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 | |
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 | |
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 | |
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(tm: &wkalrm->time); |
128 | } |
129 | |
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 | |
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 | |
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->rtc, num: 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 | |
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(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 | |
259 | disable_clks: |
260 | clk_disable_unprepare(clk: rtc->clk_reg); |
261 | disable_rtc_clk: |
262 | clk_disable_unprepare(clk: rtc->clk_rtc); |
263 | return ret; |
264 | } |
265 | |
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(clk: rtc->clk_rtc); |
277 | clk_disable_unprepare(clk: 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 | |