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 16 #define LTC1660_REG_WAKE 0x0 17 #define LTC1660_REG_DAC_A 0x1 18 #define LTC1660_REG_DAC_B 0x2 19 #define LTC1660_REG_DAC_C 0x3 20 #define LTC1660_REG_DAC_D 0x4 21 #define LTC1660_REG_DAC_E 0x5 22 #define LTC1660_REG_DAC_F 0x6 23 #define LTC1660_REG_DAC_G 0x7 24 #define LTC1660_REG_DAC_H 0x8 25 #define LTC1660_REG_SLEEP 0xe 26 27 #define LTC1660_NUM_CHANNELS 8 28 29 static const struct regmap_config ltc1660_regmap_config = { 30 .reg_bits = 4, 31 .val_bits = 12, 32 }; 33 34 enum ltc1660_supported_device_ids { 35 ID_LTC1660, 36 ID_LTC1665, 37 }; 38 39 struct ltc1660_priv { 40 struct spi_device *spi; 41 struct regmap *regmap; 42 struct regulator *vref_reg; 43 unsigned int value[LTC1660_NUM_CHANNELS]; 44 unsigned int vref_mv; 45 }; 46 47 static int ltc1660_read_raw(struct iio_dev *indio_dev, 48 struct iio_chan_spec const *chan, 49 int *val, 50 int *val2, 51 long mask) 52 { 53 struct ltc1660_priv *priv = iio_priv(indio_dev); 54 55 switch (mask) { 56 case IIO_CHAN_INFO_RAW: 57 *val = priv->value[chan->channel]; 58 return IIO_VAL_INT; 59 case IIO_CHAN_INFO_SCALE: 60 *val = regulator_get_voltage(priv->vref_reg); 61 if (*val < 0) { 62 dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n", 63 *val); 64 return *val; 65 } 66 67 /* Convert to mV */ 68 *val /= 1000; 69 *val2 = chan->scan_type.realbits; 70 return IIO_VAL_FRACTIONAL_LOG2; 71 default: 72 return -EINVAL; 73 } 74 } 75 76 static int ltc1660_write_raw(struct iio_dev *indio_dev, 77 struct iio_chan_spec const *chan, 78 int val, 79 int val2, 80 long mask) 81 { 82 struct ltc1660_priv *priv = iio_priv(indio_dev); 83 int ret; 84 85 switch (mask) { 86 case IIO_CHAN_INFO_RAW: 87 if (val2 != 0) 88 return -EINVAL; 89 90 if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0)) 91 return -EINVAL; 92 93 ret = regmap_write(priv->regmap, chan->channel, 94 (val << chan->scan_type.shift)); 95 if (!ret) 96 priv->value[chan->channel] = val; 97 98 return ret; 99 default: 100 return -EINVAL; 101 } 102 } 103 104 #define LTC1660_CHAN(chan, bits) { \ 105 .type = IIO_VOLTAGE, \ 106 .indexed = 1, \ 107 .output = 1, \ 108 .channel = chan, \ 109 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 110 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 111 .scan_type = { \ 112 .sign = 'u', \ 113 .realbits = (bits), \ 114 .storagebits = 16, \ 115 .shift = 12 - (bits), \ 116 }, \ 117 } 118 119 #define LTC1660_OCTAL_CHANNELS(bits) { \ 120 LTC1660_CHAN(LTC1660_REG_DAC_A, bits), \ 121 LTC1660_CHAN(LTC1660_REG_DAC_B, bits), \ 122 LTC1660_CHAN(LTC1660_REG_DAC_C, bits), \ 123 LTC1660_CHAN(LTC1660_REG_DAC_D, bits), \ 124 LTC1660_CHAN(LTC1660_REG_DAC_E, bits), \ 125 LTC1660_CHAN(LTC1660_REG_DAC_F, bits), \ 126 LTC1660_CHAN(LTC1660_REG_DAC_G, bits), \ 127 LTC1660_CHAN(LTC1660_REG_DAC_H, bits), \ 128 } 129 130 static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = { 131 [ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10), 132 [ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8), 133 }; 134 135 static const struct iio_info ltc1660_info = { 136 .read_raw = <c1660_read_raw, 137 .write_raw = <c1660_write_raw, 138 }; 139 140 static int __maybe_unused