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193 lines
4.4 KiB
193 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Driver for the SGS-Thomson M48T35 Timekeeper RAM chip |
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* |
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* Copyright (C) 2000 Silicon Graphics, Inc. |
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* Written by Ulf Carlsson ([email protected]) |
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* |
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* Copyright (C) 2008 Thomas Bogendoerfer |
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* |
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* Based on code written by Paul Gortmaker. |
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*/ |
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#include <linux/module.h> |
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#include <linux/rtc.h> |
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#include <linux/slab.h> |
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#include <linux/platform_device.h> |
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#include <linux/bcd.h> |
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#include <linux/io.h> |
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#include <linux/err.h> |
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struct m48t35_rtc { |
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u8 pad[0x7ff8]; /* starts at 0x7ff8 */ |
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#ifdef CONFIG_SGI_IP27 |
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u8 hour; |
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u8 min; |
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u8 sec; |
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u8 control; |
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u8 year; |
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u8 month; |
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u8 date; |
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u8 day; |
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#else |
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u8 control; |
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u8 sec; |
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u8 min; |
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u8 hour; |
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u8 day; |
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u8 date; |
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u8 month; |
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u8 year; |
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#endif |
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}; |
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#define M48T35_RTC_SET 0x80 |
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#define M48T35_RTC_READ 0x40 |
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struct m48t35_priv { |
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struct rtc_device *rtc; |
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struct m48t35_rtc __iomem *reg; |
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size_t size; |
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unsigned long baseaddr; |
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spinlock_t lock; |
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}; |
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static int m48t35_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct m48t35_priv *priv = dev_get_drvdata(dev); |
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u8 control; |
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/* |
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* Only the values that we read from the RTC are set. We leave |
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* tm_wday, tm_yday and tm_isdst untouched. Even though the |
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* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated |
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* by the RTC when initially set to a non-zero value. |
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*/ |
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spin_lock_irq(&priv->lock); |
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control = readb(&priv->reg->control); |
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writeb(control | M48T35_RTC_READ, &priv->reg->control); |
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tm->tm_sec = readb(&priv->reg->sec); |
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tm->tm_min = readb(&priv->reg->min); |
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tm->tm_hour = readb(&priv->reg->hour); |
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tm->tm_mday = readb(&priv->reg->date); |
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tm->tm_mon = readb(&priv->reg->month); |
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tm->tm_year = readb(&priv->reg->year); |
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writeb(control, &priv->reg->control); |
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spin_unlock_irq(&priv->lock); |
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tm->tm_sec = bcd2bin(tm->tm_sec); |
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tm->tm_min = bcd2bin(tm->tm_min); |
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tm->tm_hour = bcd2bin(tm->tm_hour); |
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tm->tm_mday = bcd2bin(tm->tm_mday); |
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tm->tm_mon = bcd2bin(tm->tm_mon); |
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tm->tm_year = bcd2bin(tm->tm_year); |
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/* |
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* Account for differences between how the RTC uses the values |
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* and how they are defined in a struct rtc_time; |
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*/ |
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tm->tm_year += 70; |
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if (tm->tm_year <= 69) |
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tm->tm_year += 100; |
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tm->tm_mon--; |
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return 0; |
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} |
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static int m48t35_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct m48t35_priv *priv = dev_get_drvdata(dev); |
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unsigned char mon, day, hrs, min, sec; |
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unsigned int yrs; |
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u8 control; |
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yrs = tm->tm_year + 1900; |
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mon = tm->tm_mon + 1; /* tm_mon starts at zero */ |
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day = tm->tm_mday; |
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hrs = tm->tm_hour; |
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min = tm->tm_min; |
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sec = tm->tm_sec; |
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if (yrs < 1970) |
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return -EINVAL; |
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yrs -= 1970; |
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if (yrs > 255) /* They are unsigned */ |
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return -EINVAL; |
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if (yrs > 169) |
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return -EINVAL; |
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if (yrs >= 100) |
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yrs -= 100; |
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sec = bin2bcd(sec); |
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min = bin2bcd(min); |
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hrs = bin2bcd(hrs); |
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day = bin2bcd(day); |
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mon = bin2bcd(mon); |
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yrs = bin2bcd(yrs); |
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spin_lock_irq(&priv->lock); |
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control = readb(&priv->reg->control); |
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writeb(control | M48T35_RTC_SET, &priv->reg->control); |
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writeb(yrs, &priv->reg->year); |
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writeb(mon, &priv->reg->month); |
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writeb(day, &priv->reg->date); |
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writeb(hrs, &priv->reg->hour); |
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writeb(min, &priv->reg->min); |
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writeb(sec, &priv->reg->sec); |
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writeb(control, &priv->reg->control); |
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spin_unlock_irq(&priv->lock); |
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return 0; |
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} |
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static const struct rtc_class_ops m48t35_ops = { |
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.read_time = m48t35_read_time, |
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.set_time = m48t35_set_time, |
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}; |
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static int m48t35_probe(struct platform_device *pdev) |
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{ |
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struct resource *res; |
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struct m48t35_priv *priv; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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if (!res) |
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return -ENODEV; |
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priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->size = resource_size(res); |
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if (!devm_request_mem_region(&pdev->dev, res->start, priv->size, |
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pdev->name)) |
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return -EBUSY; |
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priv->baseaddr = res->start; |
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priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size); |
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if (!priv->reg) |
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return -ENOMEM; |
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spin_lock_init(&priv->lock); |
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platform_set_drvdata(pdev, priv); |
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priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35", |
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&m48t35_ops, THIS_MODULE); |
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return PTR_ERR_OR_ZERO(priv->rtc); |
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} |
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static struct platform_driver m48t35_platform_driver = { |
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.driver = { |
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.name = "rtc-m48t35", |
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}, |
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.probe = m48t35_probe, |
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}; |
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module_platform_driver(m48t35_platform_driver); |
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MODULE_AUTHOR("Thomas Bogendoerfer <[email protected]>"); |
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MODULE_DESCRIPTION("M48T35 RTC driver"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:rtc-m48t35");
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