Quelle  rtc-omap.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
/*
 * TI OMAP Real Time Clock interface for Linux
 *
 * Copyright (C) 2003 MontaVista Software, Inc.
 * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
 *
 * Copyright (C) 2006 David Brownell (new RTC framework)
 * Copyright (C) 2014 Johan Hovold <johan@kernel.org>
 */

#include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinconf-generic.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/rtc.h>
#include <linux/rtc/rtc-omap.h>

/*
 * The OMAP RTC is a year/month/day/hours/minutes/seconds BCD clock
 * with century-range alarm matching, driven by the 32kHz clock.
 *
 * The main user-visible ways it differs from PC RTCs are by omitting
 * "don't care" alarm fields and sub-second periodic IRQs, and having
 * an autoadjust mechanism to calibrate to the true oscillator rate.
 *
 * Board-specific wiring options include using split power mode with
 * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
 * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
 * low power modes) for OMAP1 boards (OMAP-L138 has this built into
 * the SoC). See the BOARD-SPECIFIC CUSTOMIZATION comment.
 */

/* RTC registers */
#define OMAP_RTC_SECONDS_REG  0x00
#define OMAP_RTC_MINUTES_REG  0x04
#define OMAP_RTC_HOURS_REG  0x08
#define OMAP_RTC_DAYS_REG  0x0C
#define OMAP_RTC_MONTHS_REG  0x10
#define OMAP_RTC_YEARS_REG  0x14
#define OMAP_RTC_WEEKS_REG  0x18

#define OMAP_RTC_ALARM_SECONDS_REG 0x20
#define OMAP_RTC_ALARM_MINUTES_REG 0x24
#define OMAP_RTC_ALARM_HOURS_REG 0x28
#define OMAP_RTC_ALARM_DAYS_REG  0x2c
#define OMAP_RTC_ALARM_MONTHS_REG 0x30
#define OMAP_RTC_ALARM_YEARS_REG 0x34

#define OMAP_RTC_CTRL_REG  0x40
#define OMAP_RTC_STATUS_REG  0x44
#define OMAP_RTC_INTERRUPTS_REG  0x48

#define OMAP_RTC_COMP_LSB_REG  0x4c
#define OMAP_RTC_COMP_MSB_REG  0x50
#define OMAP_RTC_OSC_REG  0x54

#define OMAP_RTC_SCRATCH0_REG  0x60
#define OMAP_RTC_SCRATCH1_REG  0x64
#define OMAP_RTC_SCRATCH2_REG  0x68

#define OMAP_RTC_KICK0_REG  0x6c
#define OMAP_RTC_KICK1_REG  0x70

#define OMAP_RTC_IRQWAKEEN  0x7c

#define OMAP_RTC_ALARM2_SECONDS_REG 0x80
#define OMAP_RTC_ALARM2_MINUTES_REG 0x84
#define OMAP_RTC_ALARM2_HOURS_REG 0x88
#define OMAP_RTC_ALARM2_DAYS_REG 0x8c
#define OMAP_RTC_ALARM2_MONTHS_REG 0x90
#define OMAP_RTC_ALARM2_YEARS_REG 0x94

#define OMAP_RTC_PMIC_REG  0x98

/* OMAP_RTC_CTRL_REG bit fields: */
#define OMAP_RTC_CTRL_SPLIT  BIT(7)
#define OMAP_RTC_CTRL_DISABLE  BIT(6)
#define OMAP_RTC_CTRL_SET_32_COUNTER BIT(5)
#define OMAP_RTC_CTRL_TEST  BIT(4)
#define OMAP_RTC_CTRL_MODE_12_24 BIT(3)
#define OMAP_RTC_CTRL_AUTO_COMP  BIT(2)
#define OMAP_RTC_CTRL_ROUND_30S  BIT(1)
#define OMAP_RTC_CTRL_STOP  BIT(0)

/* OMAP_RTC_STATUS_REG bit fields: */
#define OMAP_RTC_STATUS_POWER_UP BIT(7)
#define OMAP_RTC_STATUS_ALARM2  BIT(7)
#define OMAP_RTC_STATUS_ALARM  BIT(6)
#define OMAP_RTC_STATUS_1D_EVENT BIT(5)
#define OMAP_RTC_STATUS_1H_EVENT BIT(4)
#define OMAP_RTC_STATUS_1M_EVENT BIT(3)
#define OMAP_RTC_STATUS_1S_EVENT BIT(2)
#define OMAP_RTC_STATUS_RUN  BIT(1)
#define OMAP_RTC_STATUS_BUSY  BIT(0)

