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b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
b5b2bdfc LJ |
2 | /* |
3 | * rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer | |
4 | * | |
5 | * Copyright (C) 2014 STMicroelectronics Limited | |
6 | * | |
7 | * Author: David Paris <david.paris@st.com> for STMicroelectronics | |
8 | * Lee Jones <lee.jones@linaro.org> for STMicroelectronics | |
9 | * | |
10 | * Based on the original driver written by Stuart Menefy. | |
b5b2bdfc LJ |
11 | */ |
12 | ||
13 | #include <linux/clk.h> | |
14 | #include <linux/delay.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/io.h> | |
17 | #include <linux/irq.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/of.h> | |
21 | #include <linux/of_irq.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/rtc.h> | |
24 | ||
25 | #include <dt-bindings/mfd/st-lpc.h> | |
26 | ||
27 | /* Low Power Timer */ | |
28 | #define LPC_LPT_LSB_OFF 0x400 | |
29 | #define LPC_LPT_MSB_OFF 0x404 | |
30 | #define LPC_LPT_START_OFF 0x408 | |
31 | ||
32 | /* Low Power Alarm */ | |
33 | #define LPC_LPA_LSB_OFF 0x410 | |
34 | #define LPC_LPA_MSB_OFF 0x414 | |
35 | #define LPC_LPA_START_OFF 0x418 | |
36 | ||
37 | /* LPC as WDT */ | |
38 | #define LPC_WDT_OFF 0x510 | |
39 | #define LPC_WDT_FLAG_OFF 0x514 | |
40 | ||
41 | struct st_rtc { | |
42 | struct rtc_device *rtc_dev; | |
43 | struct rtc_wkalrm alarm; | |
b5b2bdfc LJ |
44 | struct clk *clk; |
45 | unsigned long clkrate; | |
46 | void __iomem *ioaddr; | |
47 | bool irq_enabled:1; | |
48 | spinlock_t lock; | |
49 | short irq; | |
50 | }; | |
51 | ||
52 | static void st_rtc_set_hw_alarm(struct st_rtc *rtc, | |
53 | unsigned long msb, unsigned long lsb) | |
54 | { | |
55 | unsigned long flags; | |
56 | ||
57 | spin_lock_irqsave(&rtc->lock, flags); | |
58 | ||
59 | writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); | |
60 | ||
61 | writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF); | |
62 | writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF); | |
63 | writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF); | |
64 | ||
65 | writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); | |
66 | ||
67 | spin_unlock_irqrestore(&rtc->lock, flags); | |
68 | } | |
69 | ||
70 | static irqreturn_t st_rtc_handler(int this_irq, void *data) | |
71 | { | |
72 | struct st_rtc *rtc = (struct st_rtc *)data; | |
73 | ||
74 | rtc_update_irq(rtc->rtc_dev, 1, RTC_AF); | |
75 | ||
76 | return IRQ_HANDLED; | |
77 | } | |
78 | ||
79 | static int st_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
80 | { | |
81 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
82 | unsigned long lpt_lsb, lpt_msb; | |
83 | unsigned long long lpt; | |
84 | unsigned long flags; | |
85 | ||
86 | spin_lock_irqsave(&rtc->lock, flags); | |
87 | ||
88 | do { | |
89 | lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF); | |
90 | lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF); | |
91 | } while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb); | |
92 | ||
93 | spin_unlock_irqrestore(&rtc->lock, flags); | |
94 | ||
95 | lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb; | |
96 | do_div(lpt, rtc->clkrate); | |
f4b82d39 | 97 | rtc_time64_to_tm(lpt, tm); |
b5b2bdfc LJ |
98 | |
99 | return 0; | |
100 | } | |
101 | ||
102 | static int st_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
103 | { | |
104 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
f4b82d39 BG |
105 | unsigned long long lpt, secs; |
106 | unsigned long flags; | |
b5b2bdfc | 107 | |
f4b82d39 | 108 | secs = rtc_tm_to_time64(tm); |
