diff options
Diffstat (limited to 'drivers/rtc/rtc-stm32.c')
| -rw-r--r-- | drivers/rtc/rtc-stm32.c | 944 |
1 files changed, 944 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c new file mode 100644 index 000000000..76753c71d --- /dev/null +++ b/drivers/rtc/rtc-stm32.c @@ -0,0 +1,944 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) STMicroelectronics 2017 + * Author: Amelie Delaunay <amelie.delaunay@st.com> + */ + +#include <linux/bcd.h> +#include <linux/clk.h> +#include <linux/errno.h> +#include <linux/iopoll.h> +#include <linux/ioport.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_wakeirq.h> +#include <linux/regmap.h> +#include <linux/rtc.h> + +#define DRIVER_NAME "stm32_rtc" + +/* STM32_RTC_TR bit fields */ +#define STM32_RTC_TR_SEC_SHIFT 0 +#define STM32_RTC_TR_SEC GENMASK(6, 0) +#define STM32_RTC_TR_MIN_SHIFT 8 +#define STM32_RTC_TR_MIN GENMASK(14, 8) +#define STM32_RTC_TR_HOUR_SHIFT 16 +#define STM32_RTC_TR_HOUR GENMASK(21, 16) + +/* STM32_RTC_DR bit fields */ +#define STM32_RTC_DR_DATE_SHIFT 0 +#define STM32_RTC_DR_DATE GENMASK(5, 0) +#define STM32_RTC_DR_MONTH_SHIFT 8 +#define STM32_RTC_DR_MONTH GENMASK(12, 8) +#define STM32_RTC_DR_WDAY_SHIFT 13 +#define STM32_RTC_DR_WDAY GENMASK(15, 13) +#define STM32_RTC_DR_YEAR_SHIFT 16 +#define STM32_RTC_DR_YEAR GENMASK(23, 16) + +/* STM32_RTC_CR bit fields */ +#define STM32_RTC_CR_FMT BIT(6) +#define STM32_RTC_CR_ALRAE BIT(8) +#define STM32_RTC_CR_ALRAIE BIT(12) + +/* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */ +#define STM32_RTC_ISR_ALRAWF BIT(0) +#define STM32_RTC_ISR_INITS BIT(4) +#define STM32_RTC_ISR_RSF BIT(5) +#define STM32_RTC_ISR_INITF BIT(6) +#define STM32_RTC_ISR_INIT BIT(7) +#define STM32_RTC_ISR_ALRAF BIT(8) + +/* STM32_RTC_PRER bit fields */ +#define STM32_RTC_PRER_PRED_S_SHIFT 0 +#define STM32_RTC_PRER_PRED_S GENMASK(14, 0) +#define STM32_RTC_PRER_PRED_A_SHIFT 16 +#define STM32_RTC_PRER_PRED_A GENMASK(22, 16) + +/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */ +#define STM32_RTC_ALRMXR_SEC_SHIFT 0 +#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0) +#define STM32_RTC_ALRMXR_SEC_MASK BIT(7) +#define STM32_RTC_ALRMXR_MIN_SHIFT 8 +#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8) +#define STM32_RTC_ALRMXR_MIN_MASK BIT(15) +#define STM32_RTC_ALRMXR_HOUR_SHIFT 16 +#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16) +#define STM32_RTC_ALRMXR_PM BIT(22) +#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23) +#define STM32_RTC_ALRMXR_DATE_SHIFT 24 +#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24) +#define STM32_RTC_ALRMXR_WDSEL BIT(30) +#define STM32_RTC_ALRMXR_WDAY_SHIFT 24 +#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24) +#define STM32_RTC_ALRMXR_DATE_MASK BIT(31) + +/* STM32_RTC_SR/_SCR bit fields */ +#define STM32_RTC_SR_ALRA BIT(0) + +/* STM32_RTC_VERR bit fields */ +#define STM32_RTC_VERR_MINREV_SHIFT 0 +#define STM32_RTC_VERR_MINREV GENMASK(3, 0) +#define STM32_RTC_VERR_MAJREV_SHIFT 4 +#define STM32_RTC_VERR_MAJREV GENMASK(7, 4) + +/* STM32_RTC_WPR key constants */ +#define RTC_WPR_1ST_KEY 0xCA +#define RTC_WPR_2ND_KEY 0x53 +#define RTC_WPR_WRONG_KEY 0xFF + +/* Max STM32 RTC register offset is 0x3FC */ +#define UNDEF_REG 0xFFFF + +/* STM32 RTC driver time helpers */ +#define SEC_PER_DAY (24 * 60 * 60) + +struct stm32_rtc; + +struct stm32_rtc_registers { + u16 tr; + u16 dr; + u16 cr; + u16 isr; + u16 prer; + u16 alrmar; + u16 wpr; + u16 sr; + u16 scr; + u16 verr; +}; + +struct stm32_rtc_events { + u32 alra; +}; + +struct stm32_rtc_data { + const struct stm32_rtc_registers regs; + const struct stm32_rtc_events events; + void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags); + bool has_pclk; + bool need_dbp; + bool need_accuracy; +}; + +struct stm32_rtc { + struct rtc_device *rtc_dev; + void __iomem *base; + struct regmap *dbp; + unsigned int dbp_reg; + unsigned int dbp_mask; + struct clk *pclk; + struct clk *rtc_ck; + const struct stm32_rtc_data *data; + int irq_alarm; +}; + +static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + + writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + regs->wpr); + writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + regs->wpr); +} + +static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + + writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + regs->wpr); +} + +static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int isr = readl_relaxed(rtc->base + regs->isr); + + if (!