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290 lines
7.2 KiB
290 lines
7.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2007-2009 ST-Ericsson AB |
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* Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC. |
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* Author: Linus Walleij <[email protected]> |
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* Based on rtc-pl031.c by Deepak Saxena <[email protected]> |
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* Copyright 2006 (c) MontaVista Software, Inc. |
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*/ |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/rtc.h> |
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#include <linux/clk.h> |
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#include <linux/interrupt.h> |
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#include <linux/pm.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/slab.h> |
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/* |
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* Registers in the COH 901 331 |
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*/ |
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/* Alarm value 32bit (R/W) */ |
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#define COH901331_ALARM 0x00U |
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/* Used to set current time 32bit (R/W) */ |
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#define COH901331_SET_TIME 0x04U |
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/* Indication if current time is valid 32bit (R/-) */ |
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#define COH901331_VALID 0x08U |
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/* Read the current time 32bit (R/-) */ |
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#define COH901331_CUR_TIME 0x0cU |
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/* Event register for the "alarm" interrupt */ |
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#define COH901331_IRQ_EVENT 0x10U |
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/* Mask register for the "alarm" interrupt */ |
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#define COH901331_IRQ_MASK 0x14U |
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/* Force register for the "alarm" interrupt */ |
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#define COH901331_IRQ_FORCE 0x18U |
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/* |
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* Reference to RTC block clock |
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* Notice that the frequent clk_enable()/clk_disable() on this |
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* clock is mainly to be able to turn on/off other clocks in the |
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* hierarchy as needed, the RTC clock is always on anyway. |
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*/ |
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struct coh901331_port { |
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struct rtc_device *rtc; |
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struct clk *clk; |
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void __iomem *virtbase; |
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int irq; |
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#ifdef CONFIG_PM_SLEEP |
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u32 irqmaskstore; |
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#endif |
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}; |
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static irqreturn_t coh901331_interrupt(int irq, void *data) |
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{ |
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struct coh901331_port *rtap = data; |
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clk_enable(rtap->clk); |
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/* Ack IRQ */ |
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writel(1, rtap->virtbase + COH901331_IRQ_EVENT); |
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/* |
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* Disable the interrupt. This is necessary because |
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* the RTC lives on a lower-clocked line and will |
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* not release the IRQ line until after a few (slower) |
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* clock cycles. The interrupt will be re-enabled when |
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* a new alarm is set anyway. |
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*/ |
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writel(0, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable(rtap->clk); |
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/* Set alarm flag */ |
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rtc_update_irq(rtap->rtc, 1, RTC_AF); |
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return IRQ_HANDLED; |
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} |
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static int coh901331_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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clk_enable(rtap->clk); |
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/* Check if the time is valid */ |
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if (!readl(rtap->virtbase + COH901331_VALID)) { |
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clk_disable(rtap->clk); |
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return -EINVAL; |
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} |
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rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm); |
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clk_disable(rtap->clk); |
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return 0; |
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} |
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static int coh901331_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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clk_enable(rtap->clk); |
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writel(rtc_tm_to_time64(tm), rtap->virtbase + COH901331_SET_TIME); |
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clk_disable(rtap->clk); |
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return 0; |
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} |
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static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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clk_enable(rtap->clk); |
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rtc_time64_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time); |
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alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U; |
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alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U; |
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clk_disable(rtap->clk); |
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return 0; |
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} |
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static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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unsigned long time = rtc_tm_to_time64(&alarm->time); |
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clk_enable(rtap->clk); |
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writel(time, rtap->virtbase + COH901331_ALARM); |
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writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable(rtap->clk); |
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return 0; |
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} |
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static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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clk_enable(rtap->clk); |
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if (enabled) |
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writel(1, rtap->virtbase + COH901331_IRQ_MASK); |
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else |
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writel(0, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable(rtap->clk); |
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return 0; |
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} |
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static const struct rtc_class_ops coh901331_ops = { |
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.read_time = coh901331_read_time, |
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.set_time = coh901331_set_time, |