/* OMAP_RTC_INTERRUPTS_REG bit fields: */
#define OMAP_RTC_INTERRUPTS_IT_ALARM2 BIT(4)
#define OMAP_RTC_INTERRUPTS_IT_ALARM BIT(3)
#define OMAP_RTC_INTERRUPTS_IT_TIMER BIT(2)

/* OMAP_RTC_OSC_REG bit fields: */
#define OMAP_RTC_OSC_32KCLK_EN  BIT(6)
#define OMAP_RTC_OSC_SEL_32KCLK_SRC BIT(3)
#define OMAP_RTC_OSC_OSC32K_GZ_DISABLE BIT(4)

/* OMAP_RTC_IRQWAKEEN bit fields: */
#define OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN BIT(1)

/* OMAP_RTC_PMIC bit fields: */
#define OMAP_RTC_PMIC_POWER_EN_EN BIT(16)
#define OMAP_RTC_PMIC_EXT_WKUP_EN(x) BIT(x)
#define OMAP_RTC_PMIC_EXT_WKUP_POL(x) BIT(4 + x)

/* OMAP_RTC_KICKER values */
#define KICK0_VALUE   0x83e70b13
#define KICK1_VALUE   0x95a4f1e0

struct omap_rtc;

struct omap_rtc_device_type {
 bool has_32kclk_en;
 bool has_irqwakeen;
 bool has_pmic_mode;
 bool has_power_up_reset;
 void (*lock)(struct omap_rtc *rtc);
 void (*unlock)(struct omap_rtc *rtc);
};

struct omap_rtc {
 struct rtc_device *rtc;
 void __iomem *base;
 struct clk *clk;
 int irq_alarm;
 int irq_timer;
 u8 interrupts_reg;
 bool is_pmic_controller;
 bool has_ext_clk;
 bool is_suspending;
 const struct omap_rtc_device_type *type;
 struct pinctrl_dev *pctldev;
};

static inline u8 rtc_read(struct omap_rtc *rtc, unsigned int reg)
{
 return readb(rtc->base + reg);
}

static inline u32 rtc_readl(struct omap_rtc *rtc, unsigned int reg)
{
 return readl(rtc->base + reg);
}

static inline void rtc_write(struct omap_rtc *rtc, unsigned int reg, u8 val)
{
 writeb(val, rtc->base + reg);
}

static inline void rtc_writel(struct omap_rtc *rtc, unsigned int reg, u32 val)
{
 writel(val, rtc->base + reg);
}

static void am3352_rtc_unlock(struct omap_rtc *rtc)
{
 rtc_writel(rtc, OMAP_RTC_KICK0_REG, KICK0_VALUE);
 rtc_writel(rtc, OMAP_RTC_KICK1_REG, KICK1_VALUE);
}

static void am3352_rtc_lock(struct omap_rtc *rtc)
{
 rtc_writel(rtc, OMAP_RTC_KICK0_REG, 0);
 rtc_writel(rtc, OMAP_RTC_KICK1_REG, 0);
}

static void default_rtc_unlock(struct omap_rtc *rtc)
{
}

static void default_rtc_lock(struct omap_rtc *rtc)
{
}

/*
 * We rely on the rtc framework to handle locking (rtc->ops_lock),
 * so the only other requirement is that register accesses which
 * require BUSY to be clear are made with IRQs locally disabled
 */
static void rtc_wait_not_busy(struct omap_rtc *rtc)
{
 int count;
 u8 status;

 /* BUSY may stay active for 1/32768 second (~30 usec) */
 for (count = 0; count < 50; count++) {
  status = rtc_read(rtc, OMAP_RTC_STATUS_REG);
  if (!(status & OMAP_RTC_STATUS_BUSY))
   break;
  udelay(1);
 }
 /* now we have ~15 usec to read/write various registers */
}

static irqreturn_t rtc_irq(int irq, void *dev_id)
{
 struct omap_rtc *rtc = dev_id;
 unsigned long events = 0;
 u8 irq_data;

 irq_data = rtc_read(rtc, OMAP_RTC_STATUS_REG);

 /* alarm irq? */
 if (irq_data & OMAP_RTC_STATUS_ALARM) {
  rtc->type->unlock(rtc);
  rtc_write(rtc, OMAP_RTC_STATUS_REG, OMAP_RTC_STATUS_ALARM);
  rtc->type->lock(rtc);
  events |= RTC_IRQF | RTC_AF;
 }

