1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * 1-Wire implementation for the ds2781 chip
4 *
5 * Author: Renata Sayakhova <renata@oktetlabs.ru>
6 *
7 * Based on w1-ds2780 driver
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/device.h>
13#include <linux/types.h>
14#include <linux/platform_device.h>
15#include <linux/mutex.h>
16
17#include <linux/w1.h>
18
19#include "w1_ds2781.h"
20
21#define W1_FAMILY_DS2781	0x3D
22
23static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
24			size_t count, int io)
25{
26	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
27
28	if (addr > DS2781_DATA_SIZE || addr < 0)
29		return 0;
30
31	count = min_t(int, count, DS2781_DATA_SIZE - addr);
32
33	if (w1_reset_select_slave(sl) == 0) {
34		if (io) {
35			w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
36			w1_write_8(sl->master, addr);
37			w1_write_block(sl->master, buf, count);
38		} else {
39			w1_write_8(sl->master, W1_DS2781_READ_DATA);
40			w1_write_8(sl->master, addr);
41			count = w1_read_block(sl->master, buf, count);
42		}
43	}
44
45	return count;
46}
47
48int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
49			int io)
50{
51	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
52	int ret;
53
54	if (!dev)
55		return -ENODEV;
56
57	mutex_lock(&sl->master->bus_mutex);
58
59	ret = w1_ds2781_do_io(dev, buf, addr, count, io);
60
61	mutex_unlock(&sl->master->bus_mutex);
62
63	return ret;
64}
65EXPORT_SYMBOL(w1_ds2781_io);
66
67int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
68{
69	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
70
71	if (!dev)
72		return -EINVAL;
73
74	mutex_lock(&sl->master->bus_mutex);
75
76	if (w1_reset_select_slave(sl) == 0) {
77		w1_write_8(sl->master, cmd);
78		w1_write_8(sl->master, addr);
79	}
80
81	mutex_unlock(&sl->master->bus_mutex);
82	return 0;
83}
84EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
85
86static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
87			     struct bin_attribute *bin_attr, char *buf,
88			     loff_t off, size_t count)
89{
90	struct device *dev = container_of(kobj, struct device, kobj);
91	return w1_ds2781_io(dev, buf, off, count, 0);
92}
93
94static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
95
96static struct bin_attribute *w1_ds2781_bin_attrs[] = {
97	&bin_attr_w1_slave,
98	NULL,
99};
100
101static const struct attribute_group w1_ds2781_group = {
102	.bin_attrs = w1_ds2781_bin_attrs,
103};
104
105static const struct attribute_group *w1_ds2781_groups[] = {
106	&w1_ds2781_group,
107	NULL,
108};
109
110static int w1_ds2781_add_slave(struct w1_slave *sl)
111{
112	int ret;
113	struct platform_device *pdev;
114
115	pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
116	if (!pdev)
117		return -ENOMEM;
118	pdev->dev.parent = &sl->dev;
119
120	ret = platform_device_add(pdev);
121	if (ret)
122		goto pdev_add_failed;
123
124	dev_set_drvdata(&sl->dev, pdev);
125
126	return 0;
127
128pdev_add_failed:
129	platform_device_put(pdev);
130
131	return ret;
132}
133
134static void w1_ds2781_remove_slave(struct w1_slave *sl)
135{
136	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
137
138	platform_device_unregister(pdev);
139}
140
141static const struct w1_family_ops w1_ds2781_fops = {
142	.add_slave    = w1_ds2781_add_slave,
143	.remove_slave = w1_ds2781_remove_slave,
144	.groups       = w1_ds2781_groups,
145};
146
147static struct w1_family w1_ds2781_family = {
148	.fid = W1_FAMILY_DS2781,
149	.fops = &w1_ds2781_fops,
150};
151module_w1_family(w1_ds2781_family);
152
153MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
154MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
155MODULE_LICENSE("GPL");
156MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));
157