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
w1_ds2760_io(struct device * dev,char * buf,int addr,size_t count,int io)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
w1_ds2760_read(struct device * dev,char * buf,int addr,size_t count)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
w1_ds2760_write(struct device * dev,char * buf,int addr,size_t count)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
w1_ds2760_read_bin(struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)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
new_bat_id(void)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
release_bat_id(int id)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
w1_ds2760_add_slave(struct w1_slave * sl)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
w1_ds2760_remove_slave(struct w1_slave * sl)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
w1_ds2760_init(void)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
w1_ds2760_exit(void)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");
210