drivers/w1/slaves/w1_ds2780.c

   1 /*
   2  * 1-Wire implementation for the ds2780 chip
   3  *
   4  * Copyright (C) 2010 Indesign, LLC
   5  *
   6  * Author: Clifton Barnes <cabarnes@indesign-llc.com>
   7  *
   8  * Based on w1-ds2760 driver
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/device.h>
  19 #include <linux/types.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mutex.h>
  22 #include <linux/idr.h>
  23
  24 #include "../w1.h"
  25 #include "../w1_int.h"
  26 #include "../w1_family.h"
  27 #include "w1_ds2780.h"
  28
  29 static int w1_ds2780_do_io(struct device *dev, char *buf, int addr,
  30                         size_t count, int io)
  31 {
  32         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  33
  34         if (addr > DS2780_DATA_SIZE || addr < 0)
  35                 return 0;
  36
  37         count = min_t(int, count, DS2780_DATA_SIZE - addr);
  38
  39         if (w1_reset_select_slave(sl) == 0) {
  40                 if (io) {
  41                         w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
  42                         w1_write_8(sl->master, addr);
  43                         w1_write_block(sl->master, buf, count);
  44                 } else {
  45                         w1_write_8(sl->master, W1_DS2780_READ_DATA);
  46                         w1_write_8(sl->master, addr);
  47                         count = w1_read_block(sl->master, buf, count);
  48                 }
  49         }
  50
  51         return count;
  52 }
  53
  54 int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
  55                         int io)
  56 {
  57         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  58         int ret;
  59
  60         if (!dev)
  61                 return -ENODEV;
  62
  63         mutex_lock(&sl->master->mutex);
  64
  65         ret = w1_ds2780_do_io(dev, buf, addr, count, io);
  66
  67         mutex_unlock(&sl->master->mutex);
  68
  69         return ret;
  70 }
  71 EXPORT_SYMBOL(w1_ds2780_io);
  72
  73 int w1_ds2780_io_nolock(struct device *dev, char *buf, int addr, size_t count,
  74                         int io)
  75 {
  76         int ret;
  77
  78         if (!dev)
  79                 return -ENODEV;
  80
  81         ret = w1_ds2780_do_io(dev, buf, addr, count, io);
  82
  83         return ret;
  84 }
  85 EXPORT_SYMBOL(w1_ds2780_io_nolock);
  86
  87 int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
  88 {
  89         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  90
  91         if (!dev)
  92                 return -EINVAL;
  93
  94         mutex_lock(&sl->master->mutex);
  95
  96         if (w1_reset_select_slave(sl) == 0) {
  97                 w1_write_8(sl->master, cmd);
  98                 w1_write_8(sl->master, addr);
  99         }
 100
 101         mutex_unlock(&sl->master->mutex);
 102         return 0;
 103 }
 104 EXPORT_SYMBOL(w1_ds2780_eeprom_cmd);
 105
 106 static ssize_t w1_ds2780_read_bin(struct file *filp,
 107                                   struct kobject *kobj,
 108                                   struct bin_attribute *bin_attr,
 109                                   char *buf, loff_t off, size_t count)
 110 {
 111         struct device *dev = container_of(kobj, struct device, kobj);
 112         return w1_ds2780_io(dev, buf, off, count, 0);
 113 }
 114
 115 static struct bin_attribute w1_ds2780_bin_attr = {
 116         .attr = {
 117                 .name = "w1_slave",
 118                 .mode = S_IRUGO,
 119         },
 120         .size = DS2780_DATA_SIZE,
 121         .read = w1_ds2780_read_bin,
 122 };
 123
 124 static DEFINE_IDR(bat_idr);
 125 static DEFINE_MUTEX(bat_idr_lock);
 126
 127 static int new_bat_id(void)
 128 {
 129         int ret;
 130
 131         while (1) {
 132                 int id;
 133
 134                 ret = idr_pre_get(&bat_idr, GFP_KERNEL);
 135                 if (ret == 0)
 136                         return -ENOMEM;
 137
 138                 mutex_lock(&bat_idr_lock);
 139                 ret = idr_get_new(&bat_idr, NULL, &id);
 140                 mutex_unlock(&bat_idr_lock);
 141
 142                 if (ret == 0) {
 143                         ret = id & MAX_ID_MASK;
 144                         break;
 145                 } else if (ret == -EAGAIN) {
 146                         continue;
 147                 } else {
 148                         break;
 149                 }
 150         }
 151
 152         return ret;
 153 }
 154
 155 static void release_bat_id(int id)
 156 {
 157         mutex_lock(&bat_idr_lock);
 158         idr_remove(&bat_idr, id);
 159         mutex_unlock(&bat_idr_lock);
 160 }
 161
 162 static int w1_ds2780_add_slave(struct w1_slave *sl)
 163 {
 164         int ret;
 165         int id;
 166         struct platform_device *pdev;
 167
 168         id = new_bat_id();
 169         if (id < 0) {
 170                 ret = id;
 171                 goto noid;
 172         }
 173
 174         pdev = platform_device_alloc("ds2780-battery", id);
 175         if (!pdev) {
 176                 ret = -ENOMEM;
 177                 goto pdev_alloc_failed;
 178         }
 179         pdev->dev.parent = &sl->dev;
 180
 181         ret = platform_device_add(pdev);
 182         if (ret)
 183                 goto pdev_add_failed;
 184
 185         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
 186         if (ret)
 187                 goto bin_attr_failed;
 188
 189         dev_set_drvdata(&sl->dev, pdev);
 190
 191         return 0;
 192
 193 bin_attr_failed:
 194 pdev_add_failed:
 195         platform_device_unregister(pdev);
 196 pdev_alloc_failed:
 197         release_bat_id(id);
 198 noid:
 199         return ret;
 200 }
 201
 202 static void w1_ds2780_remove_slave(struct w1_slave *sl)
 203 {
 204         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 205         int id = pdev->id;
 206
 207         platform_device_unregister(pdev);
 208         release_bat_id(id);
 209         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
 210 }
 211
 212 static struct w1_family_ops w1_ds2780_fops = {
 213         .add_slave    = w1_ds2780_add_slave,
 214         .remove_slave = w1_ds2780_remove_slave,
 215 };
 216
 217 static struct w1_family w1_ds2780_family = {
 218         .fid = W1_FAMILY_DS2780,
 219         .fops = &w1_ds2780_fops,
 220 };
 221
 222 static int __init w1_ds2780_init(void)
 223 {
 224         idr_init(&bat_idr);
 225         return w1_register_family(&w1_ds2780_family);
 226 }
 227
 228 static void __exit w1_ds2780_exit(void)
 229 {
 230         w1_unregister_family(&w1_ds2780_family);
 231         idr_destroy(&bat_idr);
 232 }
 233
 234 module_init(w1_ds2780_init);
 235 module_exit(w1_ds2780_exit);
 236
 237 MODULE_LICENSE("GPL");
 238 MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
 239 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");