1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302 4 * 5 * Copyright 2010 Analog Devices Inc. 6 * 7 * Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk> 8 */ 9 #include <linux/device.h> 10 #include <linux/kernel.h> 11 #include <linux/slab.h> 12 #include <linux/sysfs.h> 13 #include <linux/spi/spi.h> 14 #include <linux/module.h> 15 #include <linux/err.h> 16 #include <linux/hwmon.h> 17 #include <linux/hwmon-sysfs.h> 18 #include <linux/bitops.h> 19 20 /* 21 * AD7314 temperature masks 22 */ 23 #define AD7314_TEMP_MASK 0x7FE0 24 #define AD7314_TEMP_SHIFT 5 25 #define AD7314_LEADING_ZEROS_MASK BIT(15) 26 27 /* 28 * ADT7301 and ADT7302 temperature masks 29 */ 30 #define ADT7301_TEMP_MASK 0x3FFF 31 #define ADT7301_LEADING_ZEROS_MASK (BIT(15) | BIT(14)) 32 33 enum ad7314_variant { 34 adt7301, 35 adt7302, 36 ad7314, 37 }; 38 39 struct ad7314_data { 40 struct spi_device *spi_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_temperature_show(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 if (ret & AD7314_LEADING_ZEROS_MASK) { 71 /* Invalid read-out, leading zero part is missing */ 72 return -EIO; 73 } 74 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT; 75 data = sign_extend32(data, 9); 76 77 return sprintf(buf, "%d\n", 250 * data); 78 case adt7301: 79 case adt7302: 80 if (ret & ADT7301_LEADING_ZEROS_MASK) { 81 /* Invalid read-out, leading zero part is missing */ 82 return -EIO; 83 } 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 = ret & ADT7301_TEMP_MASK; 90 data = sign_extend32(data, 13); 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_RO(temp1_input, ad7314_temperature, 0); 100 101 static struct attribute *ad7314_attrs[] = { 102 &sensor_dev_attr_temp1_input.dev_attr.attr, 103 NULL, 104 }; 105 106 ATTRIBUTE_GROUPS(ad7314); 107 108 static int ad7314_probe(struct spi_device *spi_dev) 109 { 110 struct ad7314_data *chip; 111 struct device *hwmon_dev; 112 113 chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL); 114 if (chip == NULL) 115 return -ENOMEM; 116 117 chip->spi_dev = spi_dev; 118 hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev, 119 spi_dev->modalias, 120 chip, ad7314_groups); 121 return PTR_ERR_OR_ZERO(hwmon_dev); 122 } 123 124 static const struct spi_device_id ad7314_id[] = { 125 { "adt7301", adt7301 }, 126 { "adt7302", adt7302 }, 127 { "ad7314", ad7314 }, 128 { } 129 }; 130 MODULE_DEVICE_TABLE(spi, ad7314_id); 131 132 static struct spi_driver ad7314_driver = { 133 .driver = { 134 .name = "ad7314", 135 }, 136 .probe = ad7314_probe, 137 .id_table = ad7314_id, 138 }; 139 140 module_spi_driver(ad7314_driver); 141 142 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 143 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver"); 144 MODULE_LICENSE("GPL v2"); 145