(isr & STM32_RTC_ISR_INITF)) { + isr |= STM32_RTC_ISR_INIT; + writel_relaxed(isr, rtc->base + regs->isr); + + /* + * It takes around 2 rtc_ck clock cycles to enter in + * initialization phase mode (and have INITF flag set). As + * slowest rtc_ck frequency may be 32kHz and highest should be + * 1MHz, we poll every 10 us with a timeout of 100ms. + */ + return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr, isr, + (isr & STM32_RTC_ISR_INITF), + 10, 100000); + } + + return 0; +} + +static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int isr = readl_relaxed(rtc->base + regs->isr); + + isr &= ~STM32_RTC_ISR_INIT; + writel_relaxed(isr, rtc->base + regs->isr); +} + +static int stm32_rtc_wait_sync(struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int isr = readl_relaxed(rtc->base + regs->isr); + + isr &= ~STM32_RTC_ISR_RSF; + writel_relaxed(isr, rtc->base + regs->isr); + + /* + * Wait for RSF to be set to ensure the calendar registers are + * synchronised, it takes around 2 rtc_ck clock cycles + */ + return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr, + isr, + (isr & STM32_RTC_ISR_RSF), + 10, 100000); +} + +static void stm32_rtc_clear_event_flags(struct stm32_rtc *rtc, + unsigned int flags) +{ + rtc->data->clear_events(rtc, flags); +} + +static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id) +{ + struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id; + const struct stm32_rtc_registers *regs = &rtc->data->regs; + const struct stm32_rtc_events *evts = &rtc->data->events; + unsigned int status, cr; + + rtc_lock(rtc->rtc_dev); + + status = readl_relaxed(rtc->base + regs->sr); + cr = readl_relaxed(rtc->base + regs->cr); + + if ((status & evts->alra) && + (cr & STM32_RTC_CR_ALRAIE)) { + /* Alarm A flag - Alarm interrupt */ + dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n"); + + /* Pass event to the kernel */ + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); + + /* Clear event flags, otherwise new events won't be received */ + stm32_rtc_clear_event_flags(rtc, evts->alra); + } + + rtc_unlock(rtc->rtc_dev); + + return IRQ_HANDLED; +} + +/* Convert rtc_time structure from bin to bcd format */ +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); + /* + * Number of days since Sunday + * - on kernel side, 0=Sunday...6=Saturday + * - on rtc side, 0=invalid,1=Monday...7=Sunday + */ + tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday; +} + +/* Convert rtc_time structure from bcd to bin format */ +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; + tm->tm_year = bcd2bin(tm->tm_year) + 100; + /* + * Number of days since Sunday + * - on kernel side, 0=Sunday...6=Saturday + * - on rtc side, 0=invalid,1=Monday...7=Sunday + */ + tm->tm_wday %= 7; +} + +static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int tr, dr; + + /* Time and Date in BCD format */ + tr = readl_relaxed(rtc->base + regs->tr); + dr = readl_relaxed(rtc->base + regs->dr); + + tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; + tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; + tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; + + tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; + tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; + tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; + tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT; + + /* We don't report tm_yday and tm_isdst */ + + bcd2tm(tm); + + return 0; +} + +static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int tr, dr; + int ret = 0; + + tm2bcd(tm); + + /* Time in BCD format */ + tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) | + ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) | + ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR); + + /* Date in BCD format */ + dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) | + ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) | + ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) | + ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY); + + stm32_rtc_wpr_unlock(rtc); + + ret = stm32_rtc_enter_init_mode(rtc); + if (ret) { + dev_err(dev, "Can't enter in init mode. Set time aborted.