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 #include <linux/bitops.h> 20 21 /* 22 * AD7314 temperature masks 23 */ 24 #define AD7314_TEMP_MASK 0x7FE0 25 #define AD7314_TEMP_SHIFT 5 26 27 /* 28 * ADT7301 and ADT7302 temperature masks 29 */ 30 #define ADT7301_TEMP_MASK 0x3FFF 31 32 enum ad7314_variant { 33 adt7301, 34 adt7302, 35 ad7314, 36 }; 37 38 struct ad7314_data { 39 struct spi_device *spi_dev; 40 struct device *hwmon_dev; 41 u16 rx ____cacheline_aligned; 42 }; 43 44 static int ad7314_spi_read(struct ad7314_data *chip) 45 { 46 int ret; 47 48 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx)); 49 if (ret < 0) { 50 dev_err(&chip->spi_dev->dev, "SPI read error\n"); 51 return ret; 52 } 53 54 return be16_to_cpu(chip->rx); 55 } 56 57 static ssize_t ad7314_show_temperature(struct device *dev, 58 struct device_attribute *attr, 59 char *buf) 60 { 61 struct ad7314_data *chip = dev_get_drvdata(dev); 62 s16 data; 63 int ret; 64 65 ret = ad7314_spi_read(chip); 66 if (ret < 0) 67 return ret; 68 switch (spi_get_device_id(chip->spi_dev)->driver_data) { 69 case ad7314: 70 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT; 71 data = sign_extend32(data, 9); 72 73 return sprintf(buf, "%d\n", 250 * data); 74 case adt7301: 75 case adt7302: 76 /* 77 * Documented as a 13 bit twos complement register 78 * with a sign bit - which is a 14 bit 2's complement 79 * register. 1lsb - 31.25 milli degrees centigrade 80 */ 81 data = ret & ADT7301_TEMP_MASK; 82 data = sign_extend32(data, 13); 83 84 return sprintf(buf, "%d\n", 85 DIV_ROUND_CLOSEST(data * 3125, 100)); 86 default: 87 return -EINVAL; 88 } 89 } 90 91 static ssize_t ad7314_show_name(struct device *dev, 92 struct device_attribute *devattr, char *buf) 93 { 94 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); 95 } 96 97 static DEVICE_ATTR(name, S_IRUGO, ad7314_show_name, NULL); 98 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 99 ad7314_show_temperature, NULL, 0); 100 101 static struct attribute *ad7314_attributes[] = { 102 &dev_attr_name.attr, 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 ad7314_probe(struct spi_device *spi_dev) 112 { 113 int ret; 114 struct ad7314_data *chip; 115 116 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL); 117 if (chip == NULL) 118 return -ENOMEM; 119 120 spi_set_drvdata(spi_dev, chip); 121 122 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); 123 if (ret < 0) 124 return ret; 125 126 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 chip->spi_dev = spi_dev; 132 133 return 0; 134 error_remove_group: 135 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 136 return ret; 137 } 138 139 static int ad7314_remove(struct spi_device *spi_dev) 140 { 141 struct ad7314_data *chip = spi_get_drvdata(spi_dev); 142 143 hwmon_device_unregister(chip->hwmon_dev); 144 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 145 146 return 0; 147 } 148 149 static const struct spi_device_id ad7314_id[] = { 150 { "adt7301", adt7301 }, 151 { "adt7302", adt7302 }, 152 { "ad7314", ad7314 }, 153 { } 154 }; 155 MODULE_DEVICE_TABLE(spi, ad7314_id); 156 157 static struct spi_driver ad7314_driver = { 158 .driver = { 159 .name = "ad7314", 160 .owner = THIS_MODULE, 161 }, 162 .probe = ad7314_probe, 163 .remove = ad7314_remove, 164 .id_table = ad7314_id, 165 }; 166 167 module_spi_driver(ad7314_driver); 168 169 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 170 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver"); 171 MODULE_LICENSE("GPL v2"); 172