1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
|
/*
* Copyright (C) 2012 Sven Schnelle <svens@stackframe.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/types.h>
#include <linux/bcd.h>
#include <linux/rtc-ds2404.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/io.h>
#define DS2404_STATUS_REG 0x200
#define DS2404_CONTROL_REG 0x201
#define DS2404_RTC_REG 0x202
#define DS2404_WRITE_SCRATCHPAD_CMD 0x0f
#define DS2404_READ_SCRATCHPAD_CMD 0xaa
#define DS2404_COPY_SCRATCHPAD_CMD 0x55
#define DS2404_READ_MEMORY_CMD 0xf0
struct ds2404;
struct ds2404_chip_ops {
int (*map_io)(struct ds2404 *chip, struct platform_device *pdev,
struct ds2404_platform_data *pdata);
void (*unmap_io)(struct ds2404 *chip);
};
#define DS2404_RST 0
#define DS2404_CLK 1
#define DS2404_DQ 2
struct ds2404_gpio {
const char *name;
unsigned int gpio;
};
struct ds2404 {
struct ds2404_gpio *gpio;
struct ds2404_chip_ops *ops;
struct rtc_device *rtc;
};
static struct ds2404_gpio ds2404_gpio[] = {
{ "RTC RST", 0 },
{ "RTC CLK", 0 },
{ "RTC DQ", 0 },
};
static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev,
struct ds2404_platform_data *pdata)
{
int i, err;
ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst;
ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk;
ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq;
for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) {
err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name);
if (err) {
dev_err(&pdev->dev, "error mapping gpio %s: %d\n",
ds2404_gpio[i].name, err);
goto err_request;
}
if (i != DS2404_DQ)
gpio_direction_output(ds2404_gpio[i].gpio, 1);
}
chip->gpio = ds2404_gpio;
return 0;
err_request:
while (--i >= 0)
gpio_free(ds2404_gpio[i].gpio);
return err;
}
static void ds2404_gpio_unmap(struct ds2404 *chip)
{
int i;
for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++)
gpio_free(ds2404_gpio[i].gpio);
}
static struct ds2404_chip_ops ds2404_gpio_ops = {
.map_io = ds2404_gpio_map,
.unmap_io = ds2404_gpio_unmap,
};
static void ds2404_reset(struct device *dev)
{
gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0);
udelay(1000);
gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1);
gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0);
udelay(10);
}
static void ds2404_write_byte(struct device *dev, u8 byte)
{
int i;
gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1);
for (i = 0; i < 8; i++) {
gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i));
udelay(10);
gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
udelay(10);
gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
udelay(10);
}
}
static u8 ds2404_read_byte(struct device *dev)
{
int i;
u8 ret = 0;
gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
for (i = 0; i < 8; i++) {
gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
udelay(10);
if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
ret |= 1 << i;
gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
udelay(10);
}
return ret;
}
static void ds2404_read_memory(struct device *dev, u16 offset,
int length, u8 *out)
{
ds2404_reset(dev);
ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD);
ds2404_write_byte(dev, offset & 0xff);
ds2404_write_byte(dev, (offset >> 8) & 0xff);
while (length--)
*out++ = ds2404_read_byte(dev);
}
static void ds2404_write_memory(struct device *dev, u16 offset,
int length, u8 *out)
{
int i;
u8 ta01, ta02, es;
ds2404_reset(dev);
ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD);
ds2404_write_byte(dev, offset & 0xff);
ds2404_write_byte(dev, (offset >> 8) & 0xff);
for (i = 0; i < length; i++)
ds2404_write_byte(dev, out[i]);
ds2404_reset(dev);
ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD);
ta01 = ds2404_read_byte(dev);
ta02 = ds2404_read_byte(dev);
es = ds2404_read_byte(dev);
for (i = 0; i < length; i++) {
if (out[i] != ds2404_read_byte(dev)) {
dev_err(dev, "read invalid data\n");
return;
}
}
ds2404_reset(dev);
ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD);
ds2404_write_byte(dev, ta01);
ds2404_write_byte(dev, ta02);
ds2404_write_byte(dev, es);
gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
;
}
static void ds2404_enable_osc(struct device *dev)
{
u8 in[1] = { 0x10 }; /* enable oscillator */
ds2404_write_memory(dev, 0x201, 1, in);
}
static int ds2404_read_time(struct device *dev, struct rtc_time *dt)
{
unsigned long time = 0;
ds2404_read_memory(dev, 0x203, 4, (u8 *)&time);
time = le32_to_cpu(time);
rtc_time_to_tm(time, dt);
return rtc_valid_tm(dt);
}
static int ds2404_set_mmss(struct device *dev, unsigned long secs)
{
u32 time = cpu_to_le32(secs);
ds2404_write_memory(dev, 0x203, 4, (u8 *)&time);
return 0;
}
static const struct rtc_class_ops ds2404_rtc_ops = {
.read_time = ds2404_read_time,
.set_mmss = ds2404_set_mmss,
};
static int rtc_probe(struct platform_device *pdev)
{
struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct ds2404 *chip;
int retval = -EBUSY;
chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->ops = &ds2404_gpio_ops;
retval = chip->ops->map_io(chip, pdev, pdata);
if (retval)
goto err_chip;
dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n",
chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio,
chip->gpio[DS2404_DQ].gpio);
platform_set_drvdata(pdev, chip);
chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404",
&ds2404_rtc_ops, THIS_MODULE);
if (IS_ERR(chip->rtc)) {
retval = PTR_ERR(chip->rtc);
goto err_io;
}
ds2404_enable_osc(&pdev->dev);
return 0;
err_io:
chip->ops->unmap_io(chip);
err_chip:
return retval;
}
static int rtc_remove(struct platform_device *dev)
{
struct ds2404 *chip = platform_get_drvdata(dev);
chip->ops->unmap_io(chip);
return 0;
}
static struct platform_driver rtc_device_driver = {
.probe = rtc_probe,
.remove = rtc_remove,
.driver = {
.name = "ds2404",
.owner = THIS_MODULE,
},
};
module_platform_driver(rtc_device_driver);
MODULE_DESCRIPTION("DS2404 RTC");
MODULE_AUTHOR("Sven Schnelle");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ds2404");
|
