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bd207cfb LW |
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 | */ | |
46 | static 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 | ||
77 | static 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 | ||
115 | static 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 | ||
149 | static 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 | ||
179 | static 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 | ||
200 | static 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 | ||
208 | static 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 | ||
249 | static 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 | ||
257 | static 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 | ||
265 | static int __init ab3100_rtc_init(void) | |
266 | { | |
267 | return platform_driver_probe(&ab3100_rtc_driver, | |
268 | ab3100_rtc_probe); | |
269 | } | |
270 | ||
271 | static void __exit ab3100_rtc_exit(void) | |
272 | { | |
273 | platform_driver_unregister(&ab3100_rtc_driver); | |
274 | } | |
275 | ||
276 | module_init(ab3100_rtc_init); | |
277 | module_exit(ab3100_rtc_exit); | |
278 | ||
279 | MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); | |
280 | MODULE_DESCRIPTION("AB3100 RTC Driver"); | |
281 | MODULE_LICENSE("GPL"); |