\n"); + goto end; + } + + writel_relaxed(tr, rtc->base + regs->tr); + writel_relaxed(dr, rtc->base + regs->dr); + + stm32_rtc_exit_init_mode(rtc); + + ret = stm32_rtc_wait_sync(rtc); +end: + stm32_rtc_wpr_lock(rtc); + + return ret; +} + +static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + const struct stm32_rtc_events *evts = &rtc->data->events; + struct rtc_time *tm = &alrm->time; + unsigned int alrmar, cr, status; + + alrmar = readl_relaxed(rtc->base + regs->alrmar); + cr = readl_relaxed(rtc->base + regs->cr); + status = readl_relaxed(rtc->base + regs->sr); + + if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) { + /* + * Date/day doesn't matter in Alarm comparison so alarm + * triggers every day + */ + tm->tm_mday = -1; + tm->tm_wday = -1; + } else { + if (alrmar & STM32_RTC_ALRMXR_WDSEL) { + /* Alarm is set to a day of week */ + tm->tm_mday = -1; + tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >> + STM32_RTC_ALRMXR_WDAY_SHIFT; + tm->tm_wday %= 7; + } else { + /* Alarm is set to a day of month */ + tm->tm_wday = -1; + tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >> + STM32_RTC_ALRMXR_DATE_SHIFT; + } + } + + if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) { + /* Hours don't matter in Alarm comparison */ + tm->tm_hour = -1; + } else { + tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >> + STM32_RTC_ALRMXR_HOUR_SHIFT; + if (alrmar & STM32_RTC_ALRMXR_PM) + tm->tm_hour += 12; + } + + if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) { + /* Minutes don't matter in Alarm comparison */ + tm->tm_min = -1; + } else { + tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >> + STM32_RTC_ALRMXR_MIN_SHIFT; + } + + if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) { + /* Seconds don't matter in Alarm comparison */ + tm->tm_sec = -1; + } else { + tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >> + STM32_RTC_ALRMXR_SEC_SHIFT; + } + + bcd2tm(tm); + + alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0; + alrm->pending = (status & evts->alra) ? 1 : 0; + + return 0; +} + +static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + const struct stm32_rtc_events *evts = &rtc->data->events; + unsigned int cr; + + cr = readl_relaxed(rtc->base + regs->cr); + + stm32_rtc_wpr_unlock(rtc); + + /* We expose Alarm A to the kernel */ + if (enabled) + cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); + else + cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); + writel_relaxed(cr, rtc->base + regs->cr); + + /* Clear event flags, otherwise new events won't be received */ + stm32_rtc_clear_event_flags(rtc, evts->alra); + + stm32_rtc_wpr_lock(rtc); + + return 0; +} + +static int stm32_rtc_valid_alrm(struct device *dev, struct rtc_time *tm) +{ + static struct rtc_time now; + time64_t max_alarm_time64; + int max_day_forward; + int next_month; + int next_year; + + /* + * Assuming current date is M-D-Y H:M:S. + * RTC alarm can't be set on a specific month and year. + * So the valid alarm range is: + * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S + */ + stm32_rtc_read_time(dev, &now); + + /* + * Find the next month and the year of the next month. + * Note: tm_mon and next_month are from 0 to 11 + */ + next_month = now.tm_mon + 1; + if (next_month == 12) { + next_month = 0; + next_year = now.tm_year + 1; + } else { + next_year = now.tm_year; + } + + /* Find the maximum limit of alarm in days. */ + max_day_forward = rtc_month_days(now.tm_mon, now.tm_year) + - now.tm_mday + + min(rtc_month_days(next_month, next_year), now.tm_mday); + + /* Convert to timestamp and compare the alarm time and its upper limit */ + max_alarm_time64 = rtc_tm_to_time64(&now) + max_day_forward * SEC_PER_DAY; + return rtc_tm_to_time64(tm) <= max_alarm_time64 ? 