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1 | /* |
2 | * RTC Driver for X-Powers AC100 | |
3 | * | |
4 | * Copyright (c) 2016 Chen-Yu Tsai | |
5 | * | |
6 | * Chen-Yu Tsai <wens@csie.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
15 | * more details. | |
16 | */ | |
17 | ||
18 | #include <linux/bcd.h> | |
19 | #include <linux/device.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/mfd/ac100.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/mutex.h> | |
25 | #include <linux/of.h> | |
26 | #include <linux/platform_device.h> | |
27 | #include <linux/regmap.h> | |
28 | #include <linux/rtc.h> | |
29 | #include <linux/types.h> | |
30 | ||
31 | /* Control register */ | |
32 | #define AC100_RTC_CTRL_24HOUR BIT(0) | |
33 | ||
34 | /* RTC */ | |
35 | #define AC100_RTC_SEC_MASK GENMASK(6, 0) | |
36 | #define AC100_RTC_MIN_MASK GENMASK(6, 0) | |
37 | #define AC100_RTC_HOU_MASK GENMASK(5, 0) | |
38 | #define AC100_RTC_WEE_MASK GENMASK(2, 0) | |
39 | #define AC100_RTC_DAY_MASK GENMASK(5, 0) | |
40 | #define AC100_RTC_MON_MASK GENMASK(4, 0) | |
41 | #define AC100_RTC_YEA_MASK GENMASK(7, 0) | |
42 | #define AC100_RTC_YEA_LEAP BIT(15) | |
43 | #define AC100_RTC_UPD_TRIGGER BIT(15) | |
44 | ||
45 | /* Alarm (wall clock) */ | |
46 | #define AC100_ALM_INT_ENABLE BIT(0) | |
47 | ||
48 | #define AC100_ALM_SEC_MASK GENMASK(6, 0) | |
49 | #define AC100_ALM_MIN_MASK GENMASK(6, 0) | |
50 | #define AC100_ALM_HOU_MASK GENMASK(5, 0) | |
51 | #define AC100_ALM_WEE_MASK GENMASK(2, 0) | |
52 | #define AC100_ALM_DAY_MASK GENMASK(5, 0) | |
53 | #define AC100_ALM_MON_MASK GENMASK(4, 0) | |
54 | #define AC100_ALM_YEA_MASK GENMASK(7, 0) | |
55 | #define AC100_ALM_ENABLE_FLAG BIT(15) | |
56 | #define AC100_ALM_UPD_TRIGGER BIT(15) | |
57 | ||
58 | /* | |
59 | * The year parameter passed to the driver is usually an offset relative to | |
60 | * the year 1900. This macro is used to convert this offset to another one | |
61 | * relative to the minimum year allowed by the hardware. | |
62 | * | |
63 | * The year range is 1970 - 2069. This range is selected to match Allwinner's | |
64 | * driver. | |
65 | */ | |
66 | #define AC100_YEAR_MIN 1970 | |
67 | #define AC100_YEAR_MAX 2069 | |
68 | #define AC100_YEAR_OFF (AC100_YEAR_MIN - 1900) | |
69 | ||
70 | struct ac100_rtc_dev { | |
71 | struct rtc_device *rtc; | |
72 | struct device *dev; | |
73 | struct regmap *regmap; | |
74 | int irq; | |
75 | unsigned long alarm; | |
76 | }; | |
77 | ||
78 | static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm) | |
79 | { | |
80 | struct ac100_rtc_dev *chip = dev_get_drvdata(dev); | |
81 | struct regmap *regmap = chip->regmap; | |
82 | u16 reg[7]; | |
83 | int ret; | |
84 | ||
85 | ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7); | |
86 | if (ret) | |
87 | return ret; | |
88 | ||
89 | rtc_tm->tm_sec = bcd2bin(reg[0] & AC100_RTC_SEC_MASK); | |
90 | rtc_tm->tm_min = bcd2bin(reg[1] & AC100_RTC_MIN_MASK); | |
91 | rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK); | |
92 | rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK); | |
93 | rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK); | |
94 | rtc_tm->tm_mon = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1; | |
95 | rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) + | |
96 | AC100_YEAR_OFF; | |
97 | ||
98 | return rtc_valid_tm(rtc_tm); | |
99 | } | |
100 | ||
101 | static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm) | |
102 | { | |
103 | struct ac100_rtc_dev *chip = dev_get_drvdata(dev); | |
104 | struct regmap *regmap = chip->regmap; | |
105 | int year; | |
106 | u16 reg[8]; | |
107 | ||
108 | /* our RTC has a limited year range... */ | |
109 | year = rtc_tm->tm_year - AC100_YEAR_OFF; | |
110 | if (year < 0 || year > (AC100_YEAR_MAX - 1900)) { | |
111 | dev_err(dev, "rtc only supports year in range %d - %d\n", | |
