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 power mode 22 */ 23 #define AD7314_PD 0x2000 24 25 /* 26 * AD7314 temperature masks 27 */ 28 #define AD7314_TEMP_SIGN 0x200 29 #define AD7314_TEMP_MASK 0x7FE0 30 #define AD7314_TEMP_OFFSET 5 31 32 /* 33 * ADT7301 and ADT7302 temperature masks 34 */ 35 #define ADT7301_TEMP_SIGN 0x2000 36 #define ADT7301_TEMP_MASK 0x3FFF 37 38 enum ad7314_variant { 39 adt7301, 40 adt7302, 41 ad7314, 42 }; 43 44 struct ad7314_data { 45 struct spi_device *spi_dev; 46 struct device *hwmon_dev; 47 u16 rx ____cacheline_aligned; 48 }; 49 50 static int ad7314_spi_read(struct ad7314_data *chip) 51 { 52 int ret; 53 54 ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx)); 55 if (ret < 0) { 56 dev_err(&chip->spi_dev->dev, "SPI read error\n"); 57 return ret; 58 } 59 60 return be16_to_cpu(chip->rx); 61 } 62 63 static ssize_t ad7314_show_temperature(struct device *dev, 64 struct device_attribute *attr, 65 char *buf) 66 { 67 struct ad7314_data *chip = dev_get_drvdata(dev); 68 s16 data; 69 int ret; 70 71 ret = ad7314_spi_read(chip); 72 if (ret < 0) 73 return ret; 74 switch (spi_get_device_id(chip->spi_dev)->driver_data) { 75 case ad7314: 76 data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_OFFSET; 77 data = (data << 6) >> 6; 78 79 return sprintf(buf, "%d\n", 250 * data); 80 case adt7301: 81 case adt7302: 82 /* 83 * Documented as a 13 bit twos complement register 84 * with a sign bit - which is a 14 bit 2's complement 85 * register. 1lsb - 31.25 milli degrees centigrade 86 */ 87 data = ret & ADT7301_TEMP_MASK; 88 data = (data << 2) >> 2; 89 90 return sprintf(buf, "%d\n", 91 DIV_ROUND_CLOSEST(data * 3125, 100)); 92 default: 93 return -EINVAL; 94 } 95 } 96 97 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, 98 ad7314_show_temperature, NULL, 0); 99 100 static struct attribute *ad7314_attributes[] = { 101 &sensor_dev_attr_temp1_input.dev_attr.attr, 102 NULL, 103 }; 104 105 static const struct attribute_group ad7314_group = { 106 .attrs = ad7314_attributes, 107 }; 108 109 static int __devinit ad7314_probe(struct spi_device *spi_dev) 110 { 111 int ret; 112 struct ad7314_data *chip; 113 114 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 115 if (chip == NULL) { 116 ret = -ENOMEM; 117 goto error_ret; 118 } 119 dev_set_drvdata(&spi_dev->dev, chip); 120 121 ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group); 122 if (ret < 0) 123 goto error_free_chip; 124 chip->hwmon_dev = hwmon_device_register(&spi_dev->dev); 125 if (IS_ERR(chip->hwmon_dev)) { 126 ret = PTR_ERR(chip->hwmon_dev); 127 goto error_remove_group; 128 } 129 chip->spi_dev = spi_dev; 130 131 return 0; 132 error_remove_group: 133 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 134 error_free_chip: 135 kfree(chip); 136 error_ret: 137 return ret; 138 } 139 140 static int __devexit ad7314_remove(struct spi_device *spi_dev) 141 { 142 struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev); 143 144 hwmon_device_unregister(chip->hwmon_dev); 145 sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group); 146 kfree(chip); 147 148 return 0; 149 } 150 151 static const struct spi_device_id ad7314_id[] = { 152 { "adt7301", adt7301 }, 153 { "adt7302", adt7302 }, 154 { "ad7314", ad7314 }, 155 { } 156 }; 157 MODULE_DEVICE_TABLE(spi, ad7314_id); 158 159 static struct spi_driver ad7314_driver = { 160 .driver = { 161 .name = "ad7314", 162 .owner = THIS_MODULE, 163 }, 164 .probe = ad7314_probe, 165 .remove = __devexit_p(ad7314_remove), 166 .id_table = ad7314_id, 167 }; 168 169 module_spi_driver(ad7314_driver); 170 171 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 172 MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital" 173 " temperature sensor driver"); 174 MODULE_LICENSE("GPL v2"); 175