tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007-2009 ST-Ericsson AB
4 * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
5 * Author: Linus Walleij <linus.walleij@stericsson.com>
6 * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
7 * Copyright 2006 (c) MontaVista Software, Inc.
8 */
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/mod_devicetable.h>
12#include <linux/rtc.h>
13#include <linux/clk.h>
14#include <linux/interrupt.h>
15#include <linux/pm.h>
16#include <linux/platform_device.h>
17#include <linux/io.h>
18#include <linux/slab.h>
19
20/*
21 * Registers in the COH 901 331
22 */
23/* Alarm value 32bit (R/W) */
24#define COH901331_ALARM 0x00U
25/* Used to set current time 32bit (R/W) */
26#define COH901331_SET_TIME 0x04U
27/* Indication if current time is valid 32bit (R/-) */
28#define COH901331_VALID 0x08U
29/* Read the current time 32bit (R/-) */
30#define COH901331_CUR_TIME 0x0cU
31/* Event register for the "alarm" interrupt */
32#define COH901331_IRQ_EVENT 0x10U
33/* Mask register for the "alarm" interrupt */
34#define COH901331_IRQ_MASK 0x14U
35/* Force register for the "alarm" interrupt */
36#define COH901331_IRQ_FORCE 0x18U
37
38/*
39 * Reference to RTC block clock
40 * Notice that the frequent clk_enable()/clk_disable() on this
41 * clock is mainly to be able to turn on/off other clocks in the
42 * hierarchy as needed, the RTC clock is always on anyway.
43 */
44struct coh901331_port {
45 struct rtc_device *rtc;
46 struct clk *clk;
47 void __iomem *virtbase;
48 int irq;
49#ifdef CONFIG_PM_SLEEP
50 u32 irqmaskstore;
51#endif
52};
53
54static irqreturn_t coh901331_interrupt(int irq, void *data)
55{
56 struct coh901331_port *rtap = data;
57
58 clk_enable(rtap->clk);
59 /* Ack IRQ */
60 writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
61 /*
62 * Disable the interrupt. This is necessary because
63 * the RTC lives on a lower-clocked line and will
64 * not release the IRQ line until after a few (slower)
65 * clock cycles. The interrupt will be re-enabled when
66 * a new alarm is set anyway.
67 */
68 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
69 clk_disable(rtap->clk);
70
71 /* Set alarm flag */
72 rtc_update_irq(rtap->rtc, 1, RTC_AF);
73
74 return IRQ_HANDLED;
75}
76
77static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
78{
79 struct coh901331_port *rtap = dev_get_drvdata(dev);
80
81 clk_enable(rtap->clk);
82 /* Check if the time is valid */
83 if (!readl(rtap->virtbase + COH901331_VALID)) {
84 clk_disable(rtap->clk);
85 return -EINVAL;
86 }
87
88 rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
89 clk_disable(rtap->clk);
90 return 0;
91}
92
93static int coh901331_set_time(struct device *dev, struct rtc_time *tm)
94{
95 struct coh901331_port *rtap = dev_get_drvdata(dev);
96
97 clk_enable(rtap->clk);
98 writel(rtc_tm_to_time64(tm), rtap->virtbase + COH901331_SET_TIME);
99 clk_disable(rtap->clk);
100
101 return 0;
102}
103
104static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
105{
106 struct coh901331_port *rtap = dev_get_drvdata(dev);
107
108 clk_enable(rtap->clk);
109 rtc_time64_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
110 alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
111 alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
112 clk_disable(rtap->clk);
113
114 return 0;
115}
116
117static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
118{
119 struct coh901331_port *rtap = dev_get_drvdata(dev);
120 unsigned long time = rtc_tm_to_time64(&alarm->time);
121
122 clk_enable(rtap->clk);
123 writel(time, rtap->virtbase + COH901331_ALARM);
124 writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
125 clk_disable(rtap->clk);
126
127 return 0;
128}
129
130static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
131{
132 struct coh901331_port *rtap = dev_get_drvdata(dev);
133
134 clk_enable(rtap->clk);
135 if (enabled)
136 writel(1, rtap->virtbase + COH901331_IRQ_MASK);
137 else
138 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