112 | AC100_YEAR_MIN, AC100_YEAR_MAX); | |
113 | return -EINVAL; | |
114 | } | |
115 | ||
116 | /* convert to BCD */ | |
117 | reg[0] = bin2bcd(rtc_tm->tm_sec) & AC100_RTC_SEC_MASK; | |
118 | reg[1] = bin2bcd(rtc_tm->tm_min) & AC100_RTC_MIN_MASK; | |
119 | reg[2] = bin2bcd(rtc_tm->tm_hour) & AC100_RTC_HOU_MASK; | |
120 | reg[3] = bin2bcd(rtc_tm->tm_wday) & AC100_RTC_WEE_MASK; | |
121 | reg[4] = bin2bcd(rtc_tm->tm_mday) & AC100_RTC_DAY_MASK; | |
122 | reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK; | |
123 | reg[6] = bin2bcd(year) & AC100_RTC_YEA_MASK; | |
124 | /* trigger write */ | |
125 | reg[7] = AC100_RTC_UPD_TRIGGER; | |
126 | ||
127 | /* Is it a leap year? */ | |
128 | if (is_leap_year(year + AC100_YEAR_OFF + 1900)) | |
129 | reg[6] |= AC100_RTC_YEA_LEAP; | |
130 | ||
131 | return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8); | |
132 | } | |
133 | ||
134 | static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en) | |
135 | { | |
136 | struct ac100_rtc_dev *chip = dev_get_drvdata(dev); | |
137 | struct regmap *regmap = chip->regmap; | |
138 | unsigned int val; | |
139 | ||
140 | val = en ? AC100_ALM_INT_ENABLE : 0; | |
141 | ||
142 | return regmap_write(regmap, AC100_ALM_INT_ENA, val); | |
143 | } | |
144 | ||
145 | static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
146 | { | |
147 | struct ac100_rtc_dev *chip = dev_get_drvdata(dev); | |
148 | struct regmap *regmap = chip->regmap; | |
149 | struct rtc_time *alrm_tm = &alrm->time; | |
150 | u16 reg[7]; | |
151 | unsigned int val; | |
152 | int ret; | |
153 | ||
154 | ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val); | |
155 | if (ret) | |
156 | return ret; | |
157 | ||
158 | alrm->enabled = !!(val & AC100_ALM_INT_ENABLE); | |
159 | ||
160 | ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7); | |
161 | if (ret) | |
162 | return ret; | |
163 | ||
164 | alrm_tm->tm_sec = bcd2bin(reg[0] & AC100_ALM_SEC_MASK); | |
165 | alrm_tm->tm_min = bcd2bin(reg[1] & AC100_ALM_MIN_MASK); | |
166 | alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK); | |
167 | alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK); | |
168 | alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK); | |
169 | alrm_tm->tm_mon = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1; | |
170 | alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) + | |
171 | AC100_YEAR_OFF; | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
176 | static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
177 | { | |
178 | struct ac100_rtc_dev *chip = dev_get_drvdata(dev); | |
179 | struct regmap *regmap = chip->regmap; | |
180 | struct rtc_time *alrm_tm = &alrm->time; | |
181 | u16 reg[8]; | |
182 | int year; | |
183 | int ret; | |
184 | ||
185 | /* our alarm has a limited year range... */ | |
186 | year = alrm_tm->tm_year - AC100_YEAR_OFF; | |
187 | if (year < 0 || year > (AC100_YEAR_MAX - 1900)) { | |
188 | dev_err(dev, "alarm only supports year in range %d - %d\n", | |
189 | AC100_YEAR_MIN, AC100_YEAR_MAX); | |
190 | return -EINVAL; | |
191 | } | |
192 | ||
193 | /* convert to BCD */ | |
194 | reg[0] = (bin2bcd(alrm_tm->tm_sec) & AC100_ALM_SEC_MASK) | | |
195 | AC100_ALM_ENABLE_FLAG; | |
196 | reg[1] = (bin2bcd(alrm_tm->tm_min) & AC100_ALM_MIN_MASK) | | |
197 | AC100_ALM_ENABLE_FLAG; | |
198 | reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) | | |
199 | AC100_ALM_ENABLE_FLAG; | |
200 | /* Do not enable weekday alarm */ | |
201 | reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK; | |
202 | reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) | | |
203 | AC100_ALM_ENABLE_FLAG; | |
204 | reg[5] = (bin2bcd(alrm_tm->tm_mon + 1) & AC100_ALM_MON_MASK) | | |
205 | AC100_ALM_ENABLE_FLAG; | |
206 | reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) | | |
207 | AC100_ALM_ENABLE_FLAG; | |
208 | /* trigger write */ | |
