tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2007-2009 ST-Ericsson AB
3 * License terms: GNU General Public License (GPL) version 2
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/rtc.h>
12#include <linux/clk.h>
13#include <linux/interrupt.h>
14#include <linux/pm.h>
15#include <linux/platform_device.h>
16#include <linux/io.h>
17#include <linux/slab.h>
18
19/*
20 * Registers in the COH 901 331
21 */
22/* Alarm value 32bit (R/W) */
23#define COH901331_ALARM 0x00U
24/* Used to set current time 32bit (R/W) */
25#define COH901331_SET_TIME 0x04U
26/* Indication if current time is valid 32bit (R/-) */
27#define COH901331_VALID 0x08U
28/* Read the current time 32bit (R/-) */
29#define COH901331_CUR_TIME 0x0cU
30/* Event register for the "alarm" interrupt */
31#define COH901331_IRQ_EVENT 0x10U
32/* Mask register for the "alarm" interrupt */
33#define COH901331_IRQ_MASK 0x14U
34/* Force register for the "alarm" interrupt */
35#define COH901331_IRQ_FORCE 0x18U
36
37/*
38 * Reference to RTC block clock
39 * Notice that the frequent clk_enable()/clk_disable() on this
40 * clock is mainly to be able to turn on/off other clocks in the
41 * hierarchy as needed, the RTC clock is always on anyway.
42 */
43struct coh901331_port {
44 struct rtc_device *rtc;
45 struct clk *clk;
46 u32 phybase;
47 u32 physize;
48 void __iomem *virtbase;
49 int irq;
50#ifdef CONFIG_PM_SLEEP
51 u32 irqmaskstore;
52#endif
53};
54
55static irqreturn_t coh901331_interrupt(int irq, void *data)
56{
57 struct coh901331_port *rtap = data;
58
59 clk_enable(rtap->clk);
60 /* Ack IRQ */
61 writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
62 /*
63 * Disable the interrupt. This is necessary because
64 * the RTC lives on a lower-clocked line and will
65 * not release the IRQ line until after a few (slower)
66 * clock cycles. The interrupt will be re-enabled when
67 * a new alarm is set anyway.
68 */
69 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
70 clk_disable(rtap->clk);
71
72 /* Set alarm flag */
73 rtc_update_irq(rtap->rtc, 1, RTC_AF);
74
75 return IRQ_HANDLED;
76}
77
78static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
79{
80 struct coh901331_port *rtap = dev_get_drvdata(dev);
81
82 clk_enable(rtap->clk);
83 /* Check if the time is valid */
84 if (readl(rtap->virtbase + COH901331_VALID)) {
85 rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
86 clk_disable(rtap->clk);
87 return rtc_valid_tm(tm);
88 }
89 clk_disable(rtap->clk);
90 return -EINVAL;
91}
92
93static int coh901331_set_mmss(struct device *dev, unsigned long secs)
94{
95 struct coh901331_port *rtap = dev_get_drvdata(dev);
96
97 clk_enable(rtap->clk);
98 writel(secs, 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_time_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;
121
122 rtc_tm_to_time(&alarm->time, &time);
123 clk_enable(rtap->clk);
124 writel(time, rtap->virtbase + COH901331_ALARM);
125 writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
126 clk_disable(rtap->clk);
127
128 return 0;
129}
130
131static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
132{
133 struct coh901331_port *rtap = dev_get_drvdata(dev);
134
135 clk_enable(rtap->clk);
136 if (enabled)
137 writel(1, rtap->virtbase + COH901331_IRQ_MASK);
138 else
139 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
140 clk_disable(rtap->clk);
141
142 return 0;
143}
144
145static struct rtc_class_ops coh901331_ops = {
146 .read_time = coh901331_read_time,
147 .set_mmss = coh901331_set_mmss,
148 .read_alarm = coh901331_read_alarm,
149 .set_alarm = coh901331_set_alarm,
150 .alarm_irq_enable = coh901331_alarm_irq_enable,
151};
152
153static int __exit coh901331_remove(struct platform_device *pdev)
