Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices. The RTC provides calendar and clock functionality together with periodic tick and alarm interrupt support.
Signed-off-by: Joachim Eastwood <[email protected]> --- drivers/rtc/Kconfig | 11 ++ drivers/rtc/Makefile | 1 + drivers/rtc/rtc-lpc24xx.c | 379 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 391 insertions(+) create mode 100644 drivers/rtc/rtc-lpc24xx.c diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 6149ae01e11f..42b890716b1c 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -1427,6 +1427,17 @@ config RTC_DRV_JZ4740 This driver can also be buillt as a module. If so, the module will be called rtc-jz4740. +config RTC_DRV_LPC24XX + depends on OF && (ARCH_LPC18XX || TEST_COMPILE) + tristate "NXP LPC2K RTC" + help + This enables support for the NXP RTC found which can be found on + LPC24xx/178x/18xx/43xx devices. + + If you have one of the devices above enable this driver to use + the hardware RTC. This driver can also be buillt as a module. If + so, the module will be called rtc-lpc24xx. + config RTC_DRV_LPC32XX depends on ARCH_LPC32XX tristate "NXP LPC32XX RTC" diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index c31731c29762..8687a2e13247 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -73,6 +73,7 @@ obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o obj-$(CONFIG_RTC_DRV_ISL12057) += rtc-isl12057.o obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o obj-$(CONFIG_RTC_DRV_LP8788) += rtc-lp8788.o +obj-$(CONFIG_RTC_DRV_LPC24XX) += rtc-lpc24xx.o obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o obj-$(CONFIG_RTC_DRV_LOONGSON1) += rtc-ls1x.o obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o diff --git a/drivers/rtc/rtc-lpc24xx.c b/drivers/rtc/rtc-lpc24xx.c new file mode 100644 index 000000000000..ffa6e568b308 --- /dev/null +++ b/drivers/rtc/rtc-lpc24xx.c @@ -0,0 +1,379 @@ +/* + * Driver for NXP LPC24xx/178x/18xx/43xx Real-Time Clock (RTC) + * + * Copyright (C) 2011 NXP Semiconductors + * Copyright (C) 2015 Joachim Eastwood <[email protected]> + * + * 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 */ +#define LPC24XX_ILR 0x00 +#define LPC24XX_CTC 0x04 +#define LPC24XX_CCR 0x08 +#define LPC24XX_CIIR 0x0c +#define LPC24XX_AMR 0x10 +#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_CISS 0x40 /* LPC24xx only */ +#define LPC178X_CALIBRATION 0x40 /* LPC178x and up */ +#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 +#define LPC24XX_PREINT 0x80 /* LPC24xx only */ +#define LPC24XX_PREFRAC 0x84 /* LPC24xx only */ + +#define LPC24XX_RTCCIF BIT(0) +#define LPC24XX_RTCALF BIT(1) +#define LPC24XX_RTSSF BIT(2) /* LPC24xx only */ + +#define LPC24XX_CLKEN BIT(0) +#define LPC24XX_CTCRST BIT(1) +#define LPC24XX_CLKSRC BIT(4) /* LPC24xx only */ +#define LPC178X_CCALEN BIT(4) /* LPC178x and up */ + +#define LPC24XX_IMSEC BIT(0) +#define LPC24XX_IMMIN BIT(1) +#define LPC24XX_IMHOUR BIT(2) +#define LPC24XX_IMDOM BIT(3) +#define LPC24XX_IMDOW BIT(4) +#define LPC24XX_IMDOY BIT(5) +#define LPC24XX_IMMON BIT(6) +#define LPC24XX_IMYEAR BIT(7) + +#define LPC24XX_ALARM_DISABLE 0xff + +#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)) + +/* lpc2k-rtc driver feature flags */ +#define HAVE_SUBSECOND BIT(0) +#define HAVE_CALIBRATION BIT(1) +#define HAVE_PRESCALER BIT(2) + +struct lpc24xx_rtc { + void __iomem *rtc_base; + struct rtc_device *rtc; + struct clk *clk_rtc; + struct clk *clk_reg; + u32 features; +}; + +static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + u32 rtc_ctrl; + + /* Disable RTC during update */ + rtc_ctrl = rtc_readl(rtc, LPC24XX_CCR); + rtc_writel(rtc, LPC24XX_CCR, rtc_ctrl & ~LPC24XX_CLKEN); + + 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, rtc_ctrl | LPC24XX_CLKEN); + + 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); + + if (rtc_valid_tm(tm) < 0) { + dev_warn(dev, "retrieved date and time is invalid\n"); + rtc_time64_to_tm(0, tm); + lpc24xx_rtc_set_time(dev, tm); + } + + 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 IRQs 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 enabled) +{ + struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); + + if (enabled) + 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 *dev) +{ + unsigned long events = RTC_IRQF; + struct lpc24xx_rtc *rtc = dev; + u32 rtc_iir; + + /* Check interrupt cause */ + rtc_iir = rtc_readl(rtc, LPC24XX_ILR); + + /* 1s tick */ + if (rtc_iir & LPC24XX_RTCCIF) + events |= RTC_UF; + + /* Alarm */ + 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 const struct of_device_id lpc24xx_rtc_match[] = { + { .compatible = "nxp,lpc1788-rtc", .data = (void *)HAVE_CALIBRATION}, + { } +}; +MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match); + +static int lpc24xx_rtc_probe(struct platform_device *pdev) +{ + const struct of_device_id *match; + struct lpc24xx_rtc *rtc; + struct resource *res; + u32 rtc_ccr = 0; + int irq, ret; + + match = of_match_device(lpc24xx_rtc_match, &pdev->dev); + if (!match) { + dev_err(&pdev->dev, "no device match found\n"); + return -ENODEV; + } + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + rtc->features = (u32)match->data; + + 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 the counter increment state */ + rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF); + + if (rtc->features & HAVE_PRESCALER) { + /* Clock source is 32k oscillator */ + rtc_ccr = LPC24XX_CLKSRC; + rtc_writel(rtc, LPC24XX_CCR, rtc_ccr); + + /* Set prescaler to divide by 1 */ + rtc_writel(rtc, LPC24XX_PREINT, 0); + rtc_writel(rtc, LPC24XX_PREFRAC, 0); + } + + if (rtc->features & HAVE_SUBSECOND) { + /* Disable sub-second interrupt */ + rtc_writel(rtc, LPC24XX_CISS, 0); + } + + /* Only 1-second interrupt will generate interrupt */ + rtc_writel(rtc, LPC24XX_CIIR, LPC24XX_IMSEC); + + /* Enable RTC count */ + rtc_writel(rtc, LPC24XX_CCR, rtc_ccr | LPC24XX_CLKEN); + + 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, "lpc2k-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); + + /* + * Disable alarm, but leave RTC enabled so it + * remains valid across reset cycles. + */ + rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); + rtc_writel(rtc, LPC24XX_CCR, 0); + + clk_disable_unprepare(rtc->clk_rtc); + clk_disable_unprepare(rtc->clk_reg); + + return 0; +} + +static struct platform_driver lpc24xx_rtc_driver = { + .probe = lpc24xx_rtc_probe, + .remove = lpc24xx_rtc_remove, + .driver = { + .name = "lpc2k-rtc", + .of_match_table = lpc24xx_rtc_match, + }, +}; +module_platform_driver(lpc24xx_rtc_driver); + +MODULE_AUTHOR("Kevin Wells <[email protected]"); +MODULE_DESCRIPTION("RTC driver for the LPC24xx SoC"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:lpc2k-rtc"); -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
