1 /* 2 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302 3 * 4 * Copyright 2010 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2 or later. 7 * 8 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk> 9 */ 10 #include <linux/device.h> 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/sysfs.h> 14 #include <linux/spi/spi.h> 15 #include <linux/module.h> 16 #include <linux/err.h> 17 #include <linux/hwmon.h> 18 #include <linux/hwmon-sysfs.h> 19 20 /* 21 * AD7314 power mode 22 */ 23 #define AD7314_PD 0x2000 24 25 /* 26 * AD7314 temperature masks 27 */ 28 #define AD7314_TEMP_SIGN 0x200 29 #define AD7314_TEMP_MASK 0x7FE0 30 #define AD7314_TEMP_OFFSET 5 31 32 /* 33 * ADT7301 and ADT7302 temperature masks 34 */ 35 #define ADT7301_TEMP_SIGN 0x2000 36 #define ADT7301_TEMP_MASK 0x3FFF 37 38 enum ad7314_variant { 39 adt7301, 40 adt7302, 41 ad7314, 42 }; 43 44 struct ad7314_data { 45 struct spi_device *spi_dev; 46 struct device *hwmon_dev; 47 u16 rx ____cacheline_aligned; 48 }; 49 50 static int ad7314_spi_read(struct ad7314_data *chip, s16 *data) 51 { 52 int ret; 53 54 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx)); 55 if (ret < 0) { 56 dev_err(&chip->spi_dev->dev, "SPI read error\n"); 57 return ret; 58 } 59 60 *data = be16_to_cpu(chip->rx); 61 62 return ret; 63 } 64 65 static ssize_t ad7314_show_temperature(struct device *dev, 66 struct device_attribute *attr, 67 char *buf) 68 { 69 struct ad7314_data *chip = dev_get_drvdata(dev); 70 s16 data; 71 int ret; 72 73 ret = ad7314_spi_read(chip, &data); 74 if (ret < 0) 75 return ret; 76 switch (spi_get_device_id(chip->spi_dev)->driver_data) { 77 case ad7314: 78 data = (data & AD7314_TEMP_MASK) >> AD7314_TEMP_OFFSET; 79 data = (data << 6) >> 6; 80 81 return sprintf(buf, "%d\n", 250 * data); 82 case adt7301: 83 case adt7302: 84 /* 85 * Documented as a 13 bit twos complement register 86 * with a sign bit - which is a 14 bit 2's complement 87 * register. 1lsb - 31.25 milli degrees centigrade 88 */ 89 data &= ADT7301_TEMP_MASK; 90 data = (data << 2) >> 2; 91 92 return sprintf(buf, "%d\n", 93 DIV_ROUND_CLOSEST(data * 3125, 100)); 94 default: 95 return -EINVAL; 96 } 97 } 98 99 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 100 ad7314_show_temperature, NULL, 0); 101 102 static struct attribute *ad7314_attributes[] = { 103 &sensor_dev_attr_temp1_input.dev_attr.attr, 104 NULL, 105 }; 106 107 static const struct attribute_group ad7314_group = { 108 .attrs = ad7314_attributes, 109 }; 110 111 static int __devinit ad7314_probe(struct spi_device *spi_dev) 112 { 113 int ret; 114 struct ad7314_data *chip; 115 116 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 117 if (chip == NULL) { 118 ret = -ENOMEM; 119 goto error_ret; 120 } 121 dev_set_drvdata(&spi_dev->dev, chip); 122 123 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); 124 if (ret < 0) 125 goto error_free_chip; 126 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev); 127 if (IS_ERR(chip->hwmon_dev)) { 128 ret = PTR_ERR(chip->hwmon_dev); 129 goto error_remove_group; 130 } 131 132 return 0; 133 error_remove_group: 134 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 135 error_free_chip: 136 kfree(chip); 137 error_ret: 138 return ret; 139 } 140 141 static int __devexit ad7314_remove(struct spi_device *spi_dev) 142 { 143 struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev); 144 145 hwmon_device_unregister(chip->hwmon_dev); 146 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 147 kfree(chip); 148 149 return 0; 150 } 151 152 static const struct spi_device_id ad7314_id[] = { 153 { "adt7301", adt7301 }, 154 { "adt7302", adt7302 }, 155 { "ad7314", ad7314 }, 156 { } 157 }; 158 MODULE_DEVICE_TABLE(spi, ad7314_id); 159 160 static struct spi_driver ad7314_driver = { 161 .driver = { 162 .name = "ad7314", 163 .owner = THIS_MODULE, 164 }, 165 .probe = ad7314_probe, 166 .remove = __devexit_p(ad7314_remove), 167 .id_table = ad7314_id, 168 }; 169 170 static __init int ad7314_init(void) 171 { 172 return spi_register_driver(&ad7314_driver); 173 } 174 module_init(ad7314_init); 175 176 static __exit void ad7314_exit(void) 177 { 178 spi_unregister_driver(&ad7314_driver); 179 } 180 module_exit(ad7314_exit); 181 182 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 183 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital" 184 " temperature sensor driver"); 185 MODULE_LICENSE("GPL v2"); 186