1 /* 2 * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver 3 * 4 * Copyright (C) 2012 Avionic Design GmbH 5 * Copyright (C) 2016 Intel 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Datasheets: 12 * http://www.ti.com/lit/ds/symlink/adc081c021.pdf 13 * http://www.ti.com/lit/ds/symlink/adc101c021.pdf 14 * http://www.ti.com/lit/ds/symlink/adc121c021.pdf 15 * 16 * The devices have a very similar interface and differ mostly in the number of 17 * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2 18 * bits of value registers are reserved. 19 */ 20 21 #include <linux/err.h> 22 #include <linux/i2c.h> 23 #include <linux/module.h> 24 #include <linux/of.h> 25 26 #include <linux/iio/iio.h> 27 #include <linux/iio/buffer.h> 28 #include <linux/iio/trigger_consumer.h> 29 #include <linux/iio/triggered_buffer.h> 30 #include <linux/regulator/consumer.h> 31 32 struct adc081c { 33 struct i2c_client *i2c; 34 struct regulator *ref; 35 36 /* 8, 10 or 12 */ 37 int bits; 38 }; 39 40 #define REG_CONV_RES 0x00 41 42 static int adc081c_read_raw(struct iio_dev *iio, 43 struct iio_chan_spec const *channel, int *value, 44 int *shift, long mask) 45 { 46 struct adc081c *adc = iio_priv(iio); 47 int err; 48 49 switch (mask) { 50 case IIO_CHAN_INFO_RAW: 51 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES); 52 if (err < 0) 53 return err; 54 55 *value = (err & 0xFFF) >> (12 - adc->bits); 56 return IIO_VAL_INT; 57 58 case IIO_CHAN_INFO_SCALE: 59 err = regulator_get_voltage(adc->ref); 60 if (err < 0) 61 return err; 62 63 *value = err / 1000; 64 *shift = adc->bits; 65 66 return IIO_VAL_FRACTIONAL_LOG2; 67 68 default: 69 break; 70 } 71 72 return -EINVAL; 73 } 74 75 #define ADCxx1C_CHAN(_bits) { \ 76 .type = IIO_VOLTAGE, \ 77 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 78 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 79 .scan_type = { \ 80 .sign = 'u', \ 81 .realbits = (_bits), \ 82 .storagebits = 16, \ 83 .shift = 12 - (_bits), \ 84 .endianness = IIO_CPU, \ 85 }, \ 86 } 87 88 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits) \ 89 static const struct iio_chan_spec _name ## _channels[] = { \ 90 ADCxx1C_CHAN((_bits)), \ 91 IIO_CHAN_SOFT_TIMESTAMP(1), \ 92 }; \ 93 94 #define ADC081C_NUM_CHANNELS 2 95 96 struct adcxx1c_model { 97 const struct iio_chan_spec* channels; 98 int bits; 99 }; 100 101 #define ADCxx1C_MODEL(_name, _bits) \ 102 { \ 103 .channels = _name ## _channels, \ 104 .bits = (_bits), \ 105 } 106 107 DEFINE_ADCxx1C_CHANNELS(adc081c, 8); 108 DEFINE_ADCxx1C_CHANNELS(adc101c, 10); 109 DEFINE_ADCxx1C_CHANNELS(adc121c, 12); 110 111 /* Model ids are indexes in _models array */ 112 enum adcxx1c_model_id { 113 ADC081C = 0, 114 ADC101C = 1, 115 ADC121C = 2, 116 }; 117 118 static struct adcxx1c_model adcxx1c_models[] = { 119 ADCxx1C_MODEL(adc081c, 8), 120 ADCxx1C_MODEL(adc101c, 10), 121 ADCxx1C_MODEL(adc121c, 12), 122 }; 123 124 static const struct iio_info adc081c_info = { 125 .read_raw = adc081c_read_raw, 126 .driver_module = THIS_MODULE, 127 }; 128 129 static irqreturn_t adc081c_trigger_handler(int irq, void *p) 130 { 131 struct iio_poll_func *pf = p; 132 struct iio_dev *indio_dev = pf->indio_dev; 133 struct adc081c *data = iio_priv(indio_dev); 134 u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */ 135 int ret; 136 137 ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES); 138 if (ret < 0) 139 goto out; 140 buf[0] = ret; 141 iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns()); 142 out: 143 iio_trigger_notify_done(indio_dev->trig); 144 return IRQ_HANDLED; 145 } 146 147 static int adc081c_probe(struct i2c_client *client, 148 const struct i2c_device_id *id) 149 { 150 struct iio_dev *iio; 151 struct adc081c *adc; 152 struct adcxx1c_model *model = &adcxx1c_models[id->driver_data]; 153 int err; 154 155 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) 156 return -EOPNOTSUPP; 157 158 iio = devm_iio_device_alloc(&client->dev, sizeof(*adc)); 159 if (!iio) 160 return -ENOMEM; 161 162 adc = iio_priv(iio); 163 adc->i2c = client; 164 adc->bits = model->bits; 165 166 adc->ref = devm_regulator_get(&client->dev, "vref"); 167 if (IS_ERR(adc->ref)) 168 return PTR_ERR(adc->ref); 169 170 err = regulator_enable(adc->ref); 171 if (err < 0) 172 return err; 173 174 iio->dev.parent = &client->dev; 175 iio->name = dev_name(&client->dev); 176 iio->modes = INDIO_DIRECT_MODE; 177 iio->info = &adc081c_info; 178 179 iio->channels = model->channels; 180 iio->num_channels = ADC081C_NUM_CHANNELS; 181 182 err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL); 183 if (err < 0) { 184 dev_err(&client->dev, "iio triggered buffer setup failed\n"); 185 goto err_regulator_disable; 186 } 187 188 err = iio_device_register(iio); 189 if (err < 0) 190 goto err_buffer_cleanup; 191 192 i2c_set_clientdata(client, iio); 193 194 return 0; 195 196 err_buffer_cleanup: 197 iio_triggered_buffer_cleanup(iio); 198 err_regulator_disable: 199 regulator_disable(adc->ref); 200 201 return err; 202 } 203 204 static int adc081c_remove(struct i2c_client *client) 205 { 206 struct iio_dev *iio = i2c_get_clientdata(client); 207 struct adc081c *adc = iio_priv(iio); 208 209 iio_device_unregister(iio); 210 iio_triggered_buffer_cleanup(iio); 211 regulator_disable(adc->ref); 212 213 return 0; 214 } 215 216 static const struct i2c_device_id adc081c_id[] = { 217 { "adc081c", ADC081C }, 218 { "adc101c", ADC101C }, 219 { "adc121c", ADC121C }, 220 { } 221 }; 222 MODULE_DEVICE_TABLE(i2c, adc081c_id); 223 224 #ifdef CONFIG_OF 225 static const struct of_device_id adc081c_of_match[] = { 226 { .compatible = "ti,adc081c" }, 227 { .compatible = "ti,adc101c" }, 228 { .compatible = "ti,adc121c" }, 229 { } 230 }; 231 MODULE_DEVICE_TABLE(of, adc081c_of_match); 232 #endif 233 234 static struct i2c_driver adc081c_driver = { 235 .driver = { 236 .name = "adc081c", 237 .of_match_table = of_match_ptr(adc081c_of_match), 238 }, 239 .probe = adc081c_probe, 240 .remove = adc081c_remove, 241 .id_table = adc081c_id, 242 }; 243 module_i2c_driver(adc081c_driver); 244 245 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>"); 246 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver"); 247 MODULE_LICENSE("GPL v2"); 248