drivers/rtc/rtc-fsl-ftm-alarm.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Freescale FlexTimer Module (FTM) alarm device driver.
   4  *
   5  * Copyright 2014 Freescale Semiconductor, Inc.
   6  * Copyright 2019 NXP
   7  *
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/of.h>
  18 #include <linux/of_device.h>
  19 #include <linux/module.h>
  20 #include <linux/fsl/ftm.h>
  21 #include <linux/rtc.h>
  22 #include <linux/time.h>
  23 #include <linux/acpi.h>
  24 #include <linux/pm_wakeirq.h>
  25
  26 #define FTM_SC_CLK(c)           ((c) << FTM_SC_CLK_MASK_SHIFT)
  27
  28 /*
  29  * Select Fixed frequency clock (32KHz) as clock source
  30  * of FlexTimer Module
  31  */
  32 #define FTM_SC_CLKS_FIXED_FREQ  0x02
  33 #define FIXED_FREQ_CLK          32000
  34
  35 /* Select 128 (2^7) as divider factor */
  36 #define MAX_FREQ_DIV            (1 << FTM_SC_PS_MASK)
  37
  38 /* Maximum counter value in FlexTimer's CNT registers */
  39 #define MAX_COUNT_VAL           0xffff
  40
  41 struct ftm_rtc {
  42         struct rtc_device *rtc_dev;
  43         void __iomem *base;
  44         bool big_endian;
  45         u32 alarm_freq;
  46 };
  47
  48 static inline u32 rtc_readl(struct ftm_rtc *dev, u32 reg)
  49 {
  50         if (dev->big_endian)
  51                 return ioread32be(dev->base + reg);
  52         else
  53                 return ioread32(dev->base + reg);
  54 }
  55
  56 static inline void rtc_writel(struct ftm_rtc *dev, u32 reg, u32 val)
  57 {
  58         if (dev->big_endian)
  59                 iowrite32be(val, dev->base + reg);
  60         else
  61                 iowrite32(val, dev->base + reg);
  62 }
  63
  64 static inline void ftm_counter_enable(struct ftm_rtc *rtc)
  65 {
  66         u32 val;
  67
  68         /* select and enable counter clock source */
  69         val = rtc_readl(rtc, FTM_SC);
  70         val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
  71         val |= (FTM_SC_PS_MASK | FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ));
  72         rtc_writel(rtc, FTM_SC, val);
  73 }
  74
  75 static inline void ftm_counter_disable(struct ftm_rtc *rtc)
  76 {
  77         u32 val;
  78
  79         /* disable counter clock source */
  80         val = rtc_readl(rtc, FTM_SC);
  81         val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
  82         rtc_writel(rtc, FTM_SC, val);
  83 }
  84
  85 static inline void ftm_irq_acknowledge(struct ftm_rtc *rtc)
  86 {
  87         unsigned int timeout = 100;
  88
  89         /*
  90          *Fix errata A-007728 for flextimer
  91          *      If the FTM counter reaches the FTM_MOD value between
  92          *      the reading of the TOF bit and the writing of 0 to
  93          *      the TOF bit, the process of clearing the TOF bit
  94          *      does not work as expected when FTMx_CONF[NUMTOF] != 0
  95          *      and the current TOF count is less than FTMx_CONF[NUMTOF].
  96          *      If the above condition is met, the TOF bit remains set.
  97          *      If the TOF interrupt is enabled (FTMx_SC[TOIE] = 1),the
  98          *      TOF interrupt also remains asserted.
  99          *
 100          *      Above is the errata discription
 101          *
 102          *      In one word: software clearing TOF bit not works when
 103          *      FTMx_CONF[NUMTOF] was seted as nonzero and FTM counter
 104          *      reaches the FTM_MOD value.
 105          *
 106          *      The workaround is clearing TOF bit until it works
 107          *      (FTM counter doesn't always reache the FTM_MOD anyway),
 108          *      which may cost some cycles.
