1/*
2 * 1-Wire implementation for the ds2781 chip
3 *
4 * Author: Renata Sayakhova <renata@oktetlabs.ru>
5 *
6 * Based on w1-ds2780 driver
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/device.h>
17#include <linux/types.h>
18#include <linux/platform_device.h>
19#include <linux/mutex.h>
20#include <linux/idr.h>
21
22#include "../w1.h"
23#include "../w1_int.h"
24#include "../w1_family.h"
25#include "w1_ds2781.h"
26
27static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
28			size_t count, int io)
29{
30	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
31
32	if (addr > DS2781_DATA_SIZE || addr < 0)
33		return 0;
34
35	count = min_t(int, count, DS2781_DATA_SIZE - addr);
36
37	if (w1_reset_select_slave(sl) == 0) {
38		if (io) {
39			w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
40			w1_write_8(sl->master, addr);
41			w1_write_block(sl->master, buf, count);
42		} else {
43			w1_write_8(sl->master, W1_DS2781_READ_DATA);
44			w1_write_8(sl->master, addr);
45			count = w1_read_block(sl->master, buf, count);
46		}
47	}
48
49	return count;
50}
51
52int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
53			int io)
54{
55	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
56	int ret;
57
58	if (!dev)
59		return -ENODEV;
60
61	mutex_lock(&sl->master->bus_mutex);
62
63	ret = w1_ds2781_do_io(dev, buf, addr, count, io);
64
65	mutex_unlock(&sl->master->bus_mutex);
66
67	return ret;
68}
69EXPORT_SYMBOL(w1_ds2781_io);
70
71int w1_ds2781_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->bus_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->bus_mutex);
86	return 0;
87}
88EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
89
90static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
91			     struct bin_attribute *bin_attr, char *buf,
92			     loff_t off, size_t count)
93{
94	struct device *dev = container_of(kobj, struct device, kobj);
95	return w1_ds2781_io(dev, buf, off, count, 0);
96}
97
98static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
99
100static struct bin_attribute *w1_ds2781_bin_attrs[] = {
101	&bin_attr_w1_slave,
102	NULL,
103};
104
105static const struct attribute_group w1_ds2781_group = {
106	.bin_attrs = w1_ds2781_bin_attrs,
107};
108
109static const struct attribute_group *w1_ds2781_groups[] = {
110	&w1_ds2781_group,
111	NULL,
112};
113
114static DEFINE_IDA(bat_ida);
115
116static int w1_ds2781_add_slave(struct w1_slave *sl)
117{
118	int ret;
119	int id;
120	struct platform_device *pdev;
121
122	id = ida_simple_get(&bat_ida, 0, 0, GFP_KERNEL);
123	if (id < 0) {
124		ret = id;
125		goto noid;
126	}
127
128	pdev = platform_device_alloc("ds2781-battery", id);
129	if (!pdev) {
130		ret = -ENOMEM;
131		goto pdev_alloc_failed;
132	}
133	pdev->dev.parent = &sl->dev;
134
135	ret = platform_device_add(pdev);
136	if (ret)
137		goto pdev_add_failed;
138
139	dev_set_drvdata(&sl->dev, pdev);
140
141	return 0;
142
143pdev_add_failed:
144	platform_device_put(pdev);
145pdev_alloc_failed:
146	ida_simple_remove(&bat_ida, id);
147noid:
148	return ret;
149}
150
151static void w1_ds2781_remove_slave(struct w1_slave *sl)
152{
153	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
154	int id = pdev->id;
155
156	platform_device_unregister(pdev);
157	ida_simple_remove(&bat_ida, id);
158}
159
160static struct w1_family_ops w1_ds2781_fops = {
161	.add_slave    = w1_ds2781_add_slave,
162	.remove_slave = w1_ds2781_remove_slave,
163	.groups       = w1_ds2781_groups,
164};
165
166static struct w1_family w1_ds2781_family = {
167	.fid = W1_FAMILY_DS2781,
168	.fops = &w1_ds2781_fops,
169};
170
171static int __init w1_ds2781_init(void)
172{
173	ida_init(&bat_ida);
174	return w1_register_family(&w1_ds2781_family);
175}
176
177static void __exit w1_ds2781_exit(void)
178{
179	w1_unregister_family(&w1_ds2781_family);
180	ida_destroy(&bat_ida);
181}
182
183module_init(w1_ds2781_init);
184module_exit(w1_ds2781_exit);
185
186MODULE_LICENSE("GPL");
187MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
188MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
189MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));
190