diff options
Diffstat (limited to 'drivers/rtc/rtc-pic32.c')
| -rw-r--r-- | drivers/rtc/rtc-pic32.c | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pic32.c b/drivers/rtc/rtc-pic32.c new file mode 100644 index 000000000..64e1e4578 --- /dev/null +++ b/drivers/rtc/rtc-pic32.c @@ -0,0 +1,411 @@ +/* + * PIC32 RTC driver + * + * Joshua Henderson <joshua.henderson@microchip.com> + * Copyright (C) 2016 Microchip Technology Inc. All rights reserved. + * + * 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. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/clk.h> +#include <linux/rtc.h> +#include <linux/bcd.h> + +#include <asm/mach-pic32/pic32.h> + +#define PIC32_RTCCON 0x00 +#define PIC32_RTCCON_ON BIT(15) +#define PIC32_RTCCON_SIDL BIT(13) +#define PIC32_RTCCON_RTCCLKSEL (3 << 9) +#define PIC32_RTCCON_RTCCLKON BIT(6) +#define PIC32_RTCCON_RTCWREN BIT(3) +#define PIC32_RTCCON_RTCSYNC BIT(2) +#define PIC32_RTCCON_HALFSEC BIT(1) +#define PIC32_RTCCON_RTCOE BIT(0) + +#define PIC32_RTCALRM 0x10 +#define PIC32_RTCALRM_ALRMEN BIT(15) +#define PIC32_RTCALRM_CHIME BIT(14) +#define PIC32_RTCALRM_PIV BIT(13) +#define PIC32_RTCALRM_ALARMSYNC BIT(12) +#define PIC32_RTCALRM_AMASK 0x0F00 +#define PIC32_RTCALRM_ARPT 0xFF + +#define PIC32_RTCHOUR 0x23 +#define PIC32_RTCMIN 0x22 +#define PIC32_RTCSEC 0x21 +#define PIC32_RTCYEAR 0x33 +#define PIC32_RTCMON 0x32 +#define PIC32_RTCDAY 0x31 + +#define PIC32_ALRMTIME 0x40 +#define PIC32_ALRMDATE 0x50 + +#define PIC32_ALRMHOUR 0x43 +#define PIC32_ALRMMIN 0x42 +#define PIC32_ALRMSEC 0x41 +#define PIC32_ALRMYEAR 0x53 +#define PIC32_ALRMMON 0x52 +#define PIC32_ALRMDAY 0x51 + +struct pic32_rtc_dev { + struct rtc_device *rtc; + void __iomem *reg_base; + struct clk *clk; + spinlock_t alarm_lock; + int alarm_irq; + bool alarm_clk_enabled; +}; + +static void pic32_rtc_alarm_clk_enable(struct pic32_rtc_dev *pdata, + bool enable) +{ + unsigned long flags; + + spin_lock_irqsave(&pdata->alarm_lock, flags); + if (enable) { + if (!pdata->alarm_clk_enabled) { + clk_enable(pdata->clk); + pdata->alarm_clk_enabled = true; + } + } else { + if (pdata->alarm_clk_enabled) { + clk_disable(pdata->clk); + pdata->alarm_clk_enabled = false; + } + } + spin_unlock_irqrestore(&pdata->alarm_lock, flags); +} + +static irqreturn_t pic32_rtc_alarmirq(int irq, void *id) +{ + struct pic32_rtc_dev *pdata = (struct pic32_rtc_dev *)id; + + clk_enable(pdata->clk); + rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF); + clk_disable(pdata->clk); + + pic32_rtc_alarm_clk_enable(pdata, false); + + return IRQ_HANDLED; +} + +static int pic32_rtc_setaie(struct device *dev, unsigned int enabled) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + void __iomem *base = pdata->reg_base; + + clk_enable(pdata->clk); + + writel(PIC32_RTCALRM_ALRMEN, + base + (enabled ? PIC32_SET(PIC32_RTCALRM) : + PIC32_CLR(PIC32_RTCALRM))); + + clk_disable(pdata->clk); + + pic32_rtc_alarm_clk_enable(pdata, enabled); + + return 0; +} + +static int pic32_rtc_setfreq(struct device *dev, int freq) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + void __iomem *base = pdata->reg_base; + + clk_enable(pdata->clk); + + writel(PIC32_RTCALRM_AMASK, base + PIC32_CLR(PIC32_RTCALRM)); + writel(freq << 8, base + PIC32_SET(PIC32_RTCALRM)); + writel(PIC32_RTCALRM_CHIME, base + PIC32_SET(PIC32_RTCALRM)); + + clk_disable(pdata->clk); + + return 0; +} + +static int pic32_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + void __iomem *base = pdata->reg_base; + unsigned int tries = 0; + + clk_enable(pdata->clk); + + do { + rtc_tm->tm_hour = readb(base + PIC32_RTCHOUR); + rtc_tm->tm_min = readb(base + PIC32_RTCMIN); + rtc_tm->tm_mon = readb(base + PIC32_RTCMON); + rtc_tm->tm_mday = readb(base + PIC32_RTCDAY); + rtc_tm->tm_year = readb(base + PIC32_RTCYEAR); + rtc_tm->tm_sec = readb(base + PIC32_RTCSEC); + + /* + * The only way to work out whether the system was mid-update + * when we read it is to check the second counter, and if it + * is zero, then we re-try the entire read. + */ + tries += 1; + } while (rtc_tm->tm_sec == 0 && tries < 2); + + rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); + rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); + rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); + rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); + rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon) - 1; + rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); + + rtc_tm->tm_year += 100; + + dev_dbg(dev, "read time %04d.%02d.%02d %02d:%02d:%02d\n", + 1900 + rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday, + rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec); + + clk_disable(pdata->clk); + return rtc_valid_tm(rtc_tm); +} + +static int pic32_rtc_settime(struct device *dev, struct rtc_time *tm) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + void __iomem *base = pdata->reg_base; + int year = tm->tm_year - 100; + + dev_dbg(dev, "set time %04d.%02d.%02d %02d:%02d:%02d\n", + 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, + tm->tm_hour, tm->tm_min, tm->tm_sec); + + if (year < 0 || year >= 100) { + dev_err(dev, "rtc only supports 100 years\n"); + return -EINVAL; + } + + clk_enable(pdata->clk); + writeb(bin2bcd(tm->tm_sec), base + PIC32_RTCSEC); + writeb(bin2bcd(tm->tm_min), base + PIC32_RTCMIN); + writeb(bin2bcd(tm->tm_hour), base + PIC32_RTCHOUR); + writeb(bin2bcd(tm->tm_mday), base + PIC32_RTCDAY); + writeb(bin2bcd(tm->tm_mon + 1), base + PIC32_RTCMON); + writeb(bin2bcd(year), base + PIC32_RTCYEAR); + clk_disable(pdata->clk); + + return 0; +} + +static int pic32_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + struct rtc_time *alm_tm = &alrm->time; + void __iomem *base = pdata->reg_base; + unsigned int alm_en; + + clk_enable(pdata->clk); + alm_tm->tm_sec = readb(base + PIC32_ALRMSEC); + alm_tm->tm_min = readb(base + PIC32_ALRMMIN); + alm_tm->tm_hour = readb(base + PIC32_ALRMHOUR); + alm_tm->tm_mon = readb(base + PIC32_ALRMMON); + alm_tm->tm_mday = readb(base + PIC32_ALRMDAY); + alm_tm->tm_year = readb(base + PIC32_ALRMYEAR); + + alm_en = readb(base + PIC32_RTCALRM); + + alrm->enabled = (alm_en & PIC32_RTCALRM_ALRMEN) ? 1 : 0; + + dev_dbg(dev, "getalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n", + alm_en, + 1900 + alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday, + alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec); + + alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec); + alm_tm->tm_min = bcd2bin(alm_tm->tm_min); + alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour); + alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday); + alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon) - 1; + alm_tm->tm_year = bcd2bin(alm_tm->tm_year); + + clk_disable(pdata->clk); + return 0; +} + +static int pic32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + void __iomem *base = pdata->reg_base; + + clk_enable(pdata->clk); + dev_dbg(dev, "setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n", + alrm->enabled, + 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, + tm->tm_hour, tm->tm_min, tm->tm_sec); + + writel(0x00, base + PIC32_ALRMTIME); + writel(0x00, base + PIC32_ALRMDATE); + + pic32_rtc_setaie(dev, alrm->enabled); + + clk_disable(pdata->clk); + return 0; +} + +static int pic32_rtc_proc(struct device *dev, struct seq_file *seq) +{ + struct pic32_rtc_dev *pdata = dev_get_drvdata(dev); + void __iomem *base = pdata->reg_base; + unsigned int repeat; + + clk_enable(pdata->clk); + + repeat = readw(base + PIC32_RTCALRM); + repeat &= PIC32_RTCALRM_ARPT; + seq_printf(seq, "periodic_IRQ\t: %s\n", repeat ? "yes" : "no"); + + clk_disable(pdata->clk); + return 0; +} + +static const struct rtc_class_ops pic32_rtcops = { + .read_time = pic32_rtc_gettime, + .set_time = pic32_rtc_settime, + .read_alarm = pic32_rtc_getalarm, + .set_alarm = pic32_rtc_setalarm, + .proc = pic32_rtc_proc, + .alarm_irq_enable = pic32_rtc_setaie, +}; + +static void pic32_rtc_enable(struct pic32_rtc_dev *pdata, int en) +{ + void __iomem *base = pdata->reg_base; + + if (!base) + return; + + clk_enable(pdata->clk); + if (!en) { + writel(PIC32_RTCCON_ON, base + PIC32_CLR(PIC32_RTCCON)); + } else { + pic32_syskey_unlock(); + + writel(PIC32_RTCCON_RTCWREN, base + PIC32_SET(PIC32_RTCCON)); + writel(3 << 9, base + PIC32_CLR(PIC32_RTCCON)); + + if (!(readl(base + PIC32_RTCCON) & PIC32_RTCCON_ON)) + writel(PIC32_RTCCON_ON, base + PIC32_SET(PIC32_RTCCON)); + } + clk_disable(pdata->clk); +} + +static int pic32_rtc_remove(struct platform_device *pdev) +{ + struct pic32_rtc_dev *pdata = platform_get_drvdata(pdev); + + pic32_rtc_setaie(&pdev->dev, 0); + clk_unprepare(pdata->clk); + pdata->clk = NULL; + + return 0; +} + +static int pic32_rtc_probe(struct platform_device *pdev) +{ + struct pic32_rtc_dev *pdata; + struct resource *res; + int ret; + + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + platform_set_drvdata(pdev, pdata); + + pdata->alarm_irq = platform_get_irq(pdev, 0); + if (pdata->alarm_irq < 0) { + dev_err(&pdev->dev, "no irq for alarm\n"); + return pdata->alarm_irq; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pdata->reg_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(pdata->reg_base)) + return PTR_ERR(pdata->reg_base); + + pdata->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(pdata->clk)) { + dev_err(&pdev->dev, "failed to find rtc clock source\n"); + ret = PTR_ERR(pdata->clk); + pdata->clk = NULL; + return ret; + } + + spin_lock_init(&pdata->alarm_lock); + + clk_prepare_enable(pdata->clk); + + pic32_rtc_enable(pdata, 1); + + device_init_wakeup(&pdev->dev, 1); + + pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &pic32_rtcops, + THIS_MODULE); + if (IS_ERR(pdata->rtc)) { + ret = PTR_ERR(pdata->rtc); + goto err_nortc; + } + + pdata->rtc->max_user_freq = 128; + + pic32_rtc_setfreq(&pdev->dev, 1); + ret = devm_request_irq(&pdev->dev, pdata->alarm_irq, + pic32_rtc_alarmirq, 0, + dev_name(&pdev->dev), pdata); + if (ret) { + dev_err(&pdev->dev, + "IRQ %d error %d\n", pdata->alarm_irq, ret); + goto err_nortc; + } + + clk_disable(pdata->clk); + + return 0; + +err_nortc: + pic32_rtc_enable(pdata, 0); + clk_disable_unprepare(pdata->clk); + + return ret; +} + +static const struct of_device_id pic32_rtc_dt_ids[] = { + { .compatible = "microchip,pic32mzda-rtc" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, pic32_rtc_dt_ids); + +static struct platform_driver pic32_rtc_driver = { + .probe = pic32_rtc_probe, + .remove = pic32_rtc_remove, + .driver = { + .name = "pic32-rtc", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(pic32_rtc_dt_ids), + }, +}; +module_platform_driver(pic32_rtc_driver); + +MODULE_DESCRIPTION("Microchip PIC32 RTC Driver"); +MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>"); +MODULE_LICENSE("GPL"); |