88a37fbccc3fd2da678c5ae579669e4a6ebf2c4d
[linux-2.6.git] / 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, char *buf, loff_t off,
72                                   size_t count)
73 {
74         struct device *dev = container_of(kobj, struct device, kobj);
75         return w1_ds2760_read(dev, buf, off, count);
76 }
77
78 static struct bin_attribute w1_ds2760_bin_attr = {
79         .attr = {
80                 .name = "w1_slave",
81                 .mode = S_IRUGO,
82                 .owner = THIS_MODULE,
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         return;
126 }
127
128 static int w1_ds2760_add_slave(struct w1_slave *sl)
129 {
130         int ret;
131         int id;
132         struct platform_device *pdev;
133
134         id = new_bat_id();
135         if (id < 0) {
136                 ret = id;
137                 goto noid;
138         }
139
140         pdev = platform_device_alloc("ds2760-battery", id);
141         if (!pdev) {
142                 ret = -ENOMEM;
143                 goto pdev_alloc_failed;
144         }
145         pdev->dev.parent = &sl->dev;
146
147         ret = platform_device_add(pdev);
148         if (ret)
149                 goto pdev_add_failed;
150
151         ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
152         if (ret)
153                 goto bin_attr_failed;
154
155         dev_set_drvdata(&sl->dev, pdev);
156
157         goto success;
158
159 bin_attr_failed:
160 pdev_add_failed:
161         platform_device_unregister(pdev);
162 pdev_alloc_failed:
163         release_bat_id(id);
164 noid:
165 success:
166         return ret;
167 }
168
169 static void w1_ds2760_remove_slave(struct w1_slave *sl)
170 {
171         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
172         int id = pdev->id;
173
174         platform_device_unregister(pdev);
175         release_bat_id(id);
176         sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2760_bin_attr);
177
178         return;
179 }
180
181 static struct w1_family_ops w1_ds2760_fops = {
182         .add_slave    = w1_ds2760_add_slave,
183         .remove_slave = w1_ds2760_remove_slave,
184 };
185
186 static struct w1_family w1_ds2760_family = {
187         .fid = W1_FAMILY_DS2760,
188         .fops = &w1_ds2760_fops,
189 };
190
191 static int __init w1_ds2760_init(void)
192 {
193         printk(KERN_INFO "1-Wire driver for the DS2760 battery monitor "
194                " chip  - (c) 2004-2005, Szabolcs Gyurko\n");
195         idr_init(&bat_idr);
196         return w1_register_family(&w1_ds2760_family);
197 }
198
199 static void __exit w1_ds2760_exit(void)
200 {
201         w1_unregister_family(&w1_ds2760_family);
202         idr_destroy(&bat_idr);
203 }
204
205 EXPORT_SYMBOL(w1_ds2760_read);
206 EXPORT_SYMBOL(w1_ds2760_write);
207
208 module_init(w1_ds2760_init);
209 module_exit(w1_ds2760_exit);
210
211 MODULE_LICENSE("GPL");
212 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>");
213 MODULE_DESCRIPTION("1-wire Driver Dallas 2760 battery monitor chip");