1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MOXA ART RTC driver.
4 *
5 * Copyright (C) 2013 Jonas Jensen
6 *
7 * Jonas Jensen <jonas.jensen@gmail.com>
8 *
9 * Based on code from
10 * Moxa Technology Co., Ltd. <www.moxa.com>
11 */
12
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/delay.h>
16 #include <linux/rtc.h>
17 #include <linux/platform_device.h>
18 #include <linux/module.h>
19 #include <linux/gpio.h>
20 #include <linux/of_gpio.h>
21
22 #define GPIO_RTC_RESERVED 0x0C
23 #define GPIO_RTC_DATA_SET 0x10
24 #define GPIO_RTC_DATA_CLEAR 0x14
25 #define GPIO_RTC_PIN_PULL_ENABLE 0x18
26 #define GPIO_RTC_PIN_PULL_TYPE 0x1C
27 #define GPIO_RTC_INT_ENABLE 0x20
28 #define GPIO_RTC_INT_RAW_STATE 0x24
29 #define GPIO_RTC_INT_MASKED_STATE 0x28
30 #define GPIO_RTC_INT_MASK 0x2C
31 #define GPIO_RTC_INT_CLEAR 0x30
32 #define GPIO_RTC_INT_TRIGGER 0x34
33 #define GPIO_RTC_INT_BOTH 0x38
34 #define GPIO_RTC_INT_RISE_NEG 0x3C
35 #define GPIO_RTC_BOUNCE_ENABLE 0x40
36 #define GPIO_RTC_BOUNCE_PRE_SCALE 0x44
37 #define GPIO_RTC_PROTECT_W 0x8E
38 #define GPIO_RTC_PROTECT_R 0x8F
39 #define GPIO_RTC_YEAR_W 0x8C
40 #define GPIO_RTC_YEAR_R 0x8D
41 #define GPIO_RTC_DAY_W 0x8A
42 #define GPIO_RTC_DAY_R 0x8B
43 #define GPIO_RTC_MONTH_W 0x88
44 #define GPIO_RTC_MONTH_R 0x89
45 #define GPIO_RTC_DATE_W 0x86
46 #define GPIO_RTC_DATE_R 0x87
47 #define GPIO_RTC_HOURS_W 0x84
48 #define GPIO_RTC_HOURS_R 0x85
49 #define GPIO_RTC_MINUTES_W 0x82
50 #define GPIO_RTC_MINUTES_R 0x83
51 #define GPIO_RTC_SECONDS_W 0x80
52 #define GPIO_RTC_SECONDS_R 0x81
53 #define GPIO_RTC_DELAY_TIME 8
54
55 struct moxart_rtc {
56 struct rtc_device *rtc;
57 spinlock_t rtc_lock;
58 int gpio_data, gpio_sclk, gpio_reset;
59 };
60
61 static int day_of_year[12] = { 0, 31, 59, 90, 120, 151, 181,
62 212, 243, 273, 304, 334 };
63
moxart_rtc_write_byte(struct device * dev,u8 data)64 static void moxart_rtc_write_byte(struct device *dev, u8 data)
65 {
66 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
67 int i;
68
69 for (i = 0; i < 8; i++, data >>= 1) {
70 gpio_set_value(moxart_rtc->gpio_sclk, 0);
71 gpio_set_value(moxart_rtc->gpio_data, ((data & 1) == 1));
72 udelay(GPIO_RTC_DELAY_TIME);
73 gpio_set_value(moxart_rtc->gpio_sclk, 1);
74 udelay(GPIO_RTC_DELAY_TIME);
75 }
76 }
77
moxart_rtc_read_byte(struct device * dev)78 static u8 moxart_rtc_read_byte(struct device *dev)
79 {
80 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
81 int i;
82 u8 data = 0;
83
84 for (i = 0; i < 8; i++) {
85 gpio_set_value(moxart_rtc->gpio_sclk, 0);
86 udelay(GPIO_RTC_DELAY_TIME);
87 gpio_set_value(moxart_rtc->gpio_sclk, 1);
88 udelay(GPIO_RTC_DELAY_TIME);
89 if (gpio_get_value(moxart_rtc->gpio_data))
90 data |= (1 << i);
91 udelay(GPIO_RTC_DELAY_TIME);
92 }
93 return data;
94 }
95
moxart_rtc_read_register(struct device * dev,u8 cmd)96 static u8 moxart_rtc_read_register(struct device *dev, u8 cmd)
97 {
98 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
99 u8 data;
100 unsigned long flags;
101
102 local_irq_save(flags);
103
104 gpio_direction_output(moxart_rtc->gpio_data, 0);
105 gpio_set_value(moxart_rtc->gpio_reset, 1);
106 udelay(GPIO_RTC_DELAY_TIME);
107 moxart_rtc_write_byte(dev, cmd);
108 gpio_direction_input(moxart_rtc->gpio_data);
109 udelay(GPIO_RTC_DELAY_TIME);
110 data = moxart_rtc_read_byte(dev);