 /* 1/sec periodic/update irq? */
 if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
  events |= RTC_IRQF | RTC_UF;

 rtc_update_irq(rtc->rtc, 1, events);

 return IRQ_HANDLED;
}

static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);
 u8 reg, irqwake_reg = 0;

 local_irq_disable();
 rtc_wait_not_busy(rtc);
 reg = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
 if (rtc->type->has_irqwakeen)
  irqwake_reg = rtc_read(rtc, OMAP_RTC_IRQWAKEEN);

 if (enabled) {
  reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
  irqwake_reg |= OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
 } else {
  reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
  irqwake_reg &= ~OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
 }
 rtc_wait_not_busy(rtc);
 rtc->type->unlock(rtc);
 rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, reg);
 if (rtc->type->has_irqwakeen)
  rtc_write(rtc, OMAP_RTC_IRQWAKEEN, irqwake_reg);
 rtc->type->lock(rtc);
 local_irq_enable();

 return 0;
}

/* this hardware doesn't support "don't care" alarm fields */
static void tm2bcd(struct rtc_time *tm)
{
 tm->tm_sec = bin2bcd(tm->tm_sec);
 tm->tm_min = bin2bcd(tm->tm_min);
 tm->tm_hour = bin2bcd(tm->tm_hour);
 tm->tm_mday = bin2bcd(tm->tm_mday);

 tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 tm->tm_year = bin2bcd(tm->tm_year - 100);
}

static void bcd2tm(struct rtc_time *tm)
{
 tm->tm_sec = bcd2bin(tm->tm_sec);
 tm->tm_min = bcd2bin(tm->tm_min);
 tm->tm_hour = bcd2bin(tm->tm_hour);
 tm->tm_mday = bcd2bin(tm->tm_mday);
 tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 /* epoch == 1900 */
 tm->tm_year = bcd2bin(tm->tm_year) + 100;
}

static void omap_rtc_read_time_raw(struct omap_rtc *rtc, struct rtc_time *tm)
{
 tm->tm_sec = rtc_read(rtc, OMAP_RTC_SECONDS_REG);
 tm->tm_min = rtc_read(rtc, OMAP_RTC_MINUTES_REG);
 tm->tm_hour = rtc_read(rtc, OMAP_RTC_HOURS_REG);
 tm->tm_mday = rtc_read(rtc, OMAP_RTC_DAYS_REG);
 tm->tm_mon = rtc_read(rtc, OMAP_RTC_MONTHS_REG);
 tm->tm_year = rtc_read(rtc, OMAP_RTC_YEARS_REG);
}

static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);

 /* we don't report wday/yday/isdst ... */
 local_irq_disable();
 rtc_wait_not_busy(rtc);
 omap_rtc_read_time_raw(rtc, tm);
 local_irq_enable();

 bcd2tm(tm);

 return 0;
}

static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);

 tm2bcd(tm);

 local_irq_disable();
 rtc_wait_not_busy(rtc);

 rtc->type->unlock(rtc);
 rtc_write(rtc, OMAP_RTC_YEARS_REG, tm->tm_year);
 rtc_write(rtc, OMAP_RTC_MONTHS_REG, tm->tm_mon);
 rtc_write(rtc, OMAP_RTC_DAYS_REG, tm->tm_mday);
 rtc_write(rtc, OMAP_RTC_HOURS_REG, tm->tm_hour);
 rtc_write(rtc, OMAP_RTC_MINUTES_REG, tm->tm_min);
 rtc_write(rtc, OMAP_RTC_SECONDS_REG, tm->tm_sec);
 rtc->type->lock(rtc);

 local_irq_enable();

 return 0;
}

static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);
 u8 interrupts;

 local_irq_disable();
 rtc_wait_not_busy(rtc);

 alm->time.tm_sec = rtc_read(rtc, OMAP_RTC_ALARM_SECONDS_REG);
 alm->time.tm_min = rtc_read(rtc, OMAP_RTC_ALARM_MINUTES_REG);
 alm->time.tm_hour = rtc_read(rtc, OMAP_RTC_ALARM_HOURS_REG);
 alm->time.tm_mday = rtc_read(rtc, OMAP_RTC_ALARM_DAYS_REG);
 alm->time.tm_mon = rtc_read(rtc, OMAP_RTC_ALARM_MONTHS_REG);
 alm->time.tm_year = rtc_read(rtc, OMAP_RTC_ALARM_YEARS_REG);

 local_irq_enable();

 bcd2tm(&alm->time);

 interrupts = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
 alm->enabled = !!(interrupts & OMAP_RTC_INTERRUPTS_IT_ALARM);

 return 0;
}

static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);
 u8 reg, irqwake_reg = 0;

 tm2bcd(&alm->time);

 local_irq_disable();
 rtc_wait_not_busy(rtc);

