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 temperature masks 22 */ 23 #define AD7314_TEMP_MASK 0x7FE0 24 #define AD7314_TEMP_SHIFT 5 25 26 /* 27 * ADT7301 and ADT7302 temperature masks 28 */ 29 #define ADT7301_TEMP_MASK 0x3FFF 30 31 enum ad7314_variant { 32 adt7301, 33 adt7302, 34 ad7314, 35 }; 36 37 struct ad7314_data { 38 struct spi_device *spi_dev; 39 struct device *hwmon_dev; 40 u16 rx ____cacheline_aligned; 41 }; 42 43 static int ad7314_spi_read(struct ad7314_data *chip) 44 { 45 int ret; 46 47 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx)); 48 if (ret < 0) { 49 dev_err(&chip->spi_dev->dev, "SPI read error\n"); 50 return ret; 51 } 52 53 return be16_to_cpu(chip->rx); 54 } 55 56 static ssize_t ad7314_show_temperature(struct device *dev, 57 struct device_attribute *attr, 58 char *buf) 59 { 60 struct ad7314_data *chip = dev_get_drvdata(dev); 61 s16 data; 62 int ret; 63 64 ret = ad7314_spi_read(chip); 65 if (ret < 0) 66 return ret; 67 switch (spi_get_device_id(chip->spi_dev)->driver_data) { 68 case ad7314: 69 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT; 70 data = (data << 6) >> 6; 71 72 return sprintf(buf, "%d\n", 250 * data); 73 case adt7301: 74 case adt7302: 75 /* 76 * Documented as a 13 bit twos complement register 77 * with a sign bit - which is a 14 bit 2's complement 78 * register. 1lsb - 31.25 milli degrees centigrade 79 */ 80 data = ret & ADT7301_TEMP_MASK; 81 data = (data << 2) >> 2; 82 83 return sprintf(buf, "%d\n", 84 DIV_ROUND_CLOSEST(data * 3125, 100)); 85 default: 86 return -EINVAL; 87 } 88 } 89 90 static ssize_t ad7314_show_name(struct device *dev, 91 struct device_attribute *devattr, char *buf) 92 { 93 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); 94 } 95 96 static DEVICE_ATTR(name, S_IRUGO, ad7314_show_name, NULL); 97 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 98 ad7314_show_temperature, NULL, 0); 99 100 static struct attribute *ad7314_attributes[] = { 101 &dev_attr_name.attr, 102 &sensor_dev_attr_temp1_input.dev_attr.attr, 103 NULL, 104 }; 105 106 static const struct attribute_group ad7314_group = { 107 .attrs = ad7314_attributes, 108 }; 109 110 static int ad7314_probe(struct spi_device *spi_dev) 111 { 112 int ret; 113 struct ad7314_data *chip; 114 115 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL); 116 if (chip == NULL) 117 return -ENOMEM; 118 119 spi_set_drvdata(spi_dev, chip); 120 121 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); 122 if (ret < 0) 123 return ret; 124 125 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev); 126 if (IS_ERR(chip->hwmon_dev)) { 127 ret = PTR_ERR(chip->hwmon_dev); 128 goto error_remove_group; 129 } 130 chip->spi_dev = spi_dev; 131 132 return 0; 133 error_remove_group: 134 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 135 return ret; 136 } 137 138 static int ad7314_remove(struct spi_device *spi_dev) 139 { 140 struct ad7314_data *chip = spi_get_drvdata(spi_dev); 141 142 hwmon_device_unregister(chip->hwmon_dev); 143 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 144 145 return 0; 146 } 147 148 static const struct spi_device_id ad7314_id[] = { 149 { "adt7301", adt7301 }, 150 { "adt7302", adt7302 }, 151 { "ad7314", ad7314 }, 152 { } 153 }; 154 MODULE_DEVICE_TABLE(spi, ad7314_id); 155 156 static struct spi_driver ad7314_driver = { 157 .driver = { 158 .name = "ad7314", 159 .owner = THIS_MODULE, 160 }, 161 .probe = ad7314_probe, 162 .remove = ad7314_remove, 163 .id_table = ad7314_id, 164 }; 165 166 module_spi_driver(ad7314_driver); 167 168 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 169 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver"); 170 MODULE_LICENSE("GPL v2"); 171