111 gpio_set_value(moxart_rtc->gpio_sclk, 0);
112 gpio_set_value(moxart_rtc->gpio_reset, 0);
113 udelay(GPIO_RTC_DELAY_TIME);
114
115 local_irq_restore(flags);
116
117 return data;
118 }
119
moxart_rtc_write_register(struct device * dev,u8 cmd,u8 data)120 static void moxart_rtc_write_register(struct device *dev, u8 cmd, u8 data)
121 {
122 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
123 unsigned long flags;
124
125 local_irq_save(flags);
126
127 gpio_direction_output(moxart_rtc->gpio_data, 0);
128 gpio_set_value(moxart_rtc->gpio_reset, 1);
129 udelay(GPIO_RTC_DELAY_TIME);
130 moxart_rtc_write_byte(dev, cmd);
131 moxart_rtc_write_byte(dev, data);
132 gpio_set_value(moxart_rtc->gpio_sclk, 0);
133 gpio_set_value(moxart_rtc->gpio_reset, 0);
134 udelay(GPIO_RTC_DELAY_TIME);
135
136 local_irq_restore(flags);
137 }
138
moxart_rtc_set_time(struct device * dev,struct rtc_time * tm)139 static int moxart_rtc_set_time(struct device *dev, struct rtc_time *tm)
140 {
141 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
142
143 spin_lock_irq(&moxart_rtc->rtc_lock);
144
145 moxart_rtc_write_register(dev, GPIO_RTC_PROTECT_W, 0);
146 moxart_rtc_write_register(dev, GPIO_RTC_YEAR_W,
147 (((tm->tm_year - 100) / 10) << 4) |
148 ((tm->tm_year - 100) % 10));
149
150 moxart_rtc_write_register(dev, GPIO_RTC_MONTH_W,
151 (((tm->tm_mon + 1) / 10) << 4) |
152 ((tm->tm_mon + 1) % 10));
153
154 moxart_rtc_write_register(dev, GPIO_RTC_DATE_W,
155 ((tm->tm_mday / 10) << 4) |
156 (tm->tm_mday % 10));
157
158 moxart_rtc_write_register(dev, GPIO_RTC_HOURS_W,
159 ((tm->tm_hour / 10) << 4) |
160 (tm->tm_hour % 10));
161
162 moxart_rtc_write_register(dev, GPIO_RTC_MINUTES_W,
163 ((tm->tm_min / 10) << 4) |
164 (tm->tm_min % 10));
165
166 moxart_rtc_write_register(dev, GPIO_RTC_SECONDS_W,
167 ((tm->tm_sec / 10) << 4) |
168 (tm->tm_sec % 10));
169
170 moxart_rtc_write_register(dev, GPIO_RTC_PROTECT_W, 0x80);
171
172 spin_unlock_irq(&moxart_rtc->rtc_lock);
173
174 dev_dbg(dev, "%s: success tm_year=%d tm_mon=%d\n"
175 "tm_mday=%d tm_hour=%d tm_min=%d tm_sec=%d\n",
176 __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
177 tm->tm_hour, tm->tm_min, tm->tm_sec);
178
179 return 0;
180 }
181
moxart_rtc_read_time(struct device * dev,struct rtc_time * tm)182 static int moxart_rtc_read_time(struct device *dev, struct rtc_time *tm)
183 {
184 struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
185 unsigned char v;
186
187 spin_lock_irq(&moxart_rtc->rtc_lock);
188
189 v = moxart_rtc_read_register(dev, GPIO_RTC_SECONDS_R);
190 tm->tm_sec = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
191
192 v = moxart_rtc_read_register(dev, GPIO_RTC_MINUTES_R);
193 tm->tm_min = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
194
195 v = moxart_rtc_read_register(dev, GPIO_RTC_HOURS_R);
196 if (v & 0x80) { /* 12-hour mode */
197 tm->tm_hour = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
198 if (v & 0x20) { /* PM mode */
199 tm->tm_hour += 12;
200 if (tm->tm_hour >= 24)
201 tm->tm_hour = 0;
202 }
203 } else { /* 24-hour mode */
204 tm->tm_hour = (((v & 0x30) >> 4) * 10) + (v & 0x0F);
205 }
206
207 v = moxart_rtc_read_register(dev, GPIO_RTC_DATE_R);
208 tm->tm_mday = (((v & 0x30) >> 4) * 10) + (v & 0x0F);
209
210 v = moxart_rtc_read_register(dev, GPIO_RTC_MONTH_R);
