tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * linux/drivers/acorn/char/pcf8583.c
3 *
4 * Copyright (C) 2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Driver for PCF8583 RTC & RAM chip
11 */
12#include <linux/i2c.h>
13#include <linux/slab.h>
14#include <linux/string.h>
15#include <linux/mc146818rtc.h>
16#include <linux/init.h>
17#include <linux/errno.h>
18#include <linux/bcd.h>
19
20#include "pcf8583.h"
21
22static struct i2c_driver pcf8583_driver;
23
24static unsigned short ignore[] = { I2C_CLIENT_END };
25static unsigned short normal_addr[] = { 0x50, I2C_CLIENT_END };
26
27static struct i2c_client_address_data addr_data = {
28 .normal_i2c = normal_addr,
29 .normal_i2c_range = ignore,
30 .probe = ignore,
31 .probe_range = ignore,
32 .ignore = ignore,
33 .ignore_range = ignore,
34 .force = ignore,
35};
36
37#define DAT(x) ((unsigned int)(x->dev.driver_data))
38
39static int
40pcf8583_attach(struct i2c_adapter *adap, int addr, int kind)
41{
42 struct i2c_client *c;
43 unsigned char buf[1], ad[1] = { 0 };
44 struct i2c_msg msgs[2] = {
45 { addr, 0, 1, ad },
46 { addr, I2C_M_RD, 1, buf }
47 };
48
49 c = kmalloc(sizeof(*c), GFP_KERNEL);
50 if (!c)
51 return -ENOMEM;
52
53 memset(c, 0, sizeof(*c));
54 c->addr = addr;
55 c->adapter = adap;
56 c->driver = &pcf8583_driver;
57
58 if (i2c_transfer(c->adapter, msgs, 2) == 2)
59 DAT(c) = buf[0];
60
61 return i2c_attach_client(c);
62}
63
64static int
65pcf8583_probe(struct i2c_adapter *adap)
66{
67 return i2c_probe(adap, &addr_data, pcf8583_attach);
68}
69
70static int
71pcf8583_detach(struct i2c_client *client)
72{
73 i2c_detach_client(client);
74 kfree(client);
75 return 0;
76}
77
78static int
79pcf8583_get_datetime(struct i2c_client *client, struct rtc_tm *dt)
80{
81 unsigned char buf[8], addr[1] = { 1 };
82 struct i2c_msg msgs[2] = {
83 { client->addr, 0, 1, addr },
84 { client->addr, I2C_M_RD, 6, buf }
85 };
86 int ret = -EIO;
87
88 memset(buf, 0, sizeof(buf));
89
90 ret = i2c_transfer(client->adapter, msgs, 2);
91 if (ret == 2) {
92 dt->year_off = buf[4] >> 6;
93 dt->wday = buf[5] >> 5;
94
95 buf[4] &= 0x3f;
96 buf[5] &= 0x1f;
97
98 dt->cs = BCD_TO_BIN(buf[0]);
99 dt->secs = BCD_TO_BIN(buf[1]);
100 dt->mins = BCD_TO_BIN(buf[2]);
101 dt->hours = BCD_TO_BIN(buf[3]);
102 dt->mday = BCD_TO_BIN(buf[4]);
103 dt->mon = BCD_TO_BIN(buf[5]);
104
105 ret = 0;
106 }
107
108 return ret;
109}
110
111static int
112pcf8583_set_datetime(struct i2c_client *client, struct rtc_tm *dt, int datetoo)
113{
114 unsigned char buf[8];
115 int ret, len = 6;
116
117 buf[0] = 0;
118 buf[1] = DAT(client) | 0x80;
119 buf[2] = BIN_TO_BCD(dt->cs);
120 buf[3] = BIN_TO_BCD(dt->secs);
121 buf[4] = BIN_TO_BCD(dt->mins);
122 buf[5] = BIN_TO_BCD(dt->hours);
123
124 if (datetoo) {
125 len = 8;
126 buf[6] = BIN_TO_BCD(dt->mday) | (dt->year_off << 6);
127 buf[7] = BIN_TO_BCD(dt->mon) | (dt->wday << 5);
128 }
129
130 ret = i2c_master_send(client, (char *)buf, len);
131 if (ret == len)
132 ret = 0;
133
134 buf[1] = DAT(client);
135 i2c_master_send(client, (char *)buf, 2);
136
137 return ret;
138}
139
140static int
141pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
142{
143 *ctrl = DAT(client);
144 return 0;
145}
146
147static int
148pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
149{
150 unsigned char buf[2];
151
152 buf[0] = 0;
153 buf[1] = *ctrl;
154 DAT(client) = *ctrl;
155
156 return i2c_master_send(client, (char *)buf, 2);
157}
158
159static int
160pcf8583_read_mem(struct i2c_client *client, struct mem *mem)
161{
162 unsigned char addr[1];
163 struct i2c_msg msgs[2] = {
164 { client->addr, 0, 1, addr },
165 { client->addr, I2C_M_RD, 0, mem->data }
166 };
167
168 if (mem->loc < 8)
169 return -EINVAL;
170
171 addr[0] = mem->loc;
172 msgs[1].len = mem->nr;
173
174 return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
175}
176
177static int
178pcf8583_write_mem(struct i2c_client *client, struct mem *mem)
179{
180 unsigned char addr[1];
181 struct i2c_msg msgs[2] = {
182 { client->addr, 0, 1, addr },
183 { client->addr, 0, 0, mem->data }
184 };
185
186 if (mem->loc < 8)
187 return -EINVAL;
188
189 addr[0] = mem->loc;
190 msgs[1].len = mem->nr;
191
192 return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
193}
194
195static int
196pcf8583_command(struct i2c_client *client, unsigned int cmd, void *arg)
197{
198 switch (cmd) {
199 case RTC_GETDATETIME:
200 return pcf8583_get_datetime(client, arg);
201
202 case RTC_SETTIME:
203 return pcf8583_set_datetime(client, arg, 0);
204
205 case RTC_SETDATETIME:
206 return pcf8583_set_datetime(client, arg, 1);
207
208 case RTC_GETCTRL:
209 return pcf8583_get_ctrl(client, arg);
210
211 case RTC_SETCTRL:
212 return pcf8583_set_ctrl(client, arg);
213
214 case MEM_READ:
215 return pcf8583_read_mem(client, arg);
216
217 case MEM_WRITE:
218 return pcf8583_write_mem(client, arg);
219
220 default:
221 return -EINVAL;
222 }
223}
224
225static struct i2c_driver pcf8583_driver = {
226 .name = "PCF8583",
227 .id = I2C_DRIVERID_PCF8583,
228 .flags = I2C_DF_NOTIFY,
229 .attach_adapter = pcf8583_probe,
230 .detach_client = pcf8583_detach,
231 .command = pcf8583_command
232};
233
234static __init int pcf8583_init(void)
235{
236 return i2c_add_driver(&pcf8583_driver);
237}
238
239__initcall(pcf8583_init);