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
  20 #include "../w1.h"
  21 #include "../w1_int.h"
  22 #include "../w1_family.h"
  23 #include "w1_ds2760.h"
  24
  25 static int w1_ds2760_io(struct device *dev, char *buf, int addr, size_t count,
  26                         int io)
  27 {
  28         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  29
  30         if (!dev)
  31                 return 0;
  32
  33         mutex_lock(&sl->master->mutex);
  34
  35         if (addr > DS2760_DATA_SIZE || addr < 0) {
  36                 count = 0;
  37                 goto out;
  38         }
  39         if (addr + count > DS2760_DATA_SIZE)
  40                 count = DS2760_DATA_SIZE - addr;
  41
  42         if (!w1_reset_select_slave(sl)) {
  43                 if (!io) {
  44                         w1_write_8(sl->master, W1_DS2760_READ_DATA);
  45                         w1_write_8(sl->master, addr);
  46                         count = w1_read_block(sl->master, buf, count);
  47                 } else {
  48                         w1_write_8(sl->master, W1_DS2760_WRITE_DATA);
  49                         w1_write_8(sl->master, addr);
  50                         w1_write_block(sl->master, buf, count);
  51                         /* XXX w1_write_block returns void, not n_written */
  52                 }
  53         }
  54
  55 out:
  56         mutex_unlock(&sl->master->mutex);
  57
  58         return count;
  59 }
  60
  61 int w1_ds2760_read(struct device *dev, char *buf, int addr, size_t count)
  62 {
  63         return w1_ds2760_io(dev, buf, addr, count, 0);
  64 }
  65
  66 int w1_ds2760_write(struct device *dev, char *buf, int addr, size_t count)
  67 {
  68         return w1_ds2760_io(dev, buf, addr, count, 1);
  69 }
  70
  71 static int w1_ds2760_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->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->mutex);
  86         return 0;
  87 }
  88
  89 int w1_ds2760_store_eeprom(struct device *dev, int addr)
  90 {
  91         return w1_ds2760_eeprom_cmd(dev, addr, W1_DS2760_COPY_DATA);
  92 }
  93
  94 int w1_ds2760_recall_eeprom(struct device *dev, int addr)
  95 {
  96         return w1_ds2760_eeprom_cmd(dev, addr, W1_DS2760_RECALL_DATA);
  97 }
  98
  99 static ssize_t w1_ds2760_read_bin(struct kobject *kobj,
 100                                   struct bin_attribute *bin_attr,
 101                                   char *buf, loff_t off, size_t count)
 102 {
 103         struct device *dev = container_of(kobj, struct device, kobj);
 104         return w1_ds2760_read(dev, buf, off, count);
 105 }
 106
 107 static struct bin_attribute w1_ds2760_bin_attr = {
 108         .attr = {
 109                 .name = "w1_slave",
 110                 .mode = S_IRUGO,
 111         },
 112         .size = DS2760_DATA_SIZE,
 113         .read = w1_ds2760_read_bin,
 114 };
 115
 116 static DEFINE_IDR(bat_idr);
 117 static DEFINE_MUTEX(bat_idr_lock);
 118
 119 static int new_bat_id(void)
 120 {
 121         int ret;
 122
 123         while (1) {
 124                 int id;
 125
 126                 ret = idr_pre_get(&bat_idr, GFP_KERNEL);
 127                 if (ret == 0)
 128                         return -ENOMEM;
 129
 130                 mutex_lock(&bat_idr_lock);
 131                 ret = idr_get_new(&bat_idr, NULL, &id);
 132                 mutex_unlock(&bat_idr_lock);
 133
 134                 if (ret == 0) {
 135                         ret = id & MAX_ID_MASK;
 136                         break;
 137                 } else if (ret == -EAGAIN) {
 138                         continue;
 139                 } else {
 140                         break;
 141                 }
 142         }
 143
 144         return ret;
 145 }
 146
 147 static void release_bat_id(int id)
 148 {
 149         mutex_lock(&bat_idr_lock);
 150         idr_remove(&bat_idr, id);
 151         mutex_unlock(&bat_idr_lock);
 152 }
 153
 154 static int w1_ds2760_add_slave(struct w1_slave *sl)
 155 {
 156         int ret;
 157         int id;
 158         struct platform_device *pdev;
 159
 160         id = new_bat_id();
 161         if (id < 0) {
 162                 ret = id;
 163                 goto noid;
 164         }
 165
 166         pdev = platform_device_alloc("ds2760-battery", id);
 167         if (!pdev) {
 168                 ret = -ENOMEM;
 169                 goto pdev_alloc_failed;
 170         }
 171         pdev->dev.parent = &sl->dev;
 172
 173         ret = platform_device_add(pdev);
 174         if (ret)
 175                 goto pdev_add_failed;
 176
 177         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 178         if (ret)
 179                 goto bin_attr_failed;
 180
 181         dev_set_drvdata(&sl->dev, pdev);
 182
 183         goto success;
 184
 185 bin_attr_failed:
 186 pdev_add_failed:
 187         platform_device_unregister(pdev);
 188 pdev_alloc_failed:
 189         release_bat_id(id);
 190 noid:
 191 success:
 192         return ret;
 193 }
 194
 195 static void w1_ds2760_remove_slave(struct w1_slave *sl)
 196 {
 197         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 198         int id = pdev->id;
 199
 200         platform_device_unregister(pdev);
 201         release_bat_id(id);
 202         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 203 }
 204
 205 static struct w1_family_ops w1_ds2760_fops = {
 206         .add_slave    = w1_ds2760_add_slave,
 207         .remove_slave = w1_ds2760_remove_slave,
 208 };
 209
 210 static struct w1_family w1_ds2760_family = {
 211         .fid = W1_FAMILY_DS2760,
 212         .fops = &w1_ds2760_fops,
 213 };
 214
 215 static int __init w1_ds2760_init(void)
 216 {
 217         printk(KERN_INFO "1-Wire driver for the DS2760 battery monitor "
 218                " chip  - (c) 2004-2005, Szabolcs Gyurko\n");
 219         idr_init(&bat_idr);
 220         return w1_register_family(&w1_ds2760_family);
 221 }
 222
 223 static void __exit w1_ds2760_exit(void)
 224 {
 225         w1_unregister_family(&w1_ds2760_family);
 226         idr_destroy(&bat_idr);
 227 }
 228
 229 EXPORT_SYMBOL(w1_ds2760_read);
 230 EXPORT_SYMBOL(w1_ds2760_write);
 231 EXPORT_SYMBOL(w1_ds2760_store_eeprom);
 232 EXPORT_SYMBOL(w1_ds2760_recall_eeprom);
 233
 234 module_init(w1_ds2760_init);
 235 module_exit(w1_ds2760_exit);
 236
 237 MODULE_LICENSE("GPL");
 238 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>");
 239 MODULE_DESCRIPTION("1-wire Driver Dallas 2760 battery monitor chip");