139 clk_disable(rtap->clk);
140
141 return 0;
142}
143
144static const struct rtc_class_ops coh901331_ops = {
145 .read_time = coh901331_read_time,
146 .set_time = coh901331_set_time,
147 .read_alarm = coh901331_read_alarm,
148 .set_alarm = coh901331_set_alarm,
149 .alarm_irq_enable = coh901331_alarm_irq_enable,
150};
151
152static int __exit coh901331_remove(struct platform_device *pdev)
153{
154 struct coh901331_port *rtap = platform_get_drvdata(pdev);
155
156 if (rtap)
157 clk_unprepare(rtap->clk);
158
159 return 0;
160}
161
162
163static int __init coh901331_probe(struct platform_device *pdev)
164{
165 int ret;
166 struct coh901331_port *rtap;
167 struct resource *res;
168
169 rtap = devm_kzalloc(&pdev->dev,
170 sizeof(struct coh901331_port), GFP_KERNEL);
171 if (!rtap)
172 return -ENOMEM;
173
174 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
175 rtap->virtbase = devm_ioremap_resource(&pdev->dev, res);
176 if (IS_ERR(rtap->virtbase))
177 return PTR_ERR(rtap->virtbase);
178
179 rtap->irq = platform_get_irq(pdev, 0);
180 if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
181 "RTC COH 901 331 Alarm", rtap))
182 return -EIO;
183
184 rtap->clk = devm_clk_get(&pdev->dev, NULL);
185 if (IS_ERR(rtap->clk)) {
186 ret = PTR_ERR(rtap->clk);
187 dev_err(&pdev->dev, "could not get clock\n");
188 return ret;
189 }
190
191 rtap->rtc = devm_rtc_allocate_device(&pdev->dev);
192 if (IS_ERR(rtap->rtc))
193 return PTR_ERR(rtap->rtc);
194
195 rtap->rtc->ops = &coh901331_ops;
196 rtap->rtc->range_max = U32_MAX;
197
198 /* We enable/disable the clock only to assure it works */
199 ret = clk_prepare_enable(rtap->clk);
200 if (ret) {
201 dev_err(&pdev->dev, "could not enable clock\n");
202 return ret;
203 }
204 clk_disable(rtap->clk);
205
206 platform_set_drvdata(pdev, rtap);
207
208 ret = rtc_register_device(rtap->rtc);
209 if (ret)
210 goto out_no_rtc;
211
212 return 0;
213
214 out_no_rtc:
215 clk_unprepare(rtap->clk);
216 return ret;
217}
218
219#ifdef CONFIG_PM_SLEEP
220static int coh901331_suspend(struct device *dev)
221{
222 struct coh901331_port *rtap = dev_get_drvdata(dev);
223
224 /*
225 * If this RTC alarm will be used for waking the system up,
226 * don't disable it of course. Else we just disable the alarm
227 * and await suspension.
228 */
229 if (device_may_wakeup(dev)) {
230 enable_irq_wake(rtap->irq);
231 } else {
232 clk_enable(rtap->clk);
233 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
234 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
235 clk_disable(rtap->clk);
236 }
237 clk_unprepare(rtap->clk);
238 return 0;
239}
240
241static int coh901331_resume(struct device *dev)
242{
243 int ret;
244 struct coh901331_port *rtap = dev_get_drvdata(dev);
245
246 ret = clk_prepare(rtap->clk);
247 if (ret)
248 return ret;
249
250 if (device_may_wakeup(dev)) {
251 disable_irq_wake(rtap->irq);
252 } else {
253 clk_enable(rtap->clk);
254 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
255 clk_disable(rtap->clk);
256 }
257 return 0;
258}
259#endif
260
261static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
262
263static void coh901331_shutdown(struct platform_device *pdev)
264{
265 struct coh901331_port *rtap = platform_get_drvdata(pdev);
266
267 clk_enable(rtap->clk);
268 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
269 clk_disable_unprepare(rtap->clk);
270}
271
272static const struct of_device_id coh901331_dt_match[] = {
273 { .compatible = "stericsson,coh901331" },
274 {},
275};
276MODULE_DEVICE_TABLE(of, coh901331_dt_match);
277
278static struct platform_driver coh901331_driver = {
279 .driver = {
280 .name = "rtc-coh901331",
281 .pm = &coh901331_pm_ops,
282 .of_match_table = coh901331_dt_match,
283 },
284 .remove = __exit_p(coh901331_remove),
285 .shutdown = coh901331_shutdown,
286};
287
288module_platform_driver_probe(coh901331_driver, coh901331_probe);
289
290MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
291MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
292MODULE_LICENSE("GPL");