 109          */
 110         while ((FTM_SC_TOF & rtc_readl(rtc, FTM_SC)) && timeout--)
 111                 rtc_writel(rtc, FTM_SC, rtc_readl(rtc, FTM_SC) & (~FTM_SC_TOF));
 112 }
 113
 114 static inline void ftm_irq_enable(struct ftm_rtc *rtc)
 115 {
 116         u32 val;
 117
 118         val = rtc_readl(rtc, FTM_SC);
 119         val |= FTM_SC_TOIE;
 120         rtc_writel(rtc, FTM_SC, val);
 121 }
 122
 123 static inline void ftm_irq_disable(struct ftm_rtc *rtc)
 124 {
 125         u32 val;
 126
 127         val = rtc_readl(rtc, FTM_SC);
 128         val &= ~FTM_SC_TOIE;
 129         rtc_writel(rtc, FTM_SC, val);
 130 }
 131
 132 static inline void ftm_reset_counter(struct ftm_rtc *rtc)
 133 {
 134         /*
 135          * The CNT register contains the FTM counter value.
 136          * Reset clears the CNT register. Writing any value to COUNT
 137          * updates the counter with its initial value, CNTIN.
 138          */
 139         rtc_writel(rtc, FTM_CNT, 0x00);
 140 }
 141
 142 static void ftm_clean_alarm(struct ftm_rtc *rtc)
 143 {
 144         ftm_counter_disable(rtc);
 145
 146         rtc_writel(rtc, FTM_CNTIN, 0x00);
 147         rtc_writel(rtc, FTM_MOD, ~0U);
 148
 149         ftm_reset_counter(rtc);
 150 }
 151
 152 static irqreturn_t ftm_rtc_alarm_interrupt(int irq, void *dev)
 153 {
 154         struct ftm_rtc *rtc = dev;
 155
 156         rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
 157
 158         ftm_irq_acknowledge(rtc);
 159         ftm_irq_disable(rtc);
 160         ftm_clean_alarm(rtc);
 161
 162         return IRQ_HANDLED;
 163 }
 164
 165 static int ftm_rtc_alarm_irq_enable(struct device *dev,
 166                 unsigned int enabled)
 167 {
 168         struct ftm_rtc *rtc = dev_get_drvdata(dev);
 169
 170         if (enabled)
 171                 ftm_irq_enable(rtc);
 172         else
 173                 ftm_irq_disable(rtc);
 174
 175         return 0;
 176 }
 177
 178 /*
 179  * Note:
 180  *      The function is not really getting time from the RTC
 181  *      since FlexTimer is not a RTC device, but we need to
 182  *      get time to setup alarm, so we are using system time
 183  *      for now.
 184  */
 185 static int ftm_rtc_read_time(struct device *dev, struct rtc_time *tm)
 186 {
 187         rtc_time64_to_tm(ktime_get_real_seconds(), tm);
 188
 189         return 0;
 190 }
 191
 192 static int ftm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 193 {
 194         return 0;
 195 }
 196
 197 /*
 198  * 1. Select fixed frequency clock (32KHz) as clock source;
 199  * 2. Select 128 (2^7) as divider factor;
 200  * So clock is 250 Hz (32KHz/128).
 201  *
 202  * 3. FlexTimer's CNT register is a 32bit register,
 203  * but the register's 16 bit as counter value,it's other 16 bit
 204  * is reserved.So minimum counter value is 0x0,maximum counter
 205  * value is 0xffff.
 206  * So max alarm value is 262 (65536 / 250) seconds
 207  */
 208 static int ftm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 209 {
 210         time64_t alm_time;
 211         unsigned long long cycle;
 212         struct ftm_rtc *rtc = dev_get_drvdata(dev);
 213
 214         alm_time = rtc_tm_to_time64(&alm->time);
 215
 216         ftm_clean_alarm(rtc);
 217         cycle = (alm_time - ktime_get_real_seconds()) * rtc->alarm_freq;
 218         if (cycle > MAX_COUNT_VAL) {
 219                 pr_err("Out of alarm range {0~262} seconds.\n");
 220                 return -ERANGE;
 221         }
 222
 223         ftm_irq_disable(rtc);
 224
 225         /*
 226          * The counter increments until the value of MOD is reached,
 227          * at which point the counter is reloaded with the value of CNTIN.
 228          * The TOF (the overflow flag) bit is set when the FTM counter
 229          * changes from MOD to CNTIN. So we should using the cycle - 1.