 rtc->type->unlock(rtc);
 rtc_write(rtc, OMAP_RTC_ALARM_YEARS_REG, alm->time.tm_year);
 rtc_write(rtc, OMAP_RTC_ALARM_MONTHS_REG, alm->time.tm_mon);
 rtc_write(rtc, OMAP_RTC_ALARM_DAYS_REG, alm->time.tm_mday);
 rtc_write(rtc, OMAP_RTC_ALARM_HOURS_REG, alm->time.tm_hour);
 rtc_write(rtc, OMAP_RTC_ALARM_MINUTES_REG, alm->time.tm_min);
 rtc_write(rtc, OMAP_RTC_ALARM_SECONDS_REG, alm->time.tm_sec);

 reg = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
 if (rtc->type->has_irqwakeen)
  irqwake_reg = rtc_read(rtc, OMAP_RTC_IRQWAKEEN);

 if (alm->enabled) {
  reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
  irqwake_reg |= OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
 } else {
  reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
  irqwake_reg &= ~OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
 }
 rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, reg);
 if (rtc->type->has_irqwakeen)
  rtc_write(rtc, OMAP_RTC_IRQWAKEEN, irqwake_reg);
 rtc->type->lock(rtc);

 local_irq_enable();

 return 0;
}

static struct omap_rtc *omap_rtc_power_off_rtc;

/**
 * omap_rtc_power_off_program: Set the pmic power off sequence. The RTC
 * generates pmic_pwr_enable control, which can be used to control an external
 * PMIC.
 */
int omap_rtc_power_off_program(struct device *dev)
{
 struct omap_rtc *rtc = omap_rtc_power_off_rtc;
 struct rtc_time tm;
 unsigned long now;
 int seconds;
 u32 val;

 rtc->type->unlock(rtc);
 /* enable pmic_power_en control */
 val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
 rtc_writel(rtc, OMAP_RTC_PMIC_REG, val | OMAP_RTC_PMIC_POWER_EN_EN);

again:
 /* Clear any existing ALARM2 event */
 rtc_writel(rtc, OMAP_RTC_STATUS_REG, OMAP_RTC_STATUS_ALARM2);

 /* set alarm one second from now */
 omap_rtc_read_time_raw(rtc, &tm);
 seconds = tm.tm_sec;
 bcd2tm(&tm);
 now = rtc_tm_to_time64(&tm);
 rtc_time64_to_tm(now + 1, &tm);

 tm2bcd(&tm);

 rtc_wait_not_busy(rtc);

 rtc_write(rtc, OMAP_RTC_ALARM2_SECONDS_REG, tm.tm_sec);
 rtc_write(rtc, OMAP_RTC_ALARM2_MINUTES_REG, tm.tm_min);
 rtc_write(rtc, OMAP_RTC_ALARM2_HOURS_REG, tm.tm_hour);
 rtc_write(rtc, OMAP_RTC_ALARM2_DAYS_REG, tm.tm_mday);
 rtc_write(rtc, OMAP_RTC_ALARM2_MONTHS_REG, tm.tm_mon);
 rtc_write(rtc, OMAP_RTC_ALARM2_YEARS_REG, tm.tm_year);

 /*
 * enable ALARM2 interrupt
 *
 * NOTE: this fails on AM3352 if rtc_write (writeb) is used
 */
 val = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
 rtc_writel(rtc, OMAP_RTC_INTERRUPTS_REG,
   val | OMAP_RTC_INTERRUPTS_IT_ALARM2);

 /* Retry in case roll over happened before alarm was armed. */
 if (rtc_read(rtc, OMAP_RTC_SECONDS_REG) != seconds) {
  val = rtc_read(rtc, OMAP_RTC_STATUS_REG);
  if (!(val & OMAP_RTC_STATUS_ALARM2))
   goto again;
 }

 rtc->type->lock(rtc);

 return 0;
}
EXPORT_SYMBOL(omap_rtc_power_off_program);

/*
 * omap_rtc_poweroff: RTC-controlled power off
 *
 * The RTC can be used to control an external PMIC via the pmic_power_en pin,
 * which can be configured to transition to OFF on ALARM2 events.
 *
 * Notes:
 * The one-second alarm offset is the shortest offset possible as the alarm
 * registers must be set before the next timer update and the offset
 * calculation is too heavy for everything to be done within a single access
 * period (~15 us).
 *
 * Called with local interrupts disabled.
 */
static void omap_rtc_power_off(void)
{
 struct rtc_device *rtc = omap_rtc_power_off_rtc->rtc;
 u32 val;

 omap_rtc_power_off_program(rtc->dev.parent);

