drivers/w1/slaves/w1_ds2760.c

   1 /*
   2  * 1-Wire implementation for the ds2760 chip
   3  *
   4  * Copyright © 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
   5  *
   6  * Use consistent with the GNU GPL is permitted,
   7  * provided that this copyright notice is
   8  * preserved in its entirety in all copies and derived works.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/device.h>
  15 #include <linux/types.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/mutex.h>
  18 #include <linux/idr.h>
  19 #include <linux/gfp.h>
  20
  21 #include "../w1.h"
  22 #include "../w1_int.h"
  23 #include "../w1_family.h"
  24 #include "w1_ds2760.h"
  25
  26 static int w1_ds2760_io(struct device *dev, char *buf, int addr, size_t count,
  27                         int io)
  28 {
  29         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  30
  31         if (!dev)
  32                 return 0;
  33
  34         mutex_lock(&sl->master->mutex);
  35
  36         if (addr > DS2760_DATA_SIZE || addr < 0) {
  37                 count = 0;
  38                 goto out;
  39         }
  40         if (addr + count > DS2760_DATA_SIZE)
  41                 count = DS2760_DATA_SIZE - addr;
  42
  43         if (!w1_reset_select_slave(sl)) {
  44                 if (!io) {
  45                         w1_write_8(sl->master, W1_DS2760_READ_DATA);
  46                         w1_write_8(sl->master, addr);
  47                         count = w1_read_block(sl->master, buf, count);
  48                 } else {
  49                         w1_write_8(sl->master, W1_DS2760_WRITE_DATA);
  50                         w1_write_8(sl->master, addr);
  51                         w1_write_block(sl->master, buf, count);
  52                         /* XXX w1_write_block returns void, not n_written */
  53                 }
  54         }
  55
  56 out:
  57         mutex_unlock(&sl->master->mutex);
  58
  59         return count;
  60 }
  61
  62 int w1_ds2760_read(struct device *dev, char *buf, int addr, size_t count)
  63 {
  64         return w1_ds2760_io(dev, buf, addr, count, 0);
  65 }
  66
  67 int w1_ds2760_write(struct device *dev, char *buf, int addr, size_t count)
  68 {
  69         return w1_ds2760_io(dev, buf, addr, count, 1);
  70 }
  71
  72 static int w1_ds2760_eeprom_cmd(struct device *dev, int addr, int cmd)
  73 {
  74         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  75
  76         if (!dev)
  77                 return -EINVAL;
  78
  79         mutex_lock(&sl->master->mutex);
  80
  81         if (w1_reset_select_slave(sl) == 0) {
  82                 w1_write_8(sl->master, cmd);
  83                 w1_write_8(sl->master, addr);
  84         }
  85
  86         mutex_unlock(&sl->master->mutex);
  87         return 0;
  88 }
  89
  90 int w1_ds2760_store_eeprom(struct device *dev, int addr)
  91 {
  92         return w1_ds2760_eeprom_cmd(dev, addr, W1_DS2760_COPY_DATA);
  93 }
  94
  95 int w1_ds2760_recall_eeprom(struct device *dev, int addr)
  96 {
  97         return w1_ds2760_eeprom_cmd(dev, addr, W1_DS2760_RECALL_DATA);
  98 }
  99
 100 static ssize_t w1_ds2760_read_bin(struct file *filp, struct kobject *kobj,
 101                                   struct bin_attribute *bin_attr,
 102                                   char *buf, loff_t off, size_t count)
 103 {
 104         struct device *dev = container_of(kobj, struct device, kobj);
 105         return w1_ds2760_read(dev, buf, off, count);
 106 }
 107
 108 static struct bin_attribute w1_ds2760_bin_attr = {
 109         .attr = {
 110                 .name = "w1_slave",
 111                 .mode = S_IRUGO,
 112         },
