1/* 2 * Copyright (C) 2007-2009 ST-Ericsson AB 3 * License terms: GNU General Public License (GPL) version 2 4 * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC. 5 * Author: Linus Walleij <linus.walleij@stericsson.com> 6 * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net> 7 * Copyright 2006 (c) MontaVista Software, Inc. 8 */ 9#include <linux/init.h> 10#include <linux/module.h> 11#include <linux/rtc.h> 12#include <linux/clk.h> 13#include <linux/interrupt.h> 14#include <linux/pm.h> 15#include <linux/platform_device.h> 16#include <linux/io.h> 17#include <linux/slab.h> 18 19/* 20 * Registers in the COH 901 331 21 */ 22/* Alarm value 32bit (R/W) */ 23#define COH901331_ALARM 0x00U 24/* Used to set current time 32bit (R/W) */ 25#define COH901331_SET_TIME 0x04U 26/* Indication if current time is valid 32bit (R/-) */ 27#define COH901331_VALID 0x08U 28/* Read the current time 32bit (R/-) */ 29#define COH901331_CUR_TIME 0x0cU 30/* Event register for the "alarm" interrupt */ 31#define COH901331_IRQ_EVENT 0x10U 32/* Mask register for the "alarm" interrupt */ 33#define COH901331_IRQ_MASK 0x14U 34/* Force register for the "alarm" interrupt */ 35#define COH901331_IRQ_FORCE 0x18U 36 37/* 38 * Reference to RTC block clock 39 * Notice that the frequent clk_enable()/clk_disable() on this 40 * clock is mainly to be able to turn on/off other clocks in the 41 * hierarchy as needed, the RTC clock is always on anyway. 42 */ 43struct coh901331_port { 44 struct rtc_device *rtc; 45 struct clk *clk; 46 void __iomem *virtbase; 47 int irq; 48#ifdef CONFIG_PM_SLEEP 49 u32 irqmaskstore; 50#endif 51}; 52 53static irqreturn_t coh901331_interrupt(int irq, void *data) 54{ 55 struct coh901331_port *rtap = data; 56 57 clk_enable(rtap->clk); 58 /* Ack IRQ */ 59 writel(1, rtap->virtbase + COH901331_IRQ_EVENT); 60 /* 61 * Disable the interrupt. This is necessary because 62 * the RTC lives on a lower-clocked line and will 63 * not release the IRQ line until after a few (slower) 64 * clock cycles. The interrupt will be re-enabled when 65 * a new alarm is set anyway. 66 */ 67 writel(0, rtap->virtbase + COH901331_IRQ_MASK); 68 clk_disable(rtap->clk); 69 70 /* Set alarm flag */ 71 rtc_update_irq(rtap->rtc, 1, RTC_AF); 72 73 return IRQ_HANDLED; 74} 75 76static int coh901331_read_time(struct device *dev, struct rtc_time *tm) 77{ 78 struct coh901331_port *rtap = dev_get_drvdata(dev); 79 80 clk_enable(rtap->clk); 81 /* Check if the time is valid */ 82 if (readl(rtap->virtbase + COH901331_VALID)) { 83 rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm); 84 clk_disable(rtap->clk); 85 return rtc_valid_tm(tm); 86 } 87 clk_disable(rtap->clk); 88 return -EINVAL; 89} 90 91static int coh901331_set_mmss(struct device *dev, unsigned long secs) 92{ 93 struct coh901331_port *rtap = dev_get_drvdata(dev); 94 95 clk_enable(rtap->clk); 96 writel(secs, rtap->virtbase + COH901331_SET_TIME); 97 clk_disable(rtap->clk); 98 99 return 0; 100} 101 102static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) 103{ 104 struct coh901331_port *rtap = dev_get_drvdata(dev); 105 106 clk_enable(rtap->clk); 107 rtc_time_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time); 108 alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U; 109 alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U; 110 clk_disable(rtap->clk); 111 112 return 0; 113} 114 115static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) 116{ 117 struct coh901331_port *rtap = dev_get_drvdata(dev); 118 unsigned long time; 119 120 rtc_tm_to_time(&alarm->time, &time); 121 clk_enable(rtap->clk); 122 writel(time, rtap->virtbase + COH901331_ALARM); 123 writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK); 124 clk_disable(rtap->clk); 125 126 return 0; 127} 128 129static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled) 130{ 131 struct coh901331_port *rtap = dev_get_drvdata(dev); 132 133 clk_enable(rtap->clk); 134 if (enabled) 135 