1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Maxim MAX5522 4 * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs 5 * 6 * Copyright 2022 Timesys Corp. 7 */ 8 9 #include <linux/device.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/mod_devicetable.h> 13 #include <linux/regmap.h> 14 #include <linux/regulator/consumer.h> 15 #include <linux/slab.h> 16 #include <linux/spi/spi.h> 17 #include <linux/units.h> 18 19 #include <linux/iio/iio.h> 20 21 #define MAX5522_MAX_ADDR 15 22 #define MAX5522_CTRL_NONE 0 23 #define MAX5522_CTRL_LOAD_IN_A 9 24 #define MAX5522_CTRL_LOAD_IN_B 10 25 26 #define MAX5522_REG_DATA(x) ((x) + MAX5522_CTRL_LOAD_IN_A) 27 28 struct max5522_chip_info { 29 const char *name; 30 const struct iio_chan_spec *channels; 31 unsigned int num_channels; 32 }; 33 34 struct max5522_state { 35 struct regmap *regmap; 36 const struct max5522_chip_info *chip_info; 37 unsigned short dac_cache[2]; 38 int vref_mV; 39 }; 40 41 #define MAX5522_CHANNEL(chan) { \ 42 .type = IIO_VOLTAGE, \ 43 .indexed = 1, \ 44 .output = 1, \ 45 .channel = chan, \ 46 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 47 BIT(IIO_CHAN_INFO_SCALE), \ 48 .scan_type = { \ 49 .sign = 'u', \ 50 .realbits = 10, \ 51 .storagebits = 16, \ 52 .shift = 2, \ 53 } \ 54 } 55 56 static const struct iio_chan_spec max5522_channels[] = { 57 MAX5522_CHANNEL(0), 58 MAX5522_CHANNEL(1), 59 }; 60 61 enum max5522_type { 62 ID_MAX5522, 63 }; 64 65 static const struct max5522_chip_info max5522_chip_info_tbl[] = { 66 [ID_MAX5522] = { 67 .name = "max5522", 68 .channels = max5522_channels, 69 .num_channels = 2, 70 }, 71 }; 72 73 static inline int max5522_info_to_reg(struct iio_chan_spec const *chan) 74 { 75 return MAX5522_REG_DATA(chan->channel); 76 } 77 78 static int max5522_read_raw(struct iio_dev *indio_dev, 79 struct iio_chan_spec const *chan, 80 int *val, int *val2, long info) 81 { 82 struct max5522_state *state = iio_priv(indio_dev); 83 84 switch (info) { 85 case IIO_CHAN_INFO_RAW: 86 *val = state->dac_cache[chan->channel]; 87 return IIO_VAL_INT; 88 case IIO_CHAN_INFO_SCALE: 89 *val = state->vref_mV; 90 *val2 = 10; 91 return IIO_VAL_FRACTIONAL_LOG2; 92 default: 93 return -EINVAL; 94 } 95 96 return -EINVAL; 97 } 98 99 static int max5522_write_raw(struct iio_dev *indio_dev, 100 struct iio_chan_spec const *chan, 101 int val, int val2, long info) 102 { 103 struct max5522_state *state = iio_priv(indio_dev); 104 int rval; 105 106 if (val > 1023 || val < 0) 107 return -EINVAL; 108 109 rval = regmap_write(state->regmap, max5522_info_to_reg(chan), 110 val << chan->scan_type.shift); 111 if (rval < 0) 112 return rval; 113 114 state->dac_cache[chan->channel] = val; 115 116 return 0; 117 } 118 119 static const struct iio_info max5522_info = { 120 .read_raw = max5522_read_raw, 121 .write_raw = max5522_write_raw, 122 }; 123 124 static const struct regmap_config max5522_regmap_config = { 125 .reg_bits = 4, 126 .val_bits = 12, 127 .max_register = MAX5522_MAX_ADDR, 128 }; 129 130 static int max5522_spi_probe(struct spi_device *spi) 131 { 132 struct iio_dev *indio_dev; 133 struct max5522_state *state; 134 int ret; 135 136 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 137 if (indio_dev == NULL) { 138 dev_err(&spi->dev, "failed to allocate iio device\n"); 139 return -ENOMEM; 140 } 141 142 state = iio_priv(indio_dev); 143 state->chip_info = spi_get_device_match_data(spi); 144 if (!state->chip_info) 145 return -EINVAL; 146 147 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefin"); 148 if (ret < 0) 149 return dev_err_probe(&spi->dev, ret, 150 "Failed to get vrefin regulator\n"); 151 state->vref_mV = ret / (MICRO / MILLI); 152 153 state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config); 154 155 if (IS_ERR(state->regmap)) 156 return PTR_ERR(state->regmap); 157 158 indio_dev->info = &max5522_info; 159 indio_dev->modes = INDIO_DIRECT_MODE; 160 indio_dev->channels = max5522_channels; 161 indio_dev->num_channels = ARRAY_SIZE(max5522_channels); 162 indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name; 163 164 return devm_iio_device_register(&spi->dev, indio_dev); 165 } 166 167 static const struct spi_device_id max5522_ids[] = { 168 { "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] }, 169 { } 170 }; 171 MODULE_DEVICE_TABLE(spi, max5522_ids); 172 173 static const struct of_device_id max5522_of_match[] = { 174 { 175 .compatible = "maxim,max5522", 176 .data = &max5522_chip_info_tbl[ID_MAX5522], 177 }, 178 { } 179 }; 180 MODULE_DEVICE_TABLE(of, max5522_of_match); 181 182 static struct spi_driver max5522_spi_driver = { 183 .driver = { 184 .name = "max5522", 185 .of_match_table = max5522_of_match, 186 }, 187 .probe = max5522_spi_probe, 188 .id_table = max5522_ids, 189 }; 190 module_spi_driver(max5522_spi_driver); 191 192 MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com"); 193 MODULE_DESCRIPTION("MAX5522 DAC driver"); 194 MODULE_LICENSE("GPL"); 195