Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

Linux/drivers/rtc/rtc-ab3100.c

  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, time64_t 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 hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
 52         int err = 0;
 53         int i;
 54 
 55         buf[0] = (hw_counter) & 0xFF;
 56         buf[1] = (hw_counter >> 8) & 0xFF;
 57         buf[2] = (hw_counter >> 16) & 0xFF;
 58         buf[3] = (hw_counter >> 24) & 0xFF;
 59         buf[4] = (hw_counter >> 32) & 0xFF;
 60         buf[5] = (hw_counter >> 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         time64_t 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 hw_counter;
 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                 hw_counter = ((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 = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
105         }
106 
107         rtc_time64_to_tm(time, tm);
108 
109         return rtc_valid_tm(tm);
110 }
111 
112 static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
113 {
114         time64_t time;
115         u64 hw_counter;
116         u8 buf[6];
117         u8 rtcval;
118         int err;
119 
120         /* Figure out if alarm is enabled or not */
121         err = abx500_get_register_interruptible(dev, 0,
122                                                 AB3100_RTC, &rtcval);
123         if (err)
124                 return err;
125         if (rtcval & 0x04)
126                 alarm->enabled = 1;
127         else
128                 alarm->enabled = 0;
129         /* No idea how this could be represented */
130         alarm->pending = 0;
131         /* Read out alarm registers, only 4 bytes */
132         err = abx500_get_register_page_interruptible(dev, 0,
133                                                      AB3100_AL0, buf, 4);
134         if (err)
135                 return err;
136         hw_counter = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) |
137                 ((u64) buf[1] << 24) | ((u64) buf[0] << 16);
138         time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
139 
140         rtc_time64_to_tm(time, &alarm->time);
141 
142         return rtc_valid_tm(&alarm->time);
143 }
144 
145 static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
146 {
147         u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3};
148         unsigned char buf[4];
149         time64_t secs;
150         u64 hw_counter;
151         int err;
152         int i;
153 
154         secs = rtc_tm_to_time64(&alarm->time);
155         hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
156         buf[0] = (hw_counter >> 16) & 0xFF;
157         buf[1] = (hw_counter >> 24) & 0xFF;
158         buf[2] = (hw_counter >> 32) & 0xFF;
159         buf[3] = (hw_counter >> 40) & 0xFF;
160 
161         /* Set the alarm */
162         for (i = 0; i < 4; i++) {
163                 err = abx500_set_register_interruptible(dev, 0,
164                                                         regs[i], buf[i]);
165                 if (err)
166                         return err;
167         }
168         /* Then enable the alarm */
169         return abx500_mask_and_set_register_interruptible(dev, 0,
170                                                           AB3100_RTC, (1 << 2),
171                                                           alarm->enabled << 2);
172 }
173 
174 static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled)
175 {
176         /*
177          * It's not possible to enable/disable the alarm IRQ for this RTC.
178          * It does not actually trigger any IRQ: instead its only function is
179          * to power up the system, if it wasn't on. This will manifest as
180          * a "power up cause" in the AB3100 power driver (battery charging etc)
181          * and need to be handled there instead.
182          */
183         if (enabled)
184                 return abx500_mask_and_set_register_interruptible(dev, 0,
185                                                     AB3100_RTC, (1 << 2),
186                                                     1 << 2);
187         else
188                 return abx500_mask_and_set_register_interruptible(dev, 0,
189                                                     AB3100_RTC, (1 << 2),
190                                                     0);
191 }
192 
193 static const struct rtc_class_ops ab3100_rtc_ops = {
194         .read_time      = ab3100_rtc_read_time,
195         .set_mmss64     = ab3100_rtc_set_mmss,
196         .read_alarm     = ab3100_rtc_read_alarm,
197         .set_alarm      = ab3100_rtc_set_alarm,
198         .alarm_irq_enable = ab3100_rtc_irq_enable,
199 };
200 
201 static int __init ab3100_rtc_probe(struct platform_device *pdev)
202 {
203         int err;
204         u8 regval;
205         struct rtc_device *rtc;
206 
207         /* The first RTC register needs special treatment */
208         err = abx500_get_register_interruptible(&pdev->dev, 0,
209                                                 AB3100_RTC, &regval);
210         if (err) {
211                 dev_err(&pdev->dev, "unable to read RTC register\n");
212                 return -ENODEV;
213         }
214 
215         if ((regval & 0xFE) != RTC_SETTING) {
216                 dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n",
217                          regval);
218         }
219 
220         if ((regval & 1) == 0) {
221                 /*
222                  * Set bit to detect power loss.
223                  * This bit remains until RTC power is lost.
224                  */
225                 regval = 1 | RTC_SETTING;
226                 err = abx500_set_register_interruptible(&pdev->dev, 0,
227                                                         AB3100_RTC, regval);
228                 /* Ignore any error on this write */
229         }
230 
231         rtc = devm_rtc_device_register(&pdev->dev, "ab3100-rtc",
232                                         &ab3100_rtc_ops, THIS_MODULE);
233         if (IS_ERR(rtc)) {
234                 err = PTR_ERR(rtc);
235                 return err;
236         }
237         platform_set_drvdata(pdev, rtc);
238 
239         return 0;
240 }
241 
242 static struct platform_driver ab3100_rtc_driver = {
243         .driver = {
244                 .name = "ab3100-rtc",
245         },
246 };
247 
248 module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe);
249 
250 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
251 MODULE_DESCRIPTION("AB3100 RTC Driver");
252 MODULE_LICENSE("GPL");
253 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us