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Release 4.14 drivers/rtc/rtc-xgene.c

Directory: drivers/rtc
/*
 * APM X-Gene SoC Real Time Clock Driver
 *
 * Copyright (c) 2014, Applied Micro Circuits Corporation
 * Author: Rameshwar Prasad Sahu <rsahu@apm.com>
 *         Loc Ho <lho@apm.com>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#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/delay.h>
#include <linux/rtc.h>

/* RTC CSR Registers */

#define RTC_CCVR		0x00

#define RTC_CMR			0x04

#define RTC_CLR			0x08

#define RTC_CCR			0x0C

#define  RTC_CCR_IE		BIT(0)

#define  RTC_CCR_MASK		BIT(1)

#define  RTC_CCR_EN		BIT(2)

#define  RTC_CCR_WEN		BIT(3)

#define RTC_STAT		0x10

#define  RTC_STAT_BIT		BIT(0)

#define RTC_RSTAT		0x14

#define RTC_EOI			0x18

#define RTC_VER			0x1C


struct xgene_rtc_dev {
	
struct rtc_device *rtc;
	
struct device *dev;
	
unsigned long alarm_time;
	
void __iomem *csr_base;
	
struct clk *clk;
	
unsigned int irq_wake;
};


static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct xgene_rtc_dev *pdata = dev_get_drvdata(dev); rtc_time_to_tm(readl(pdata->csr_base + RTC_CCVR), tm); return rtc_valid_tm(tm); }

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static int xgene_rtc_set_mmss(struct device *dev, unsigned long secs) { struct xgene_rtc_dev *pdata = dev_get_drvdata(dev); /* * NOTE: After the following write, the RTC_CCVR is only reflected * after the update cycle of 1 seconds. */ writel((u32) secs, pdata->csr_base + RTC_CLR); readl(pdata->csr_base + RTC_CLR); /* Force a barrier */ return 0; }

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static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct xgene_rtc_dev *pdata = dev_get_drvdata(dev); rtc_time_to_tm(pdata->alarm_time, &alrm->time); alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE; return 0; }

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static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled) { struct xgene_rtc_dev *pdata = dev_get_drvdata(dev); u32 ccr; ccr = readl(pdata->csr_base + RTC_CCR); if (enabled) { ccr &= ~RTC_CCR_MASK; ccr |= RTC_CCR_IE; } else { ccr &= ~RTC_CCR_IE; ccr |= RTC_CCR_MASK; } writel(ccr, pdata->csr_base + RTC_CCR); return 0; }

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static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct xgene_rtc_dev *pdata = dev_get_drvdata(dev); unsigned long rtc_time; unsigned long alarm_time; rtc_time = readl(pdata->csr_base + RTC_CCVR); rtc_tm_to_time(&alrm->time, &alarm_time); pdata->alarm_time = alarm_time; writel((u32) pdata->alarm_time, pdata->csr_base + RTC_CMR); xgene_rtc_alarm_irq_enable(dev, alrm->enabled); return 0; }

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static const struct rtc_class_ops xgene_rtc_ops = { .read_time = xgene_rtc_read_time, .set_mmss = xgene_rtc_set_mmss, .read_alarm = xgene_rtc_read_alarm, .set_alarm = xgene_rtc_set_alarm, .alarm_irq_enable = xgene_rtc_alarm_irq_enable, };
static irqreturn_t xgene_rtc_interrupt(int irq, void *id) { struct xgene_rtc_dev *pdata = (struct xgene_rtc_dev *) id; /* Check if interrupt asserted */ if (!(readl(pdata->csr_base + RTC_STAT) & RTC_STAT_BIT)) return IRQ_NONE; /* Clear interrupt */ readl(pdata->csr_base + RTC_EOI); rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; }

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static int xgene_rtc_probe(struct platform_device *pdev) { struct xgene_rtc_dev *pdata; struct resource *res; int ret; int irq; pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; platform_set_drvdata(pdev, pdata); pdata->dev = &pdev->dev; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); pdata->csr_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(pdata->csr_base)) return PTR_ERR(pdata->csr_base); irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "No IRQ resource\n"); return irq; } ret = devm_request_irq(&pdev->dev, irq, xgene_rtc_interrupt, 0, dev_name(&pdev->dev), pdata); if (ret) { dev_err(&pdev->dev, "Could not request IRQ\n"); return ret; } pdata->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(pdata->clk)) { dev_err(&pdev->dev, "Couldn't get the clock for RTC\n"); return -ENODEV; } clk_prepare_enable(pdata->clk); /* Turn on the clock and the crystal */ writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR); device_init_wakeup(&pdev->dev, 1); pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &xgene_rtc_ops, THIS_MODULE); if (IS_ERR(pdata->rtc)) { clk_disable_unprepare(pdata->clk); return PTR_ERR(pdata->rtc); } /* HW does not support update faster than 1 seconds */ pdata->rtc->uie_unsupported = 1; return 0; }

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static int xgene_rtc_remove(struct platform_device *pdev) { struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev); xgene_rtc_alarm_irq_enable(&pdev->dev, 0); device_init_wakeup(&pdev->dev, 0); clk_disable_unprepare(pdata->clk); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int xgene_rtc_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev); int irq; irq = platform_get_irq(pdev, 0); if (device_may_wakeup(&pdev->dev)) { if (!enable_irq_wake(irq)) pdata->irq_wake = 1; } else { xgene_rtc_alarm_irq_enable(dev, 0); clk_disable(pdata->clk); } return 0; }

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static int xgene_rtc_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev); int irq; irq = platform_get_irq(pdev, 0); if (device_may_wakeup(&pdev->dev)) { if (pdata->irq_wake) { disable_irq_wake(irq); pdata->irq_wake = 0; } } else { clk_enable(pdata->clk); xgene_rtc_alarm_irq_enable(dev, 1); } return 0; }

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#endif static SIMPLE_DEV_PM_OPS(xgene_rtc_pm_ops, xgene_rtc_suspend, xgene_rtc_resume); #ifdef CONFIG_OF static const struct of_device_id xgene_rtc_of_match[] = { {.compatible = "apm,xgene-rtc" }, { } }; MODULE_DEVICE_TABLE(of, xgene_rtc_of_match); #endif static struct platform_driver xgene_rtc_driver = { .probe = xgene_rtc_probe, .remove = xgene_rtc_remove, .driver = { .name = "xgene-rtc", .pm = &xgene_rtc_pm_ops, .of_match_table = of_match_ptr(xgene_rtc_of_match), }, }; module_platform_driver(xgene_rtc_driver); MODULE_DESCRIPTION("APM X-Gene SoC RTC driver"); MODULE_AUTHOR("Rameshwar Sahu <rsahu@apm.com>"); MODULE_LICENSE("GPL");

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Directory: drivers/rtc
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