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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/abx500.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 | u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2, |
49 | AB3100_TI3, AB3100_TI4, AB3100_TI5}; |
50 | unsigned char buf[6]; |
51 | u64 fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2; |
52 | int err = 0; |
53 | int i; |
54 | |
55 | buf[0] = (fat_time) & 0xFF; |
56 | buf[1] = (fat_time >> 8) & 0xFF; |
57 | buf[2] = (fat_time >> 16) & 0xFF; |
58 | buf[3] = (fat_time >> 24) & 0xFF; |
59 | buf[4] = (fat_time >> 32) & 0xFF; |
60 | buf[5] = (fat_time >> 40) & 0xFF; |
61 | |
62 | for (i = 0; i < 6; i++) { |
63 | err = abx500_set_register_interruptible(dev, 0, |
64 | regs[i], buf[i]); |
65 | if (err) |
66 | return err; |
67 | } |
68 | |
69 | /* Set the flag to mark that the clock is now set */ |
70 | return abx500_mask_and_set_register_interruptible(dev, 0, |
71 | AB3100_RTC, |
72 | 0x01, 0x01); |
73 | |
74 | } |
75 | |
76 | static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm) |
77 | { |
78 | unsigned long time; |
79 | u8 rtcval; |
80 | int err; |
81 | |
82 | err = abx500_get_register_interruptible(dev, 0, |
83 | AB3100_RTC, &rtcval); |
84 | if (err) |
85 | return err; |
86 | |
87 | if (!(rtcval & 0x01)) { |
88 | dev_info(dev, "clock not set (lost power)"); |
89 | return -EINVAL; |
90 | } else { |
91 | u64 fat_time; |
92 | u8 buf[6]; |
93 | |
94 | /* Read out time registers */ |
95 | err = abx500_get_register_page_interruptible(dev, 0, |
96 | AB3100_TI0, |
97 | buf, 6); |
98 | if (err != 0) |
99 | return err; |
100 | |
101 | fat_time = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) | |
102 | ((u64) buf[3] << 24) | ((u64) buf[2] << 16) | |
103 | ((u64) buf[1] << 8) | (u64) buf[0]; |
104 | time = (unsigned long) (fat_time / |
105 | (u64) (AB3100_RTC_CLOCK_RATE * 2)); |
106 | } |
107 | |
108 | rtc_time_to_tm(time, tm); |
109 | |
110 | return rtc_valid_tm(tm); |
111 | } |
112 | |
113 | static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
114 | { |
115 | unsigned long time; |
116 | u64 fat_time; |
117 | u8 buf[6]; |
118 | u8 rtcval; |
119 | int err; |
120 | |
121 | /* Figure out if alarm is enabled or not */ |
122 | err = abx500_get_register_interruptible(dev, 0, |
123 | AB3100_RTC, &rtcval); |
124 | if (err) |
125 | return err; |
126 | if (rtcval & 0x04) |
127 | alarm->enabled = 1; |
128 | else |
129 | alarm->enabled = 0; |
130 | /* No idea how this could be represented */ |
131 | alarm->pending = 0; |
132 | /* Read out alarm registers, only 4 bytes */ |
133 | err = abx500_get_register_page_interruptible(dev, 0, |
134 | AB3100_AL0, buf, 4); |
135 | if (err) |
136 | return err; |
137 | fat_time = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) | |
138 | ((u64) buf[1] << 24) | ((u64) buf[0] << 16); |
139 | time = (unsigned long) (fat_time / (u64) (AB3100_RTC_CLOCK_RATE * 2)); |
140 | |
141 | rtc_time_to_tm(time, &alarm->time); |
142 | |
143 | return rtc_valid_tm(&alarm->time); |
144 | } |
145 | |
146 | static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
147 | { |
148 | u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3}; |
149 | unsigned char buf[4]; |
150 | unsigned long secs; |
151 | u64 fat_time; |
152 | int err; |
153 | int i; |
154 | |
155 | rtc_tm_to_time(&alarm->time, &secs); |
156 | fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2; |
157 | buf[0] = (fat_time >> 16) & 0xFF; |
158 | buf[1] = (fat_time >> 24) & 0xFF; |
159 | buf[2] = (fat_time >> 32) & 0xFF; |
160 | buf[3] = (fat_time >> 40) & 0xFF; |
161 | |
162 | /* Set the alarm */ |
