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