .write_dac = ad5592r_write_dac,
 121         .read_adc = ad5592r_read_adc,
 122         .reg_write = ad5592r_reg_write,
 123         .reg_read = ad5592r_reg_read,
 124         .gpio_read = ad5593r_gpio_read,
 125 };
 126
 127 static int ad5592r_spi_probe(struct spi_device *spi)
 128 {
 129         const struct spi_device_id *id = spi_get_device_id(spi);
 130
 131         return ad5592r_probe(&spi->dev, id->name, &ad5592r_rw_ops);
 132 }
 133
 134 static int ad5592r_spi_remove(struct spi_device *spi)
 135 {
 136         return ad5592r_remove(&spi->dev);
 137 }
 138
 139 static const struct spi_device_id ad5592r_spi_ids[] = {
 140         { .name = "ad5592r", },
 141         {}
 142 };
 143 MODULE_DEVICE_TABLE(spi, ad5592r_spi_ids);
 144
 145 static const struct of_device_id ad5592r_of_match[] = {
 146         { .compatible = "adi,ad5592r", },
 147         {},
 148 };
 149 MODULE_DEVICE_TABLE(of, ad5592r_of_match);
 150
 151 static struct spi_driver ad5592r_spi_driver = {
 152         .driver = {
 153                 .name = "ad5592r",
 154                 .of_match_table = of_match_ptr(ad5592r_of_match),
 155         },
 156         .probe = ad5592r_spi_probe,
 157         .remove = ad5592r_spi_remove,
 158         .id_table = ad5592r_spi_ids,
 159 };
 160 module_spi_driver(ad5592r_spi_driver);
 161
 162 MODULE_AUTHOR("Paul Cercueil <paul.cercueil@analog.com>");
 163 MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
 164 MODULE_LICENSE("GPL v2");