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 * RTC clock driver for the AB3100 Analog Baseband Chip
5 * Author: Linus Walleij <linus.walleij@stericsson.com>
6 */
7#include <linux/module.h>
8#include <linux/kernel.h>
9#include <linux/init.h>
10#include <linux/platform_device.h>
11#include <linux/rtc.h>
12#include <linux/mfd/ab3100.h>
13
14/* Clock rate in Hz */
15#define AB3100_RTC_CLOCK_RATE 32768
16
17/*
18 * The AB3100 RTC registers. These are the same for
19 * AB3000 and AB3100.
20 * Control register:
21 * Bit 0: RTC Monitor cleared=0, active=1, if you set it
22 * to 1 it remains active until RTC power is lost.
23 * Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass
24 * Bit 2: Alarm on, 0 = off, 1 = on
25 * Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled
26 */
27#define AB3100_RTC 0x53
28/* default setting, buffer disabled, alarm on */
29#define RTC_SETTING 0x30
30/* Alarm when AL0-AL3 == TI0-TI3 */
31#define AB3100_AL0 0x56
32#define AB3100_AL1 0x57
33#define AB3100_AL2 0x58
34#define AB3100_AL3 0x59
35/* This 48-bit register that counts up at 32768 Hz */
36#define AB3100_TI0 0x5a
37#define AB3100_TI1 0x5b
38#define AB3100_TI2 0x5c
39#define AB3100_TI3 0x5d
40#define AB3100_TI4 0x5e
41#define AB3100_TI5 0x5f
42
43/*
44 * RTC clock functions and device struct declaration
45 */
46static int ab3100_rtc_set_mmss(struct device *dev, unsigned long secs)
47{
48 struct ab3100 *ab3100_data = dev_get_drvdata(dev);
49 u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2,
50 AB3100_TI3, AB3100_TI4, AB3100_TI5};
51 unsigned char buf[6];
52 u64 fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2;
53 int err = 0;
54 int i;
55
56 buf[0] = (fat_time) & 0xFF;
57 buf[1] = (fat_time >> 8) & 0xFF;
58 buf[2] = (fat_time >> 16) & 0xFF;
59 buf[3] = (fat_time >> 24) & 0xFF;
60 buf[4] = (fat_time >> 32) & 0xFF;
61 buf[5] = (fat_time >> 40) & 0xFF;
62
63 for (i = 0; i < 6; i++) {
64 err = ab3100_set_register_interruptible(ab3100_data,
65 regs[i], buf[i]);
66 if (err)
67 return err;
68 }
69
70 /* Set the flag to mark that the clock is now set */
71 return ab3100_mask_and_set_register_interruptible(ab3100_data,
72 AB3100_RTC,
73 0xFE, 0x01);
74
75}
76
77static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm)
78{
79 struct ab3100 *ab3100_data = dev_get_drvdata(dev);
80 unsigned long time;
81 u8 rtcval;
82 int err;
83
84 err = ab3100_get_register_interruptible(ab3100_data,
85 AB3100_RTC, &rtcval);
86 if (err)
87 return err;
88
89 if (!(rtcval & 0x01)) {
90 dev_info(dev, "clock not set (lost power)");
91 return -EINVAL;
92 } else {
93 u64 fat_time;
94 u8 buf[6];
95
96 /* Read out time registers */
97 err = ab3100_get_register_page_interruptible(ab3100_data,
98 AB3100_TI0,
99 buf, 6);
100 if (err != 0)
101 return err;
102
103 fat_time = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) |
104 ((u64) buf[3] << 24) | ((u64) buf[2] << 16) |
105 ((u64) buf[1] << 8) | (u64) buf[0];
106 time = (unsigned long) (fat_time /
107 (u64) (AB3100_RTC_CLOCK_RATE * 2));
108 }
109
110 rtc_time_to_tm(time, tm);
111
112 return rtc_valid_tm(tm);
113}
114
115static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
116{
117 struct ab3100 *ab3100_data = dev_get_drvdata(dev);
118 unsigned long time;
119 u64 fat_time;
120 u8 buf[6];
121 u8 rtcval;
122 int err;
123
124 /* Figure out if alarm is enabled or not */
125 err = ab3100_get_register_interruptible(ab3100_data,
126 AB3100_RTC, &rtcval);
127 if (err)
128 return err;
129 if (rtcval & 0x04)
130 alarm->enabled = 1;
131 else
132 alarm->enabled = 0;
133 /* No idea how this could be represented */
134 alarm->pending = 0;
135 /* Read out alarm registers, only 4 bytes */
136 err = ab3100_get_register_page_interruptible(ab3100_data,
137 AB3100_AL0, buf, 4);
138 if (err)
139 return err;
140 fat_time = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) |
141 ((u64) buf[1] << 24) | ((u64) buf[0] << 16);