b5b2bdfc LJ |
109 | |
110 | lpt = (unsigned long long)secs * rtc->clkrate; | |
111 | ||
112 | spin_lock_irqsave(&rtc->lock, flags); | |
113 | ||
114 | writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF); | |
115 | writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF); | |
116 | writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF); | |
117 | ||
118 | spin_unlock_irqrestore(&rtc->lock, flags); | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
123 | static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) | |
124 | { | |
125 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
126 | unsigned long flags; | |
127 | ||
128 | spin_lock_irqsave(&rtc->lock, flags); | |
129 | ||
130 | memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm)); | |
131 | ||
132 | spin_unlock_irqrestore(&rtc->lock, flags); | |
133 | ||
134 | return 0; | |
135 | } | |
136 | ||
137 | static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) | |
138 | { | |
139 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
140 | ||
141 | if (enabled && !rtc->irq_enabled) { | |
142 | enable_irq(rtc->irq); | |
143 | rtc->irq_enabled = true; | |
144 | } else if (!enabled && rtc->irq_enabled) { | |
145 | disable_irq(rtc->irq); | |
146 | rtc->irq_enabled = false; | |
147 | } | |
148 | ||
149 | return 0; | |
150 | } | |
151 | ||
152 | static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) | |
153 | { | |
154 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
155 | struct rtc_time now; | |
f4b82d39 BG |
156 | unsigned long long now_secs; |
157 | unsigned long long alarm_secs; | |
b5b2bdfc LJ |
158 | unsigned long long lpa; |
159 | ||
160 | st_rtc_read_time(dev, &now); | |
f4b82d39 BG |
161 | now_secs = rtc_tm_to_time64(&now); |
162 | alarm_secs = rtc_tm_to_time64(&t->time); | |
b5b2bdfc | 163 | |
b5b2bdfc LJ |
164 | memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm)); |
165 | ||
166 | /* Now many secs to fire */ | |
167 | alarm_secs -= now_secs; | |
168 | lpa = (unsigned long long)alarm_secs * rtc->clkrate; | |
169 | ||
170 | st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa); | |
171 | st_rtc_alarm_irq_enable(dev, t->enabled); | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
176 | static struct rtc_class_ops st_rtc_ops = { | |
177 | .read_time = st_rtc_read_time, | |
178 | .set_time = st_rtc_set_time, | |
179 | .read_alarm = st_rtc_read_alarm, | |
180 | .set_alarm = st_rtc_set_alarm, | |
181 | .alarm_irq_enable = st_rtc_alarm_irq_enable, | |
182 | }; | |
183 | ||
184 | static int st_rtc_probe(struct platform_device *pdev) | |
185 | { | |
186 | struct device_node *np = pdev->dev.of_node; | |
187 | struct st_rtc *rtc; | |
b5b2bdfc LJ |
188 | uint32_t mode; |
189 | int ret = 0; | |
190 | ||
191 | ret = of_property_read_u32(np, "st,lpc-mode", &mode); | |
192 | if (ret) { | |
193 | dev_err(&pdev->dev, "An LPC mode must be provided\n"); | |
194 | return -EINVAL; | |
195 | } | |
196 | ||
742e4097 | 197 | /* LPC can either run as a Clocksource or in RTC or WDT mode */ |
b5b2bdfc LJ |
198 | if (mode != ST_LPC_MODE_RTC) |
199 | return -ENODEV; | |
200 | ||
201 | rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL); | |
202 | if (!rtc) | |
203 | return -ENOMEM; | |
204 | ||
d482510f AB |
205 | rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); |
206 | if (IS_ERR(rtc->rtc_dev)) | |
207 | return PTR_ERR(rtc->rtc_dev); | |
208 | ||
b5b2bdfc LJ |
209 | spin_lock_init(&rtc->lock); |
210 | ||
09ef18bc | 211 | rtc->ioaddr = devm_platform_ioremap_resource(pdev, 0); |
b5b2bdfc LJ |
212 | if (IS_ERR(rtc->ioaddr)) |