 /* Set PMIC power enable and EXT_WAKEUP in case PB power on is used */
 omap_rtc_power_off_rtc->type->unlock(omap_rtc_power_off_rtc);
 val = rtc_readl(omap_rtc_power_off_rtc, OMAP_RTC_PMIC_REG);
 val |= OMAP_RTC_PMIC_POWER_EN_EN | OMAP_RTC_PMIC_EXT_WKUP_POL(0) |
   OMAP_RTC_PMIC_EXT_WKUP_EN(0);
 rtc_writel(omap_rtc_power_off_rtc, OMAP_RTC_PMIC_REG, val);
 omap_rtc_power_off_rtc->type->lock(omap_rtc_power_off_rtc);

 /*
 * Wait for alarm to trigger (within one second) and external PMIC to
 * power off the system. Add a 500 ms margin for external latencies
 * (e.g. debounce circuits).
 */
 mdelay(1500);
}

static const struct rtc_class_ops omap_rtc_ops = {
 .read_time = omap_rtc_read_time,
 .set_time = omap_rtc_set_time,
 .read_alarm = omap_rtc_read_alarm,
 .set_alarm = omap_rtc_set_alarm,
 .alarm_irq_enable = omap_rtc_alarm_irq_enable,
};

static const struct omap_rtc_device_type omap_rtc_default_type = {
 .has_power_up_reset = true,
 .lock  = default_rtc_lock,
 .unlock  = default_rtc_unlock,
};

static const struct omap_rtc_device_type omap_rtc_am3352_type = {
 .has_32kclk_en = true,
 .has_irqwakeen = true,
 .has_pmic_mode = true,
 .lock  = am3352_rtc_lock,
 .unlock  = am3352_rtc_unlock,
};

static const struct omap_rtc_device_type omap_rtc_da830_type = {
 .lock  = am3352_rtc_lock,
 .unlock  = am3352_rtc_unlock,
};

static const struct platform_device_id omap_rtc_id_table[] = {
 {
  .name = "omap_rtc",
  .driver_data = (kernel_ulong_t)&omap_rtc_default_type,
 }, {
  .name = "am3352-rtc",
  .driver_data = (kernel_ulong_t)&omap_rtc_am3352_type,
 }, {
  .name = "da830-rtc",
  .driver_data = (kernel_ulong_t)&omap_rtc_da830_type,
 }, {
  /* sentinel */
 }
};
MODULE_DEVICE_TABLE(platform, omap_rtc_id_table);

static const struct of_device_id omap_rtc_of_match[] = {
 {
  .compatible = "ti,am3352-rtc",
  .data  = &omap_rtc_am3352_type,
 }, {
  .compatible = "ti,da830-rtc",
  .data  = &omap_rtc_da830_type,
 }, {
  /* sentinel */
 }
};
MODULE_DEVICE_TABLE(of, omap_rtc_of_match);

static const struct pinctrl_pin_desc rtc_pins_desc[] = {
 PINCTRL_PIN(0, "ext_wakeup0"),
 PINCTRL_PIN(1, "ext_wakeup1"),
 PINCTRL_PIN(2, "ext_wakeup2"),
 PINCTRL_PIN(3, "ext_wakeup3"),
};

static int rtc_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
{
 return 0;
}

static const char *rtc_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
     unsigned int group)
{
 return NULL;
}

static const struct pinctrl_ops rtc_pinctrl_ops = {
 .get_groups_count = rtc_pinctrl_get_groups_count,
 .get_group_name = rtc_pinctrl_get_group_name,
 .dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
 .dt_free_map = pinconf_generic_dt_free_map,
};

#define PIN_CONFIG_ACTIVE_HIGH  (PIN_CONFIG_END + 1)

static const struct pinconf_generic_params rtc_params[] = {
 {"ti,active-high", PIN_CONFIG_ACTIVE_HIGH, 0},
};

#ifdef CONFIG_DEBUG_FS
static const struct pin_config_item rtc_conf_items[ARRAY_SIZE(rtc_params)] = {
 PCONFDUMP(PIN_CONFIG_ACTIVE_HIGH, "input active high", NULL, false),
};
#endif

static int rtc_pinconf_get(struct pinctrl_dev *pctldev,
   unsigned int pin, unsigned long *config)
{
 struct omap_rtc *rtc = pinctrl_dev_get_drvdata(pctldev);
 unsigned int param = pinconf_to_config_param(*config);
 u32 val;
 u16 arg = 0;

 val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);

 switch (param) {
 case PIN_CONFIG_INPUT_ENABLE:
  if (!(val & OMAP_RTC_PMIC_EXT_WKUP_EN(pin)))
   return -EINVAL;
  break;
 case PIN_CONFIG_ACTIVE_HIGH:
  if (val & OMAP_RTC_PMIC_EXT_WKUP_POL(pin))
   return -EINVAL;
  break;
 default:
  return -ENOTSUPP;
 }