 113         .size = DS2760_DATA_SIZE,
 114         .read = w1_ds2760_read_bin,
 115 };
 116
 117 static DEFINE_IDR(bat_idr);
 118 static DEFINE_MUTEX(bat_idr_lock);
 119
 120 static int new_bat_id(void)
 121 {
 122         int ret;
 123
 124         while (1) {
 125                 int id;
 126
 127                 ret = idr_pre_get(&bat_idr, GFP_KERNEL);
 128                 if (ret == 0)
 129                         return -ENOMEM;
 130
 131                 mutex_lock(&bat_idr_lock);
 132                 ret = idr_get_new(&bat_idr, NULL, &id);
 133                 mutex_unlock(&bat_idr_lock);
 134
 135                 if (ret == 0) {
 136                         ret = id & MAX_ID_MASK;
 137                         break;
 138                 } else if (ret == -EAGAIN) {
 139                         continue;
 140                 } else {
 141                         break;
 142                 }
 143         }
 144
 145         return ret;
 146 }
 147
 148 static void release_bat_id(int id)
 149 {
 150         mutex_lock(&bat_idr_lock);
 151         idr_remove(&bat_idr, id);
 152         mutex_unlock(&bat_idr_lock);
 153 }
 154
 155 static int w1_ds2760_add_slave(struct w1_slave *sl)
 156 {
 157         int ret;
 158         int id;
 159         struct platform_device *pdev;
 160
 161         id = new_bat_id();
 162         if (id < 0) {
 163                 ret = id;
 164                 goto noid;
 165         }
 166
 167         pdev = platform_device_alloc("ds2760-battery", id);
 168         if (!pdev) {
 169                 ret = -ENOMEM;
 170                 goto pdev_alloc_failed;
 171         }
 172         pdev->dev.parent = &sl->dev;
 173
 174         ret = platform_device_add(pdev);
 175         if (ret)
 176                 goto pdev_add_failed;
 177
 178         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 179         if (ret)
 180                 goto bin_attr_failed;
 181
 182         dev_set_drvdata(&sl->dev, pdev);
 183
 184         goto success;
 185
 186 bin_attr_failed:
 187 pdev_add_failed:
 188         platform_device_unregister(pdev);
 189 pdev_alloc_failed:
 190         release_bat_id(id);
 191 noid:
 192 success:
 193         return ret;
 194 }
 195
 196 static void w1_ds2760_remove_slave(struct w1_slave *sl)
 197 {
 198         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 199         int id = pdev->id;
 200
 201         platform_device_unregister(pdev);
 202         release_bat_id(id);
 203         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 204 }
 205
 206 static struct w1_family_ops w1_ds2760_fops = {
 207         .add_slave    = w1_ds2760_add_slave,
 208         .remove_slave = w1_ds2760_remove_slave,
 209 };
 210
 211 static struct w1_family w1_ds2760_family = {
 212         .fid = W1_FAMILY_DS2760,
 213         .fops = &w1_ds2760_fops,
 214 };
 215
 216 static int __init w1_ds2760_init(void)
 217 {
 218         printk(KERN_INFO "1-Wire driver for the DS2760 battery monitor "
 219                " chip  - (c) 2004-2005, Szabolcs Gyurko\n");
 220         idr_init(&bat_idr);
 221         return w1_register_family(&w1_ds2760_family);
 222 }
 223
 224 static void __exit w1_ds2760_exit(void)
 225 {
 226         w1_unregister_family(&w1_ds2760_family);
 227         idr_destroy(&bat_idr);
 228 }
 229
 230 EXPORT_SYMBOL(w1_ds2760_read);
 231 EXPORT_SYMBOL(w1_ds2760_write);
 232 EXPORT_SYMBOL(w1_ds2760_store_eeprom);
 233 EXPORT_SYMBOL(w1_ds2760_recall_eeprom);
 234
 235 module_init(w1_ds2760_init);
 236 module_exit(w1_ds2760_exit);
 237
 238 MODULE_LICENSE("GPL");
 239 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>");
 240 MODULE_DESCRIPTION("1-wire Driver Dallas 2760 battery monitor chip");