1 /* 2 * 1-Wire implementation for the ds2781 chip 3 * 4 * Author: Renata Sayakhova <renata@oktetlabs.ru> 5 * 6 * Based on w1-ds2780 driver 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/device.h> 17 #include <linux/types.h> 18 #include <linux/platform_device.h> 19 #include <linux/mutex.h> 20 21 #include <linux/w1.h> 22 23 #include "w1_ds2781.h" 24 25 #define W1_FAMILY_DS2781 0x3D 26 27 static int w1_ds2781_do_io(struct device *dev, char *buf, int addr, 28 size_t count, int io) 29 { 30 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 31 32 if (addr > DS2781_DATA_SIZE || addr < 0) 33 return 0; 34 35 count = min_t(int, count, DS2781_DATA_SIZE - addr); 36 37 if (w1_reset_select_slave(sl) == 0) { 38 if (io) { 39 w1_write_8(sl->master, W1_DS2781_WRITE_DATA); 40 w1_write_8(sl->master, addr); 41 w1_write_block(sl->master, buf, count); 42 } else { 43 w1_write_8(sl->master, W1_DS2781_READ_DATA); 44 w1_write_8(sl->master, addr); 45 count = w1_read_block(sl->master, buf, count); 46 } 47 } 48 49 return count; 50 } 51 52 int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count, 53 int io) 54 { 55 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 56 int ret; 57 58 if (!dev) 59 return -ENODEV; 60 61 mutex_lock(&sl->master->bus_mutex); 62 63 ret = w1_ds2781_do_io(dev, buf, addr, count, io); 64 65 mutex_unlock(&sl->master->bus_mutex); 66 67 return ret; 68 } 69 EXPORT_SYMBOL(w1_ds2781_io); 70 71 int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd) 72 { 73 struct w1_slave *sl = container_of(dev, struct w1_slave, dev); 74 75 if (!dev) 76 return -EINVAL; 77 78 mutex_lock(&sl->master->bus_mutex); 79 80 if (w1_reset_select_slave(sl) == 0) { 81 w1_write_8(sl->master, cmd); 82 w1_write_8(sl->master, addr); 83 } 84 85 mutex_unlock(&sl->master->bus_mutex); 86 return 0; 87 } 88 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd); 89 90 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj, 91 struct bin_attribute *bin_attr, char *buf, 92 loff_t off, size_t count) 93 { 94 struct device *dev = container_of(kobj, struct device, kobj); 95 return w1_ds2781_io(dev, buf, off, count, 0); 96 } 97 98 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE); 99 100 static struct bin_attribute *w1_ds2781_bin_attrs[] = { 101 &bin_attr_w1_slave, 102 NULL, 103 }; 104 105 static const struct attribute_group w1_ds2781_group = { 106 .bin_attrs = w1_ds2781_bin_attrs, 107 }; 108 109 static const struct attribute_group *w1_ds2781_groups[] = { 110 &w1_ds2781_group, 111 NULL, 112 }; 113 114 static int w1_ds2781_add_slave(struct w1_slave *sl) 115 { 116 int ret; 117 struct platform_device *pdev; 118 119 pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO); 120 if (!pdev) 121 return -ENOMEM; 122 pdev->dev.parent = &sl->dev; 123 124 ret = platform_device_add(pdev); 125 if (ret) 126 goto pdev_add_failed; 127 128 dev_set_drvdata(&sl->dev, pdev); 129 130 return 0; 131 132 pdev_add_failed: 133 platform_device_put(pdev); 134 135 return ret; 136 } 137 138 static void w1_ds2781_remove_slave(struct w1_slave *sl) 139 { 140 struct platform_device *pdev = dev_get_drvdata(&sl->dev); 141 142 platform_device_unregister(pdev); 143 } 144 145 static struct w1_family_ops w1_ds2781_fops = { 146 .add_slave = w1_ds2781_add_slave, 147 .remove_slave = w1_ds2781_remove_slave, 148 .groups = w1_ds2781_groups, 149 }; 150 151 static struct w1_family w1_ds2781_family = { 152 .fid = W1_FAMILY_DS2781, 153 .fops = &w1_ds2781_fops, 154 }; 155 module_w1_family(w1_ds2781_family); 156 157 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>"); 158 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC"); 159 MODULE_LICENSE("GPL"); 160 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781)); 161