211 tm->tm_mon = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
212 tm->tm_mon--;
213
214 v = moxart_rtc_read_register(dev, GPIO_RTC_YEAR_R);
215 tm->tm_year = (((v & 0xF0) >> 4) * 10) + (v & 0x0F);
216 tm->tm_year += 100;
217 if (tm->tm_year <= 69)
218 tm->tm_year += 100;
219
220 v = moxart_rtc_read_register(dev, GPIO_RTC_DAY_R);
221 tm->tm_wday = (v & 0x0f) - 1;
222 tm->tm_yday = day_of_year[tm->tm_mon];
223 tm->tm_yday += (tm->tm_mday - 1);
224 if (tm->tm_mon >= 2) {
225 if (!(tm->tm_year % 4) && (tm->tm_year % 100))
226 tm->tm_yday++;
227 }
228
229 tm->tm_isdst = 0;
230
231 spin_unlock_irq(&moxart_rtc->rtc_lock);
232
233 return 0;
234 }
235
236 static const struct rtc_class_ops moxart_rtc_ops = {
237 .read_time = moxart_rtc_read_time,
238 .set_time = moxart_rtc_set_time,
239 };
240
moxart_rtc_probe(struct platform_device * pdev)241 static int moxart_rtc_probe(struct platform_device *pdev)
242 {
243 struct moxart_rtc *moxart_rtc;
244 int ret = 0;
245
246 moxart_rtc = devm_kzalloc(&pdev->dev, sizeof(*moxart_rtc), GFP_KERNEL);
247 if (!moxart_rtc)
248 return -ENOMEM;
249
250 moxart_rtc->gpio_data = of_get_named_gpio(pdev->dev.of_node,
251 "gpio-rtc-data", 0);
252 if (!gpio_is_valid(moxart_rtc->gpio_data)) {
253 dev_err(&pdev->dev, "invalid gpio (data): %d\n",
254 moxart_rtc->gpio_data);
255 return moxart_rtc->gpio_data;
256 }
257
258 moxart_rtc->gpio_sclk = of_get_named_gpio(pdev->dev.of_node,
259 "gpio-rtc-sclk", 0);
260 if (!gpio_is_valid(moxart_rtc->gpio_sclk)) {
261 dev_err(&pdev->dev, "invalid gpio (sclk): %d\n",
262 moxart_rtc->gpio_sclk);
263 return moxart_rtc->gpio_sclk;
264 }
265
266 moxart_rtc->gpio_reset = of_get_named_gpio(pdev->dev.of_node,
267 "gpio-rtc-reset", 0);
268 if (!gpio_is_valid(moxart_rtc->gpio_reset)) {
269 dev_err(&pdev->dev, "invalid gpio (reset): %d\n",
270 moxart_rtc->gpio_reset);
271 return moxart_rtc->gpio_reset;
272 }
273
274 spin_lock_init(&moxart_rtc->rtc_lock);
275 platform_set_drvdata(pdev, moxart_rtc);
276
277 ret = devm_gpio_request(&pdev->dev, moxart_rtc->gpio_data, "rtc_data");
278 if (ret) {
279 dev_err(&pdev->dev, "can't get rtc_data gpio\n");
280 return ret;
281 }
282
283 ret = devm_gpio_request_one(&pdev->dev, moxart_rtc->gpio_sclk,
284 GPIOF_DIR_OUT, "rtc_sclk");
285 if (ret) {
286 dev_err(&pdev->dev, "can't get rtc_sclk gpio\n");
287 return ret;
288 }
289
290 ret = devm_gpio_request_one(&pdev->dev, moxart_rtc->gpio_reset,
291 GPIOF_DIR_OUT, "rtc_reset");
292 if (ret) {
293 dev_err(&pdev->dev, "can't get rtc_reset gpio\n");
294 return ret;
295 }
296
297 moxart_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
298 &moxart_rtc_ops,
299 THIS_MODULE);
300 if (IS_ERR(moxart_rtc->rtc)) {
301 dev_err(&pdev->dev, "devm_rtc_device_register failed\n");
302 return PTR_ERR(moxart_rtc->rtc);
303 }
304
305 return 0;
306 }
307
308 static const struct of_device_id moxart_rtc_match[] = {
309 { .compatible = "moxa,moxart-rtc" },
310 { },
311 };
312 MODULE_DEVICE_TABLE(of, moxart_rtc_match);
313
314 static struct platform_driver moxart_rtc_driver = {
315 .probe = moxart_rtc_probe,
316 .driver = {
317 .name = "moxart-rtc",
318 .of_match_table = moxart_rtc_match,
319 },
320 };
321 module_platform_driver(moxart_rtc_driver);
322
323 MODULE_DESCRIPTION("MOXART RTC driver");
324 MODULE_LICENSE("GPL");
325 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
326