0 : -EINVAL; +} + +static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + struct rtc_time *tm = &alrm->time; + unsigned int cr, isr, alrmar; + int ret = 0; + + /* + * RTC alarm can't be set on a specific date, unless this date is + * up to the same day of month next month. + */ + if (stm32_rtc_valid_alrm(dev, tm) < 0) { + dev_err(dev, "Alarm can be set only on upcoming month.\n"); + return -EINVAL; + } + + tm2bcd(tm); + + alrmar = 0; + /* tm_year and tm_mon are not used because not supported by RTC */ + alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) & + STM32_RTC_ALRMXR_DATE; + /* 24-hour format */ + alrmar &= ~STM32_RTC_ALRMXR_PM; + alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) & + STM32_RTC_ALRMXR_HOUR; + alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) & + STM32_RTC_ALRMXR_MIN; + alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) & + STM32_RTC_ALRMXR_SEC; + + stm32_rtc_wpr_unlock(rtc); + + /* Disable Alarm */ + cr = readl_relaxed(rtc->base + regs->cr); + cr &= ~STM32_RTC_CR_ALRAE; + writel_relaxed(cr, rtc->base + regs->cr); + + /* + * Poll Alarm write flag to be sure that Alarm update is allowed: it + * takes around 2 rtc_ck clock cycles + */ + ret = readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr, + isr, + (isr & STM32_RTC_ISR_ALRAWF), + 10, 100000); + + if (ret) { + dev_err(dev, "Alarm update not allowed\n"); + goto end; + } + + /* Write to Alarm register */ + writel_relaxed(alrmar, rtc->base + regs->alrmar); + + stm32_rtc_alarm_irq_enable(dev, alrm->enabled); +end: + stm32_rtc_wpr_lock(rtc); + + return ret; +} + +static const struct rtc_class_ops stm32_rtc_ops = { + .read_time = stm32_rtc_read_time, + .set_time = stm32_rtc_set_time, + .read_alarm = stm32_rtc_read_alarm, + .set_alarm = stm32_rtc_set_alarm, + .alarm_irq_enable = stm32_rtc_alarm_irq_enable, +}; + +static void stm32_rtc_clear_events(struct stm32_rtc *rtc, + unsigned int flags) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + + /* Flags are cleared by writing 0 in RTC_ISR */ + writel_relaxed(readl_relaxed(rtc->base + regs->isr) & ~flags, + rtc->base + regs->isr); +} + +static const struct stm32_rtc_data stm32_rtc_data = { + .has_pclk = false, + .need_dbp = true, + .need_accuracy = false, + .regs = { + .tr = 0x00, + .dr = 0x04, + .cr = 0x08, + .isr = 0x0C, + .prer = 0x10, + .alrmar = 0x1C, + .wpr = 0x24, + .sr = 0x0C, /* set to ISR offset to ease alarm management */ + .scr = UNDEF_REG, + .verr = UNDEF_REG, + }, + .events = { + .alra = STM32_RTC_ISR_ALRAF, + }, + .clear_events = stm32_rtc_clear_events, +}; + +static const struct stm32_rtc_data stm32h7_rtc_data = { + .has_pclk = true, + .need_dbp = true, + .need_accuracy = false, + .regs = { + .tr = 0x00, + .dr = 0x04, + .cr = 0x08, + .isr = 0x0C, + .prer = 0x10, + .alrmar = 0x1C, + .wpr = 0x24, + .sr = 0x0C, /* set to ISR offset to ease alarm management */ + .scr = UNDEF_REG, + .verr = UNDEF_REG, + }, + .events = { + .alra = STM32_RTC_ISR_ALRAF, + }, + .clear_events = stm32_rtc_clear_events, +}; + +static void stm32mp1_rtc_clear_events(struct stm32_rtc *rtc, + unsigned int flags) +{ + struct stm32_rtc_registers regs = rtc->data->regs; + + /* Flags are cleared by writing 1 in RTC_SCR */ + writel_relaxed(flags, rtc->base + regs.scr); +} + +static const struct stm32_rtc_data stm32mp1_data = { + .has_pclk = true, + .need_dbp = false, + .need_accuracy = true, + .regs = { + .tr = 0x00, + .dr = 0x04, + .cr = 0x18, + .isr = 0x0C, /* named RTC_ICSR on stm32mp1 */ + .prer = 0x10, + .alrmar = 0x40, + .wpr = 0x24, + .sr = 0x50, + .scr = 0x5C, + .verr = 0x3F4, + }, + .events = { + .alra = STM32_RTC_SR_ALRA, + }, + .clear_events = stm32mp1_rtc_clear_events, +}; + +static const struct of_device_id