209 | reg[7] = AC100_ALM_UPD_TRIGGER; | |
210 | ||
211 | ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8); | |
212 | if (ret) | |
213 | return ret; | |
214 | ||
215 | return ac100_rtc_alarm_irq_enable(dev, alrm->enabled); | |
216 | } | |
217 | ||
218 | static irqreturn_t ac100_rtc_irq(int irq, void *data) | |
219 | { | |
220 | struct ac100_rtc_dev *chip = data; | |
221 | struct regmap *regmap = chip->regmap; | |
222 | unsigned int val = 0; | |
223 | int ret; | |
224 | ||
225 | mutex_lock(&chip->rtc->ops_lock); | |
226 | ||
227 | /* read status */ | |
228 | ret = regmap_read(regmap, AC100_ALM_INT_STA, &val); | |
229 | if (ret) | |
230 | goto out; | |
231 | ||
232 | if (val & AC100_ALM_INT_ENABLE) { | |
233 | /* signal rtc framework */ | |
234 | rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF); | |
235 | ||
236 | /* clear status */ | |
237 | ret = regmap_write(regmap, AC100_ALM_INT_STA, val); | |
238 | if (ret) | |
239 | goto out; | |
240 | ||
241 | /* disable interrupt */ | |
242 | ret = ac100_rtc_alarm_irq_enable(chip->dev, 0); | |
243 | if (ret) | |
244 | goto out; | |
245 | } | |
246 | ||
247 | out: | |
248 | mutex_unlock(&chip->rtc->ops_lock); | |
249 | return IRQ_HANDLED; | |
250 | } | |
251 | ||
252 | static const struct rtc_class_ops ac100_rtc_ops = { | |
253 | .read_time = ac100_rtc_get_time, | |
254 | .set_time = ac100_rtc_set_time, | |
255 | .read_alarm = ac100_rtc_get_alarm, | |
256 | .set_alarm = ac100_rtc_set_alarm, | |
257 | .alarm_irq_enable = ac100_rtc_alarm_irq_enable, | |
258 | }; | |
259 | ||
260 | static int ac100_rtc_probe(struct platform_device *pdev) | |
261 | { | |
262 | struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent); | |
263 | struct ac100_rtc_dev *chip; | |
264 | int ret; | |
265 | ||
266 | chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); | |
267 | platform_set_drvdata(pdev, chip); | |
268 | chip->dev = &pdev->dev; | |
269 | chip->regmap = ac100->regmap; | |
270 | ||
271 | chip->irq = platform_get_irq(pdev, 0); | |
272 | if (chip->irq < 0) { | |
273 | dev_err(&pdev->dev, "No IRQ resource\n"); | |
274 | return chip->irq; | |
275 | } | |
276 | ||
277 | ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL, | |
278 | ac100_rtc_irq, | |
279 | IRQF_SHARED | IRQF_ONESHOT, | |
280 | dev_name(&pdev->dev), chip); | |
281 | if (ret) { | |
282 | dev_err(&pdev->dev, "Could not request IRQ\n"); | |
283 | return ret; | |
284 | } | |
285 | ||
286 | /* always use 24 hour mode */ | |
287 | regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR, | |
288 | AC100_RTC_CTRL_24HOUR); | |
289 | ||
290 | /* disable counter alarm interrupt */ | |
291 | regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0); | |
292 | ||
293 | /* clear counter alarm pending interrupts */ | |
294 | regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE); | |
295 | ||
296 | chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100", | |
297 | &ac100_rtc_ops, THIS_MODULE); | |
298 | if (IS_ERR(chip->rtc)) { | |
299 | dev_err(&pdev->dev, "unable to register device\n"); | |
300 | return PTR_ERR(chip->rtc); | |
301 | } | |
302 | ||
303 | dev_info(&pdev->dev, "RTC enabled\n"); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static const struct of_device_id ac100_rtc_match[] = { | |
309 | { .compatible = "x-powers,ac100-rtc" }, | |
310 | { }, | |
311 | }; | |
312 | MODULE_DEVICE_TABLE(of, ac100_rtc_match); | |
313 | ||
314 | static struct platform_driver ac100_rtc_driver = { | |
315 | .probe = ac100_rtc_probe, | |
316 | .driver = { | |
317 | .name = "ac100-rtc", | |
318 | .of_match_table = of_match_ptr(ac100_rtc_match), | |
319 | }, | |
320 | }; | |
321 | module_platform_driver(ac100_rtc_driver); | |
322 | ||
323 | MODULE_DESCRIPTION("X-Powers AC100 RTC driver"); | |
324 | MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>"); | |
325 | MODULE_LICENSE("GPL v2"); |