drivers/rtc/rtc-mc13783.c

   1 /*
   2  * Real Time Clock driver for Freescale MC13783 PMIC
   3  *
   4  * (C) 2009 Sascha Hauer, Pengutronix
   5  * (C) 2009 Uwe Kleine-Koenig, Pengutronix
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/mfd/mc13783.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/rtc.h>
  17
  18 #define DRIVER_NAME "mc13783-rtc"
  19
  20 #define MC13783_RTCTOD  20
  21 #define MC13783_RTCTODA 21
  22 #define MC13783_RTCDAY  22
  23 #define MC13783_RTCDAYA 23
  24
  25 struct mc13783_rtc {
  26         struct rtc_device *rtc;
  27         struct mc13783 *mc13783;
  28         int valid;
  29 };
  30
  31 static int mc13783_rtc_read_time(struct device *dev, struct rtc_time *tm)
  32 {
  33         struct mc13783_rtc *priv = dev_get_drvdata(dev);
  34         unsigned int seconds, days1, days2;
  35         unsigned long s1970;
  36         int ret;
  37
  38         mc13783_lock(priv->mc13783);
  39
  40         if (!priv->valid) {
  41                 ret = -ENODATA;
  42                 goto out;
  43         }
  44
  45         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days1);
  46         if (unlikely(ret))
  47                 goto out;
  48
  49         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCTOD, &seconds);
  50         if (unlikely(ret))
  51                 goto out;
  52
  53         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days2);
  54 out:
  55         mc13783_unlock(priv->mc13783);
  56
  57         if (ret)
  58                 return ret;
  59
  60         if (days2 == days1 + 1) {
  61                 if (seconds >= 86400 / 2)
  62                         days2 = days1;
  63                 else
  64                         days1 = days2;
  65         }
  66
  67         if (days1 != days2)
  68                 return -EIO;
  69
  70         s1970 = days1 * 86400 + seconds;
  71
  72         rtc_time_to_tm(s1970, tm);
  73
  74         return rtc_valid_tm(tm);
  75 }
  76
  77 static int mc13783_rtc_set_mmss(struct device *dev, unsigned long secs)
  78 {
  79         struct mc13783_rtc *priv = dev_get_drvdata(dev);
  80         unsigned int seconds, days;
  81         int ret;
  82
  83         seconds = secs % 86400;
  84         days = secs / 86400;
  85
  86         mc13783_lock(priv->mc13783);
  87
  88         /*
  89          * first write seconds=0 to prevent a day switch between writing days
  90          * and seconds below
  91          */
  92         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, 0);
  93         if (unlikely(ret))
  94                 goto out;
  95
  96         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCDAY, days);
  97         if (unlikely(ret))
  98                 goto out;
  99
 100         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, seconds);
 101         if (unlikely(ret))
 102                 goto out;
 103
 104         ret = mc13783_ackirq(priv->mc13783, MC13783_IRQ_RTCRST);
 105         if (unlikely(ret))
 106                 goto out;
 107
 108         ret = mc13783_unmask(priv->mc13783, MC13783_IRQ_RTCRST);
 109 out:
 110         priv->valid = !ret;
 111
 112         mc13783_unlock(priv->mc13783);
 113
 114         return ret;
 115 }
 116
 117 static irqreturn_t mc13783_rtc_update_handler(int irq, void *dev)
 118 {
 119         struct mc13783_rtc *priv = dev;
 120         struct mc13783 *mc13783 = priv->mc13783;
 121
 122         dev_dbg(&priv->rtc->dev, "1HZ\n");
 123
 124         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
 125
 126         mc13783_ackirq(mc13783, irq);
 127
 128         return IRQ_HANDLED;
 129 }
 130
 131 static int mc13783_rtc_update_irq_enable(struct device *dev,
 132                 unsigned int enabled)
 133 {
 134         struct mc13783_rtc *priv = dev_get_drvdata(dev);
 135         int ret = -ENODATA;
 136
 137         mc13783_lock(priv->mc13783);
