LXR linux/drivers/rtc/rtc-coh901331.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2007-2009 ST-Ericsson AB
   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/mod_devicetable.h>
  12#include <linux/rtc.h>
  13#include <linux/clk.h>
  14#include <linux/interrupt.h>
  15#include <linux/pm.h>
  16#include <linux/platform_device.h>
  17#include <linux/io.h>
  18#include <linux/slab.h>
  19
  20/*
  21 * Registers in the COH 901 331
  22 */
  23/* Alarm value 32bit (R/W) */
  24#define COH901331_ALARM         0x00U
  25/* Used to set current time 32bit (R/W) */
  26#define COH901331_SET_TIME      0x04U
  27/* Indication if current time is valid 32bit (R/-) */
  28#define COH901331_VALID         0x08U
  29/* Read the current time 32bit (R/-) */
  30#define COH901331_CUR_TIME      0x0cU
  31/* Event register for the "alarm" interrupt */
  32#define COH901331_IRQ_EVENT     0x10U
  33/* Mask register for the "alarm" interrupt */
  34#define COH901331_IRQ_MASK      0x14U
  35/* Force register for the "alarm" interrupt */
  36#define COH901331_IRQ_FORCE     0x18U
  37
  38/*
  39 * Reference to RTC block clock
  40 * Notice that the frequent clk_enable()/clk_disable() on this
  41 * clock is mainly to be able to turn on/off other clocks in the
  42 * hierarchy as needed, the RTC clock is always on anyway.
  43 */
  44struct coh901331_port {
  45        struct rtc_device *rtc;
  46        struct clk *clk;
  47        void __iomem *virtbase;
  48        int irq;
  49#ifdef CONFIG_PM_SLEEP
  50        u32 irqmaskstore;
  51#endif
  52};
  53
  54static irqreturn_t coh901331_interrupt(int irq, void *data)
  55{
  56        struct coh901331_port *rtap = data;
  57
  58        clk_enable(rtap->clk);
  59        /* Ack IRQ */
  60        writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
  61        /*
  62         * Disable the interrupt. This is necessary because
  63         * the RTC lives on a lower-clocked line and will
  64         * not release the IRQ line until after a few (slower)
  65         * clock cycles. The interrupt will be re-enabled when
  66         * a new alarm is set anyway.
  67         */
  68        writel(0, rtap->virtbase + COH901331_IRQ_MASK);
  69        clk_disable(rtap->clk);
  70
  71        /* Set alarm flag */
  72        rtc_update_irq(rtap->rtc, 1, RTC_AF);
  73
  74        return IRQ_HANDLED;
  75}
  76
  77static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
  78{
  79        struct coh901331_port *rtap = dev_get_drvdata(dev);
  80
  81        clk_enable(rtap->clk);
  82        /* Check if the time is valid */
  83        if (!readl(rtap->virtbase + COH901331_VALID)) {
  84                clk_disable(rtap->clk);
  85                return -EINVAL;
  86        }
  87
  88        rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
  89        clk_disable(rtap->clk);
  90        return 0;
  91}
  92
  93static int coh901331_set_time(struct device *dev, struct rtc_time *tm)
  94{
  95        struct coh901331_port *rtap = dev_get_drvdata(dev);
  96
  97        clk_enable(rtap->clk);
  98        writel(rtc_tm_to_time64(tm), rtap->virtbase + COH901331_SET_TIME);
  99        clk_disable(rtap->clk);
 100
 101        return 0;
 102}
 103
 104static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 105{
 106        struct coh901331_port *rtap = dev_get_drvdata(dev);
 107
 108        clk_enable(rtap->clk);
 109        rtc_time64_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
 110        alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
 111        alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
 112        clk_disable(rtap->clk);
 113
 114        return 0;
 115}
 116
 117static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 118{
 119        struct coh901331_port *rtap = dev_get_drvdata(dev);
 120        unsigned long time =  rtc_tm_to_time64(&alarm->time);
 121
 122        clk_enable(rtap->clk);
 123        writel(time, rtap->virtbase + COH901331_ALARM);
 124        writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
 125        clk_disable(rtap->clk);
 126
 127        return 0;
 128}
 129
 130static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
 131{
 132        struct coh901331_port *rtap = dev_get_drvdata(dev);
 133
 134        clk_enable(rtap->clk);
 135        if (enabled)
 136                writel(1, rtap->virtbase + COH901331_IRQ_MASK);
 137        else
 138                writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 139        clk_disable(rtap->clk);
 140
 141        return 0;
 142}
 143
 144static const struct rtc_class_ops coh901331_ops = {
 145        .read_time = coh901331_read_time,
 146        .set_time = coh901331_set_time,
