diff options
Diffstat (limited to 'drivers/rtc/rtc-m48t59.c')
| -rw-r--r-- | drivers/rtc/rtc-m48t59.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c new file mode 100644 index 000000000..f0f6b9b6d --- /dev/null +++ b/drivers/rtc/rtc-m48t59.c @@ -0,0 +1,488 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ST M48T59 RTC driver + * + * Copyright (c) 2007 Wind River Systems, Inc. + * + * Author: Mark Zhan <rongkai.zhan@windriver.com> + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/rtc/m48t59.h> +#include <linux/bcd.h> +#include <linux/slab.h> + +#ifndef NO_IRQ +#define NO_IRQ (-1) +#endif + +#define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg)) +#define M48T59_WRITE(val, reg) \ + (pdata->write_byte(dev, pdata->offset + reg, val)) + +#define M48T59_SET_BITS(mask, reg) \ + M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg)) +#define M48T59_CLEAR_BITS(mask, reg) \ + M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg)) + +struct m48t59_private { + void __iomem *ioaddr; + int irq; + struct rtc_device *rtc; + spinlock_t lock; /* serialize the NVRAM and RTC access */ +}; + +/* + * This is the generic access method when the chip is memory-mapped + */ +static void +m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val) +{ + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + + writeb(val, m48t59->ioaddr+ofs); +} + +static u8 +m48t59_mem_readb(struct device *dev, u32 ofs) +{ + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + + return readb(m48t59->ioaddr+ofs); +} + +/* + * NOTE: M48T59 only uses BCD mode + */ +static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + unsigned long flags; + u8 val; + + spin_lock_irqsave(&m48t59->lock, flags); + /* Issue the READ command */ + M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL); + + tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)); + /* tm_mon is 0-11 */ + tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1; + tm->tm_mday = bcd2bin(M48T59_READ(M48T59_MDAY)); + + val = M48T59_READ(M48T59_WDAY); + if ((pdata->type == M48T59RTC_TYPE_M48T59) && + (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) { + dev_dbg(dev, "Century bit is enabled\n"); + tm->tm_year += 100; /* one century */ + } +#ifdef CONFIG_SPARC + /* Sun SPARC machines count years since 1968 */ + tm->tm_year += 68; +#endif + + tm->tm_wday = bcd2bin(val & 0x07); + tm->tm_hour = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F); + tm->tm_min = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F); + tm->tm_sec = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F); + + /* Clear the READ bit */ + M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL); + spin_unlock_irqrestore(&m48t59->lock, flags); + + dev_dbg(dev, "RTC read time %ptR\n", tm); + return 0; +} + +static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + unsigned long flags; + u8 val = 0; + int year = tm->tm_year; + +#ifdef CONFIG_SPARC + /* Sun SPARC machines count years since 1968 */ + year -= 68; +#endif + + dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n", + year + 1900, tm->tm_mon, tm->tm_mday, + tm->tm_hour, tm->tm_min, tm->tm_sec); + + if (year < 0) + return -EINVAL; + + spin_lock_irqsave(&m48t59->lock, flags); + /* Issue the WRITE command */ + M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); + + M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC); + M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN); + M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR); + M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY); + /* tm_mon is 0-11 */ + M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH); + M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR); + + if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100)) + val = (M48T59_WDAY_CEB | M48T59_WDAY_CB); + val |= (bin2bcd(tm->tm_wday) & 0x07); + M48T59_WRITE(val, M48T59_WDAY); + + /* Clear the WRITE bit */ + M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); + spin_unlock_irqrestore(&m48t59->lock, flags); + return 0; +} + +/* + * Read alarm time and date in RTC + */ +static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + