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 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 = sign_extend32(data, 9); 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 = sign_extend32(data, 13); 82 83 return sprintf(buf, "%d\n", 84 DIV_ROUND_CLOSEST(data * 3125, 100)); 85 default: 86 return -EINVAL; 87 } 88 } 89 90 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 91 ad7314_show_temperature, NULL, 0); 92 93 static struct attribute *ad7314_attrs[] = { 94 &sensor_dev_attr_temp1_input.dev_attr.attr, 95 NULL, 96 }; 97 98 ATTRIBUTE_GROUPS(ad7314); 99 100 static int ad7314_probe(struct spi_device *spi_dev) 101 { 102 struct ad7314_data *chip; 103 struct device *hwmon_dev; 104 105 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL); 106 if (chip == NULL) 107 return -ENOMEM; 108 109 chip->spi_dev = spi_dev; 110 hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev, 111 spi_dev->modalias, 112 chip, ad7314_groups); 113 return PTR_ERR_OR_ZERO(hwmon_dev); 114 } 115 116 static const struct spi_device_id ad7314_id[] = { 117 { "adt7301", adt7301 }, 118 { "adt7302", adt7302 }, 119 { "ad7314", ad7314 }, 120 { } 121 }; 122 MODULE_DEVICE_TABLE(spi, ad7314_id); 123 124 static struct spi_driver ad7314_driver = { 125 .driver = { 126 .name = "ad7314", 127 }, 128 .probe = ad7314_probe, 129 .id_table = ad7314_id, 130 }; 131 132 module_spi_driver(ad7314_driver); 133 134 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 135 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver"); 136 MODULE_LICENSE("GPL v2"); 137