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.read_alarm = coh901331_read_alarm, |
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.set_alarm = coh901331_set_alarm, |
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.alarm_irq_enable = coh901331_alarm_irq_enable, |
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}; |
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static int __exit coh901331_remove(struct platform_device *pdev) |
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{ |
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struct coh901331_port *rtap = platform_get_drvdata(pdev); |
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if (rtap) |
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clk_unprepare(rtap->clk); |
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return 0; |
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} |
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static int __init coh901331_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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struct coh901331_port *rtap; |
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rtap = devm_kzalloc(&pdev->dev, |
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sizeof(struct coh901331_port), GFP_KERNEL); |
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if (!rtap) |
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return -ENOMEM; |
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rtap->virtbase = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(rtap->virtbase)) |
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return PTR_ERR(rtap->virtbase); |
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rtap->irq = platform_get_irq(pdev, 0); |
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if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0, |
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"RTC COH 901 331 Alarm", rtap)) |
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return -EIO; |
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rtap->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(rtap->clk)) { |
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ret = PTR_ERR(rtap->clk); |
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dev_err(&pdev->dev, "could not get clock\n"); |
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return ret; |
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} |
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rtap->rtc = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(rtap->rtc)) |
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return PTR_ERR(rtap->rtc); |
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rtap->rtc->ops = &coh901331_ops; |
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rtap->rtc->range_max = U32_MAX; |
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/* We enable/disable the clock only to assure it works */ |
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ret = clk_prepare_enable(rtap->clk); |
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if (ret) { |
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dev_err(&pdev->dev, "could not enable clock\n"); |
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return ret; |
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} |
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clk_disable(rtap->clk); |
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platform_set_drvdata(pdev, rtap); |
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ret = rtc_register_device(rtap->rtc); |
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if (ret) |
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goto out_no_rtc; |
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return 0; |
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out_no_rtc: |
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clk_unprepare(rtap->clk); |
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return ret; |
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} |
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#ifdef CONFIG_PM_SLEEP |
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static int coh901331_suspend(struct device *dev) |
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{ |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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/* |
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* If this RTC alarm will be used for waking the system up, |
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* don't disable it of course. Else we just disable the alarm |
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* and await suspension. |
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*/ |
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if (device_may_wakeup(dev)) { |
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enable_irq_wake(rtap->irq); |
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} else { |
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clk_enable(rtap->clk); |
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rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK); |
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writel(0, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable(rtap->clk); |
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} |
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clk_unprepare(rtap->clk); |
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return 0; |
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} |
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static int coh901331_resume(struct device *dev) |
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{ |
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int ret; |
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struct coh901331_port *rtap = dev_get_drvdata(dev); |
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ret = clk_prepare(rtap->clk); |
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if (ret) |
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return ret; |
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if (device_may_wakeup(dev)) { |
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disable_irq_wake(rtap->irq); |
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} else { |
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clk_enable(rtap->clk); |
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writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable(rtap->clk); |
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} |
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return 0; |
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} |
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#endif |
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static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume); |
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static void coh901331_shutdown(struct platform_device *pdev) |
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{ |
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struct coh901331_port *rtap = platform_get_drvdata(pdev); |
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clk_enable(rtap->clk); |
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writel(0, rtap->virtbase + COH901331_IRQ_MASK); |
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clk_disable_unprepare(rtap->clk); |
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} |
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static const struct of_device_id coh901331_dt_match[] = { |
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{ .compatible = "stericsson,coh901331" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, coh901331_dt_match); |
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static struct platform_driver coh901331_driver = { |
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.driver = { |
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.name = "rtc-coh901331", |
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.pm = &coh901331_pm_ops, |
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.of_match_table = coh901331_dt_match, |
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}, |
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.remove = __exit_p(coh901331_remove), |
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.shutdown = coh901331_shutdown, |
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}; |
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module_platform_driver_probe(coh901331_driver, coh901331_probe); |
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MODULE_AUTHOR("Linus Walleij <[email protected]>"); |
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MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver"); |
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MODULE_LICENSE("GPL");
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