 *config = pinconf_to_config_packed(param, arg);

 return 0;
}

static int rtc_pinconf_set(struct pinctrl_dev *pctldev,
   unsigned int pin, unsigned long *configs,
   unsigned int num_configs)
{
 struct omap_rtc *rtc = pinctrl_dev_get_drvdata(pctldev);
 u32 val;
 unsigned int param;
 u32 param_val;
 int i;

 val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);

 /* active low by default */
 val |= OMAP_RTC_PMIC_EXT_WKUP_POL(pin);

 for (i = 0; i < num_configs; i++) {
  param = pinconf_to_config_param(configs[i]);
  param_val = pinconf_to_config_argument(configs[i]);

  switch (param) {
  case PIN_CONFIG_INPUT_ENABLE:
   if (param_val)
    val |= OMAP_RTC_PMIC_EXT_WKUP_EN(pin);
   else
    val &= ~OMAP_RTC_PMIC_EXT_WKUP_EN(pin);
   break;
  case PIN_CONFIG_ACTIVE_HIGH:
   val &= ~OMAP_RTC_PMIC_EXT_WKUP_POL(pin);
   break;
  default:
   dev_err(&rtc->rtc->dev, "Property %u not supported\n",
    param);
   return -ENOTSUPP;
  }
 }

 rtc->type->unlock(rtc);
 rtc_writel(rtc, OMAP_RTC_PMIC_REG, val);
 rtc->type->lock(rtc);

 return 0;
}

static const struct pinconf_ops rtc_pinconf_ops = {
 .is_generic = true,
 .pin_config_get = rtc_pinconf_get,
 .pin_config_set = rtc_pinconf_set,
};

static struct pinctrl_desc rtc_pinctrl_desc = {
 .pins = rtc_pins_desc,
 .npins = ARRAY_SIZE(rtc_pins_desc),
 .pctlops = &rtc_pinctrl_ops,
 .confops = &rtc_pinconf_ops,
 .custom_params = rtc_params,
 .num_custom_params = ARRAY_SIZE(rtc_params),
#ifdef CONFIG_DEBUG_FS
 .custom_conf_items = rtc_conf_items,
#endif
 .owner = THIS_MODULE,
};

static int omap_rtc_scratch_read(void *priv, unsigned int offset, void *_val,
     size_t bytes)
{
 struct omap_rtc *rtc = priv;
 u32 *val = _val;
 int i;

 for (i = 0; i < bytes / 4; i++)
  val[i] = rtc_readl(rtc,
       OMAP_RTC_SCRATCH0_REG + offset + (i * 4));

 return 0;
}

static int omap_rtc_scratch_write(void *priv, unsigned int offset, void *_val,
      size_t bytes)
{
 struct omap_rtc *rtc = priv;
 u32 *val = _val;
 int i;

 rtc->type->unlock(rtc);
 for (i = 0; i < bytes / 4; i++)
  rtc_writel(rtc,
      OMAP_RTC_SCRATCH0_REG + offset + (i * 4), val[i]);
 rtc->type->lock(rtc);

 return 0;
}

static struct nvmem_config omap_rtc_nvmem_config = {
 .name = "omap_rtc_scratch",
 .word_size = 4,
 .stride = 4,
 .size = OMAP_RTC_KICK0_REG - OMAP_RTC_SCRATCH0_REG,
 .reg_read = omap_rtc_scratch_read,
 .reg_write = omap_rtc_scratch_write,
};

static int omap_rtc_probe(struct platform_device *pdev)
{
 struct omap_rtc *rtc;
 u8 reg, mask, new_ctrl;
 const struct platform_device_id *id_entry;
 int ret;

 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 if (!rtc)
  return -ENOMEM;

 rtc->type = device_get_match_data(&pdev->dev);
 if (rtc->type) {
  rtc->is_pmic_controller = rtc->type->has_pmic_mode &&
   of_device_is_system_power_controller(pdev->dev.of_node);
 } else {
  id_entry = platform_get_device_id(pdev);
  rtc->type = (void *)id_entry->driver_data;
 }

 rtc->irq_timer = platform_get_irq(pdev, 0);
 if (rtc->irq_timer < 0)
  return rtc->irq_timer;

 rtc->irq_alarm = platform_get_irq(pdev, 1);
 if (rtc->irq_alarm < 0)
  return rtc->irq_alarm;

 rtc->clk = devm_clk_get(&pdev->dev, "ext-clk");
 if (!IS_ERR(rtc->clk))
  rtc->has_ext_clk = true;
 else
  rtc->clk = devm_clk_get(&pdev->dev, "int-clk");

 if (!IS_ERR(rtc->clk))
  clk_prepare_enable(rtc->clk);

 rtc->base = devm_platform_ioremap_resource(pdev, 0);
 if (IS_ERR(rtc->base)) {
  clk_disable_unprepare(rtc->clk);
  return PTR_ERR(rtc->base);
 }

 platform_set_drvdata(pdev, rtc);

