diff options
Diffstat (limited to 'drivers/rtc/rtc-lpc24xx.c')
| -rw-r--r-- | drivers/rtc/rtc-lpc24xx.c | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-lpc24xx.c b/drivers/rtc/rtc-lpc24xx.c new file mode 100644 index 000000000..14dc7b04f --- /dev/null +++ b/drivers/rtc/rtc-lpc24xx.c @@ -0,0 +1,310 @@ +/* + * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC) + * + * Copyright (C) 2011 NXP Semiconductors + * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> + * + * 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/clk.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> + +/* LPC24xx RTC register offsets and bits */ +#define LPC24XX_ILR 0x00 +#define LPC24XX_RTCCIF BIT(0) +#define LPC24XX_RTCALF BIT(1) +#define LPC24XX_CTC 0x04 +#define LPC24XX_CCR 0x08 +#define LPC24XX_CLKEN BIT(0) +#define LPC178X_CCALEN BIT(4) +#define LPC24XX_CIIR 0x0c +#define LPC24XX_AMR 0x10 +#define LPC24XX_ALARM_DISABLE 0xff +#define LPC24XX_CTIME0 0x14 +#define LPC24XX_CTIME1 0x18 +#define LPC24XX_CTIME2 0x1c +#define LPC24XX_SEC 0x20 +#define LPC24XX_MIN 0x24 +#define LPC24XX_HOUR 0x28 +#define LPC24XX_DOM 0x2c +#define LPC24XX_DOW 0x30 +#define LPC24XX_DOY 0x34 +#define LPC24XX_MONTH 0x38 +#define LPC24XX_YEAR 0x3c +#define LPC24XX_ALSEC 0x60 +#define LPC24XX_ALMIN 0x64 +#define LPC24XX_ALHOUR 0x68 +#define LPC24XX_ALDOM 0x6c +#define LPC24XX_ALDOW 0x70 +#define LPC24XX_ALDOY 0x74 +#define LPC24XX_ALMON 0x78 +#define LPC24XX_ALYEAR 0x7c + +/* Macros to read fields in consolidated time (CT) registers */ +#define CT0_SECS(x) (((x) >> 0) & 0x3f) +#define CT0_MINS(x) (((x) >> 8) & 0x3f) +#define CT0_HOURS(x) (((x) >> 16) & 0x1f) +#define CT0_DOW(x) (((x) >> 24) & 0x07) +#define CT1_DOM(x) (((x) >> 0) & 0x1f) +#define CT1_MONTH(x) (((x) >> 8) & 0x0f) +#define CT1_YEAR(x) (((x) >> 16) & 0xfff) +#define CT2_DOY(x) (((x) >> 0) & 0xfff) + +#define rtc_readl(dev, reg) readl((dev)->rtc_base + (reg)) +#define rtc_writel(dev, reg, val) writel((val), (dev)->rtc_base + (reg)) + +struct lpc24xx_rtc { + void __iomem *rtc_base; + struct rtc_device *rtc; + struct clk *clk_rtc; + struct clk *clk_reg; +}; + +static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + + /* Disable RTC during update */ + rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); + + rtc_writel(rtc, LPC24XX_SEC, tm->tm_sec); + rtc_writel(rtc, LPC24XX_MIN, tm->tm_min); + rtc_writel(rtc, LPC24XX_HOUR, tm->tm_hour); + rtc_writel(rtc, LPC24XX_DOW, tm->tm_wday); + rtc_writel(rtc, LPC24XX_DOM, tm->tm_mday); + rtc_writel(rtc, LPC24XX_DOY, tm->tm_yday); + rtc_writel(rtc, LPC24XX_MONTH, tm->tm_mon); + rtc_writel(rtc, LPC24XX_YEAR, tm->tm_year); + + rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); + + return 0; +} + +static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + u32 ct0, ct1, ct2; + + ct0 = rtc_readl(rtc, LPC24XX_CTIME0); + ct1 = rtc_readl(rtc, LPC24XX_CTIME1); + ct2 = rtc_readl(rtc, LPC24XX_CTIME2); + + tm->tm_sec = CT0_SECS(ct0); + tm->tm_min = CT0_MINS(ct0); + tm->tm_hour = CT0_HOURS(ct0); + tm->tm_wday = CT0_DOW(ct0); + tm->tm_mon = CT1_MONTH(ct1); + tm->tm_mday = CT1_DOM(ct1); + tm->tm_year = CT1_YEAR(ct1); + tm->tm_yday = CT2_DOY(ct2); + + return 0; +} + +static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &wkalrm->time; + + tm->tm_sec = rtc_readl(rtc, LPC24XX_ALSEC); + tm->tm_min = rtc_readl(rtc, LPC24XX_ALMIN); + tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR); + tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM); + tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW); + tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY); + tm->tm_mon = rtc_readl(rtc, LPC24XX_ALMON); + tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR); + + wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0; + wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF); + + return rtc_valid_tm(&wkalrm->time); +} + +static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &wkalrm->time; + + /* Disable alarm irq during update */ + rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); + + rtc_writel(rtc, LPC24XX_ALSEC, tm->tm_sec); + rtc_writel(rtc, LPC24XX_ALMIN, tm->tm_min); + rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour); + rtc_writel(rtc, LPC24XX_ALDOM, tm->tm_mday); + rtc_writel(rtc, LPC24XX_ALDOW, tm->tm_wday); + rtc_writel(rtc, LPC24XX_ALDOY, tm->tm_yday); + rtc_writel(rtc, LPC24XX_ALMON, tm->tm_mon); + rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year); + + if (wkalrm->enabled) + rtc_writel(rtc, LPC24XX_AMR, 0); + + return 0; +} + +static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + + if (enable) + rtc_writel(rtc, LPC24XX_AMR, 0); + else + rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); + + return 0; +} + +static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data) +{ + unsigned long events = RTC_IRQF; + struct lpc24xx_rtc *rtc = data; + u32 rtc_iir; + + /* Check interrupt cause */ + rtc_iir = rtc_readl(rtc, LPC24XX_ILR); + if (rtc_iir & LPC24XX_RTCALF) { + events |= RTC_AF; + rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); + } + + /* Clear interrupt status and report event */ + rtc_writel(rtc, LPC24XX_ILR, rtc_iir); + rtc_update_irq(rtc->rtc, 1, events); + + return IRQ_HANDLED; +} + +static const struct rtc_class_ops lpc24xx_rtc_ops = { + .read_time = lpc24xx_rtc_read_time, + .set_time = lpc24xx_rtc_set_time, + .read_alarm = lpc24xx_rtc_read_alarm, + .set_alarm = lpc24xx_rtc_set_alarm, + .alarm_irq_enable = lpc24xx_rtc_alarm_irq_enable, +}; + +static int lpc24xx_rtc_probe(struct platform_device *pdev) +{ + struct lpc24xx_rtc *rtc; + struct resource *res; + int irq, ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rtc->rtc_base)) + return PTR_ERR(rtc->rtc_base); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_warn(&pdev->dev, "can't get interrupt resource\n"); + return irq; + } + + rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc"); + if (IS_ERR(rtc->clk_rtc)) { + dev_err(&pdev->dev, "error getting rtc clock\n"); + return PTR_ERR(rtc->clk_rtc); + } + + rtc->clk_reg = devm_clk_get(&pdev->dev, "reg"); + if (IS_ERR(rtc->clk_reg)) { + dev_err(&pdev->dev, "error getting reg clock\n"); + return PTR_ERR(rtc->clk_reg); + } + + ret = clk_prepare_enable(rtc->clk_rtc); + if (ret) { + dev_err(&pdev->dev, "unable to enable rtc clock\n"); + return ret; + } + + ret = clk_prepare_enable(rtc->clk_reg); + if (ret) { + dev_err(&pdev->dev, "unable to enable reg clock\n"); + goto disable_rtc_clk; + } + + platform_set_drvdata(pdev, rtc); + + /* Clear any pending interrupts */ + rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF); + + /* Enable RTC count */ + rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); + + ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0, + pdev->name, rtc); + if (ret < 0) { + dev_warn(&pdev->dev, "can't request interrupt\n"); + goto disable_clks; + } + + rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc", + &lpc24xx_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc)) { + dev_err(&pdev->dev, "can't register rtc device\n"); + ret = PTR_ERR(rtc->rtc); + goto disable_clks; + } + + return 0; + +disable_clks: + clk_disable_unprepare(rtc->clk_reg); +disable_rtc_clk: + clk_disable_unprepare(rtc->clk_rtc); + return ret; +} + +static int lpc24xx_rtc_remove(struct platform_device *pdev) +{ + struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev); + + /* Ensure all interrupt sources are masked */ + rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); + rtc_writel(rtc, LPC24XX_CIIR, 0); + + rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); + + clk_disable_unprepare(rtc->clk_rtc); + clk_disable_unprepare(rtc->clk_reg); + + return 0; +} + +static const struct of_device_id lpc24xx_rtc_match[] = { + { .compatible = "nxp,lpc1788-rtc" }, + { } +}; +MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match); + +static struct platform_driver lpc24xx_rtc_driver = { + .probe = lpc24xx_rtc_probe, + .remove = lpc24xx_rtc_remove, + .driver = { + .name = "lpc24xx-rtc", + .of_match_table = lpc24xx_rtc_match, + }, +}; +module_platform_driver(lpc24xx_rtc_driver); + +MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>"); +MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs"); +MODULE_LICENSE("GPL"); |