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 | |
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 | |
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(lock: &sl->master->bus_mutex); |
62 | |
63 | return ret; |
64 | } |
65 | EXPORT_SYMBOL(w1_ds2781_io); |
66 | |
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(lock: &sl->master->bus_mutex); |
82 | return 0; |
83 | } |
84 | EXPORT_SYMBOL(w1_ds2781_eeprom_cmd); |
85 | |
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 = kobj_to_dev(kobj); |
91 | |
92 | return w1_ds2781_io(dev, buf, off, count, 0); |
93 | } |
94 | |
95 | static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE); |
96 | |
97 | static struct bin_attribute *w1_ds2781_bin_attrs[] = { |
98 | &bin_attr_w1_slave, |
99 | NULL, |
100 | }; |
101 | |
102 | static const struct attribute_group w1_ds2781_group = { |
103 | .bin_attrs = w1_ds2781_bin_attrs, |
104 | }; |
105 | |
106 | static const struct attribute_group *w1_ds2781_groups[] = { |
107 | &w1_ds2781_group, |
108 | NULL, |
109 | }; |
110 | |
111 | static int w1_ds2781_add_slave(struct w1_slave *sl) |
112 | { |
113 | int ret; |
114 | struct platform_device *pdev; |
115 | |
116 | pdev = platform_device_alloc(name: "ds2781-battery" , PLATFORM_DEVID_AUTO); |
117 | if (!pdev) |
118 | return -ENOMEM; |
119 | pdev->dev.parent = &sl->dev; |
120 | |
121 | ret = platform_device_add(pdev); |
122 | if (ret) |
123 | goto pdev_add_failed; |
124 | |
125 | dev_set_drvdata(dev: &sl->dev, data: pdev); |
126 | |
127 | return 0; |
128 | |
129 | pdev_add_failed: |
130 | platform_device_put(pdev); |
131 | |
132 | return ret; |
133 | } |
134 | |
135 | static void w1_ds2781_remove_slave(struct w1_slave *sl) |
136 | { |
137 | struct platform_device *pdev = dev_get_drvdata(dev: &sl->dev); |
138 | |
139 | platform_device_unregister(pdev); |
140 | } |
141 | |
142 | static const struct w1_family_ops w1_ds2781_fops = { |
143 | .add_slave = w1_ds2781_add_slave, |
144 | .remove_slave = w1_ds2781_remove_slave, |
145 | .groups = w1_ds2781_groups, |
146 | }; |
147 | |
148 | static struct w1_family w1_ds2781_family = { |
149 | .fid = W1_FAMILY_DS2781, |
150 | .fops = &w1_ds2781_fops, |
151 | }; |
152 | module_w1_family(w1_ds2781_family); |
153 | |
154 | MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>" ); |
155 | MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC" ); |
156 | MODULE_LICENSE("GPL" ); |
157 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781)); |
158 | |