stm32_rtc_of_match[] = { + { .compatible = "st,stm32-rtc", .data = &stm32_rtc_data }, + { .compatible = "st,stm32h7-rtc", .data = &stm32h7_rtc_data }, + { .compatible = "st,stm32mp1-rtc", .data = &stm32mp1_data }, + {} +}; +MODULE_DEVICE_TABLE(of, stm32_rtc_of_match); + +static int stm32_rtc_init(struct platform_device *pdev, + struct stm32_rtc *rtc) +{ + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr; + unsigned int rate; + int ret; + + rate = clk_get_rate(rtc->rtc_ck); + + /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */ + pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT; + pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT; + + if (rate > (pred_a_max + 1) * (pred_s_max + 1)) { + dev_err(&pdev->dev, "rtc_ck rate is too high: %dHz\n", rate); + return -EINVAL; + } + + if (rtc->data->need_accuracy) { + for (pred_a = 0; pred_a <= pred_a_max; pred_a++) { + pred_s = (rate / (pred_a + 1)) - 1; + + if (pred_s <= pred_s_max && ((pred_s + 1) * (pred_a + 1)) == rate) + break; + } + } else { + for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) { + pred_s = (rate / (pred_a + 1)) - 1; + + if (((pred_s + 1) * (pred_a + 1)) == rate) + break; + } + } + + /* + * Can't find a 1Hz, so give priority to RTC power consumption + * by choosing the higher possible value for prediv_a + */ + if (pred_s > pred_s_max || pred_a > pred_a_max) { + pred_a = pred_a_max; + pred_s = (rate / (pred_a + 1)) - 1; + + dev_warn(&pdev->dev, "rtc_ck is %s\n", + (rate < ((pred_a + 1) * (pred_s + 1))) ? + "fast" : "slow"); + } + + cr = readl_relaxed(rtc->base + regs->cr); + + prer = readl_relaxed(rtc->base + regs->prer); + prer &= STM32_RTC_PRER_PRED_S | STM32_RTC_PRER_PRED_A; + + pred_s = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & + STM32_RTC_PRER_PRED_S; + pred_a = (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & + STM32_RTC_PRER_PRED_A; + + /* quit if there is nothing to initialize */ + if ((cr & STM32_RTC_CR_FMT) == 0 && prer == (pred_s | pred_a)) + return 0; + + stm32_rtc_wpr_unlock(rtc); + + ret = stm32_rtc_enter_init_mode(rtc); + if (ret) { + dev_err(&pdev->dev, + "Can't enter in init mode. Prescaler config failed.\n"); + goto end; + } + + writel_relaxed(pred_s, rtc->base + regs->prer); + writel_relaxed(pred_a | pred_s, rtc->base + regs->prer); + + /* Force 24h time format */ + cr &= ~STM32_RTC_CR_FMT; + writel_relaxed(cr, rtc->base + regs->cr); + + stm32_rtc_exit_init_mode(rtc); + + ret = stm32_rtc_wait_sync(rtc); +end: + stm32_rtc_wpr_lock(rtc); + + return ret; +} + +static int stm32_rtc_probe(struct platform_device *pdev) +{ + struct stm32_rtc *rtc; + const struct stm32_rtc_registers *regs; + int ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + rtc->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(rtc->base)) + return PTR_ERR(rtc->base); + + rtc->data = (struct stm32_rtc_data *) + of_device_get_match_data(&pdev->dev); + regs = &rtc->data->regs; + + if (rtc->data->need_dbp) { + rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, + "st,syscfg"); + if (IS_ERR(rtc->dbp)) { + dev_err(&pdev->dev, "no st,syscfg\n"); + return PTR_ERR(rtc->dbp); + } + + ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg", + 1, &rtc->dbp_reg); + if (ret) { + dev_err(&pdev->dev, "can't read DBP register offset\n"); + return ret; + } + + ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg", + 2, &rtc->dbp_mask); + if (ret) { + dev_err(&pdev->dev, "can't read DBP register mask\n"); + return ret; + } + } + + if (!rtc->data->has_pclk) { + rtc->pclk = NULL; + rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL); + } else { + rtc->pclk = devm_clk_get(&pdev->dev, "pclk"); + if (IS_ERR(rtc->pclk)) + return dev_err_probe(&pdev->dev, PTR_ERR(rtc->pclk), "no pclk clock"); + + rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck"); + } + if (IS_ERR(rtc->rtc_ck)) + return dev_err_probe(&pdev->dev, PTR_ERR(rtc->rtc_ck), "no rtc_ck clock"); + + if (rtc->data->has_pclk) { + ret = clk_prepare_enable(rtc->pclk); + if (ret) + return ret; + } + + ret = clk_prepare_enable(rtc->rtc_ck); + if (ret) + goto err_no_rtc_ck; + + if (rtc->data->need_dbp) + regmap_update_bits(rtc->dbp, rtc->dbp_reg, + rtc->dbp_mask, rtc->dbp_mask); + + /* + * After a system reset, RTC_ISR.INITS flag can be read to check if + * the calendar has been initialized or not. INITS flag is reset by a + * power-on reset (no vbat, no power-supply). It is not reset if + * rtc_ck parent clock has changed (so RTC prescalers need to be + * changed). That's why we cannot rely on this flag to know if RTC + * init has to be done. + */ + ret = stm32_rtc_init(pdev, rtc); + if (ret) + goto err; + + rtc->irq_alarm = platform_get_irq(pdev, 0); + if (rtc->irq_alarm <= 0) { + ret = rtc->irq_alarm; + goto err; + } + + ret = device_init_wakeup(&pdev->dev, true); + if (ret) + goto err; + + ret = dev_pm_set_wake_irq(&pdev->dev, rtc->irq_alarm); + if (ret) + goto err; + + platform_set_drvdata(pdev, rtc); + + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, + &stm32_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc_dev)) { + ret = PTR_ERR(rtc->rtc_dev); + dev_err(&pdev->dev, "rtc device registration failed, err=%d\n", + ret); + goto err; + } + + /* Handle RTC alarm interrupts */ + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL, + stm32_rtc_alarm_irq, IRQF_ONESHOT, + pdev->name, rtc); + if (ret) { + dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n", + rtc->irq_alarm); + goto err; + } + + /* + * If INITS flag is reset (calendar year field set to 0x00), calendar + * must be initialized + */ + if (!(readl_relaxed(rtc->base + regs->isr) & STM32_RTC_ISR_INITS)) + dev_warn(&pdev->dev, "Date/Time must be initialized\n"); + + if (regs->verr != UNDEF_REG) { + u32 ver = readl_relaxed(rtc->base + regs->verr); + + dev_info(&pdev->dev, "registered rev:%d.%d\n", + (ver >> STM32_RTC_VERR_MAJREV_SHIFT) & 0xF, + (ver >> STM32_RTC_VERR_MINREV_SHIFT) & 0xF); + } + + return 0; + +err: + clk_disable_unprepare(rtc->rtc_ck); +err_no_rtc_ck: + if (rtc->data->has_pclk) + clk_disable_unprepare(rtc->pclk); + + if (rtc->data->need_dbp) + regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0); + + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); + + return ret; +} + +static void stm32_rtc_remove(struct platform_device *pdev) +{ + struct stm32_rtc *rtc = platform_get_drvdata(pdev); + const struct stm32_rtc_registers *regs = &rtc->data->regs; + unsigned int cr; + + /* Disable interrupts */ + stm32_rtc_wpr_unlock(rtc); + cr = readl_relaxed(rtc->base + regs->cr); + cr &= ~STM32_RTC_CR_ALRAIE; + writel_relaxed(cr, rtc->base + regs->cr); + stm32_rtc_wpr_lock(rtc); + + clk_disable_unprepare(rtc->rtc_ck); + if (rtc->data->has_pclk) + clk_disable_unprepare(rtc->pclk); + + /* Enable backup domain write protection if needed */ + if (rtc->data->need_dbp) + regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0); + + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); +} + +static int stm32_rtc_suspend(struct device *dev) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + + if (rtc->data->has_pclk) + clk_disable_unprepare(rtc->pclk); + + return 0; +} + +static int stm32_rtc_resume(struct device *dev) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + int ret = 0; + + if (rtc->data->has_pclk) { + ret = clk_prepare_enable(rtc->pclk); + if (ret) + return ret; + } + + ret = stm32_rtc_wait_sync(rtc); + if (ret < 0) { + if (rtc->data->has_pclk) + clk_disable_unprepare(rtc->pclk); + return ret; + } + + return ret; +} + +static const struct dev_pm_ops stm32_rtc_pm_ops = { + NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_rtc_suspend, stm32_rtc_resume) +}; + +static struct platform_driver stm32_rtc_driver = { + .probe = stm32_rtc_probe, + .remove_new = stm32_rtc_remove, + .driver = { + .name = DRIVER_NAME, + .pm = &stm32_rtc_pm_ops, + .of_match_table = stm32_rtc_of_match, + }, +}; + +module_platform_driver(stm32_rtc_driver); + +MODULE_ALIAS("platform:" DRIVER_NAME); +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver"); +MODULE_LICENSE("GPL v2"); |