unsigned long flags; + u8 val; + + /* If no irq, we don't support ALARM */ + if (m48t59->irq == NO_IRQ) + return -EIO; + + spin_lock_irqsave(&m48t59->lock, flags); + /* Issue the READ command */ + M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL); + + tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)); +#ifdef CONFIG_SPARC + /* Sun SPARC machines count years since 1968 */ + tm->tm_year += 68; +#endif + /* tm_mon is 0-11 */ + tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1; + + val = M48T59_READ(M48T59_WDAY); + if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) + tm->tm_year += 100; /* one century */ + + tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE)); + tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR)); + tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN)); + tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC)); + + /* Clear the READ bit */ + M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL); + spin_unlock_irqrestore(&m48t59->lock, flags); + + dev_dbg(dev, "RTC read alarm time %ptR\n", tm); + return rtc_valid_tm(tm); +} + +/* + * Set alarm time and date in RTC + */ +static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + u8 mday, hour, min, sec; + unsigned long flags; + int year = tm->tm_year; + +#ifdef CONFIG_SPARC + /* Sun SPARC machines count years since 1968 */ + year -= 68; +#endif + + /* If no irq, we don't support ALARM */ + if (m48t59->irq == NO_IRQ) + return -EIO; + + if (year < 0) + return -EINVAL; + + /* + * 0xff means "always match" + */ + mday = tm->tm_mday; + mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff; + if (mday == 0xff) + mday = M48T59_READ(M48T59_MDAY); + + hour = tm->tm_hour; + hour = (hour < 24) ? bin2bcd(hour) : 0x00; + + min = tm->tm_min; + min = (min < 60) ? bin2bcd(min) : 0x00; + + sec = tm->tm_sec; + sec = (sec < 60) ? bin2bcd(sec) : 0x00; + + spin_lock_irqsave(&m48t59->lock, flags); + /* Issue the WRITE command */ + M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); + + M48T59_WRITE(mday, M48T59_ALARM_DATE); + M48T59_WRITE(hour, M48T59_ALARM_HOUR); + M48T59_WRITE(min, M48T59_ALARM_MIN); + M48T59_WRITE(sec, M48T59_ALARM_SEC); + + /* Clear the WRITE bit */ + M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL); + spin_unlock_irqrestore(&m48t59->lock, flags); + + dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n", + year + 1900, tm->tm_mon, tm->tm_mday, + tm->tm_hour, tm->tm_min, tm->tm_sec); + return 0; +} + +/* + * Handle commands from user-space + */ +static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + unsigned long flags; + + spin_lock_irqsave(&m48t59->lock, flags); + if (enabled) + M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR); + else + M48T59_WRITE(0x00, M48T59_INTR); + spin_unlock_irqrestore(&m48t59->lock, flags); + + return 0; +} + +static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + unsigned long flags; + u8 val; + + spin_lock_irqsave(&m48t59->lock, flags); + val = M48T59_READ(M48T59_FLAGS); + spin_unlock_irqrestore(&m48t59->lock, flags); + + seq_printf(seq, "battery\t\t: %s\n", + (val & M48T59_FLAGS_BF) ? "low" : "normal"); + return 0; +} + +/* + * IRQ handler for the RTC + */ +static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id) +{ + struct device *dev = (struct device *)dev_id; + struct m48t59_plat_data *pdata = dev_get_platdata(dev); + struct m48t59_private *m48t59 = dev_get_drvdata(dev); + u8 event; + + spin_lock(&m48t59->lock); + event = M48T59_READ(M48T59_FLAGS); + spin_unlock(&m48t59->lock); + + if (event & M48T59_FLAGS_AF) { + rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF)); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static const struct rtc_class_ops m48t59_rtc_ops = { + .read_time = m48t59_rtc_read_time, + .set_time = m48t59_rtc_set_time, + .read_alarm = m48t59_rtc_readalarm, + .set_alarm = m48t59_rtc_setalarm, + .proc = m48t59_rtc_proc, + .alarm_irq_enable = m48t59_rtc_alarm_irq_enable, +}; + +static int m48t59_nvram_read(void *priv, unsigned int offset, void *val, + size_t size) +{ + struct platform_device *pdev = priv; + struct device *dev = &pdev->dev; + struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); + struct m48t59_private *m48t59 = platform_get_drvdata(pdev); + ssize_t cnt = 0; + unsigned long flags; + u8 *buf = val; + + spin_lock_irqsave(&m48t59->lock, flags); + + for (; cnt < size; cnt++) + *buf++ = M48T59_READ(cnt); + + spin_unlock_irqrestore(&m48t59->lock, flags); + + return 0; +} + +static int m48t59_nvram_write(void *priv, unsigned int offset, void *val, + size_t size) +{ + struct platform_device *pdev = priv; + struct device *dev = &pdev->dev; + struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); + struct m48t59_private *m48t59 = platform_get_drvdata(pdev); + ssize_t cnt = 0; + unsigned long flags; + u8 *buf = val; + + spin_lock_irqsave(&m48t59->lock, flags); + + for (; cnt < size; cnt++) + M48T59_WRITE(*buf++, cnt); + + spin_unlock_irqrestore(&m48t59->lock, flags); + + return 0; +} + +static int m48t59_rtc_probe(struct platform_device *pdev) +{ + struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev); + struct m48t59_private *m48t59 = NULL; + struct resource *res; + int ret = -ENOMEM; + struct nvmem_config nvmem_cfg = { + .name = "m48t59-", + .word_size = 1, + .stride = 1, + .reg_read = m48t59_nvram_read, + .reg_write = m48t59_nvram_write, + .priv = pdev, + }; + + /* This chip could be memory-mapped or I/O-mapped */ + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + res = platform_get_resource(pdev, IORESOURCE_IO, 0); + if (!res) + return -EINVAL; + } + + if (res->flags & IORESOURCE_IO) { + /* If we are I/O-mapped, the platform should provide + * the operations accessing chip registers. + */ + if (!pdata || !pdata->write_byte || !pdata->read_byte) + return -EINVAL; + } else if (res->flags & IORESOURCE_MEM) { + /* we are memory-mapped */ + if (!pdata) { + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), + GFP_KERNEL); + if (!pdata) + return -ENOMEM; + /* Ensure we only kmalloc platform data once */ + pdev->dev.platform_data = pdata; + } + if (!pdata->type) + pdata->type = M48T59RTC_TYPE_M48T59; + + /* Try to use the generic memory read/write ops */ + if (!pdata->write_byte) + pdata->write_byte = m48t59_mem_writeb; + if (!pdata->read_byte) + pdata->read_byte = m48t59_mem_readb; + } + + m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL); + if (!m48t59) + return -ENOMEM; + + m48t59->ioaddr = pdata->ioaddr; + + if (!m48t59->ioaddr) { + /* ioaddr not mapped externally */ + m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start, + resource_size(res)); + if (!m48t59->ioaddr) + return ret; + } + + /* Try to get irq number. We also can work in + * the mode without IRQ. + */ + m48t59->irq = platform_get_irq_optional(pdev, 0); + if (m48t59->irq <= 0) + m48t59->irq = NO_IRQ; + + if (m48t59->irq != NO_IRQ) { + ret = devm_request_irq(&pdev->dev, m48t59->irq, + m48t59_rtc_interrupt, IRQF_SHARED, + "rtc-m48t59", &pdev->dev); + if (ret) + return ret; + } + + m48t59->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(m48t59->rtc)) + return PTR_ERR(m48t59->rtc); + + switch (pdata->type) { + case M48T59RTC_TYPE_M48T59: + pdata->offset = 0x1ff0; + break; + case M48T59RTC_TYPE_M48T02: + clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features); + pdata->offset = 0x7f0; + break; + case M48T59RTC_TYPE_M48T08: + clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features); + pdata->offset = 0x1ff0; + break; + default: + dev_err(&pdev->dev, "Unknown RTC type\n"); + return -ENODEV; + } + + spin_lock_init(&m48t59->lock); + platform_set_drvdata(pdev, m48t59); + + m48t59->rtc->ops = &m48t59_rtc_ops; + + nvmem_cfg.size = pdata->offset; + ret = devm_rtc_nvmem_register(m48t59->rtc, &nvmem_cfg); + if (ret) + return ret; + + ret = devm_rtc_register_device(m48t59->rtc); + if (ret) + return ret; + + return 0; +} + +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:rtc-m48t59"); + +static struct platform_driver m48t59_rtc_driver = { + .driver = { + .name = "rtc-m48t59", + }, + .probe = m48t59_rtc_probe, +}; + +module_platform_driver(m48t59_rtc_driver); + +MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>"); +MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver"); +MODULE_LICENSE("GPL"); |