writel(1, rtap->virtbase + COH901331_IRQ_MASK); 136 else 137 writel(0, rtap->virtbase + COH901331_IRQ_MASK); 138 clk_disable(rtap->clk); 139 140 return 0; 141} 142 143static struct rtc_class_ops coh901331_ops = { 144 .read_time = coh901331_read_time, 145 .set_mmss = coh901331_set_mmss, 146 .read_alarm = coh901331_read_alarm, 147 .set_alarm = coh901331_set_alarm, 148 .alarm_irq_enable = coh901331_alarm_irq_enable, 149}; 150 151static int __exit coh901331_remove(struct platform_device *pdev) 152{ 153 struct coh901331_port *rtap = platform_get_drvdata(pdev); 154 155 if (rtap) 156 clk_unprepare(rtap->clk); 157 158 return 0; 159} 160 161 162static int __init coh901331_probe(struct platform_device *pdev) 163{ 164 int ret; 165 struct coh901331_port *rtap; 166 struct resource *res; 167 168 rtap = devm_kzalloc(&pdev->dev, 169 sizeof(struct coh901331_port), GFP_KERNEL); 170 if (!rtap) 171 return -ENOMEM; 172 173 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 174 rtap->virtbase = devm_ioremap_resource(&pdev->dev, res); 175 if (IS_ERR(rtap->virtbase)) 176 return PTR_ERR(rtap->virtbase); 177 178 rtap->irq = platform_get_irq(pdev, 0); 179 if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0, 180 "RTC COH 901 331 Alarm", rtap)) 181 return -EIO; 182 183 rtap->clk = devm_clk_get(&pdev->dev, NULL); 184 if (IS_ERR(rtap->clk)) { 185 ret = PTR_ERR(rtap->clk); 186 dev_err(&pdev->dev, "could not get clock\n"); 187 return ret; 188 } 189 190 /* We enable/disable the clock only to assure it works */ 191 ret = clk_prepare_enable(rtap->clk); 192 if (ret) { 193 dev_err(&pdev->dev, "could not enable clock\n"); 194 return ret; 195 } 196 clk_disable(rtap->clk); 197 198 platform_set_drvdata(pdev, rtap); 199 rtap->rtc = devm_rtc_device_register(&pdev->dev, "coh901331", 200 &coh901331_ops, THIS_MODULE); 201 if (IS_ERR(rtap->rtc)) { 202 ret = PTR_ERR(rtap->rtc); 203 goto out_no_rtc; 204 } 205 206 return 0; 207 208 out_no_rtc: 209 clk_unprepare(rtap->clk); 210 return ret; 211} 212 213#ifdef CONFIG_PM_SLEEP 214static int coh901331_suspend(struct device *dev) 215{ 216 struct coh901331_port *rtap = dev_get_drvdata(dev); 217 218 /* 219 * If this RTC alarm will be used for waking the system up, 220 * don't disable it of course. Else we just disable the alarm 221 * and await suspension. 222 */ 223 if (device_may_wakeup(dev)) { 224 enable_irq_wake(rtap->irq); 225 } else { 226 clk_enable(rtap->clk); 227 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK); 228 writel(0, rtap->virtbase + COH901331_IRQ_MASK); 229 clk_disable(rtap->clk); 230 } 231 clk_unprepare(rtap->clk); 232 return 0; 233} 234 235static int coh901331_resume(struct device *dev) 236{ 237 struct coh901331_port *rtap = dev_get_drvdata(dev); 238 239 clk_prepare(rtap->clk); 240 if (device_may_wakeup(dev)) { 241 disable_irq_wake(rtap->irq); 242 } else { 243 clk_enable(rtap->clk); 244 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK); 245 clk_disable(rtap->clk); 246 } 247 return 0; 248} 249#endif 250 251static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume); 252 253static void coh901331_shutdown(struct platform_device *pdev) 254{ 255 struct coh901331_port *rtap = platform_get_drvdata(pdev); 256 257 clk_enable(rtap->clk); 258 writel(0, rtap->virtbase + COH901331_IRQ_MASK); 259 clk_disable_unprepare(rtap->clk); 260} 261 262static const struct of_device_id coh901331_dt_match[] = { 263 { .compatible = "stericsson,coh901331" }, 264 {}, 265}; 266 267static struct platform_driver coh901331_driver = { 268 .driver = { 269 .name = "rtc-coh901331", 270 .pm = &coh901331_pm_ops, 271 .of_match_table = coh901331_dt_match, 272 }, 273 .remove = __exit_p(coh901331_remove), 274 .shutdown = coh901331_shutdown, 275}; 276 277module_platform_driver_probe(coh901331_driver, coh901331_probe); 278 279MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); 280MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver"); 281MODULE_LICENSE("GPL"); 282