163 | for (i = 0; i < 4; i++) { |
164 | err = abx500_set_register_interruptible(dev, 0, |
165 | regs[i], buf[i]); |
166 | if (err) |
167 | return err; |
168 | } |
169 | /* Then enable the alarm */ |
170 | return abx500_mask_and_set_register_interruptible(dev, 0, |
171 | AB3100_RTC, (1 << 2), |
172 | alarm->enabled << 2); |
173 | } |
174 | |
175 | static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled) |
176 | { |
177 | /* |
178 | * It's not possible to enable/disable the alarm IRQ for this RTC. |
179 | * It does not actually trigger any IRQ: instead its only function is |
180 | * to power up the system, if it wasn't on. This will manifest as |
181 | * a "power up cause" in the AB3100 power driver (battery charging etc) |
182 | * and need to be handled there instead. |
183 | */ |
184 | if (enabled) |
185 | return abx500_mask_and_set_register_interruptible(dev, 0, |
186 | AB3100_RTC, (1 << 2), |
187 | 1 << 2); |
188 | else |
189 | return abx500_mask_and_set_register_interruptible(dev, 0, |
190 | AB3100_RTC, (1 << 2), |
191 | 0); |
192 | } |
193 | |
194 | static const struct rtc_class_ops ab3100_rtc_ops = { |
195 | .read_time = ab3100_rtc_read_time, |
196 | .set_mmss = ab3100_rtc_set_mmss, |
197 | .read_alarm = ab3100_rtc_read_alarm, |
198 | .set_alarm = ab3100_rtc_set_alarm, |
199 | .alarm_irq_enable = ab3100_rtc_irq_enable, |
200 | }; |
201 | |
202 | static int __init ab3100_rtc_probe(struct platform_device *pdev) |
203 | { |
204 | int err; |
205 | u8 regval; |
206 | struct rtc_device *rtc; |
207 | |
208 | /* The first RTC register needs special treatment */ |
209 | err = abx500_get_register_interruptible(&pdev->dev, 0, |
210 | AB3100_RTC, ®val); |
211 | if (err) { |
212 | dev_err(&pdev->dev, "unable to read RTC register\n"); |
213 | return -ENODEV; |
214 | } |
215 | |
216 | if ((regval & 0xFE) != RTC_SETTING) { |
217 | dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n", |
218 | regval); |
219 | } |
220 | |
221 | if ((regval & 1) == 0) { |
222 | /* |
223 | * Set bit to detect power loss. |
224 | * This bit remains until RTC power is lost. |
225 | */ |
226 | regval = 1 | RTC_SETTING; |
227 | err = abx500_set_register_interruptible(&pdev->dev, 0, |
228 | AB3100_RTC, regval); |
229 | /* Ignore any error on this write */ |
230 | } |
231 | |
232 | rtc = rtc_device_register("ab3100-rtc", &pdev->dev, &ab3100_rtc_ops, |
233 | THIS_MODULE); |
234 | if (IS_ERR(rtc)) { |
235 | err = PTR_ERR(rtc); |
236 | return err; |
237 | } |
238 | platform_set_drvdata(pdev, rtc); |
239 | |
240 | return 0; |
241 | } |
242 | |
243 | static int __exit ab3100_rtc_remove(struct platform_device *pdev) |
244 | { |
245 | struct rtc_device *rtc = platform_get_drvdata(pdev); |
246 | |
247 | rtc_device_unregister(rtc); |
248 | platform_set_drvdata(pdev, NULL); |
249 | return 0; |
250 | } |
251 | |
252 | static struct platform_driver ab3100_rtc_driver = { |
253 | .driver = { |
254 | .name = "ab3100-rtc", |
255 | .owner = THIS_MODULE, |
256 | }, |
257 | .remove = __exit_p(ab3100_rtc_remove), |
258 | }; |
259 | |
260 | static int __init ab3100_rtc_init(void) |
261 | { |
262 | return platform_driver_probe(&ab3100_rtc_driver, |
263 | ab3100_rtc_probe); |
264 | } |
265 | |
266 | static void __exit ab3100_rtc_exit(void) |
267 | { |
268 | platform_driver_unregister(&ab3100_rtc_driver); |
269 | } |
270 | |
271 | module_init(ab3100_rtc_init); |
272 | module_exit(ab3100_rtc_exit); |
273 | |
274 | MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); |
275 | MODULE_DESCRIPTION("AB3100 RTC Driver"); |
276 | MODULE_LICENSE("GPL"); |
277 |
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