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(&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, 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(&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
259disable_clks:
260	clk_disable_unprepare(rtc->clk_reg);
261disable_rtc_clk:
262	clk_disable_unprepare(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(rtc->clk_rtc);
277	clk_disable_unprepare(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