142 time = (unsigned long) (fat_time / (u64) (AB3100_RTC_CLOCK_RATE * 2));
143
144 rtc_time_to_tm(time, &alarm->time);
145
146 return rtc_valid_tm(&alarm->time);
147}
148
149static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
150{
151 struct ab3100 *ab3100_data = dev_get_drvdata(dev);
152 u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3};
153 unsigned char buf[4];
154 unsigned long secs;
155 u64 fat_time;
156 int err;
157 int i;
158
159 rtc_tm_to_time(&alarm->time, &secs);
160 fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2;
161 buf[0] = (fat_time >> 16) & 0xFF;
162 buf[1] = (fat_time >> 24) & 0xFF;
163 buf[2] = (fat_time >> 32) & 0xFF;
164 buf[3] = (fat_time >> 40) & 0xFF;
165
166 /* Set the alarm */
167 for (i = 0; i < 4; i++) {
168 err = ab3100_set_register_interruptible(ab3100_data,
169 regs[i], buf[i]);
170 if (err)
171 return err;
172 }
173 /* Then enable the alarm */
174 return ab3100_mask_and_set_register_interruptible(ab3100_data,
175 AB3100_RTC, ~(1 << 2),
176 alarm->enabled << 2);
177}
178
179static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled)
180{
181 struct ab3100 *ab3100_data = dev_get_drvdata(dev);
182
183 /*
184 * It's not possible to enable/disable the alarm IRQ for this RTC.
185 * It does not actually trigger any IRQ: instead its only function is
186 * to power up the system, if it wasn't on. This will manifest as
187 * a "power up cause" in the AB3100 power driver (battery charging etc)
188 * and need to be handled there instead.
189 */
190 if (enabled)
191 return ab3100_mask_and_set_register_interruptible(ab3100_data,
192 AB3100_RTC, ~(1 << 2),
193 1 << 2);
194 else
195 return ab3100_mask_and_set_register_interruptible(ab3100_data,
196 AB3100_RTC, ~(1 << 2),
197 0);
198}
199
200static const struct rtc_class_ops ab3100_rtc_ops = {
201 .read_time = ab3100_rtc_read_time,
202 .set_mmss = ab3100_rtc_set_mmss,
203 .read_alarm = ab3100_rtc_read_alarm,
204 .set_alarm = ab3100_rtc_set_alarm,
205 .alarm_irq_enable = ab3100_rtc_irq_enable,
206};
207
208static int __init ab3100_rtc_probe(struct platform_device *pdev)
209{
210 int err;
211 u8 regval;
212 struct rtc_device *rtc;
213 struct ab3100 *ab3100_data = platform_get_drvdata(pdev);
214
215 /* The first RTC register needs special treatment */
216 err = ab3100_get_register_interruptible(ab3100_data,
217 AB3100_RTC, ®val);
218 if (err) {
219 dev_err(&pdev->dev, "unable to read RTC register\n");
220 return -ENODEV;
221 }
222
223 if ((regval & 0xFE) != RTC_SETTING) {
224 dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n",
225 regval);
226 }
227
228 if ((regval & 1) == 0) {
229 /*
230 * Set bit to detect power loss.
231 * This bit remains until RTC power is lost.
232 */
233 regval = 1 | RTC_SETTING;
234 err = ab3100_set_register_interruptible(ab3100_data,
235 AB3100_RTC, regval);
236 /* Ignore any error on this write */
237 }
238
239 rtc = rtc_device_register("ab3100-rtc", &pdev->dev, &ab3100_rtc_ops,
240 THIS_MODULE);
241 if (IS_ERR(rtc)) {
242 err = PTR_ERR(rtc);
243 return err;
244 }
245
246 return 0;
247}
248
249static int __exit ab3100_rtc_remove(struct platform_device *pdev)
250{
251 struct rtc_device *rtc = platform_get_drvdata(pdev);
252
253 rtc_device_unregister(rtc);
254 return 0;
255}
256
257static struct platform_driver ab3100_rtc_driver = {
258 .driver = {
259 .name = "ab3100-rtc",
260 .owner = THIS_MODULE,
261 },
262 .remove = __exit_p(ab3100_rtc_remove),
263};
264
265static int __init ab3100_rtc_init(void)
266{
267 return platform_driver_probe(&ab3100_rtc_driver,
268 ab3100_rtc_probe);
269}
270
271static void __exit ab3100_rtc_exit(void)
272{
273 platform_driver_unregister(&ab3100_rtc_driver);
274}
275
276module_init(ab3100_rtc_init);
277module_exit(ab3100_rtc_exit);
278
279MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
280MODULE_DESCRIPTION("AB3100 RTC Driver");
281MODULE_LICENSE("GPL");