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 SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 91 ad7314_show_temperature, NULL, 0); 92 93 static struct attribute *ad7314_attributes[] = { 94 &sensor_dev_attr_temp1_input.dev_attr.attr, 95 NULL, 96 }; 97 98 static const struct attribute_group ad7314_group = { 99 .attrs = ad7314_attributes, 100 }; 101 102 static int __devinit ad7314_probe(struct spi_device *spi_dev) 103 { 104 int ret; 105 struct ad7314_data *chip; 106 107 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 108 if (chip == NULL) { 109 ret = -ENOMEM; 110 goto error_ret; 111 } 112 dev_set_drvdata(&spi_dev->dev, chip); 113 114 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); 115 if (ret < 0) 116 goto error_free_chip; 117 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev); 118 if (IS_ERR(chip->hwmon_dev)) { 119 ret = PTR_ERR(chip->hwmon_dev); 120 goto error_remove_group; 121 } 122 chip->spi_dev = spi_dev; 123 124 return 0; 125 error_remove_group: 126 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 127 error_free_chip: 128 kfree(chip); 129 error_ret: 130 return ret; 131 } 132 133 static int __devexit ad7314_remove(struct spi_device *spi_dev) 134 { 135 struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev); 136 137 hwmon_device_unregister(chip->hwmon_dev); 138 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 139 kfree(chip); 140 141 return 0; 142 } 143 144 static const struct spi_device_id ad7314_id[] = { 145 { "adt7301", adt7301 }, 146 { "adt7302", adt7302 }, 147 { "ad7314", ad7314 }, 148 { } 149 }; 150 MODULE_DEVICE_TABLE(spi, ad7314_id); 151 152 static struct spi_driver ad7314_driver = { 153 .driver = { 154 .name = "ad7314", 155 .owner = THIS_MODULE, 156 }, 157 .probe = ad7314_probe, 158 .remove = __devexit_p(ad7314_remove), 159 .id_table = ad7314_id, 160 }; 161 162 module_spi_driver(ad7314_driver); 163 164 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 165 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital" 166 " temperature sensor driver"); 167 MODULE_LICENSE("GPL v2"); 168