 /* Enable the clock/module so that we can access the registers */
 pm_runtime_enable(&pdev->dev);
 pm_runtime_get_sync(&pdev->dev);

 rtc->type->unlock(rtc);

 /*
 * disable interrupts
 *
 * NOTE: ALARM2 is not cleared on AM3352 if rtc_write (writeb) is used
 */
 rtc_writel(rtc, OMAP_RTC_INTERRUPTS_REG, 0);

 /* enable RTC functional clock */
 if (rtc->type->has_32kclk_en) {
  reg = rtc_read(rtc, OMAP_RTC_OSC_REG);
  rtc_write(rtc, OMAP_RTC_OSC_REG, reg | OMAP_RTC_OSC_32KCLK_EN);
 }

 /* clear old status */
 reg = rtc_read(rtc, OMAP_RTC_STATUS_REG);

 mask = OMAP_RTC_STATUS_ALARM;

 if (rtc->type->has_pmic_mode)
  mask |= OMAP_RTC_STATUS_ALARM2;

 if (rtc->type->has_power_up_reset) {
  mask |= OMAP_RTC_STATUS_POWER_UP;
  if (reg & OMAP_RTC_STATUS_POWER_UP)
   dev_info(&pdev->dev, "RTC power up reset detected\n");
 }

 if (reg & mask)
  rtc_write(rtc, OMAP_RTC_STATUS_REG, reg & mask);

 /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 reg = rtc_read(rtc, OMAP_RTC_CTRL_REG);
 if (reg & OMAP_RTC_CTRL_STOP)
  dev_info(&pdev->dev, "already running\n");

 /* force to 24 hour mode */
 new_ctrl = reg & (OMAP_RTC_CTRL_SPLIT | OMAP_RTC_CTRL_AUTO_COMP);
 new_ctrl |= OMAP_RTC_CTRL_STOP;

 /*
 * BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 *
 *  - Device wake-up capability setting should come through chip
 *    init logic. OMAP1 boards should initialize the "wakeup capable"
 *    flag in the platform device if the board is wired right for
 *    being woken up by RTC alarm. For OMAP-L138, this capability
 *    is built into the SoC by the "Deep Sleep" capability.
 *
 *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 *    rather than nPWRON_RESET, should forcibly enable split
 *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 *    is write-only, and always reads as zero...)
 */

 if (new_ctrl & OMAP_RTC_CTRL_SPLIT)
  dev_info(&pdev->dev, "split power mode\n");

 if (reg != new_ctrl)
  rtc_write(rtc, OMAP_RTC_CTRL_REG, new_ctrl);

 /*
 * If we have the external clock then switch to it so we can keep
 * ticking across suspend.
 */
 if (rtc->has_ext_clk) {
  reg = rtc_read(rtc, OMAP_RTC_OSC_REG);
  reg &= ~OMAP_RTC_OSC_OSC32K_GZ_DISABLE;
  reg |= OMAP_RTC_OSC_32KCLK_EN | OMAP_RTC_OSC_SEL_32KCLK_SRC;
  rtc_write(rtc, OMAP_RTC_OSC_REG, reg);
 }

 rtc->type->lock(rtc);

 device_init_wakeup(&pdev->dev, true);

 rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 if (IS_ERR(rtc->rtc)) {
  ret = PTR_ERR(rtc->rtc);
  goto err;
 }

 rtc->rtc->ops = &omap_rtc_ops;
 rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
 omap_rtc_nvmem_config.priv = rtc;

 /* handle periodic and alarm irqs */
 ret = devm_request_irq(&pdev->dev, rtc->irq_timer, rtc_irq, 0,
   dev_name(&rtc->rtc->dev), rtc);
 if (ret)
  goto err;

 if (rtc->irq_timer != rtc->irq_alarm) {
  ret = devm_request_irq(&pdev->dev, rtc->irq_alarm, rtc_irq, 0,
    dev_name(&rtc->rtc->dev), rtc);
  if (ret)
   goto err;
 }

