1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC)
4 *
5 * Copyright (C) 2011 NXP Semiconductors
6 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
7 */
8
9 #include <linux/clk.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_device.h>
15 #include <linux/platform_device.h>
16 #include <linux/rtc.h>
17
18 /* LPC24xx RTC register offsets and bits */
19 #define LPC24XX_ILR 0x00
20 #define LPC24XX_RTCCIF BIT(0)
21 #define LPC24XX_RTCALF BIT(1)
22 #define LPC24XX_CTC 0x04
23 #define LPC24XX_CCR 0x08
24 #define LPC24XX_CLKEN BIT(0)
25 #define LPC178X_CCALEN BIT(4)
26 #define LPC24XX_CIIR 0x0c
27 #define LPC24XX_AMR 0x10
28 #define LPC24XX_ALARM_DISABLE 0xff
29 #define LPC24XX_CTIME0 0x14
30 #define LPC24XX_CTIME1 0x18
31 #define LPC24XX_CTIME2 0x1c
32 #define LPC24XX_SEC 0x20
33 #define LPC24XX_MIN 0x24
34 #define LPC24XX_HOUR 0x28
35 #define LPC24XX_DOM 0x2c
36 #define LPC24XX_DOW 0x30
37 #define LPC24XX_DOY 0x34
38 #define LPC24XX_MONTH 0x38
39 #define LPC24XX_YEAR 0x3c
40 #define LPC24XX_ALSEC 0x60
41 #define LPC24XX_ALMIN 0x64
42 #define LPC24XX_ALHOUR 0x68
43 #define LPC24XX_ALDOM 0x6c
44 #define LPC24XX_ALDOW 0x70
45 #define LPC24XX_ALDOY 0x74
46 #define LPC24XX_ALMON 0x78
47 #define LPC24XX_ALYEAR 0x7c
48
49 /* Macros to read fields in consolidated time (CT) registers */
50 #define CT0_SECS(x) (((x) >> 0) & 0x3f)
51 #define CT0_MINS(x) (((x) >> 8) & 0x3f)
52 #define CT0_HOURS(x) (((x) >> 16) & 0x1f)
53 #define CT0_DOW(x) (((x) >> 24) & 0x07)
54 #define CT1_DOM(x) (((x) >> 0) & 0x1f)
55 #define CT1_MONTH(x) (((x) >> 8) & 0x0f)
56 #define CT1_YEAR(x) (((x) >> 16) & 0xfff)
57 #define CT2_DOY(x) (((x) >> 0) & 0xfff)
58
59 #define rtc_readl(dev, reg) readl((dev)->rtc_base + (reg))
60 #define rtc_writel(dev, reg, val) writel((val), (dev)->rtc_base + (reg))
61
62 struct lpc24xx_rtc {
63 void __iomem *rtc_base;
64 struct rtc_device *rtc;
65 struct clk *clk_rtc;
66 struct clk *clk_reg;
67 };
68
lpc24xx_rtc_set_time(struct device * dev,struct rtc_time * tm)69 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
70 {
71 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
72
73 /* Disable RTC during update */
74 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
75
76 rtc_writel(rtc, LPC24XX_SEC, tm->tm_sec);
77 rtc_writel(rtc, LPC24XX_MIN, tm->tm_min);
78 rtc_writel(rtc, LPC24XX_HOUR, tm->tm_hour);
79 rtc_writel(rtc, LPC24XX_DOW, tm->tm_wday);
80 rtc_writel(rtc, LPC24XX_DOM, tm->tm_mday);
81 rtc_writel(rtc, LPC24XX_DOY, tm->tm_yday);
82 rtc_writel(rtc, LPC24XX_MONTH, tm->tm_mon);
83 rtc_writel(rtc, LPC24XX_YEAR, tm->tm_year);
84
85 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
86
87 return 0;
88 }
89
lpc24xx_rtc_read_time(struct device * dev,struct rtc_time * tm)90 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
91 {
92 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
93 u32 ct0, ct1, ct2;
94
95 ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
96 ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
97 ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
98
99 tm->tm_sec = CT0_SECS(ct0);
100 tm->tm_min = CT0_MINS(ct0);
101 tm->tm_hour = CT0_HOURS(ct0);
102 tm->tm_wday = CT0_DOW(ct0);
103 tm->tm_mon = CT1_MONTH(ct1);
104 tm->tm_mday = CT1_DOM(ct1);
105 tm->tm_year = CT1_YEAR(ct1);
106 tm->tm_yday = CT2_DOY(ct2);
107
108 return 0;
109 }
110
lpc24xx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * wkalrm)111 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
112 {
113 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
114 struct rtc_time *tm = &wkalrm->time;
115
116 tm->tm_sec = rtc_readl(rtc, LPC24XX_ALSEC);
117 tm->tm_min = rtc_readl(rtc, LPC24XX_ALMIN);
118 tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
119 tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
120 tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
121 tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
122 tm->tm_mon = rtc_readl(rtc, LPC24XX_ALMON);
123 tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
124
125 wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
126 wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
127
128 return rtc_valid_tm(&wkalrm->time);
129 }
130
lpc24xx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * wkalrm)131 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
132 {
133 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
134 struct rtc_time *tm = &wkalrm->time;
135
136 /* Disable alarm irq during update */
137 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
138
139 rtc_writel(rtc, LPC24XX_ALSEC, tm->tm_sec);
140 rtc_writel(rtc, LPC24XX_ALMIN, tm->tm_min);
141 rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
