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 */ 46static 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 76static 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 113static 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 146static 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 175static 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 194static 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 202static 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 = devm_rtc_device_register(&pdev->dev, "ab3100-rtc", 233 &ab3100_rtc_ops, 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 243static struct platform_driver ab3100_rtc_driver = { 244 .driver = { 245 .name = "ab3100-rtc", 246 .owner = THIS_MODULE, 247 }, 248}; 249 250module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe); 251 252MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); 253MODULE_DESCRIPTION("AB3100 RTC Driver"); 254MODULE_LICENSE("GPL"); 255