1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * BD79703 ROHM Digital to Analog converter 4 * 5 * Copyright (c) 2024, ROHM Semiconductor. 6 */ 7 8 #include <linux/bits.h> 9 #include <linux/device.h> 10 #include <linux/module.h> 11 #include <linux/regmap.h> 12 #include <linux/regulator/consumer.h> 13 #include <linux/spi/spi.h> 14 #include <linux/iio/iio.h> 15 16 #define BD79703_MAX_REGISTER 0xf 17 #define BD79703_DAC_BITS 8 18 #define BD79703_REG_OUT_ALL GENMASK(2, 0) 19 20 /* 21 * The BD79703 uses 12-bit SPI commands. First four bits (high bits) define 22 * channel(s) which are operated on, and also the mode. The mode can be to set 23 * a DAC word only, or set DAC word and output. The data-sheet is not very 24 * specific on how a previously set DAC word can be 'taken in to use'. Thus 25 * this driver only uses the 'set DAC and output it' -mode. 26 * 27 * The BD79703 latches last 12-bits when the chip-select is toggled. Thus we 28 * can use 16-bit transfers which should be widely supported. To simplify this 29 * further, we treat the last 8 bits as a value, and first 8 bits as an 30 * address. This allows us to separate channels/mode by address and treat the 31 * 8-bit register value as DAC word. The highest 4 bits of address will be 32 * discarded when the transfer is latched. 33 */ 34 static const struct regmap_config bd79703_regmap_config = { 35 .reg_bits = 8, 36 .val_bits = 8, 37 .max_register = BD79703_MAX_REGISTER, 38 .cache_type = REGCACHE_MAPLE, 39 }; 40 41 /* Dynamic driver private data */ 42 struct bd79703_data { 43 struct regmap *regmap; 44 int vfs; 45 }; 46 47 /* Static, IC type specific data for different variants */ 48 struct bd7970x_chip_data { 49 const char *name; 50 const struct iio_chan_spec *channels; 51 int num_channels; 52 bool has_vfs; 53 }; 54 55 static int bd79703_read_raw(struct iio_dev *idev, 56 struct iio_chan_spec const *chan, int *val, 57 int *val2, long mask) 58 { 59 struct bd79703_data *data = iio_priv(idev); 60 61 if (mask != IIO_CHAN_INFO_SCALE) 62 return -EINVAL; 63 64 *val = data->vfs / 1000; 65 *val2 = BD79703_DAC_BITS; 66 67 return IIO_VAL_FRACTIONAL_LOG2; 68 } 69 70 static int bd79703_write_raw(struct iio_dev *idev, 71 struct iio_chan_spec const *chan, int val, 72 int val2, long mask) 73 { 74 struct bd79703_data *data = iio_priv(idev); 75 76 if (val < 0 || val >= 1 << BD79703_DAC_BITS) 77 return -EINVAL; 78 79 return regmap_write(data->regmap, chan->address, val); 80 }; 81 82 static const struct iio_info bd79703_info = { 83 .read_raw = bd79703_read_raw, 84 .write_raw = bd79703_write_raw, 85 }; 86 87 #define BD79703_CHAN_ADDR(_chan, _addr) { \ 88 .type = IIO_VOLTAGE, \ 89 .indexed = 1, \ 90 .output = 1, \ 91 .channel = (_chan), \ 92 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 93 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 94 .address = (_addr), \ 95 } 96 97 #define BD79703_CHAN(_chan) BD79703_CHAN_ADDR((_chan), (_chan) + 1) 98 99 static const struct iio_chan_spec bd79700_channels[] = { 100 BD79703_CHAN(0), 101 BD79703_CHAN(1), 102 }; 103 104 static const struct iio_chan_spec bd79701_channels[] = { 105 BD79703_CHAN(0), 106 BD79703_CHAN(1), 107 BD79703_CHAN(2), 108 }; 109 110 /* 111 * The BD79702 has 4 channels. They aren't mapped to BD79703 channels 0, 1, 2 112 * and 3, but to the channels 0, 1, 4, 5. So the addressing used with SPI 113 * accesses is 1, 2, 5 and 6 for them. Thus, they're not constant offset to 114 * the channel number as with other IC variants. 