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 int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
  30                         int io)
  31 {
  32         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  33
  34         if (!dev)
  35                 return -ENODEV;
  36
  37         mutex_lock(&sl->master->mutex);
  38
  39         if (addr > DS2780_DATA_SIZE || addr < 0) {
  40                 count = 0;
  41                 goto out;
  42         }
  43         count = min_t(int, count, DS2780_DATA_SIZE - addr);
  44
  45         if (w1_reset_select_slave(sl) == 0) {
  46                 if (io) {
  47                         w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
  48                         w1_write_8(sl->master, addr);
  49                         w1_write_block(sl->master, buf, count);
  50                         /* XXX w1_write_block returns void, not n_written */
  51                 } else {
  52                         w1_write_8(sl->master, W1_DS2780_READ_DATA);
  53                         w1_write_8(sl->master, addr);
  54                         count = w1_read_block(sl->master, buf, count);
  55                 }
  56         }
  57
  58 out:
  59         mutex_unlock(&sl->master->mutex);
  60
  61         return count;
  62 }
  63 EXPORT_SYMBOL(w1_ds2780_io);
  64
  65 int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
  66 {
  67         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  68
  69         if (!dev)
  70                 return -EINVAL;
  71
  72         mutex_lock(&sl->master->mutex);
  73
  74         if (w1_reset_select_slave(sl) == 0) {
  75                 w1_write_8(sl->master, cmd);
  76                 w1_write_8(sl->master, addr);
  77         }
  78
  79         mutex_unlock(&sl->master->mutex);
  80         return 0;
  81 }
  82 EXPORT_SYMBOL(w1_ds2780_eeprom_cmd);
  83
  84 static ssize_t w1_ds2780_read_bin(struct file *filp,
  85                                   struct kobject *kobj,
  86                                   struct bin_attribute *bin_attr,
  87                                   char *buf, loff_t off, size_t count)
  88 {
  89         struct device *dev = container_of(kobj, struct device, kobj);
  90         return w1_ds2780_io(dev, buf, off, count, 0);
  91 }
  92
  93 static struct bin_attribute w1_ds2780_bin_attr = {
  94         .attr = {
  95                 .name = "w1_slave",
  96                 .mode = S_IRUGO,
  97         },
  98         .size = DS2780_DATA_SIZE,
  99         .read = w1_ds2780_read_bin,
 100 };
 101
 102 static DEFINE_IDR(bat_idr);
 103 static DEFINE_MUTEX(bat_idr_lock);
 104
 105 static int new_bat_id(void)
 106 {
 107         int ret;
 108
 109         while (1) {
 110                 int id;
 111
 112                 ret = idr_pre_get(&bat_idr, GFP_KERNEL);
 113                 if (ret == 0)
 114                         return -ENOMEM;
 115
 116                 mutex_lock(&bat_idr_lock);
 117                 ret = idr_get_new(&bat_idr, NULL, &id);
 118                 mutex_unlock(&bat_idr_lock);
 119
 120                 if (ret == 0) {
 121                         ret = id & MAX_ID_MASK;
 122                         break;
 123                 } else if (ret == -EAGAIN) {
 124                         continue;
 125                 } else {
 126                         break;
 127                 }
 128         }
 129
 130         return ret;
 131 }
 132
 133 static void release_bat_id(int id)
 134 {
 135         mutex_lock(&bat_idr_lock);
 136         idr_remove(&bat_idr, id);
 137         mutex_unlock(&bat_idr_lock);
 138 }
 139
 140 static int w1_ds2780_add_slave(struct w1_slave *sl)
 141 {
 142         int ret;
 143         int id;
 144         struct platform_device *pdev;
 145
 146         id = new_bat_id();
 147         if (id < 0) {
 148                 ret = id;
 149                 goto noid;
 150         }
 151
 152         pdev = platform_device_alloc("ds2780-battery", id);
 153         if (!pdev) {
 154                 ret = -ENOMEM;
 155                 goto pdev_alloc_failed;
 156         }
 157         pdev->dev.parent = &sl->dev;
 158
 159         ret = platform_device_add(pdev);
 160         if (ret)
 161                 goto pdev_add_failed;
 162
 163         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
 164         if (ret)
 165                 goto bin_attr_failed;
 166
 167         dev_set_drvdata(&sl->dev, pdev);
 168
 169         return 0;
 170
 171 bin_attr_failed:
 172 pdev_add_failed:
 173         platform_device_unregister(pdev);
 174 pdev_alloc_failed:
 175         release_bat_id(id);
 176 noid:
 177         return ret;
 178 }
 179
 180 static void w1_ds2780_remove_slave(struct w1_slave *sl)
 181 {
 182         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 183         int id = pdev->id;
 184
 185         platform_device_unregister(pdev);
 186         release_bat_id(id);
 187         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
 188 }
 189
 190 static struct w1_family_ops w1_ds2780_fops = {
 191         .add_slave    = w1_ds2780_add_slave,
 192         .remove_slave = w1_ds2780_remove_slave,
 193 };
 194
 195 static struct w1_family w1_ds2780_family = {
 196         .fid = W1_FAMILY_DS2780,
 197         .fops = &w1_ds2780_fops,
 198 };
 199
 200 static int __init w1_ds2780_init(void)
 201 {
 202         idr_init(&bat_idr);
 203         return w1_register_family(&w1_ds2780_family);
 204 }
 205
 206 static void __exit w1_ds2780_exit(void)
 207 {
 208         w1_unregister_family(&w1_ds2780_family);
 209         idr_destroy(&bat_idr);
 210 }
 211
 212 module_init(w1_ds2780_init);
 213 module_exit(w1_ds2780_exit);
 214
 215 MODULE_LICENSE("GPL");
 216 MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
 217 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");