 138         if (!priv->valid)
 139                 goto out;
 140
 141         ret = (enabled ? mc13783_unmask : mc13783_mask)(priv->mc13783,
 142                         MC13783_IRQ_1HZ);
 143 out:
 144         mc13783_unlock(priv->mc13783);
 145
 146         return ret;
 147 }
 148
 149 static const struct rtc_class_ops mc13783_rtc_ops = {
 150         .read_time = mc13783_rtc_read_time,
 151         .set_mmss = mc13783_rtc_set_mmss,
 152         .update_irq_enable = mc13783_rtc_update_irq_enable,
 153 };
 154
 155 static irqreturn_t mc13783_rtc_reset_handler(int irq, void *dev)
 156 {
 157         struct mc13783_rtc *priv = dev;
 158         struct mc13783 *mc13783 = priv->mc13783;
 159
 160         dev_dbg(&priv->rtc->dev, "RTCRST\n");
 161         priv->valid = 0;
 162
 163         mc13783_mask(mc13783, irq);
 164
 165         return IRQ_HANDLED;
 166 }
 167
 168 static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
 169 {
 170         int ret;
 171         struct mc13783_rtc *priv;
 172
 173         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 174         if (!priv)
 175                 return -ENOMEM;
 176
 177         priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
 178         platform_set_drvdata(pdev, priv);
 179
 180         priv->valid = 1;
 181
 182         mc13783_lock(priv->mc13783);
 183
 184         ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_RTCRST,
 185                         mc13783_rtc_reset_handler, DRIVER_NAME, priv);
 186         if (ret)
 187                 goto err_reset_irq_request;
 188
 189         ret = mc13783_irq_request_nounmask(priv->mc13783, MC13783_IRQ_1HZ,
 190                         mc13783_rtc_update_handler, DRIVER_NAME, priv);
 191         if (ret)
 192                 goto err_update_irq_request;
 193
 194         mc13783_unlock(priv->mc13783);
 195
 196         priv->rtc = rtc_device_register(pdev->name,
 197                         &pdev->dev, &mc13783_rtc_ops, THIS_MODULE);
 198
 199         if (IS_ERR(priv->rtc)) {
 200                 ret = PTR_ERR(priv->rtc);
 201
 202                 mc13783_lock(priv->mc13783);
 203
 204                 mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
 205 err_update_irq_request:
 206
 207                 mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
 208 err_reset_irq_request:
 209
 210                 mc13783_unlock(priv->mc13783);
 211
 212                 platform_set_drvdata(pdev, NULL);
 213                 kfree(priv);
 214         }
 215
 216         return ret;
 217 }
 218
 219 static int __devexit mc13783_rtc_remove(struct platform_device *pdev)
 220 {
 221         struct mc13783_rtc *priv = platform_get_drvdata(pdev);
 222
 223         rtc_device_unregister(priv->rtc);
 224
 225         mc13783_lock(priv->mc13783);
 226
 227         mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
 228         mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
 229
 230         mc13783_unlock(priv->mc13783);
 231
 232         platform_set_drvdata(pdev, NULL);
 233
 234         kfree(priv);
 235
 236         return 0;
 237 }
 238
 239 static struct platform_driver mc13783_rtc_driver = {
 240         .remove = __devexit_p(mc13783_rtc_remove),
 241         .driver = {
 242                 .name = DRIVER_NAME,
 243                 .owner = THIS_MODULE,
 244         },
 245 };
 246
 247 static int __init mc13783_rtc_init(void)
 248 {
 249         return platform_driver_probe(&mc13783_rtc_driver, &mc13783_rtc_probe);
 250 }
 251 module_init(mc13783_rtc_init);
 252
 253 static void __exit mc13783_rtc_exit(void)
 254 {
 255         platform_driver_unregister(&mc13783_rtc_driver);
 256 }
 257 module_exit(mc13783_rtc_exit);
 258
 259 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 260 MODULE_DESCRIPTION("RTC driver for Freescale MC13783 PMIC");
 261 MODULE_LICENSE("GPL v2");
 262 MODULE_ALIAS("platform:" DRIVER_NAME);