drivers/rtc/rtc-nxp-bbnsm.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Copyright 2022 NXP.
   4
   5 #include <linux/init.h>
   6 #include <linux/io.h>
   7 #include <linux/kernel.h>
   8 #include <linux/mfd/syscon.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/pm_wakeirq.h>
  13 #include <linux/regmap.h>
  14 #include <linux/rtc.h>
  15
  16 #define BBNSM_CTRL      0x8
  17 #define BBNSM_INT_EN    0x10
  18 #define BBNSM_EVENTS    0x14
  19 #define BBNSM_RTC_LS    0x40
  20 #define BBNSM_RTC_MS    0x44
  21 #define BBNSM_TA        0x50
  22
  23 #define RTC_EN          0x2
  24 #define RTC_EN_MSK      0x3
  25 #define TA_EN           (0x2 << 2)
  26 #define TA_DIS          (0x1 << 2)
  27 #define TA_EN_MSK       (0x3 << 2)
  28 #define RTC_INT_EN      0x2
  29 #define TA_INT_EN       (0x2 << 2)
  30
  31 #define BBNSM_EVENT_TA  (0x2 << 2)
  32
  33 #define CNTR_TO_SECS_SH 15
  34
  35 struct bbnsm_rtc {
  36         struct rtc_device *rtc;
  37         struct regmap *regmap;
  38         int irq;
  39         struct clk *clk;
  40 };
  41
  42 static u32 bbnsm_read_counter(struct bbnsm_rtc *bbnsm)
  43 {
  44         u32 rtc_msb, rtc_lsb;
  45         unsigned int timeout = 100;
  46         u32 time;
  47         u32 tmp = 0;
  48
  49         do {
  50                 time = tmp;
  51                 /* read the msb */
  52                 regmap_read(bbnsm->regmap, BBNSM_RTC_MS, &rtc_msb);
  53                 /* read the lsb */
  54                 regmap_read(bbnsm->regmap, BBNSM_RTC_LS, &rtc_lsb);
  55                 /* convert to seconds */
  56                 tmp = (rtc_msb << 17) | (rtc_lsb >> 15);
  57         } while (tmp != time && --timeout);
  58
  59         return time;
  60 }
  61
  62 static int bbnsm_rtc_read_time(struct device *dev, struct rtc_time *tm)
  63 {
  64         struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
  65         unsigned long time;
  66         u32 val;
  67
  68         regmap_read(bbnsm->regmap, BBNSM_CTRL, &val);
  69         if ((val & RTC_EN_MSK) != RTC_EN)
  70                 return -EINVAL;
  71
  72         time = bbnsm_read_counter(bbnsm);
  73         rtc_time64_to_tm(time, tm);
  74
  75         return 0;
  76 }
  77
  78 static int bbnsm_rtc_set_time(struct device *dev, struct rtc_time *tm)
  79 {
  80         struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
  81         unsigned long time = rtc_tm_to_time64(tm);
  82
  83         /* disable the RTC first */
  84         regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, 0);
  85
  86         /* write the 32bit sec time to 47 bit timer counter, leaving 15 LSBs blank */
  87         regmap_write(bbnsm->regmap, BBNSM_RTC_LS, time << CNTR_TO_SECS_SH);
  88         regmap_write(bbnsm->regmap, BBNSM_RTC_MS, time >> (32 - CNTR_TO_SECS_SH));
  89
  90         /* Enable the RTC again */
  91         regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, RTC_EN);
  92
  93         return 0;
  94 }
  95
  96 static int bbnsm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  97 {
  98         struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
  99         u32 bbnsm_events, bbnsm_ta;
 100
 101         regmap_read(bbnsm->regmap, BBNSM_TA, &bbnsm_ta);
 102         rtc_time64_to_tm(bbnsm_ta, &alrm->time);
 103
 104         regmap_read(bbnsm->regmap, BBNSM_EVENTS, &bbnsm_events);
 105         alrm->pending = (bbnsm_events & BBNSM_EVENT_TA) ? 1 : 0;
 106
 107         return 0;
 108 }
 109
 110 static int bbnsm_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 111 {
 112         struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
 113
 114         /* enable the alarm event */
 115         regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN_MSK, enable ? TA_EN : TA_DIS);
 116         /* enable the alarm interrupt */
 117         regmap_update_bits(bbnsm->regmap, BBNSM_INT_EN, TA_EN_MSK, enable ? TA_EN : TA_DIS);
 118
 119         return 0;
 120 }
 121
 122 static int bbnsm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 123 {
 124         struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