ltc1660_suspend(struct device *dev) 141 { 142 struct ltc1660_priv *priv = iio_priv(spi_get_drvdata( 143 to_spi_device(dev))); 144 return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00); 145 } 146 147 static int __maybe_unused ltc1660_resume(struct device *dev) 148 { 149 struct ltc1660_priv *priv = iio_priv(spi_get_drvdata( 150 to_spi_device(dev))); 151 return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00); 152 } 153 static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume); 154 155 static int ltc1660_probe(struct spi_device *spi) 156 { 157 struct iio_dev *indio_dev; 158 struct ltc1660_priv *priv; 159 const struct spi_device_id *id = spi_get_device_id(spi); 160 int ret; 161 162 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv)); 163 if (indio_dev == NULL) 164 return -ENOMEM; 165 166 priv = iio_priv(indio_dev); 167 priv->regmap = devm_regmap_init_spi(spi, <c1660_regmap_config); 168 if (IS_ERR(priv->regmap)) { 169 dev_err(&spi->dev, "failed to register spi regmap %ld\n", 170 PTR_ERR(priv->regmap)); 171 return PTR_ERR(priv->regmap); 172 } 173 174 priv->vref_reg = devm_regulator_get(&spi->dev, "vref"); 175 if (IS_ERR(priv->vref_reg)) { 176 dev_err(&spi->dev, "vref regulator not specified\n"); 177 return PTR_ERR(priv->vref_reg); 178 } 179 180 ret = regulator_enable(priv->vref_reg); 181 if (ret) { 182 dev_err(&spi->dev, "failed to enable vref regulator: %d\n", 183 ret); 184 return ret; 185 } 186 187 priv->spi = spi; 188 spi_set_drvdata(spi, indio_dev); 189 indio_dev->info = <c1660_info; 190 indio_dev->modes = INDIO_DIRECT_MODE; 191 indio_dev->channels = ltc1660_channels[id->driver_data]; 192 indio_dev->num_channels = LTC1660_NUM_CHANNELS; 193 indio_dev->name = id->name; 194 195 ret = iio_device_register(indio_dev); 196 if (ret) { 197 dev_err(&spi->dev, "failed to register iio device: %d\n", 198 ret); 199 goto error_disable_reg; 200 } 201 202 return 0; 203 204 error_disable_reg: 205 regulator_disable(priv->vref_reg); 206 207 return ret; 208 } 209 210 static int ltc1660_remove(struct spi_device *spi) 211 { 212 struct iio_dev *indio_dev = spi_get_drvdata(spi); 213 struct ltc1660_priv *priv = iio_priv(indio_dev); 214 215 iio_device_unregister(indio_dev); 216 regulator_disable(priv->vref_reg); 217 218 return 0; 219 } 220 221 static const struct of_device_id ltc1660_dt_ids[] = { 222 { .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 }, 223 { .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 }, 224 { /* sentinel */ } 225 }; 226 MODULE_DEVICE_TABLE(of, ltc1660_dt_ids); 227 228 static const struct spi_device_id ltc1660_id[] = { 229 {"ltc1660", ID_LTC1660}, 230 {"ltc1665", ID_LTC1665}, 231 { /* sentinel */ } 232 }; 233 MODULE_DEVICE_TABLE(spi, ltc1660_id); 234 235 static struct spi_driver ltc1660_driver = { 236 .driver = { 237 .name = "ltc1660", 238 .of_match_table = ltc1660_dt_ids, 239 .pm = <c1660_pm_ops, 240 }, 241 .probe = ltc1660_probe, 242 .remove = ltc1660_remove, 243 .id_table = ltc1660_id, 244 }; 245 module_spi_driver(ltc1660_driver); 246 247 MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>"); 248 MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC"); 249 MODULE_LICENSE("GPL v2"); 250