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 ssize_t w1_ds2760_read_bin(struct kobject *kobj,
  72                                   struct bin_attribute *bin_attr,
  73                                   char *buf, loff_t off, size_t count)
  74 {
  75         struct device *dev = container_of(kobj, struct device, kobj);
  76         return w1_ds2760_read(dev, buf, off, count);
  77 }
  78
  79 static struct bin_attribute w1_ds2760_bin_attr = {
  80         .attr = {
  81                 .name = "w1_slave",
  82                 .mode = S_IRUGO,
  83         },
  84         .size = DS2760_DATA_SIZE,
  85         .read = w1_ds2760_read_bin,
  86 };
  87
  88 static DEFINE_IDR(bat_idr);
  89 static DEFINE_MUTEX(bat_idr_lock);
  90
  91 static int new_bat_id(void)
  92 {
  93         int ret;
  94
  95         while (1) {
  96                 int id;
  97
  98                 ret = idr_pre_get(&bat_idr, GFP_KERNEL);
  99                 if (ret == 0)
 100                         return -ENOMEM;
 101
 102                 mutex_lock(&bat_idr_lock);
 103                 ret = idr_get_new(&bat_idr, NULL, &id);
 104                 mutex_unlock(&bat_idr_lock);
 105
 106                 if (ret == 0) {
 107                         ret = id & MAX_ID_MASK;
 108                         break;
 109                 } else if (ret == -EAGAIN) {
 110                         continue;
 111                 } else {
 112                         break;
 113                 }
 114         }
 115
 116         return ret;
 117 }
 118
 119 static void release_bat_id(int id)
 120 {
 121         mutex_lock(&bat_idr_lock);
 122         idr_remove(&bat_idr, id);
 123         mutex_unlock(&bat_idr_lock);
 124 }
 125
 126 static int w1_ds2760_add_slave(struct w1_slave *sl)
 127 {
 128         int ret;
 129         int id;
 130         struct platform_device *pdev;
 131
 132         id = new_bat_id();
 133         if (id < 0) {
 134                 ret = id;
 135                 goto noid;
 136         }
 137
 138         pdev = platform_device_alloc("ds2760-battery", id);
 139         if (!pdev) {
 140                 ret = -ENOMEM;
 141                 goto pdev_alloc_failed;
 142         }
 143         pdev->dev.parent = &sl->dev;
 144
 145         ret = platform_device_add(pdev);
 146         if (ret)
 147                 goto pdev_add_failed;
 148
 149         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 150         if (ret)
 151                 goto bin_attr_failed;
 152
 153         dev_set_drvdata(&sl->dev, pdev);
 154
 155         goto success;
 156
 157 bin_attr_failed:
 158 pdev_add_failed:
 159         platform_device_unregister(pdev);
 160 pdev_alloc_failed:
 161         release_bat_id(id);
 162 noid:
 163 success:
 164         return ret;
 165 }
 166
 167 static void w1_ds2760_remove_slave(struct w1_slave *sl)
 168 {
 169         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 170         int id = pdev->id;
 171
 172         platform_device_unregister(pdev);
 173         release_bat_id(id);
 174         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
 175 }
 176
 177 static struct w1_family_ops w1_ds2760_fops = {
 178         .add_slave    = w1_ds2760_add_slave,
 179         .remove_slave = w1_ds2760_remove_slave,
 180 };
 181
 182 static struct w1_family w1_ds2760_family = {
 183         .fid = W1_FAMILY_DS2760,
 184         .fops = &w1_ds2760_fops,
 185 };
 186
 187 static int __init w1_ds2760_init(void)
 188 {
 189         printk(KERN_INFO "1-Wire driver for the DS2760 battery monitor "
 190                " chip  - (c) 2004-2005, Szabolcs Gyurko\n");
 191         idr_init(&bat_idr);
 192         return w1_register_family(&w1_ds2760_family);
 193 }
 194
 195 static void __exit w1_ds2760_exit(void)
 196 {
 197         w1_unregister_family(&w1_ds2760_family);
 198         idr_destroy(&bat_idr);
 199 }
 200
 201 EXPORT_SYMBOL(w1_ds2760_read);
 202 EXPORT_SYMBOL(w1_ds2760_write);
 203
 204 module_init(w1_ds2760_init);
 205 module_exit(w1_ds2760_exit);
 206
 207 MODULE_LICENSE("GPL");
 208 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>");
 209 MODULE_DESCRIPTION("1-wire Driver Dallas 2760 battery monitor chip");