ltc1660.c 6.0 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
  4. *
  5. * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
  6. */
  7. #include <linux/bitops.h>
  8. #include <linux/iio/iio.h>
  9. #include <linux/iio/sysfs.h>
  10. #include <linux/init.h>
  11. #include <linux/module.h>
  12. #include <linux/regulator/consumer.h>
  13. #include <linux/regmap.h>
  14. #include <linux/spi/spi.h>
  15. #define LTC1660_REG_WAKE 0x0
  16. #define LTC1660_REG_DAC_A 0x1
  17. #define LTC1660_REG_DAC_B 0x2
  18. #define LTC1660_REG_DAC_C 0x3
  19. #define LTC1660_REG_DAC_D 0x4
  20. #define LTC1660_REG_DAC_E 0x5
  21. #define LTC1660_REG_DAC_F 0x6
  22. #define LTC1660_REG_DAC_G 0x7
  23. #define LTC1660_REG_DAC_H 0x8
  24. #define LTC1660_REG_SLEEP 0xe
  25. #define LTC1660_NUM_CHANNELS 8
  26. static const struct regmap_config ltc1660_regmap_config = {
  27. .reg_bits = 4,
  28. .val_bits = 12,
  29. };
  30. enum ltc1660_supported_device_ids {
  31. ID_LTC1660,
  32. ID_LTC1665,
  33. };
  34. struct ltc1660_priv {
  35. struct spi_device *spi;
  36. struct regmap *regmap;
  37. struct regulator *vref_reg;
  38. unsigned int value[LTC1660_NUM_CHANNELS];
  39. unsigned int vref_mv;
  40. };
  41. static int ltc1660_read_raw(struct iio_dev *indio_dev,
  42. struct iio_chan_spec const *chan,
  43. int *val,
  44. int *val2,
  45. long mask)
  46. {
  47. struct ltc1660_priv *priv = iio_priv(indio_dev);
  48. switch (mask) {
  49. case IIO_CHAN_INFO_RAW:
  50. *val = priv->value[chan->channel];
  51. return IIO_VAL_INT;
  52. case IIO_CHAN_INFO_SCALE:
  53. *val = regulator_get_voltage(priv->vref_reg);
  54. if (*val < 0) {
  55. dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
  56. *val);
  57. return *val;
  58. }
  59. /* Convert to mV */
  60. *val /= 1000;
  61. *val2 = chan->scan_type.realbits;
  62. return IIO_VAL_FRACTIONAL_LOG2;
  63. default:
  64. return -EINVAL;
  65. }
  66. }
  67. static int ltc1660_write_raw(struct iio_dev *indio_dev,
  68. struct iio_chan_spec const *chan,
  69. int val,
  70. int val2,
  71. long mask)
  72. {
  73. struct ltc1660_priv *priv = iio_priv(indio_dev);
  74. int ret;
  75. switch (mask) {
  76. case IIO_CHAN_INFO_RAW:
  77. if (val2 != 0)
  78. return -EINVAL;
  79. if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
  80. return -EINVAL;
  81. ret = regmap_write(priv->regmap, chan->channel,
  82. (val << chan->scan_type.shift));
  83. if (!ret)
  84. priv->value[chan->channel] = val;
  85. return ret;
  86. default:
  87. return -EINVAL;
  88. }
  89. }
  90. #define LTC1660_CHAN(chan, bits) { \
  91. .type = IIO_VOLTAGE, \
  92. .indexed = 1, \
  93. .output = 1, \
  94. .channel = chan, \
  95. .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
  96. .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
  97. .scan_type = { \
  98. .sign = 'u', \
  99. .realbits = (bits), \
  100. .storagebits = 16, \
  101. .shift = 12 - (bits), \
  102. }, \
  103. }
  104. #define LTC1660_OCTAL_CHANNELS(bits) { \
  105. LTC1660_CHAN(LTC1660_REG_DAC_A, bits), \
  106. LTC1660_CHAN(LTC1660_REG_DAC_B, bits), \
  107. LTC1660_CHAN(LTC1660_REG_DAC_C, bits), \
  108. LTC1660_CHAN(LTC1660_REG_DAC_D, bits), \
  109. LTC1660_CHAN(LTC1660_REG_DAC_E, bits), \
  110. LTC1660_CHAN(LTC1660_REG_DAC_F, bits), \
  111. LTC1660_CHAN(LTC1660_REG_DAC_G, bits), \
  112. LTC1660_CHAN(LTC1660_REG_DAC_H, bits), \
  113. }
  114. static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
  115. [ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
  116. [ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