115 */ 116 static const struct iio_chan_spec bd79702_channels[] = { 117 BD79703_CHAN_ADDR(0, 1), 118 BD79703_CHAN_ADDR(1, 2), 119 BD79703_CHAN_ADDR(2, 5), 120 BD79703_CHAN_ADDR(3, 6), 121 }; 122 123 static const struct iio_chan_spec bd79703_channels[] = { 124 BD79703_CHAN(0), 125 BD79703_CHAN(1), 126 BD79703_CHAN(2), 127 BD79703_CHAN(3), 128 BD79703_CHAN(4), 129 BD79703_CHAN(5), 130 }; 131 132 static const struct bd7970x_chip_data bd79700_chip_data = { 133 .name = "bd79700", 134 .channels = bd79700_channels, 135 .num_channels = ARRAY_SIZE(bd79700_channels), 136 .has_vfs = false, 137 }; 138 139 static const struct bd7970x_chip_data bd79701_chip_data = { 140 .name = "bd79701", 141 .channels = bd79701_channels, 142 .num_channels = ARRAY_SIZE(bd79701_channels), 143 .has_vfs = false, 144 }; 145 146 static const struct bd7970x_chip_data bd79702_chip_data = { 147 .name = "bd79702", 148 .channels = bd79702_channels, 149 .num_channels = ARRAY_SIZE(bd79702_channels), 150 .has_vfs = true, 151 }; 152 153 static const struct bd7970x_chip_data bd79703_chip_data = { 154 .name = "bd79703", 155 .channels = bd79703_channels, 156 .num_channels = ARRAY_SIZE(bd79703_channels), 157 .has_vfs = true, 158 }; 159 160 static int bd79703_probe(struct spi_device *spi) 161 { 162 const struct bd7970x_chip_data *cd; 163 struct device *dev = &spi->dev; 164 struct bd79703_data *data; 165 struct iio_dev *idev; 166 int ret; 167 168 cd = spi_get_device_match_data(spi); 169 if (!cd) 170 return -ENODEV; 171 172 idev = devm_iio_device_alloc(dev, sizeof(*data)); 173 if (!idev) 174 return -ENOMEM; 175 176 data = iio_priv(idev); 177 178 data->regmap = devm_regmap_init_spi(spi, &bd79703_regmap_config); 179 if (IS_ERR(data->regmap)) 180 return dev_err_probe(dev, PTR_ERR(data->regmap), 181 "Failed to initialize Regmap\n"); 182 183 /* 184 * BD79703 has a separate VFS pin, whereas the BD79700 and BD79701 use 185 * VCC for their full-scale output voltage. 186 */ 187 if (cd->has_vfs) { 188 ret = devm_regulator_get_enable(dev, "vcc"); 189 if (ret) 190 return dev_err_probe(dev, ret, "Failed to enable VCC\n"); 191 192 ret = devm_regulator_get_enable_read_voltage(dev, "vfs"); 193 if (ret < 0) 194 return dev_err_probe(dev, ret, "Failed to get Vfs\n"); 195 } else { 196 ret = devm_regulator_get_enable_read_voltage(dev, "vcc"); 197 if (ret < 0) 198 return dev_err_probe(dev, ret, "Failed to get VCC\n"); 199 } 200 data->vfs = ret; 201 202 idev->channels = cd->channels; 203 idev->num_channels = cd->num_channels; 204 idev->modes = INDIO_DIRECT_MODE; 205 idev->info = &bd79703_info; 206 idev->name = cd->name; 207 208 /* Initialize all to output zero */ 209 ret = regmap_write(data->regmap, BD79703_REG_OUT_ALL, 0); 210 if (ret) 211 return ret; 212 213 return devm_iio_device_register(dev, idev); 214 } 215 216 static const struct spi_device_id bd79703_id[] = { 217 { "bd79700", (kernel_ulong_t)&bd79700_chip_data }, 218 { "bd79701", (kernel_ulong_t)&bd79701_chip_data }, 219 { "bd79702", (kernel_ulong_t)&bd79702_chip_data }, 220 { "bd79703", (kernel_ulong_t)&bd79703_chip_data }, 221 { } 222 }; 223 MODULE_DEVICE_TABLE(spi, bd79703_id); 224 225 static const struct of_device_id bd79703_of_match[] = { 226 { .compatible = "rohm,bd79700", .data = &bd79700_chip_data }, 227 { .compatible = "rohm,bd79701", .data = &bd79701_chip_data }, 228 { .compatible = "rohm,bd79702", .data = &bd79702_chip_data }, 229 { .compatible = "rohm,bd79703", .data = &bd79703_chip_data }, 230 { } 231 }; 232 MODULE_DEVICE_TABLE(of, bd79703_of_match); 233 234 static struct spi_driver bd79703_driver = { 235 .driver = { 236 .name = "bd79703", 237 .of_match_table = bd79703_of_match, 238 }, 239 .probe = bd79703_probe, 240 .id_table = bd79703_id, 241 }; 242 module_spi_driver(bd79703_driver); 243 244 MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>"); 245 MODULE_DESCRIPTION("ROHM BD79703 DAC driver"); 246 MODULE_LICENSE("GPL"); 247