tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC)
3 *
4 * Copyright (C) 2011 NXP Semiconductors
5 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 */
13
14#include <linux/clk.h>
15#include <linux/io.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/of_device.h>
20#include <linux/platform_device.h>
21#include <linux/rtc.h>
22
23/* LPC24xx RTC register offsets and bits */
24#define LPC24XX_ILR 0x00
25#define LPC24XX_RTCCIF BIT(0)
26#define LPC24XX_RTCALF BIT(1)
27#define LPC24XX_CTC 0x04
28#define LPC24XX_CCR 0x08
29#define LPC24XX_CLKEN BIT(0)
30#define LPC178X_CCALEN BIT(4)
31#define LPC24XX_CIIR 0x0c
32#define LPC24XX_AMR 0x10
33#define LPC24XX_ALARM_DISABLE 0xff
34#define LPC24XX_CTIME0 0x14
35#define LPC24XX_CTIME1 0x18
36#define LPC24XX_CTIME2 0x1c
37#define LPC24XX_SEC 0x20
38#define LPC24XX_MIN 0x24
39#define LPC24XX_HOUR 0x28
40#define LPC24XX_DOM 0x2c
41#define LPC24XX_DOW 0x30
42#define LPC24XX_DOY 0x34
43#define LPC24XX_MONTH 0x38
44#define LPC24XX_YEAR 0x3c
45#define LPC24XX_ALSEC 0x60
46#define LPC24XX_ALMIN 0x64
47#define LPC24XX_ALHOUR 0x68
48#define LPC24XX_ALDOM 0x6c
49#define LPC24XX_ALDOW 0x70
50#define LPC24XX_ALDOY 0x74
51#define LPC24XX_ALMON 0x78
52#define LPC24XX_ALYEAR 0x7c
53
54/* Macros to read fields in consolidated time (CT) registers */
55#define CT0_SECS(x) (((x) >> 0) & 0x3f)
56#define CT0_MINS(x) (((x) >> 8) & 0x3f)
57#define CT0_HOURS(x) (((x) >> 16) & 0x1f)
58#define CT0_DOW(x) (((x) >> 24) & 0x07)
59#define CT1_DOM(x) (((x) >> 0) & 0x1f)
60#define CT1_MONTH(x) (((x) >> 8) & 0x0f)
61#define CT1_YEAR(x) (((x) >> 16) & 0xfff)
62#define CT2_DOY(x) (((x) >> 0) & 0xfff)
63
64#define rtc_readl(dev, reg) readl((dev)->rtc_base + (reg))
65#define rtc_writel(dev, reg, val) writel((val), (dev)->rtc_base + (reg))
66
67struct lpc24xx_rtc {
68 void __iomem *rtc_base;
69 struct rtc_device *rtc;
70 struct clk *clk_rtc;
71 struct clk *clk_reg;
72};
73
74static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
75{
76 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
77
78 /* Disable RTC during update */
79 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
80
81 rtc_writel(rtc, LPC24XX_SEC, tm->tm_sec);
82 rtc_writel(rtc, LPC24XX_MIN, tm->tm_min);
83 rtc_writel(rtc, LPC24XX_HOUR, tm->tm_hour);
84 rtc_writel(rtc, LPC24XX_DOW, tm->tm_wday);
85 rtc_writel(rtc, LPC24XX_DOM, tm->tm_mday);
86 rtc_writel(rtc, LPC24XX_DOY, tm->tm_yday);
87 rtc_writel(rtc, LPC24XX_MONTH, tm->tm_mon);
88 rtc_writel(rtc, LPC24XX_YEAR, tm->tm_year);
89
90 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
91
92 return 0;
93}
94
95static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
96{
97 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
98 u32 ct0, ct1, ct2;
99
100 ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
101 ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
102 ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
103
104 tm->tm_sec = CT0_SECS(ct0);
105 tm->tm_min = CT0_MINS(ct0);
106 tm->tm_hour = CT0_HOURS(ct0);
107 tm->tm_wday = CT0_DOW(ct0);
108 tm->tm_mon = CT1_MONTH(ct1);
109 tm->tm_mday = CT1_DOM(ct1);
110 tm->tm_year = CT1_YEAR(ct1);
111 tm->tm_yday = CT2_DOY(ct2);
112
113 return rtc_valid_tm(tm);
114}
115
116static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
117{
118 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
119 struct rtc_time *tm = &wkalrm->time;
120
121 tm->tm_sec = rtc_readl(rtc, LPC24XX_ALSEC);
122 tm->tm_min = rtc_readl(rtc, LPC24XX_ALMIN);
123 tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
124 tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
125 tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
126 tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
127 tm->tm_mon = rtc_readl(rtc, LPC24XX_ALMON);
128 tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
129
130 wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
131 wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
132
133 return rtc_valid_tm(&wkalrm->time);
134}
135
136static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
137{
138 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
139 struct rtc_time *tm = &wkalrm->time;
140
141 /* Disable alarm irq during update */
142 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
143
144 rtc_writel(rtc, LPC24XX_ALSEC, tm->tm_sec);
145 rtc_writel(rtc, LPC24XX_ALMIN, tm->tm_min);
146 rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
147 rtc_writel(rtc, LPC24XX_ALDOM, tm->tm_mday);
148 rtc_writel(rtc, LPC24XX_ALDOW, tm->tm_wday);