 125         unsigned long time = rtc_tm_to_time64(&alrm->time);
 126
 127         /* disable the alarm */
 128         regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN, TA_EN);
 129
 130         /* write the seconds to TA */
 131         regmap_write(bbnsm->regmap, BBNSM_TA, time);
 132
 133         return bbnsm_rtc_alarm_irq_enable(dev, alrm->enabled);
 134 }
 135
 136 static const struct rtc_class_ops bbnsm_rtc_ops = {
 137         .read_time = bbnsm_rtc_read_time,
 138         .set_time = bbnsm_rtc_set_time,
 139         .read_alarm = bbnsm_rtc_read_alarm,
 140         .set_alarm = bbnsm_rtc_set_alarm,
 141         .alarm_irq_enable = bbnsm_rtc_alarm_irq_enable,
 142 };
 143
 144 static irqreturn_t bbnsm_rtc_irq_handler(int irq, void *dev_id)
 145 {
 146         struct device *dev = dev_id;
 147         struct bbnsm_rtc  *bbnsm = dev_get_drvdata(dev);
 148         u32 val;
 149
 150         regmap_read(bbnsm->regmap, BBNSM_EVENTS, &val);
 151         if (val & BBNSM_EVENT_TA) {
 152                 bbnsm_rtc_alarm_irq_enable(dev, false);
 153                 /* clear the alarm event */
 154                 regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, TA_EN_MSK, BBNSM_EVENT_TA);
 155                 rtc_update_irq(bbnsm->rtc, 1, RTC_AF | RTC_IRQF);
 156
 157                 return IRQ_HANDLED;
 158         }
 159
 160         return IRQ_NONE;
 161 }
 162
 163 static int bbnsm_rtc_probe(struct platform_device *pdev)
 164 {
 165         struct device_node *np = pdev->dev.of_node;
 166         struct bbnsm_rtc *bbnsm;
 167         int ret;
 168
 169         bbnsm = devm_kzalloc(&pdev->dev, sizeof(*bbnsm), GFP_KERNEL);
 170         if (!bbnsm)
 171                 return -ENOMEM;
 172
 173         bbnsm->rtc = devm_rtc_allocate_device(&pdev->dev);
 174         if (IS_ERR(bbnsm->rtc))
 175                 return PTR_ERR(bbnsm->rtc);
 176
 177         bbnsm->regmap = syscon_node_to_regmap(np->parent);
 178         if (IS_ERR(bbnsm->regmap)) {
 179                 dev_dbg(&pdev->dev, "bbnsm get regmap failed\n");
 180                 return PTR_ERR(bbnsm->regmap);
 181         }
 182
 183         bbnsm->irq = platform_get_irq(pdev, 0);
 184         if (bbnsm->irq < 0)
 185                 return bbnsm->irq;
 186
 187         platform_set_drvdata(pdev, bbnsm);
 188
 189         /* clear all the pending events */
 190         regmap_write(bbnsm->regmap, BBNSM_EVENTS, 0x7A);
 191
 192         device_init_wakeup(&pdev->dev, true);
 193         dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
 194
 195         ret = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_rtc_irq_handler,
 196                                IRQF_SHARED, "rtc alarm", &pdev->dev);
 197         if (ret) {
 198                 dev_err(&pdev->dev, "failed to request irq %d: %d\n",
 199                         bbnsm->irq, ret);
 200                 goto err;
 201         }
 202
 203         bbnsm->rtc->ops = &bbnsm_rtc_ops;
 204         bbnsm->rtc->range_max = U32_MAX;
 205
 206         ret = devm_rtc_register_device(bbnsm->rtc);
 207         if (ret)
 208                 goto err;
 209
 210         return 0;
 211
 212 err:
 213         dev_pm_clear_wake_irq(&pdev->dev);
 214         device_init_wakeup(&pdev->dev, false);
 215         return ret;
 216 }
 217
 218 static void bbnsm_rtc_remove(struct platform_device *pdev)
 219 {
 220         dev_pm_clear_wake_irq(&pdev->dev);
 221         device_init_wakeup(&pdev->dev, false);
 222 }
 223
 224 static const struct of_device_id bbnsm_dt_ids[] = {
 225         { .compatible = "nxp,imx93-bbnsm-rtc" },
 226         { /* sentinel */ },
 227 };
 228 MODULE_DEVICE_TABLE(of, bbnsm_dt_ids);
 229
 230 static struct platform_driver bbnsm_rtc_driver = {
 231         .driver = {
 232                 .name = "bbnsm_rtc",
 233                 .of_match_table = bbnsm_dt_ids,
 234         },
 235         .probe = bbnsm_rtc_probe,
 236         .remove = bbnsm_rtc_remove,
 237 };
 238 module_platform_driver(bbnsm_rtc_driver);
 239
 240 MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
 241 MODULE_DESCRIPTION("NXP BBNSM RTC Driver");
 242 MODULE_LICENSE("GPL");