 /* Support ext_wakeup pinconf */
 rtc_pinctrl_desc.name = dev_name(&pdev->dev);

 rtc->pctldev = devm_pinctrl_register(&pdev->dev, &rtc_pinctrl_desc, rtc);
 if (IS_ERR(rtc->pctldev)) {
  dev_err(&pdev->dev, "Couldn't register pinctrl driver\n");
  ret = PTR_ERR(rtc->pctldev);
  goto err;
 }

 ret = devm_rtc_register_device(rtc->rtc);
 if (ret)
  goto err;

 devm_rtc_nvmem_register(rtc->rtc, &omap_rtc_nvmem_config);

 if (rtc->is_pmic_controller) {
  if (!pm_power_off) {
   omap_rtc_power_off_rtc = rtc;
   pm_power_off = omap_rtc_power_off;
  }
 }

 return 0;

err:
 clk_disable_unprepare(rtc->clk);
 device_init_wakeup(&pdev->dev, false);
 rtc->type->lock(rtc);
 pm_runtime_put_sync(&pdev->dev);
 pm_runtime_disable(&pdev->dev);

 return ret;
}

static void omap_rtc_remove(struct platform_device *pdev)
{
 struct omap_rtc *rtc = platform_get_drvdata(pdev);
 u8 reg;

 if (pm_power_off == omap_rtc_power_off &&
   omap_rtc_power_off_rtc == rtc) {
  pm_power_off = NULL;
  omap_rtc_power_off_rtc = NULL;
 }

 device_init_wakeup(&pdev->dev, false);

 if (!IS_ERR(rtc->clk))
  clk_disable_unprepare(rtc->clk);

 rtc->type->unlock(rtc);
 /* leave rtc running, but disable irqs */
 rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0);

 if (rtc->has_ext_clk) {
  reg = rtc_read(rtc, OMAP_RTC_OSC_REG);
  reg &= ~OMAP_RTC_OSC_SEL_32KCLK_SRC;
  rtc_write(rtc, OMAP_RTC_OSC_REG, reg);
 }

 rtc->type->lock(rtc);

 /* Disable the clock/module */
 pm_runtime_put_sync(&pdev->dev);
 pm_runtime_disable(&pdev->dev);
}

static int __maybe_unused omap_rtc_suspend(struct device *dev)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);

 rtc->interrupts_reg = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);

 rtc->type->unlock(rtc);
 /*
 * FIXME: the RTC alarm is not currently acting as a wakeup event
 * source on some platforms, and in fact this enable() call is just
 * saving a flag that's never used...
 */
 if (device_may_wakeup(dev))
  enable_irq_wake(rtc->irq_alarm);
 else
  rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0);
 rtc->type->lock(rtc);

 rtc->is_suspending = true;

 return 0;
}

static int __maybe_unused omap_rtc_resume(struct device *dev)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);

 rtc->type->unlock(rtc);
 if (device_may_wakeup(dev))
  disable_irq_wake(rtc->irq_alarm);
 else
  rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, rtc->interrupts_reg);
 rtc->type->lock(rtc);

 rtc->is_suspending = false;

 return 0;
}

static int __maybe_unused omap_rtc_runtime_suspend(struct device *dev)
{
 struct omap_rtc *rtc = dev_get_drvdata(dev);

 if (rtc->is_suspending && !rtc->has_ext_clk)
  return -EBUSY;

 return 0;
}

static const struct dev_pm_ops omap_rtc_pm_ops = {
 SET_SYSTEM_SLEEP_PM_OPS(omap_rtc_suspend, omap_rtc_resume)
 SET_RUNTIME_PM_OPS(omap_rtc_runtime_suspend, NULL, NULL)
};

static void omap_rtc_shutdown(struct platform_device *pdev)
{
 struct omap_rtc *rtc = platform_get_drvdata(pdev);
 u8 mask;

 /*
 * Keep the ALARM interrupt enabled to allow the system to power up on
 * alarm events.
 */
 rtc->type->unlock(rtc);
 mask = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
 mask &= OMAP_RTC_INTERRUPTS_IT_ALARM;
 rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, mask);
 rtc->type->lock(rtc);
}

static struct platform_driver omap_rtc_driver = {
 .probe  = omap_rtc_probe,
 .remove  = omap_rtc_remove,
 .shutdown = omap_rtc_shutdown,
 .driver  = {
  .name = "omap_rtc",
  .pm = &omap_rtc_pm_ops,
  .of_match_table = omap_rtc_of_match,
 },
 .id_table = omap_rtc_id_table,
};

module_platform_driver(omap_rtc_driver);

MODULE_AUTHOR("George G. Davis (and others)");
MODULE_DESCRIPTION("TI OMAP1, AM33xx, DA8xx/OMAP-L13x, AM43xx and DRA7xx RTC driver");
MODULE_LICENSE("GPL");