 147        .read_alarm = coh901331_read_alarm,
 148        .set_alarm = coh901331_set_alarm,
 149        .alarm_irq_enable = coh901331_alarm_irq_enable,
 150};
 151
 152static int __exit coh901331_remove(struct platform_device *pdev)
 153{
 154        struct coh901331_port *rtap = platform_get_drvdata(pdev);
 155
 156        if (rtap)
 157                clk_unprepare(rtap->clk);
 158
 159        return 0;
 160}
 161
 162
 163static int __init coh901331_probe(struct platform_device *pdev)
 164{
 165        int ret;
 166        struct coh901331_port *rtap;
 167
 168        rtap = devm_kzalloc(&pdev->dev,
 169                            sizeof(struct coh901331_port), GFP_KERNEL);
 170        if (!rtap)
 171                return -ENOMEM;
 172
 173        rtap->virtbase  = devm_platform_ioremap_resource(pdev, 0);
 174        if (IS_ERR(rtap->virtbase))
 175                return PTR_ERR(rtap->virtbase);
 176
 177        rtap->irq = platform_get_irq(pdev, 0);
 178        if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
 179                             "RTC COH 901 331 Alarm", rtap))
 180                return -EIO;
 181
 182        rtap->clk = devm_clk_get(&pdev->dev, NULL);
 183        if (IS_ERR(rtap->clk)) {
 184                ret = PTR_ERR(rtap->clk);
 185                dev_err(&pdev->dev, "could not get clock\n");
 186                return ret;
 187        }
 188
 189        rtap->rtc = devm_rtc_allocate_device(&pdev->dev);
 190        if (IS_ERR(rtap->rtc))
 191                return PTR_ERR(rtap->rtc);
 192
 193        rtap->rtc->ops = &coh901331_ops;
 194        rtap->rtc->range_max = U32_MAX;
 195
 196        /* We enable/disable the clock only to assure it works */
 197        ret = clk_prepare_enable(rtap->clk);
 198        if (ret) {
 199                dev_err(&pdev->dev, "could not enable clock\n");
 200                return ret;
 201        }
 202        clk_disable(rtap->clk);
 203
 204        platform_set_drvdata(pdev, rtap);
 205
 206        ret = devm_rtc_register_device(rtap->rtc);
 207        if (ret)
 208                goto out_no_rtc;
 209
 210        return 0;
 211
 212 out_no_rtc:
 213        clk_unprepare(rtap->clk);
 214        return ret;
 215}
 216
 217#ifdef CONFIG_PM_SLEEP
 218static int coh901331_suspend(struct device *dev)
 219{
 220        struct coh901331_port *rtap = dev_get_drvdata(dev);
 221
 222        /*
 223         * If this RTC alarm will be used for waking the system up,
 224         * don't disable it of course. Else we just disable the alarm
 225         * and await suspension.
 226         */
 227        if (device_may_wakeup(dev)) {
 228                enable_irq_wake(rtap->irq);
 229        } else {
 230                clk_enable(rtap->clk);
 231                rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
 232                writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 233                clk_disable(rtap->clk);
 234        }
 235        clk_unprepare(rtap->clk);
 236        return 0;
 237}
 238
 239static int coh901331_resume(struct device *dev)
 240{
 241        int ret;
 242        struct coh901331_port *rtap = dev_get_drvdata(dev);
 243
 244        ret = clk_prepare(rtap->clk);
 245        if (ret)
 246                return ret;
 247
 248        if (device_may_wakeup(dev)) {
 249                disable_irq_wake(rtap->irq);
 250        } else {
 251                clk_enable(rtap->clk);
 252                writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
 253                clk_disable(rtap->clk);
 254        }
 255        return 0;
 256}
 257#endif
 258
 259static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
 260
 261static void coh901331_shutdown(struct platform_device *pdev)
 262{
 263        struct coh901331_port *rtap = platform_get_drvdata(pdev);
 264
 265        clk_enable(rtap->clk);
 266        writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 267        clk_disable_unprepare(rtap->clk);
 268}
 269
 270static const struct of_device_id coh901331_dt_match[] = {
 271        { .compatible = "stericsson,coh901331" },
 272        {},
 273};
 274MODULE_DEVICE_TABLE(of, coh901331_dt_match);
 275
 276static struct platform_driver coh901331_driver = {
 277        .driver = {
 278                .name = "rtc-coh901331",
 279                .pm = &coh901331_pm_ops,
 280                .of_match_table = coh901331_dt_match,
 281        },
 282        .remove = __exit_p(coh901331_remove),
 283        .shutdown = coh901331_shutdown,
 284};
 285
 286module_platform_driver_probe(coh901331_driver, coh901331_probe);
 287
 288MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 289MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
 290MODULE_LICENSE("GPL");
 291