213 | return PTR_ERR(rtc->ioaddr); | |
214 | ||
215 | rtc->irq = irq_of_parse_and_map(np, 0); | |
216 | if (!rtc->irq) { | |
217 | dev_err(&pdev->dev, "IRQ missing or invalid\n"); | |
218 | return -EINVAL; | |
219 | } | |
220 | ||
221 | ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0, | |
222 | pdev->name, rtc); | |
223 | if (ret) { | |
224 | dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq); | |
225 | return ret; | |
226 | } | |
227 | ||
228 | enable_irq_wake(rtc->irq); | |
229 | disable_irq(rtc->irq); | |
230 | ||
231 | rtc->clk = clk_get(&pdev->dev, NULL); | |
232 | if (IS_ERR(rtc->clk)) { | |
233 | dev_err(&pdev->dev, "Unable to request clock\n"); | |
234 | return PTR_ERR(rtc->clk); | |
235 | } | |
236 | ||
237 | clk_prepare_enable(rtc->clk); | |
238 | ||
239 | rtc->clkrate = clk_get_rate(rtc->clk); | |
240 | if (!rtc->clkrate) { | |
241 | dev_err(&pdev->dev, "Unable to fetch clock rate\n"); | |
242 | return -EINVAL; | |
243 | } | |
244 | ||
245 | device_set_wakeup_capable(&pdev->dev, 1); | |
246 | ||
247 | platform_set_drvdata(pdev, rtc); | |
248 | ||
d482510f | 249 | rtc->rtc_dev->ops = &st_rtc_ops; |
b64c984a AB |
250 | rtc->rtc_dev->range_max = U64_MAX; |
251 | do_div(rtc->rtc_dev->range_max, rtc->clkrate); | |
d482510f AB |
252 | |
253 | ret = rtc_register_device(rtc->rtc_dev); | |
254 | if (ret) { | |
b5b2bdfc | 255 | clk_disable_unprepare(rtc->clk); |
d482510f | 256 | return ret; |
b5b2bdfc LJ |
257 | } |
258 | ||
259 | return 0; | |
260 | } | |
261 | ||
b5b2bdfc LJ |
262 | #ifdef CONFIG_PM_SLEEP |
263 | static int st_rtc_suspend(struct device *dev) | |
264 | { | |
265 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
266 | ||
267 | if (device_may_wakeup(dev)) | |
268 | return 0; | |
269 | ||
270 | writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); | |
271 | writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF); | |
272 | writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); | |
273 | ||
274 | return 0; | |
275 | } | |
276 | ||
277 | static int st_rtc_resume(struct device *dev) | |
278 | { | |
279 | struct st_rtc *rtc = dev_get_drvdata(dev); | |
280 | ||
281 | rtc_alarm_irq_enable(rtc->rtc_dev, 0); | |
282 | ||
283 | /* | |
284 | * clean 'rtc->alarm' to allow a new | |
285 | * .set_alarm to the upper RTC layer | |
286 | */ | |
287 | memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm)); | |
288 | ||
289 | writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF); | |
290 | writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF); | |
291 | writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); | |
292 | writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF); | |
293 | writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); | |
294 | ||
295 | return 0; | |
296 | } | |
297 | #endif | |
298 | ||
299 | static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume); | |
300 | ||
301 | static const struct of_device_id st_rtc_match[] = { | |
302 | { .compatible = "st,stih407-lpc" }, | |
303 | {} | |
304 | }; | |
305 | MODULE_DEVICE_TABLE(of, st_rtc_match); | |
306 | ||
307 | static struct platform_driver st_rtc_platform_driver = { | |
308 | .driver = { | |
309 | .name = "st-lpc-rtc", | |
310 | .pm = &st_rtc_pm_ops, | |
311 | .of_match_table = st_rtc_match, | |
312 | }, | |
313 | .probe = st_rtc_probe, | |
b5b2bdfc LJ |
314 | }; |
315 | ||
316 | module_platform_driver(st_rtc_platform_driver); | |
317 | ||
318 | MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver"); | |
319 | MODULE_AUTHOR("David Paris <david.paris@st.com>"); | |
320 | MODULE_LICENSE("GPL"); |