diff options
Diffstat (limited to 'drivers/rtc/rtc-pl031.c')
| -rw-r--r-- | drivers/rtc/rtc-pl031.c | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c new file mode 100644 index 000000000..82eb7da2c --- /dev/null +++ b/drivers/rtc/rtc-pl031.c @@ -0,0 +1,490 @@ +/* + * drivers/rtc/rtc-pl031.c + * + * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC + * + * Author: Deepak Saxena <dsaxena@plexity.net> + * + * Copyright 2006 (c) MontaVista Software, Inc. + * + * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com> + * Copyright 2010 (c) ST-Ericsson AB + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <linux/module.h> +#include <linux/rtc.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/amba/bus.h> +#include <linux/io.h> +#include <linux/bcd.h> +#include <linux/delay.h> +#include <linux/pm_wakeirq.h> +#include <linux/slab.h> + +/* + * Register definitions + */ +#define RTC_DR 0x00 /* Data read register */ +#define RTC_MR 0x04 /* Match register */ +#define RTC_LR 0x08 /* Data load register */ +#define RTC_CR 0x0c /* Control register */ +#define RTC_IMSC 0x10 /* Interrupt mask and set register */ +#define RTC_RIS 0x14 /* Raw interrupt status register */ +#define RTC_MIS 0x18 /* Masked interrupt status register */ +#define RTC_ICR 0x1c /* Interrupt clear register */ +/* ST variants have additional timer functionality */ +#define RTC_TDR 0x20 /* Timer data read register */ +#define RTC_TLR 0x24 /* Timer data load register */ +#define RTC_TCR 0x28 /* Timer control register */ +#define RTC_YDR 0x30 /* Year data read register */ +#define RTC_YMR 0x34 /* Year match register */ +#define RTC_YLR 0x38 /* Year data load register */ + +#define RTC_CR_EN (1 << 0) /* counter enable bit */ +#define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */ + +#define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */ + +/* Common bit definitions for Interrupt status and control registers */ +#define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */ +#define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */ + +/* Common bit definations for ST v2 for reading/writing time */ +#define RTC_SEC_SHIFT 0 +#define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */ +#define RTC_MIN_SHIFT 6 +#define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */ +#define RTC_HOUR_SHIFT 12 +#define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */ +#define RTC_WDAY_SHIFT 17 +#define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */ +#define RTC_MDAY_SHIFT 20 +#define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */ +#define RTC_MON_SHIFT 25 +#define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */ + +#define RTC_TIMER_FREQ 32768 + +/** + * struct pl031_vendor_data - per-vendor variations + * @ops: the vendor-specific operations used on this silicon version + * @clockwatch: if this is an ST Microelectronics silicon version with a + * clockwatch function + * @st_weekday: if this is an ST Microelectronics silicon version that need + * the weekday fix + * @irqflags: special IRQ flags per variant + */ +struct pl031_vendor_data { + struct rtc_class_ops ops; + bool clockwatch; + bool st_weekday; + unsigned long irqflags; +}; + +struct pl031_local { + struct pl031_vendor_data *vendor; + struct rtc_device *rtc; + void __iomem *base; +}; + +static int pl031_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + unsigned long imsc; + + /* Clear any pending alarm interrupts. */ + writel(RTC_BIT_AI, ldata->base + RTC_ICR); + + imsc = readl(ldata->base + RTC_IMSC); + + if (enabled == 1) + writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC); + else + writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC); + + return 0; +} + +/* + * Convert Gregorian date to ST v2 RTC format. + */ +static int pl031_stv2_tm_to_time(struct device *dev, + struct rtc_time *tm, unsigned long *st_time, + unsigned long *bcd_year) +{ + int year = tm->tm_year + 1900; + int wday = tm->tm_wday; + + /* wday masking is not working in hardware so wday must be valid */ + if (wday < -1 || wday > 6) { + dev_err(dev, "invalid wday value %d\n", tm->tm_wday); + return -EINVAL; + } else if (wday == -1) { + /* wday is not provided, calculate it here */ + unsigned long time; + struct rtc_time calc_tm; + + rtc_tm_to_time(tm, &time); + rtc_time_to_tm(time, &calc_tm); + wday = calc_tm.tm_wday; + } + + *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8); + + *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT) + | (tm->tm_mday << RTC_MDAY_SHIFT) + | ((wday + 1) << RTC_WDAY_SHIFT) + | (tm->tm_hour << RTC_HOUR_SHIFT) + | (tm->tm_min << RTC_MIN_SHIFT) + | (tm->tm_sec << RTC_SEC_SHIFT); + + return 0; +} + +/* + * Convert ST v2 RTC format to Gregorian date. + */ +static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year, + struct rtc_time *tm) +{ + tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100); + tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1; + tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT); + tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1; + tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT); + tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT); + tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT); + + tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); + tm->tm_year -= 1900; + + return 0; +} + +static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR), + readl(ldata->base + RTC_YDR), tm); + + return 0; +} + +static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned long time; + unsigned long bcd_year; + struct pl031_local *ldata = dev_get_drvdata(dev); + int ret; + + ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year); + if (ret == 0) { + writel(bcd_year, ldata->base + RTC_YLR); + writel(time, ldata->base + RTC_LR); + } + + return ret; +} + +static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + int ret; + + ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR), + readl(ldata->base + RTC_YMR), &alarm->time); + + alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI; + alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI; + + return ret; +} + +static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + unsigned long time; + unsigned long bcd_year; + int ret; + + /* At the moment, we can only deal with non-wildcarded alarm times. */ + ret = rtc_valid_tm(&alarm->time); + if (ret == 0) { + ret = pl031_stv2_tm_to_time(dev, &alarm->time, + &time, &bcd_year); + if (ret == 0) { + writel(bcd_year, ldata->base + RTC_YMR); + writel(time, ldata->base + RTC_MR); + + pl031_alarm_irq_enable(dev, alarm->enabled); + } + } + + return ret; +} + +static irqreturn_t pl031_interrupt(int irq, void *dev_id) +{ + struct pl031_local *ldata = dev_id; + unsigned long rtcmis; + unsigned long events = 0; + + rtcmis = readl(ldata->base + RTC_MIS); + if (rtcmis & RTC_BIT_AI) { + writel(RTC_BIT_AI, ldata->base + RTC_ICR); + events |= (RTC_AF | RTC_IRQF); + rtc_update_irq(ldata->rtc, 1, events); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int pl031_read_time(struct device *dev, struct rtc_time *tm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + rtc_time_to_tm(readl(ldata->base + RTC_DR), tm); + + return 0; +} + +static int pl031_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned long time; + struct pl031_local *ldata = dev_get_drvdata(dev); + int ret; + + ret = rtc_tm_to_time(tm, &time); + + if (ret == 0) + writel(time, ldata->base + RTC_LR); + + return ret; +} + +static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + + rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time); + + alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI; + alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI; + + return 0; +} + +static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct pl031_local *ldata = dev_get_drvdata(dev); + unsigned long time; + int ret; + + /* At the moment, we can only deal with non-wildcarded alarm times. */ + ret = rtc_valid_tm(&alarm->time); + if (ret == 0) { + ret = rtc_tm_to_time(&alarm->time, &time); + if (ret == 0) { + writel(time, ldata->base + RTC_MR); + pl031_alarm_irq_enable(dev, alarm->enabled); + } + } + + return ret; +} + +static int pl031_remove(struct amba_device *adev) +{ + struct pl031_local *ldata = dev_get_drvdata(&adev->dev); + + dev_pm_clear_wake_irq(&adev->dev); + device_init_wakeup(&adev->dev, false); + if (adev->irq[0]) + free_irq(adev->irq[0], ldata); + rtc_device_unregister(ldata->rtc); + amba_release_regions(adev); + + return 0; +} + +static int pl031_probe(struct amba_device *adev, const struct amba_id *id) +{ + int ret; + struct pl031_local *ldata; + struct pl031_vendor_data *vendor = id->data; + struct rtc_class_ops *ops; + unsigned long time, data; + + ret = amba_request_regions(adev, NULL); + if (ret) + goto err_req; + + ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local), + GFP_KERNEL); + ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops), + GFP_KERNEL); + if (!ldata || !ops) { + ret = -ENOMEM; + goto out; + } + + ldata->vendor = vendor; + ldata->base = devm_ioremap(&adev->dev, adev->res.start, + resource_size(&adev->res)); + if (!ldata->base) { + ret = -ENOMEM; + goto out; + } + + amba_set_drvdata(adev, ldata); + + dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev)); + dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev)); + + data = readl(ldata->base + RTC_CR); + /* Enable the clockwatch on ST Variants */ + if (vendor->clockwatch) + data |= RTC_CR_CWEN; + else + data |= RTC_CR_EN; + writel(data, ldata->base + RTC_CR); + + /* + * On ST PL031 variants, the RTC reset value does not provide correct + * weekday for 2000-01-01. Correct the erroneous sunday to saturday. + */ + if (vendor->st_weekday) { + if (readl(ldata->base + RTC_YDR) == 0x2000) { + time = readl(ldata->base + RTC_DR); + if ((time & + (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK)) + == 0x02120000) { + time = time | (0x7 << RTC_WDAY_SHIFT); + writel(0x2000, ldata->base + RTC_YLR); + writel(time, ldata->base + RTC_LR); + } + } + } + + if (!adev->irq[0]) { + /* When there's no interrupt, no point in exposing the alarm */ + ops->read_alarm = NULL; + ops->set_alarm = NULL; + ops->alarm_irq_enable = NULL; + } + + device_init_wakeup(&adev->dev, true); + ldata->rtc = rtc_device_register("pl031", &adev->dev, ops, + THIS_MODULE); + if (IS_ERR(ldata->rtc)) { + ret = PTR_ERR(ldata->rtc); + goto out; + } + + if (adev->irq[0]) { + ret = request_irq(adev->irq[0], pl031_interrupt, + vendor->irqflags, "rtc-pl031", ldata); + if (ret) + goto out_no_irq; + dev_pm_set_wake_irq(&adev->dev, adev->irq[0]); + } + return 0; + +out_no_irq: + rtc_device_unregister(ldata->rtc); +out: + amba_release_regions(adev); +err_req: + + return ret; +} + +/* Operations for the original ARM version */ +static struct pl031_vendor_data arm_pl031 = { + .ops = { + .read_time = pl031_read_time, + .set_time = pl031_set_time, + .read_alarm = pl031_read_alarm, + .set_alarm = pl031_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, +}; + +/* The First ST derivative */ +static struct pl031_vendor_data stv1_pl031 = { + .ops = { + .read_time = pl031_read_time, + .set_time = pl031_set_time, + .read_alarm = pl031_read_alarm, + .set_alarm = pl031_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, + .clockwatch = true, + .st_weekday = true, +}; + +/* And the second ST derivative */ +static struct pl031_vendor_data stv2_pl031 = { + .ops = { + .read_time = pl031_stv2_read_time, + .set_time = pl031_stv2_set_time, + .read_alarm = pl031_stv2_read_alarm, + .set_alarm = pl031_stv2_set_alarm, + .alarm_irq_enable = pl031_alarm_irq_enable, + }, + .clockwatch = true, + .st_weekday = true, + /* + * This variant shares the IRQ with another block and must not + * suspend that IRQ line. + * TODO check if it shares with IRQF_NO_SUSPEND user, else we can + * remove IRQF_COND_SUSPEND + */ + .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND, +}; + +static const struct amba_id pl031_ids[] = { + { + .id = 0x00041031, + .mask = 0x000fffff, + .data = &arm_pl031, + }, + /* ST Micro variants */ + { + .id = 0x00180031, + .mask = 0x00ffffff, + .data = &stv1_pl031, + }, + { + .id = 0x00280031, + .mask = 0x00ffffff, + .data = &stv2_pl031, + }, + {0, 0}, +}; + +MODULE_DEVICE_TABLE(amba, pl031_ids); + +static struct amba_driver pl031_driver = { + .drv = { + .name = "rtc-pl031", + }, + .id_table = pl031_ids, + .probe = pl031_probe, + .remove = pl031_remove, +}; + +module_amba_driver(pl031_driver); + +MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); +MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver"); +MODULE_LICENSE("GPL"); |