2 * RTC Driver for X-Powers AC100
4 * Copyright (c) 2016 Chen-Yu Tsai
6 * Chen-Yu Tsai <wens@csie.org>
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.
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
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>
26 #include <linux/platform_device.h>
27 #include <linux/regmap.h>
28 #include <linux/rtc.h>
29 #include <linux/types.h>
31 /* Control register */
32 #define AC100_RTC_CTRL_24HOUR BIT(0)
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)
45 /* Alarm (wall clock) */
46 #define AC100_ALM_INT_ENABLE BIT(0)
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)
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.
63 * The year range is 1970 - 2069. This range is selected to match Allwinner's
66 #define AC100_YEAR_MIN 1970
67 #define AC100_YEAR_MAX 2069
68 #define AC100_YEAR_OFF (AC100_YEAR_MIN - 1900)
70 struct ac100_rtc_dev {
71 struct rtc_device *rtc;
73 struct regmap *regmap;
78 static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
80 struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
81 struct regmap *regmap = chip->regmap;
85 ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
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) +
98 return rtc_valid_tm(rtc_tm);
101 static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
103 struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
104 struct regmap *regmap = chip->regmap;
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);
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;
125 reg[7] = AC100_RTC_UPD_TRIGGER;
127 /* Is it a leap year? */
128 if (is_leap_year(year + AC100_YEAR_OFF + 1900))
129 reg[6] |= AC100_RTC_YEA_LEAP;
131 return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
134 static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
136 struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
137 struct regmap *regmap = chip->regmap;
140 val = en ? AC100_ALM_INT_ENABLE : 0;
142 return regmap_write(regmap, AC100_ALM_INT_ENA, val);
145 static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
147 struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
148 struct regmap *regmap = chip->regmap;
149 struct rtc_time *alrm_tm = &alrm->time;
154 ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
158 alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
160 ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
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) +
176 static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
178 struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
179 struct regmap *regmap = chip->regmap;
180 struct rtc_time *alrm_tm = &alrm->time;
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);
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;
209 reg[7] = AC100_ALM_UPD_TRIGGER;
211 ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
215 return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);
218 static irqreturn_t ac100_rtc_irq(int irq, void *data)
220 struct ac100_rtc_dev *chip = data;
221 struct regmap *regmap = chip->regmap;
222 unsigned int val = 0;
225 mutex_lock(&chip->rtc->ops_lock);
228 ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
232 if (val & AC100_ALM_INT_ENABLE) {
233 /* signal rtc framework */
234 rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
237 ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
241 /* disable interrupt */
242 ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);
248 mutex_unlock(&chip->rtc->ops_lock);
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,
260 static int ac100_rtc_probe(struct platform_device *pdev)
262 struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
263 struct ac100_rtc_dev *chip;
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;
271 chip->irq = platform_get_irq(pdev, 0);
273 dev_err(&pdev->dev, "No IRQ resource\n");
277 ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,
279 IRQF_SHARED | IRQF_ONESHOT,
280 dev_name(&pdev->dev), chip);
282 dev_err(&pdev->dev, "Could not request IRQ\n");
286 /* always use 24 hour mode */
287 regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
288 AC100_RTC_CTRL_24HOUR);
290 /* disable counter alarm interrupt */
291 regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
293 /* clear counter alarm pending interrupts */
294 regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
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);
303 dev_info(&pdev->dev, "RTC enabled\n");
308 static const struct of_device_id ac100_rtc_match[] = {
309 { .compatible = "x-powers,ac100-rtc" },
312 MODULE_DEVICE_TABLE(of, ac100_rtc_match);
314 static struct platform_driver ac100_rtc_driver = {
315 .probe = ac100_rtc_probe,
318 .of_match_table = of_match_ptr(ac100_rtc_match),
321 module_platform_driver(ac100_rtc_driver);
323 MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
324 MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
325 MODULE_LICENSE("GPL v2");