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
w1_ds2781_do_io(struct device * dev,char * buf,int addr,size_t count,int io)23 static 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
w1_ds2781_io(struct device * dev,char * buf,int addr,size_t count,int io)48 int 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 }
65 EXPORT_SYMBOL(w1_ds2781_io);
66
w1_ds2781_eeprom_cmd(struct device * dev,int addr,int cmd)67 int 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 }
84 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
85
w1_slave_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)86 static 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
94 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
95
96 static struct bin_attribute *w1_ds2781_bin_attrs[] = {
97 &bin_attr_w1_slave,
98 NULL,
99 };
100
101 static const struct attribute_group w1_ds2781_group = {
102 .bin_attrs = w1_ds2781_bin_attrs,
103 };
104
105 static const struct attribute_group *w1_ds2781_groups[] = {
106 &w1_ds2781_group,
107 NULL,
108 };
109
w1_ds2781_add_slave(struct w1_slave * sl)110 static 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
128 pdev_add_failed:
129 platform_device_put(pdev);
130
131 return ret;
132 }
133
w1_ds2781_remove_slave(struct w1_slave * sl)134 static 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
141 static 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
147 static struct w1_family w1_ds2781_family = {
148 .fid = W1_FAMILY_DS2781,
149 .fops = &w1_ds2781_fops,
150 };
151 module_w1_family(w1_ds2781_family);
152
153 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
154 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
155 MODULE_LICENSE("GPL");
156 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));
157
