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
61struct lpc24xx_rtc {
62 void __iomem *rtc_base;
63 struct rtc_device *rtc;
64 struct clk *clk_rtc;
65 struct clk *clk_reg;
66};
67
68static 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
89static 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
110static 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(tm: &wkalrm->time);
128}
129
130static 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
153static 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
165static 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->rtc, num: 1, events);
181
182 return IRQ_HANDLED;
183}
184
185static 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
193static int lpc24xx_rtc_probe(struct platform_device *pdev)
194{
195 struct lpc24xx_rtc *rtc;
196 int irq, ret;
197
198 rtc = devm_kzalloc(dev: &pdev->dev, size: sizeof(*rtc), GFP_KERNEL);
199 if (!rtc)
200 return -ENOMEM;
201
202 rtc->rtc_base = devm_platform_ioremap_resource(pdev, index: 0);
203 if (IS_ERR(ptr: rtc->rtc_base))
204 return PTR_ERR(ptr: 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(dev: &pdev->dev, id: "rtc");
211 if (IS_ERR(ptr: rtc->clk_rtc)) {
212 dev_err(&pdev->dev, "error getting rtc clock\n");
213 return PTR_ERR(ptr: rtc->clk_rtc);
214 }
215
216 rtc->clk_reg = devm_clk_get(dev: &pdev->dev, id: "reg");
217 if (IS_ERR(ptr: rtc->clk_reg)) {
218 dev_err(&pdev->dev, "error getting reg clock\n");
219 return PTR_ERR(ptr: rtc->clk_reg);
220 }
221
222 ret = clk_prepare_enable(clk: 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(clk: 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, data: 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(dev: &pdev->dev, irq, handler: lpc24xx_rtc_interrupt, irqflags: 0,
243 devname: pdev->name, dev_id: 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(dev: &pdev->dev, name: "lpc24xx-rtc",
250 ops: &lpc24xx_rtc_ops, THIS_MODULE);
251 if (IS_ERR(ptr: rtc->rtc)) {
252 dev_err(&pdev->dev, "can't register rtc device\n");
253 ret = PTR_ERR(ptr: rtc->rtc);
254 goto disable_clks;
255 }
256
257 return 0;
258
259disable_clks:
260 clk_disable_unprepare(clk: rtc->clk_reg);
261disable_rtc_clk:
262 clk_disable_unprepare(clk: rtc->clk_rtc);
263 return ret;
264}
265
266static 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(clk: rtc->clk_rtc);
277 clk_disable_unprepare(clk: rtc->clk_reg);
278}
279
280static const struct of_device_id lpc24xx_rtc_match[] = {
281 { .compatible = "nxp,lpc1788-rtc" },
282 { }
283};
284MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
285
286static 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};
294module_platform_driver(lpc24xx_rtc_driver);
295
296MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
297MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
298MODULE_LICENSE("GPL");
299

source code of linux/drivers/rtc/rtc-lpc24xx.c