1 /* 2 * Copyright (C) 2012 Avionic Design GmbH 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/err.h> 10 #include <linux/i2c.h> 11 #include <linux/module.h> 12 13 #include <linux/iio/iio.h> 14 #include <linux/regulator/consumer.h> 15 16 struct adc081c { 17 struct i2c_client *i2c; 18 struct regulator *ref; 19 }; 20 21 #define REG_CONV_RES 0x00 22 23 static int adc081c_read_raw(struct iio_dev *iio, 24 struct iio_chan_spec const *channel, int *value, 25 int *shift, long mask) 26 { 27 struct adc081c *adc = iio_priv(iio); 28 int err; 29 30 switch (mask) { 31 case IIO_CHAN_INFO_RAW: 32 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES); 33 if (err < 0) 34 return err; 35 36 *value = (err >> 4) & 0xff; 37 return IIO_VAL_INT; 38 39 case IIO_CHAN_INFO_SCALE: 40 err = regulator_get_voltage(adc->ref); 41 if (err < 0) 42 return err; 43 44 *value = err / 1000; 45 *shift = 8; 46 47 return IIO_VAL_FRACTIONAL_LOG2; 48 49 default: 50 break; 51 } 52 53 return -EINVAL; 54 } 55 56 static const struct iio_chan_spec adc081c_channel = { 57 .type = IIO_VOLTAGE, 58 .info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT | 59 IIO_CHAN_INFO_RAW_SEPARATE_BIT, 60 }; 61 62 static const struct iio_info adc081c_info = { 63 .read_raw = adc081c_read_raw, 64 .driver_module = THIS_MODULE, 65 }; 66 67 static int adc081c_probe(struct i2c_client *client, 68 const struct i2c_device_id *id) 69 { 70 struct iio_dev *iio; 71 struct adc081c *adc; 72 int err; 73 74 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) 75 return -ENODEV; 76 77 iio = iio_device_alloc(sizeof(*adc)); 78 if (!iio) 79 return -ENOMEM; 80 81 adc = iio_priv(iio); 82 adc->i2c = client; 83 84 adc->ref = regulator_get(&client->dev, "vref"); 85 if (IS_ERR(adc->ref)) { 86 err = PTR_ERR(adc->ref); 87 goto iio_free; 88 } 89 90 err = regulator_enable(adc->ref); 91 if (err < 0) 92 goto regulator_put; 93 94 iio->dev.parent = &client->dev; 95 iio->name = dev_name(&client->dev); 96 iio->modes = INDIO_DIRECT_MODE; 97 iio->info = &adc081c_info; 98 99 iio->channels = &adc081c_channel; 100 iio->num_channels = 1; 101 102 err = iio_device_register(iio); 103 if (err < 0) 104 goto regulator_disable; 105 106 i2c_set_clientdata(client, iio); 107 108 return 0; 109 110 regulator_disable: 111 regulator_disable(adc->ref); 112 regulator_put: 113 regulator_put(adc->ref); 114 iio_free: 115 iio_device_free(iio); 116 117 return err; 118 } 119 120 static int adc081c_remove(struct i2c_client *client) 121 { 122 struct iio_dev *iio = i2c_get_clientdata(client); 123 struct adc081c *adc = iio_priv(iio); 124 125 iio_device_unregister(iio); 126 regulator_disable(adc->ref); 127 regulator_put(adc->ref); 128 iio_device_free(iio); 129 130 return 0; 131 } 132 133 static const struct i2c_device_id adc081c_id[] = { 134 { "adc081c", 0 }, 135 { } 136 }; 137 MODULE_DEVICE_TABLE(i2c, adc081c_id); 138 139 #ifdef CONFIG_OF 140 static const struct of_device_id adc081c_of_match[] = { 141 { .compatible = "ti,adc081c" }, 142 { } 143 }; 144 MODULE_DEVICE_TABLE(of, adc081c_of_match); 145 #endif 146 147 static struct i2c_driver adc081c_driver = { 148 .driver = { 149 .name = "adc081c", 150 .owner = THIS_MODULE, 151 .of_match_table = of_match_ptr(adc081c_of_match), 152 }, 153 .probe = adc081c_probe, 154 .remove = adc081c_remove, 155 .id_table = adc081c_id, 156 }; 157 module_i2c_driver(adc081c_driver); 158 159 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>"); 160 MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver"); 161 MODULE_LICENSE("GPL v2"); 162