diff options
Diffstat (limited to 'drivers/rtc/rtc-stmp3xxx.c')
| -rw-r--r-- | drivers/rtc/rtc-stmp3xxx.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c new file mode 100644 index 000000000..b76318fd5 --- /dev/null +++ b/drivers/rtc/rtc-stmp3xxx.c @@ -0,0 +1,424 @@ +/* + * Freescale STMP37XX/STMP378X Real Time Clock driver + * + * Copyright (c) 2007 Sigmatel, Inc. + * Peter Hartley, <peter.hartley@sigmatel.com> + * + * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + * Copyright 2011 Wolfram Sang, Pengutronix e.K. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/rtc.h> +#include <linux/slab.h> +#include <linux/of_device.h> +#include <linux/of.h> +#include <linux/stmp_device.h> +#include <linux/stmp3xxx_rtc_wdt.h> + +#define STMP3XXX_RTC_CTRL 0x0 +#define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001 +#define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002 +#define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004 +#define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010 + +#define STMP3XXX_RTC_STAT 0x10 +#define STMP3XXX_RTC_STAT_STALE_SHIFT 16 +#define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000 +#define STMP3XXX_RTC_STAT_XTAL32000_PRESENT 0x10000000 +#define STMP3XXX_RTC_STAT_XTAL32768_PRESENT 0x08000000 + +#define STMP3XXX_RTC_SECONDS 0x30 + +#define STMP3XXX_RTC_ALARM 0x40 + +#define STMP3XXX_RTC_WATCHDOG 0x50 + +#define STMP3XXX_RTC_PERSISTENT0 0x60 +#define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE (1 << 0) +#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN (1 << 1) +#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN (1 << 2) +#define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4) +#define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5) +#define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ (1 << 6) +#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE (1 << 7) + +#define STMP3XXX_RTC_PERSISTENT1 0x70 +/* missing bitmask in headers */ +#define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000 + +struct stmp3xxx_rtc_data { + struct rtc_device *rtc; + void __iomem *io; + int irq_alarm; +}; + +#if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG) +/** + * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC + * @dev: the parent device of the watchdog (= the RTC) + * @timeout: the desired value for the timeout register of the watchdog. + * 0 disables the watchdog + * + * The watchdog needs one register and two bits which are in the RTC domain. + * To handle the resource conflict, the RTC driver will create another + * platform_device for the watchdog driver as a child of the RTC device. + * The watchdog driver is passed the below accessor function via platform_data + * to configure the watchdog. Locking is not needed because accessing SET/CLR + * registers is atomic. + */ + +static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (timeout) { + writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG); + writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET); + writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, + rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET); + } else { + writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); + writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, + rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR); + } +} + +static struct stmp3xxx_wdt_pdata wdt_pdata = { + .wdt_set_timeout = stmp3xxx_wdt_set_timeout, +}; + +static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) +{ + int rc = -1; + struct platform_device *wdt_pdev = + platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id); + + if (wdt_pdev) { + wdt_pdev->dev.parent = &rtc_pdev->dev; + wdt_pdev->dev.platform_data = &wdt_pdata; + rc = platform_device_add(wdt_pdev); + } + + if (rc) + dev_err(&rtc_pdev->dev, + "failed to register stmp3xxx_rtc_wdt\n"); +} +#else +static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) +{ +} +#endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */ + +static int stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data) +{ + int timeout = 5000; /* 3ms according to i.MX28 Ref Manual */ + /* + * The i.MX28 Applications Processor Reference Manual, Rev. 1, 2010 + * states: + * | The order in which registers are updated is + * | Persistent 0, 1, 2, 3, 4, 5, Alarm, Seconds. + * | (This list is in bitfield order, from LSB to MSB, as they would + * | appear in the STALE_REGS and NEW_REGS bitfields of the HW_RTC_STAT + * | register. For example, the Seconds register corresponds to + * | STALE_REGS or NEW_REGS containing 0x80.) + */ + do { + if (!(readl(rtc_data->io + STMP3XXX_RTC_STAT) & + (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))) + return 0; + udelay(1); + } while (--timeout > 0); + return (readl(rtc_data->io + STMP3XXX_RTC_STAT) & + (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)) ? -ETIME : 0; +} + +/* Time read/write */ +static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm) +{ + int ret; + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + ret = stmp3xxx_wait_time(rtc_data); + if (ret) + return ret; + + rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm); + return 0; +} + +static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS); + return stmp3xxx_wait_time(rtc_data); +} + +/* interrupt(s) handler */ +static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id); + u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL); + + if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) { + writel(STMP3XXX_RTC_CTRL_ALARM_IRQ, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); + rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (enabled) { + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN, + rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + + STMP_OFFSET_REG_SET); + writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET); + } else { + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN, + rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + + STMP_OFFSET_REG_CLR); + writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); + } + return 0; +} + +static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time); + return 0; +} + +static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned long t; + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + rtc_tm_to_time(&alm->time, &t); + writel(t, rtc_data->io + STMP3XXX_RTC_ALARM); + + stmp3xxx_alarm_irq_enable(dev, alm->enabled); + + return 0; +} + +static const struct rtc_class_ops stmp3xxx_rtc_ops = { + .alarm_irq_enable = + stmp3xxx_alarm_irq_enable, + .read_time = stmp3xxx_rtc_gettime, + .set_mmss = stmp3xxx_rtc_set_mmss, + .read_alarm = stmp3xxx_rtc_read_alarm, + .set_alarm = stmp3xxx_rtc_set_alarm, +}; + +static int stmp3xxx_rtc_remove(struct platform_device *pdev) +{ + struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev); + + if (!rtc_data) + return 0; + + writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); + + return 0; +} + +static int stmp3xxx_rtc_probe(struct platform_device *pdev) +{ + struct stmp3xxx_rtc_data *rtc_data; + struct resource *r; + u32 rtc_stat; + u32 pers0_set, pers0_clr; + u32 crystalfreq = 0; + int err; + + rtc_data = devm_kzalloc(&pdev->dev, sizeof(*rtc_data), GFP_KERNEL); + if (!rtc_data) + return -ENOMEM; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!r) { + dev_err(&pdev->dev, "failed to get resource\n"); + return -ENXIO; + } + + rtc_data->io = devm_ioremap(&pdev->dev, r->start, resource_size(r)); + if (!rtc_data->io) { + dev_err(&pdev->dev, "ioremap failed\n"); + return -EIO; + } + + rtc_data->irq_alarm = platform_get_irq(pdev, 0); + + rtc_stat = readl(rtc_data->io + STMP3XXX_RTC_STAT); + if (!(rtc_stat & STMP3XXX_RTC_STAT_RTC_PRESENT)) { + dev_err(&pdev->dev, "no device onboard\n"); + return -ENODEV; + } + + platform_set_drvdata(pdev, rtc_data); + + /* + * Resetting the rtc stops the watchdog timer that is potentially + * running. So (assuming it is running on purpose) don't reset if the + * watchdog is enabled. + */ + if (readl(rtc_data->io + STMP3XXX_RTC_CTRL) & + STMP3XXX_RTC_CTRL_WATCHDOGEN) { + dev_info(&pdev->dev, + "Watchdog is running, skip resetting rtc\n"); + } else { + err = stmp_reset_block(rtc_data->io); + if (err) { + dev_err(&pdev->dev, "stmp_reset_block failed: %d\n", + err); + return err; + } + } + + /* + * Obviously the rtc needs a clock input to be able to run. + * This clock can be provided by an external 32k crystal. If that one is + * missing XTAL must not be disabled in suspend which consumes a + * lot of power. Normally the presence and exact frequency (supported + * are 32000 Hz and 32768 Hz) is detectable from fuses, but as reality + * proves these fuses are not blown correctly on all machines, so the + * frequency can be overridden in the device tree. + */ + if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32000_PRESENT) + crystalfreq = 32000; + else if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32768_PRESENT) + crystalfreq = 32768; + + of_property_read_u32(pdev->dev.of_node, "stmp,crystal-freq", + &crystalfreq); + + switch (crystalfreq) { + case 32000: + /* keep 32kHz crystal running in low-power mode */ + pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | + STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; + pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP; + break; + case 32768: + /* keep 32.768kHz crystal running in low-power mode */ + pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; + pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP | + STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ; + break; + default: + dev_warn(&pdev->dev, + "invalid crystal-freq specified in device-tree. Assuming no crystal\n"); + /* fall-through */ + case 0: + /* keep XTAL on in low-power mode */ + pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP; + pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; + } + + writel(pers0_set, rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + + STMP_OFFSET_REG_SET); + + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE | pers0_clr, + rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR); + + writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN | + STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, + rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); + + rtc_data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &stmp3xxx_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc_data->rtc)) + return PTR_ERR(rtc_data->rtc); + + err = devm_request_irq(&pdev->dev, rtc_data->irq_alarm, + stmp3xxx_rtc_interrupt, 0, "RTC alarm", &pdev->dev); + if (err) { + dev_err(&pdev->dev, "Cannot claim IRQ%d\n", + rtc_data->irq_alarm); + return err; + } + + stmp3xxx_wdt_register(pdev); + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int stmp3xxx_rtc_suspend(struct device *dev) +{ + return 0; +} + +static int stmp3xxx_rtc_resume(struct device *dev) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + stmp_reset_block(rtc_data->io); + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | + STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, + rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR); + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(stmp3xxx_rtc_pm_ops, stmp3xxx_rtc_suspend, + stmp3xxx_rtc_resume); + +static const struct of_device_id rtc_dt_ids[] = { + { .compatible = "fsl,stmp3xxx-rtc", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rtc_dt_ids); + +static struct platform_driver stmp3xxx_rtcdrv = { + .probe = stmp3xxx_rtc_probe, + .remove = stmp3xxx_rtc_remove, + .driver = { + .name = "stmp3xxx-rtc", + .pm = &stmp3xxx_rtc_pm_ops, + .of_match_table = rtc_dt_ids, + }, +}; + +module_platform_driver(stmp3xxx_rtcdrv); + +MODULE_DESCRIPTION("STMP3xxx RTC Driver"); +MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and " + "Wolfram Sang <w.sang@pengutronix.de>"); +MODULE_LICENSE("GPL"); |