142 rtc_writel(rtc, LPC24XX_ALDOM, tm->tm_mday);
143 rtc_writel(rtc, LPC24XX_ALDOW, tm->tm_wday);
144 rtc_writel(rtc, LPC24XX_ALDOY, tm->tm_yday);
145 rtc_writel(rtc, LPC24XX_ALMON, tm->tm_mon);
146 rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
147
148 if (wkalrm->enabled)
149 rtc_writel(rtc, LPC24XX_AMR, 0);
150
151 return 0;
152 }
153
lpc24xx_rtc_alarm_irq_enable(struct device * dev,unsigned int enable)154 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
155 {
156 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
157
158 if (enable)
159 rtc_writel(rtc, LPC24XX_AMR, 0);
160 else
161 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
162
163 return 0;
164 }
165
lpc24xx_rtc_interrupt(int irq,void * data)166 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data)
167 {
168 unsigned long events = RTC_IRQF;
169 struct lpc24xx_rtc *rtc = data;
170 u32 rtc_iir;
171
172 /* Check interrupt cause */
173 rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
174 if (rtc_iir & LPC24XX_RTCALF) {
175 events |= RTC_AF;
176 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
177 }
178
179 /* Clear interrupt status and report event */
180 rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
181 rtc_update_irq(rtc->rtc, 1, events);
182
183 return IRQ_HANDLED;
184 }
185
186 static const struct rtc_class_ops lpc24xx_rtc_ops = {
187 .read_time = lpc24xx_rtc_read_time,
188 .set_time = lpc24xx_rtc_set_time,
189 .read_alarm = lpc24xx_rtc_read_alarm,
190 .set_alarm = lpc24xx_rtc_set_alarm,
191 .alarm_irq_enable = lpc24xx_rtc_alarm_irq_enable,
192 };
193
lpc24xx_rtc_probe(struct platform_device * pdev)194 static int lpc24xx_rtc_probe(struct platform_device *pdev)
195 {
196 struct lpc24xx_rtc *rtc;
197 int irq, ret;
198
199 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
200 if (!rtc)
201 return -ENOMEM;
202
203 rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
204 if (IS_ERR(rtc->rtc_base))
205 return PTR_ERR(rtc->rtc_base);
206
207 irq = platform_get_irq(pdev, 0);
208 if (irq < 0)
209 return irq;
210
211 rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
212 if (IS_ERR(rtc->clk_rtc)) {
213 dev_err(&pdev->dev, "error getting rtc clock\n");
214 return PTR_ERR(rtc->clk_rtc);
215 }
216
217 rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
218 if (IS_ERR(rtc->clk_reg)) {
219 dev_err(&pdev->dev, "error getting reg clock\n");
220 return PTR_ERR(rtc->clk_reg);
221 }
222
223 ret = clk_prepare_enable(rtc->clk_rtc);
224 if (ret) {
225 dev_err(&pdev->dev, "unable to enable rtc clock\n");
226 return ret;
227 }
228
229 ret = clk_prepare_enable(rtc->clk_reg);
230 if (ret) {
231 dev_err(&pdev->dev, "unable to enable reg clock\n");
232 goto disable_rtc_clk;
233 }
234
235 platform_set_drvdata(pdev, rtc);
236
237 /* Clear any pending interrupts */
238 rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF);
239
240 /* Enable RTC count */
241 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
242
243 ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
244 pdev->name, rtc);
245 if (ret < 0) {
246 dev_warn(&pdev->dev, "can't request interrupt\n");
247 goto disable_clks;
248 }
249
250 rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc",
251 &lpc24xx_rtc_ops, THIS_MODULE);
252 if (IS_ERR(rtc->rtc)) {
253 dev_err(&pdev->dev, "can't register rtc device\n");
254 ret = PTR_ERR(rtc->rtc);
255 goto disable_clks;
256 }
257
258 return 0;
259
260 disable_clks:
261 clk_disable_unprepare(rtc->clk_reg);
262 disable_rtc_clk:
263 clk_disable_unprepare(rtc->clk_rtc);
264 return ret;
265 }
266
lpc24xx_rtc_remove(struct platform_device * pdev)267 static int lpc24xx_rtc_remove(struct platform_device *pdev)
268 {
269 struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
270
271 /* Ensure all interrupt sources are masked */
272 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
273 rtc_writel(rtc, LPC24XX_CIIR, 0);
274
275 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
276
277 clk_disable_unprepare(rtc->clk_rtc);
278 clk_disable_unprepare(rtc->clk_reg);
279
280 return 0;
281 }
282
283 static const struct of_device_id lpc24xx_rtc_match[] = {
284 { .compatible = "nxp,lpc1788-rtc" },
285 { }
286 };
287 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
288
289 static struct platform_driver lpc24xx_rtc_driver = {
290 .probe = lpc24xx_rtc_probe,
291 .remove = lpc24xx_rtc_remove,
292 .driver = {
293 .name = "lpc24xx-rtc",
294 .of_match_table = lpc24xx_rtc_match,
295 },
296 };
297 module_platform_driver(lpc24xx_rtc_driver);
298
299 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
300 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
301 MODULE_LICENSE("GPL");
302