1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Analog Devices AD7405 driver 4 * 5 * Copyright 2025 Analog Devices Inc. 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/device.h> 10 #include <linux/err.h> 11 #include <linux/math64.h> 12 #include <linux/module.h> 13 #include <linux/mod_devicetable.h> 14 #include <linux/platform_device.h> 15 #include <linux/property.h> 16 #include <linux/regulator/consumer.h> 17 #include <linux/util_macros.h> 18 19 #include <linux/iio/backend.h> 20 #include <linux/iio/iio.h> 21 22 static const unsigned int ad7405_dec_rates_range[] = { 23 32, 1, 4096, 24 }; 25 26 struct ad7405_chip_info { 27 const char *name; 28 const unsigned int full_scale_mv; 29 }; 30 31 struct ad7405_state { 32 struct iio_backend *back; 33 const struct ad7405_chip_info *info; 34 unsigned int ref_frequency; 35 unsigned int dec_rate; 36 }; 37 38 static int ad7405_set_dec_rate(struct iio_dev *indio_dev, 39 const struct iio_chan_spec *chan, 40 unsigned int dec_rate) 41 { 42 struct ad7405_state *st = iio_priv(indio_dev); 43 int ret; 44 45 if (dec_rate > 4096 || dec_rate < 32) 46 return -EINVAL; 47 48 if (!iio_device_claim_direct(indio_dev)) 49 return -EBUSY; 50 51 ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate); 52 iio_device_release_direct(indio_dev); 53 54 if (ret < 0) 55 return ret; 56 57 st->dec_rate = dec_rate; 58 59 return 0; 60 } 61 62 static int ad7405_read_raw(struct iio_dev *indio_dev, 63 const struct iio_chan_spec *chan, int *val, 64 int *val2, long info) 65 { 66 struct ad7405_state *st = iio_priv(indio_dev); 67 68 switch (info) { 69 case IIO_CHAN_INFO_SCALE: 70 *val = st->info->full_scale_mv; 71 *val2 = indio_dev->channels[0].scan_type.realbits - 1; 72 return IIO_VAL_FRACTIONAL_LOG2; 73 case IIO_CHAN_INFO_OVERSAMPLING_RATIO: 74 *val = st->dec_rate; 75 return IIO_VAL_INT; 76 case IIO_CHAN_INFO_SAMP_FREQ: 77 *val = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, st->dec_rate); 78 return IIO_VAL_INT; 79 case IIO_CHAN_INFO_OFFSET: 80 *val = -(1 << (indio_dev->channels[0].scan_type.realbits - 1)); 81 return IIO_VAL_INT; 82 default: 83 return -EINVAL; 84 } 85 } 86 87 static int ad7405_write_raw(struct iio_dev *indio_dev, 88 struct iio_chan_spec const *chan, int val, 89 int val2, long info) 90 { 91 switch (info) { 92 case IIO_CHAN_INFO_OVERSAMPLING_RATIO: 93 if (val < 0) 94 return -EINVAL; 95 return ad7405_set_dec_rate(indio_dev, chan, val); 96 default: 97 return -EINVAL; 98 } 99 } 100 101 static int ad7405_read_avail(struct iio_dev *indio_dev, 102 struct iio_chan_spec const *chan, 103 const int **vals, int *type, int *length, 104 long info) 105 { 106 switch (info) { 107 case IIO_CHAN_INFO_OVERSAMPLING_RATIO: 108 *vals = ad7405_dec_rates_range; 109 *type = IIO_VAL_INT; 110 return IIO_AVAIL_RANGE; 111 default: 112 return -EINVAL; 113 } 114 } 115 116 static const struct iio_info ad7405_iio_info = { 117 .read_raw = &ad7405_read_raw, 118 .write_raw = &ad7405_write_raw, 119 .read_avail = &ad7405_read_avail, 120 }; 121 122 static const struct iio_chan_spec ad7405_channel = { 123 .type = IIO_VOLTAGE, 124 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | 125 BIT(IIO_CHAN_INFO_OFFSET), 126 .info_mask_shared_by_all = IIO_CHAN_INFO_SAMP_FREQ | 127 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), 128 .info_mask_shared_by_all_available = 129 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), 130 .indexed = 1, 131 .channel = 0, 132 .channel2 = 1, 133 .differential = 1, 134 .scan_index = 0, 135 .scan_type = { 136 .sign = 'u', 137 .realbits = 16, 138 .storagebits = 16, 139 }, 140 }; 141 142 static const struct ad7405_chip_info ad7405_chip_info = { 143 .name = "ad7405", 144 .full_scale_mv = 320, 145 }; 146 147 static const struct ad7405_chip_info adum7701_chip_info = { 148 .name = "adum7701", 149 .full_scale_mv = 320, 150 }; 151 152 static const struct ad7405_chip_info adum7702_chip_info = { 153 .name = "adum7702", 154 .full_scale_mv = 64, 155 }; 156 157 static const struct ad7405_chip_info adum7703_chip_info = { 158 .name = "adum7703", 159 .full_scale_mv = 320, 160 }; 161 162 static const char * const ad7405_power_supplies[] = { 163 "vdd1", "vdd2", 164 }; 165 166 static int ad7405_probe(struct platform_device *pdev) 167 { 168 struct device *dev = &pdev->dev; 169 struct iio_dev *indio_dev; 170 struct ad7405_state *st; 171 struct clk *clk; 172 int ret; 173 174 indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); 175 if (!indio_dev) 176 return -ENOMEM; 177 178 st = iio_priv(indio_dev); 179 180 st->info = device_get_match_data(dev); 181 if (!st->info) 182 return dev_err_probe(dev, -EINVAL, "no chip info\n"); 183 184 ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad7405_power_supplies), 185 ad7405_power_supplies); 186 if (ret) 187 return dev_err_probe(dev, ret, "failed to get and enable supplies"); 188 189 clk = devm_clk_get_enabled(dev, NULL); 190 if (IS_ERR(clk)) 191 return PTR_ERR(clk); 192 193 st->ref_frequency = clk_get_rate(clk); 194 if (!st->ref_frequency) 195 return -EINVAL; 196 197 indio_dev->name = st->info->name; 198 indio_dev->channels = &ad7405_channel; 199 indio_dev->num_channels = 1; 200 indio_dev->info = &ad7405_iio_info; 201 202 st->back = devm_iio_backend_get(dev, NULL); 203 if (IS_ERR(st->back)) 204 return dev_err_probe(dev, PTR_ERR(st->back), 205 "failed to get IIO backend"); 206 207 ret = iio_backend_chan_enable(st->back, 0); 208 if (ret) 209 return ret; 210 211 ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev); 212 if (ret) 213 return ret; 214 215 ret = devm_iio_backend_enable(dev, st->back); 216 if (ret) 217 return ret; 218 219 /* 220 * Set 256 decimation rate. The default value in the AXI_ADC register 221 * is 0, so we set the register with a decimation rate value that is 222 * functional for all parts. 223 */ 224 ret = ad7405_set_dec_rate(indio_dev, &indio_dev->channels[0], 256); 225 if (ret) 226 return ret; 227 228 return devm_iio_device_register(dev, indio_dev); 229 } 230 231 static const struct of_device_id ad7405_of_match[] = { 232 { .compatible = "adi,ad7405", .data = &ad7405_chip_info, }, 233 { .compatible = "adi,adum7701", .data = &adum7701_chip_info, }, 234 { .compatible = "adi,adum7702", .data = &adum7702_chip_info, }, 235 { .compatible = "adi,adum7703", .data = &adum7703_chip_info, }, 236 { } 237 }; 238 MODULE_DEVICE_TABLE(of, ad7405_of_match); 239 240 static struct platform_driver ad7405_driver = { 241 .driver = { 242 .name = "ad7405", 243 .of_match_table = ad7405_of_match, 244 }, 245 .probe = ad7405_probe, 246 }; 247 module_platform_driver(ad7405_driver); 248 249 MODULE_AUTHOR("Dragos Bogdan <dragos.bogdan@analog.com>"); 250 MODULE_AUTHOR("Pop Ioan Daniel <pop.ioan-daniel@analog.com>"); 251 MODULE_DESCRIPTION("Analog Devices AD7405 driver"); 252 MODULE_LICENSE("GPL"); 253 MODULE_IMPORT_NS("IIO_BACKEND"); 254