149 rtc_writel(rtc, LPC24XX_ALDOY, tm->tm_yday);
150 rtc_writel(rtc, LPC24XX_ALMON, tm->tm_mon);
151 rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
152
153 if (wkalrm->enabled)
154 rtc_writel(rtc, LPC24XX_AMR, 0);
155
156 return 0;
157}
158
159static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
160{
161 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
162
163 if (enable)
164 rtc_writel(rtc, LPC24XX_AMR, 0);
165 else
166 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
167
168 return 0;
169}
170
171static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data)
172{
173 unsigned long events = RTC_IRQF;
174 struct lpc24xx_rtc *rtc = data;
175 u32 rtc_iir;
176
177 /* Check interrupt cause */
178 rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
179 if (rtc_iir & LPC24XX_RTCALF) {
180 events |= RTC_AF;
181 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
182 }
183
184 /* Clear interrupt status and report event */
185 rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
186 rtc_update_irq(rtc->rtc, 1, events);
187
188 return IRQ_HANDLED;
189}
190
191static const struct rtc_class_ops lpc24xx_rtc_ops = {
192 .read_time = lpc24xx_rtc_read_time,
193 .set_time = lpc24xx_rtc_set_time,
194 .read_alarm = lpc24xx_rtc_read_alarm,
195 .set_alarm = lpc24xx_rtc_set_alarm,
196 .alarm_irq_enable = lpc24xx_rtc_alarm_irq_enable,
197};
198
199static int lpc24xx_rtc_probe(struct platform_device *pdev)
200{
201 struct lpc24xx_rtc *rtc;
202 struct resource *res;
203 int irq, ret;
204
205 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
206 if (!rtc)
207 return -ENOMEM;
208
209 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
210 rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
211 if (IS_ERR(rtc->rtc_base))
212 return PTR_ERR(rtc->rtc_base);
213
214 irq = platform_get_irq(pdev, 0);
215 if (irq < 0) {
216 dev_warn(&pdev->dev, "can't get interrupt resource\n");
217 return irq;
218 }
219
220 rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
221 if (IS_ERR(rtc->clk_rtc)) {
222 dev_err(&pdev->dev, "error getting rtc clock\n");
223 return PTR_ERR(rtc->clk_rtc);
224 }
225
226 rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
227 if (IS_ERR(rtc->clk_reg)) {
228 dev_err(&pdev->dev, "error getting reg clock\n");
229 return PTR_ERR(rtc->clk_reg);
230 }
231
232 ret = clk_prepare_enable(rtc->clk_rtc);
233 if (ret) {
234 dev_err(&pdev->dev, "unable to enable rtc clock\n");
235 return ret;
236 }
237
238 ret = clk_prepare_enable(rtc->clk_reg);
239 if (ret) {
240 dev_err(&pdev->dev, "unable to enable reg clock\n");
241 goto disable_rtc_clk;
242 }
243
244 platform_set_drvdata(pdev, rtc);
245
246 /* Clear any pending interrupts */
247 rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF);
248
249 /* Enable RTC count */
250 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
251
252 ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
253 pdev->name, rtc);
254 if (ret < 0) {
255 dev_warn(&pdev->dev, "can't request interrupt\n");
256 goto disable_clks;
257 }
258
259 rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc",
260 &lpc24xx_rtc_ops, THIS_MODULE);
261 if (IS_ERR(rtc->rtc)) {
262 dev_err(&pdev->dev, "can't register rtc device\n");
263 ret = PTR_ERR(rtc->rtc);
264 goto disable_clks;
265 }
266
267 return 0;
268
269disable_clks:
270 clk_disable_unprepare(rtc->clk_reg);
271disable_rtc_clk:
272 clk_disable_unprepare(rtc->clk_rtc);
273 return ret;
274}
275
276static int lpc24xx_rtc_remove(struct platform_device *pdev)
277{
278 struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
279
280 /* Ensure all interrupt sources are masked */
281 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
282 rtc_writel(rtc, LPC24XX_CIIR, 0);
283
284 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
285
286 clk_disable_unprepare(rtc->clk_rtc);
287 clk_disable_unprepare(rtc->clk_reg);
288
289 return 0;
290}
291
292static const struct of_device_id lpc24xx_rtc_match[] = {
293 { .compatible = "nxp,lpc1788-rtc" },
294 { }
295};
296MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
297
298static struct platform_driver lpc24xx_rtc_driver = {
299 .probe = lpc24xx_rtc_probe,
300 .remove = lpc24xx_rtc_remove,
301 .driver = {
302 .name = "lpc24xx-rtc",
303 .of_match_table = lpc24xx_rtc_match,
304 },
305};
306module_platform_driver(lpc24xx_rtc_driver);
307
308MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
309MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
310MODULE_LICENSE("GPL");