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