  117. };
  118. static const struct iio_info ltc1660_info = {
  119. .read_raw = &ltc1660_read_raw,
  120. .write_raw = &ltc1660_write_raw,
  121. };
  122. static int __maybe_unused ltc1660_suspend(struct device *dev)
  123. {
  124. struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
  125. to_spi_device(dev)));
  126. return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
  127. }
  128. static int __maybe_unused ltc1660_resume(struct device *dev)
  129. {
  130. struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
  131. to_spi_device(dev)));
  132. return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
  133. }
  134. static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
  135. static int ltc1660_probe(struct spi_device *spi)
  136. {
  137. struct iio_dev *indio_dev;
  138. struct ltc1660_priv *priv;
  139. const struct spi_device_id *id = spi_get_device_id(spi);
  140. int ret;
  141. indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
  142. if (indio_dev == NULL)
  143. return -ENOMEM;
  144. priv = iio_priv(indio_dev);
  145. priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
  146. if (IS_ERR(priv->regmap)) {
  147. dev_err(&spi->dev, "failed to register spi regmap %ld\n",
  148. PTR_ERR(priv->regmap));
  149. return PTR_ERR(priv->regmap);
  150. }
  151. priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
  152. if (IS_ERR(priv->vref_reg)) {
  153. dev_err(&spi->dev, "vref regulator not specified\n");
  154. return PTR_ERR(priv->vref_reg);
  155. }
  156. ret = regulator_enable(priv->vref_reg);
  157. if (ret) {
  158. dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
  159. ret);
  160. return ret;
  161. }
  162. priv->spi = spi;
  163. spi_set_drvdata(spi, indio_dev);
  164. indio_dev->info = &ltc1660_info;
  165. indio_dev->modes = INDIO_DIRECT_MODE;
  166. indio_dev->channels = ltc1660_channels[id->driver_data];
  167. indio_dev->num_channels = LTC1660_NUM_CHANNELS;
  168. indio_dev->name = id->name;
  169. ret = iio_device_register(indio_dev);
  170. if (ret) {
  171. dev_err(&spi->dev, "failed to register iio device: %d\n",
  172. ret);
  173. goto error_disable_reg;
  174. }
  175. return 0;
  176. error_disable_reg:
  177. regulator_disable(priv->vref_reg);
  178. return ret;
  179. }
  180. static int ltc1660_remove(struct spi_device *spi)
  181. {
  182. struct iio_dev *indio_dev = spi_get_drvdata(spi);
  183. struct ltc1660_priv *priv = iio_priv(indio_dev);
  184. iio_device_unregister(indio_dev);
  185. regulator_disable(priv->vref_reg);
  186. return 0;
  187. }
  188. static const struct of_device_id ltc1660_dt_ids[] = {
  189. { .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
  190. { .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
  191. { /* sentinel */ }
  192. };
  193. MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
  194. static const struct spi_device_id ltc1660_id[] = {
  195. {"ltc1660", ID_LTC1660},
  196. {"ltc1665", ID_LTC1665},
  197. { /* sentinel */ }
  198. };
  199. MODULE_DEVICE_TABLE(spi, ltc1660_id);
  200. static struct spi_driver ltc1660_driver = {
  201. .driver = {
  202. .name = "ltc1660",
  203. .of_match_table = ltc1660_dt_ids,
  204. .pm = &ltc1660_pm_ops,
  205. },
  206. .probe = ltc1660_probe,
  207. .remove = ltc1660_remove,
  208. .id_table = ltc1660_id,
  209. };
  210. module_spi_driver(ltc1660_driver);
  211. MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
  212. MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
  213. MODULE_LICENSE("GPL v2");