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