154{
155 struct coh901331_port *rtap = platform_get_drvdata(pdev);
156
157 if (rtap)
158 clk_unprepare(rtap->clk);
159
160 return 0;
161}
162
163
164static int __init coh901331_probe(struct platform_device *pdev)
165{
166 int ret;
167 struct coh901331_port *rtap;
168 struct resource *res;
169
170 rtap = devm_kzalloc(&pdev->dev,
171 sizeof(struct coh901331_port), GFP_KERNEL);
172 if (!rtap)
173 return -ENOMEM;
174
175 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
176 if (!res)
177 return -ENOENT;
178
179 rtap->phybase = res->start;
180 rtap->physize = resource_size(res);
181
182 if (devm_request_mem_region(&pdev->dev, rtap->phybase, rtap->physize,
183 "rtc-coh901331") == NULL)
184 return -EBUSY;
185
186 rtap->virtbase = devm_ioremap(&pdev->dev, rtap->phybase, rtap->physize);
187 if (!rtap->virtbase)
188 return -ENOMEM;
189
190 rtap->irq = platform_get_irq(pdev, 0);
191 if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
192 "RTC COH 901 331 Alarm", rtap))
193 return -EIO;
194
195 rtap->clk = devm_clk_get(&pdev->dev, NULL);
196 if (IS_ERR(rtap->clk)) {
197 ret = PTR_ERR(rtap->clk);
198 dev_err(&pdev->dev, "could not get clock\n");
199 return ret;
200 }
201
202 /* We enable/disable the clock only to assure it works */
203 ret = clk_prepare_enable(rtap->clk);
204 if (ret) {
205 dev_err(&pdev->dev, "could not enable clock\n");
206 return ret;
207 }
208 clk_disable(rtap->clk);
209
210 platform_set_drvdata(pdev, rtap);
211 rtap->rtc = devm_rtc_device_register(&pdev->dev, "coh901331",
212 &coh901331_ops, THIS_MODULE);
213 if (IS_ERR(rtap->rtc)) {
214 ret = PTR_ERR(rtap->rtc);
215 goto out_no_rtc;
216 }
217
218 return 0;
219
220 out_no_rtc:
221 clk_unprepare(rtap->clk);
222 return ret;
223}
224
225#ifdef CONFIG_PM_SLEEP
226static int coh901331_suspend(struct device *dev)
227{
228 struct coh901331_port *rtap = dev_get_drvdata(dev);
229
230 /*
231 * If this RTC alarm will be used for waking the system up,
232 * don't disable it of course. Else we just disable the alarm
233 * and await suspension.
234 */
235 if (device_may_wakeup(dev)) {
236 enable_irq_wake(rtap->irq);
237 } else {
238 clk_enable(rtap->clk);
239 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
240 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
241 clk_disable(rtap->clk);
242 }
243 clk_unprepare(rtap->clk);
244 return 0;
245}
246
247static int coh901331_resume(struct device *dev)
248{
249 struct coh901331_port *rtap = dev_get_drvdata(dev);
250
251 clk_prepare(rtap->clk);
252 if (device_may_wakeup(dev)) {
253 disable_irq_wake(rtap->irq);
254 } else {
255 clk_enable(rtap->clk);
256 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
257 clk_disable(rtap->clk);
258 }
259 return 0;
260}
261#endif
262
263static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
264
265static void coh901331_shutdown(struct platform_device *pdev)
266{
267 struct coh901331_port *rtap = platform_get_drvdata(pdev);
268
269 clk_enable(rtap->clk);
270 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
271 clk_disable_unprepare(rtap->clk);
272}
273
274static const struct of_device_id coh901331_dt_match[] = {
275 { .compatible = "stericsson,coh901331" },
276 {},
277};
278
279static struct platform_driver coh901331_driver = {
280 .driver = {
281 .name = "rtc-coh901331",
282 .owner = THIS_MODULE,
283 .pm = &coh901331_pm_ops,
284 .of_match_table = coh901331_dt_match,
285 },
286 .remove = __exit_p(coh901331_remove),
287 .shutdown = coh901331_shutdown,
288};
289
290module_platform_driver_probe(coh901331_driver, coh901331_probe);
291
292MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
293MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
294MODULE_LICENSE("GPL");