1 /* 2 * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com> 3 * 4 * Driver for Texas Instruments' ADC128S052, ADC122S021 and ADC124S021 ADC chip. 5 * Datasheets can be found here: 6 * http://www.ti.com/lit/ds/symlink/adc128s052.pdf 7 * http://www.ti.com/lit/ds/symlink/adc122s021.pdf 8 * http://www.ti.com/lit/ds/symlink/adc124s021.pdf 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/err.h> 16 #include <linux/spi/spi.h> 17 #include <linux/module.h> 18 #include <linux/iio/iio.h> 19 #include <linux/regulator/consumer.h> 20 21 struct adc128_configuration { 22 const struct iio_chan_spec *channels; 23 u8 num_channels; 24 }; 25 26 struct adc128 { 27 struct spi_device *spi; 28 29 struct regulator *reg; 30 struct mutex lock; 31 32 u8 buffer[2] ____cacheline_aligned; 33 }; 34 35 static int adc128_adc_conversion(struct adc128 *adc, u8 channel) 36 { 37 int ret; 38 39 mutex_lock(&adc->lock); 40 41 adc->buffer[0] = channel << 3; 42 adc->buffer[1] = 0; 43 44 ret = spi_write(adc->spi, &adc->buffer, 2); 45 if (ret < 0) { 46 mutex_unlock(&adc->lock); 47 return ret; 48 } 49 50 ret = spi_read(adc->spi, &adc->buffer, 2); 51 52 mutex_unlock(&adc->lock); 53 54 if (ret < 0) 55 return ret; 56 57 return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF); 58 } 59 60 static int adc128_read_raw(struct iio_dev *indio_dev, 61 struct iio_chan_spec const *channel, int *val, 62 int *val2, long mask) 63 { 64 struct adc128 *adc = iio_priv(indio_dev); 65 int ret; 66 67 switch (mask) { 68 case IIO_CHAN_INFO_RAW: 69 70 ret = adc128_adc_conversion(adc, channel->channel); 71 if (ret < 0) 72 return ret; 73 74 *val = ret; 75 return IIO_VAL_INT; 76 77 case IIO_CHAN_INFO_SCALE: 78 79 ret = regulator_get_voltage(adc->reg); 80 if (ret < 0) 81 return ret; 82 83 *val = ret / 1000; 84 *val2 = 12; 85 return IIO_VAL_FRACTIONAL_LOG2; 86 87 default: 88 return -EINVAL; 89 } 90 91 } 92 93 #define ADC128_VOLTAGE_CHANNEL(num) \ 94 { \ 95 .type = IIO_VOLTAGE, \ 96 .indexed = 1, \ 97 .channel = (num), \ 98 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 99 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 100 } 101 102 static const struct iio_chan_spec adc128s052_channels[] = { 103 ADC128_VOLTAGE_CHANNEL(0), 104 ADC128_VOLTAGE_CHANNEL(1), 105 ADC128_VOLTAGE_CHANNEL(2), 106 ADC128_VOLTAGE_CHANNEL(3), 107 ADC128_VOLTAGE_CHANNEL(4), 108 ADC128_VOLTAGE_CHANNEL(5), 109 ADC128_VOLTAGE_CHANNEL(6), 110 ADC128_VOLTAGE_CHANNEL(7), 111 }; 112 113 static const struct iio_chan_spec adc122s021_channels[] = { 114 ADC128_VOLTAGE_CHANNEL(0), 115 ADC128_VOLTAGE_CHANNEL(1), 116 }; 117 118 static const struct iio_chan_spec adc124s021_channels[] = { 119 ADC128_VOLTAGE_CHANNEL(0), 120 ADC128_VOLTAGE_CHANNEL(1), 121 ADC128_VOLTAGE_CHANNEL(2), 122 ADC128_VOLTAGE_CHANNEL(3), 123 }; 124 125 static const struct adc128_configuration adc128_config[] = { 126 { adc128s052_channels, ARRAY_SIZE(adc128s052_channels) }, 127 { adc122s021_channels, ARRAY_SIZE(adc122s021_channels) }, 128 { adc124s021_channels, ARRAY_SIZE(adc124s021_channels) }, 129 }; 130 131 static const struct iio_info adc128_info = { 132 .read_raw = adc128_read_raw, 133 .driver_module = THIS_MODULE, 134 }; 135 136 static int adc128_probe(struct spi_device *spi) 137 { 138 struct iio_dev *indio_dev; 139 struct adc128 *adc; 140 int config = spi_get_device_id(spi)->driver_data; 141 int ret; 142 143 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 144 if (!indio_dev) 145 return -ENOMEM; 146 147 adc = iio_priv(indio_dev); 148 adc->spi = spi; 149 150 spi_set_drvdata(spi, indio_dev); 151 152 indio_dev->dev.parent = &spi->dev; 153 indio_dev->name = spi_get_device_id(spi)->name; 154 indio_dev->modes = INDIO_DIRECT_MODE; 155 indio_dev->info = &adc128_info; 156 157 indio_dev->channels = adc128_config[config].channels; 158 indio_dev->num_channels = adc128_config[config].num_channels; 159 160 adc->reg = devm_regulator_get(&spi->dev, "vref"); 161 if (IS_ERR(adc->reg)) 162 return PTR_ERR(adc->reg); 163 164 ret = regulator_enable(adc->reg); 165 if (ret < 0) 166 return ret; 167 168 mutex_init(&adc->lock); 169 170 ret = iio_device_register(indio_dev); 171 172 return ret; 173 } 174 175 static int adc128_remove(struct spi_device *spi) 176 { 177 struct iio_dev *indio_dev = spi_get_drvdata(spi); 178 struct adc128 *adc = iio_priv(indio_dev); 179 180 iio_device_unregister(indio_dev); 181 regulator_disable(adc->reg); 182 183 return 0; 184 } 185 186 static const struct of_device_id adc128_of_match[] = { 187 { .compatible = "ti,adc128s052", }, 188 { .compatible = "ti,adc122s021", }, 189 { .compatible = "ti,adc124s021", }, 190 { /* sentinel */ }, 191 }; 192 MODULE_DEVICE_TABLE(of, adc128_of_match); 193 194 static const struct spi_device_id adc128_id[] = { 195 { "adc128s052", 0}, /* index into adc128_config */ 196 { "adc122s021", 1}, 197 { "adc124s021", 2}, 198 { } 199 }; 200 MODULE_DEVICE_TABLE(spi, adc128_id); 201 202 static struct spi_driver adc128_driver = { 203 .driver = { 204 .name = "adc128s052", 205 .of_match_table = of_match_ptr(adc128_of_match), 206 }, 207 .probe = adc128_probe, 208 .remove = adc128_remove, 209 .id_table = adc128_id, 210 }; 211 module_spi_driver(adc128_driver); 212 213 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>"); 214 MODULE_DESCRIPTION("Texas Instruments ADC128S052"); 215 MODULE_LICENSE("GPL v2"); 216