 230          */
 231         rtc_writel(rtc, FTM_MOD, cycle - 1);
 232
 233         ftm_counter_enable(rtc);
 234         ftm_irq_enable(rtc);
 235
 236         return 0;
 237
 238 }
 239
 240 static const struct rtc_class_ops ftm_rtc_ops = {
 241         .read_time              = ftm_rtc_read_time,
 242         .read_alarm             = ftm_rtc_read_alarm,
 243         .set_alarm              = ftm_rtc_set_alarm,
 244         .alarm_irq_enable       = ftm_rtc_alarm_irq_enable,
 245 };
 246
 247 static int ftm_rtc_probe(struct platform_device *pdev)
 248 {
 249         int irq;
 250         int ret;
 251         struct ftm_rtc *rtc;
 252
 253         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 254         if (unlikely(!rtc)) {
 255                 dev_err(&pdev->dev, "cannot alloc memory for rtc\n");
 256                 return -ENOMEM;
 257         }
 258
 259         platform_set_drvdata(pdev, rtc);
 260
 261         rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 262         if (IS_ERR(rtc->rtc_dev))
 263                 return PTR_ERR(rtc->rtc_dev);
 264
 265         rtc->base = devm_platform_ioremap_resource(pdev, 0);
 266         if (IS_ERR(rtc->base)) {
 267                 dev_err(&pdev->dev, "cannot ioremap resource for rtc\n");
 268                 return PTR_ERR(rtc->base);
 269         }
 270
 271         irq = platform_get_irq(pdev, 0);
 272         if (irq < 0)
 273                 return irq;
 274
 275         ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt,
 276                                0, dev_name(&pdev->dev), rtc);
 277         if (ret < 0) {
 278                 dev_err(&pdev->dev, "failed to request irq\n");
 279                 return ret;
 280         }
 281
 282         rtc->big_endian =
 283                 device_property_read_bool(&pdev->dev, "big-endian");
 284
 285         rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV;
 286         rtc->rtc_dev->ops = &ftm_rtc_ops;
 287
 288         device_init_wakeup(&pdev->dev, true);
 289         ret = dev_pm_set_wake_irq(&pdev->dev, irq);
 290         if (ret)
 291                 dev_err(&pdev->dev, "failed to enable irq wake\n");
 292
 293         ret = rtc_register_device(rtc->rtc_dev);
 294         if (ret) {
 295                 dev_err(&pdev->dev, "can't register rtc device\n");
 296                 return ret;
 297         }
 298
 299         return 0;
 300 }
 301
 302 static const struct of_device_id ftm_rtc_match[] = {
 303         { .compatible = "fsl,ls1012a-ftm-alarm", },
 304         { .compatible = "fsl,ls1021a-ftm-alarm", },
 305         { .compatible = "fsl,ls1028a-ftm-alarm", },
 306         { .compatible = "fsl,ls1043a-ftm-alarm", },
 307         { .compatible = "fsl,ls1046a-ftm-alarm", },
 308         { .compatible = "fsl,ls1088a-ftm-alarm", },
 309         { .compatible = "fsl,ls208xa-ftm-alarm", },
 310         { .compatible = "fsl,lx2160a-ftm-alarm", },
 311         { },
 312 };
 313
 314 static const struct acpi_device_id ftm_imx_acpi_ids[] = {
 315         {"NXP0011",},
 316         { }
 317 };
 318 MODULE_DEVICE_TABLE(acpi, ftm_imx_acpi_ids);
 319
 320 static struct platform_driver ftm_rtc_driver = {
 321         .probe          = ftm_rtc_probe,
 322         .driver         = {
 323                 .name   = "ftm-alarm",
 324                 .of_match_table = ftm_rtc_match,
 325                 .acpi_match_table = ACPI_PTR(ftm_imx_acpi_ids),
 326         },
 327 };
 328
 329 static int __init ftm_alarm_init(void)
 330 {
 331         return platform_driver_register(&ftm_rtc_driver);
 332 }
 333
 334 device_initcall(ftm_alarm_init);
 335
 336 MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver");
 337 MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>");
 338 MODULE_LICENSE("GPL");