tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Real Time Clock driver for Freescale MC13783 PMIC
3 *
4 * (C) 2009 Sascha Hauer, Pengutronix
5 * (C) 2009 Uwe Kleine-Koenig, Pengutronix
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 version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/mfd/mc13783.h>
13#include <linux/platform_device.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/rtc.h>
17
18#define DRIVER_NAME "mc13783-rtc"
19
20#define MC13783_RTCTOD 20
21#define MC13783_RTCTODA 21
22#define MC13783_RTCDAY 22
23#define MC13783_RTCDAYA 23
24
25struct mc13783_rtc {
26 struct rtc_device *rtc;
27 struct mc13783 *mc13783;
28 int valid;
29};
30
31static int mc13783_rtc_read_time(struct device *dev, struct rtc_time *tm)
32{
33 struct mc13783_rtc *priv = dev_get_drvdata(dev);
34 unsigned int seconds, days1, days2;
35 unsigned long s1970;
36 int ret;
37
38 mc13783_lock(priv->mc13783);
39
40 if (!priv->valid) {
41 ret = -ENODATA;
42 goto out;
43 }
44
45 ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days1);
46 if (unlikely(ret))
47 goto out;
48
49 ret = mc13783_reg_read(priv->mc13783, MC13783_RTCTOD, &seconds);
50 if (unlikely(ret))
51 goto out;
52
53 ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days2);
54out:
55 mc13783_unlock(priv->mc13783);
56
57 if (ret)
58 return ret;
59
60 if (days2 == days1 + 1) {
61 if (seconds >= 86400 / 2)
62 days2 = days1;
63 else
64 days1 = days2;
65 }
66
67 if (days1 != days2)
68 return -EIO;
69
70 s1970 = days1 * 86400 + seconds;
71
72 rtc_time_to_tm(s1970, tm);
73
74 return rtc_valid_tm(tm);
75}
76
77static int mc13783_rtc_set_mmss(struct device *dev, unsigned long secs)
78{
79 struct mc13783_rtc *priv = dev_get_drvdata(dev);
80 unsigned int seconds, days;
81 int ret;
82
83 seconds = secs % 86400;
84 days = secs / 86400;
85
86 mc13783_lock(priv->mc13783);
87
88 /*
89 * first write seconds=0 to prevent a day switch between writing days
90 * and seconds below
91 */
92 ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, 0);
93 if (unlikely(ret))
94 goto out;
95
96 ret = mc13783_reg_write(priv->mc13783, MC13783_RTCDAY, days);
97 if (unlikely(ret))
98 goto out;
99
100 ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, seconds);
101 if (unlikely(ret))
102 goto out;
103
104 ret = mc13783_ackirq(priv->mc13783, MC13783_IRQ_RTCRST);
105 if (unlikely(ret))
106 goto out;
107
108 ret = mc13783_unmask(priv->mc13783, MC13783_IRQ_RTCRST);
109out:
110 priv->valid = !ret;
111
112 mc13783_unlock(priv->mc13783);
113
114 return ret;
115}
116
117static irqreturn_t mc13783_rtc_update_handler(int irq, void *dev)
118{
119 struct mc13783_rtc *priv = dev;
120 struct mc13783 *mc13783 = priv->mc13783;
121
122 dev_dbg(&priv->rtc->dev, "1HZ\n");
123
124 rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
125
126 mc13783_ackirq(mc13783, irq);
127
128 return IRQ_HANDLED;
129}
130
131static int mc13783_rtc_update_irq_enable(struct device *dev,
132 unsigned int enabled)
133{
134 struct mc13783_rtc *priv = dev_get_drvdata(dev);
135 int ret = -ENODATA;
136
137 mc13783_lock(priv->mc13783);
138 if (!priv->valid)
139 goto out;
140
141 ret = (enabled ? mc13783_unmask : mc13783_mask)(priv->mc13783,
142 MC13783_IRQ_1HZ);
143out:
144 mc13783_unlock(priv->mc13783);
145
146 return ret;
147}
148
149static const struct rtc_class_ops mc13783_rtc_ops = {
150 .read_time = mc13783_rtc_read_time,
151 .set_mmss = mc13783_rtc_set_mmss,
152 .update_irq_enable = mc13783_rtc_update_irq_enable,
153};
154
155static irqreturn_t mc13783_rtc_reset_handler(int irq, void *dev)
156{
157 struct mc13783_rtc *priv = dev;
158 struct mc13783 *mc13783 = priv->mc13783;
159
160 dev_dbg(&priv->rtc->dev, "RTCRST\n");
161 priv->valid = 0;
162
163 mc13783_mask(mc13783, irq);
164
165 return IRQ_HANDLED;
166}
167
168static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
169{
170 int ret;
171 struct mc13783_rtc *priv;
172
173 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
174 if (!priv)
175 return -ENOMEM;
176
177 priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
178 platform_set_drvdata(pdev, priv);
179
180 priv->valid = 1;
181
182 mc13783_lock(priv->mc13783);
183
184 ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_RTCRST,
185 mc13783_rtc_reset_handler, DRIVER_NAME, priv);
186 if (ret)
187 goto err_reset_irq_request;
188
189 ret = mc13783_irq_request_nounmask(priv->mc13783, MC13783_IRQ_1HZ,
190 mc13783_rtc_update_handler, DRIVER_NAME, priv);
191 if (ret)
192 goto err_update_irq_request;
193
194 mc13783_unlock(priv->mc13783);
195
196 priv->rtc = rtc_device_register(pdev->name,
197 &pdev->dev, &mc13783_rtc_ops, THIS_MODULE);
198
199 if (IS_ERR(priv->rtc)) {
200 ret = PTR_ERR(priv->rtc);
201
202 mc13783_lock(priv->mc13783);
203
204 mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
205err_update_irq_request:
206
207 mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
208err_reset_irq_request:
209
210 mc13783_unlock(priv->mc13783);
211
212 platform_set_drvdata(pdev, NULL);
213 kfree(priv);
214 }
215
216 return ret;
217}
218
219static int __devexit mc13783_rtc_remove(struct platform_device *pdev)
220{
221 struct mc13783_rtc *priv = platform_get_drvdata(pdev);
222
223 rtc_device_unregister(priv->rtc);
224
225 mc13783_lock(priv->mc13783);
226
227 mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
228 mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
229
230 mc13783_unlock(priv->mc13783);
231
232 platform_set_drvdata(pdev, NULL);
233
234 kfree(priv);
235
236 return 0;
237}
238
239static struct platform_driver mc13783_rtc_driver = {
240 .remove = __devexit_p(mc13783_rtc_remove),
241 .driver = {
242 .name = DRIVER_NAME,
243 .owner = THIS_MODULE,
244 },
245};
246
247static int __init mc13783_rtc_init(void)
248{
249 return platform_driver_probe(&mc13783_rtc_driver, &mc13783_rtc_probe);
250}
251module_init(mc13783_rtc_init);
252
253static void __exit mc13783_rtc_exit(void)
254{
255 platform_driver_unregister(&mc13783_rtc_driver);
256}
257module_exit(mc13783_rtc_exit);
258
259MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
260MODULE_DESCRIPTION("RTC driver for Freescale MC13783 PMIC");
261MODULE_LICENSE("GPL v2");
262MODULE_ALIAS("platform:" DRIVER_NAME);