rtc-pl030.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  linux/drivers/rtc/rtc-pl030.c
  4 *
  5 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
  6 */
  7#include <linux/module.h>
  8#include <linux/rtc.h>
  9#include <linux/init.h>
 10#include <linux/interrupt.h>
 11#include <linux/amba/bus.h>
 12#include <linux/io.h>
 13#include <linux/slab.h>
 14
 15#define RTC_DR		(0)
 16#define RTC_MR		(4)
 17#define RTC_STAT	(8)
 18#define RTC_EOI		(8)
 19#define RTC_LR		(12)
 20#define RTC_CR		(16)
 21#define RTC_CR_MIE	(1 << 0)
 22
 23struct pl030_rtc {
 24	void __iomem		*base;
 25};
 26
 27static irqreturn_t pl030_interrupt(int irq, void *dev_id)
 28{
 29	struct pl030_rtc *rtc = dev_id;
 30	writel(0, rtc->base + RTC_EOI);
 31	return IRQ_HANDLED;
 32}
 33
 34static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 35{
 36	struct pl030_rtc *rtc = dev_get_drvdata(dev);
 37
 38	rtc_time64_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
 39	return 0;
 40}
 41
 42static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 43{
 44	struct pl030_rtc *rtc = dev_get_drvdata(dev);
 45
 46	writel(rtc_tm_to_time64(&alrm->time), rtc->base + RTC_MR);
 47
 48	return 0;
 49}
 50
 51static int pl030_read_time(struct device *dev, struct rtc_time *tm)
 52{
 53	struct pl030_rtc *rtc = dev_get_drvdata(dev);
 54
 55	rtc_time64_to_tm(readl(rtc->base + RTC_DR), tm);
 56
 57	return 0;
 58}
 59
 60/*
 61 * Set the RTC time.  Unfortunately, we can't accurately set
 62 * the point at which the counter updates.
 63 *
 64 * Also, since RTC_LR is transferred to RTC_CR on next rising
 65 * edge of the 1Hz clock, we must write the time one second
 66 * in advance.
 67 */
 68static int pl030_set_time(struct device *dev, struct rtc_time *tm)
 69{
 70	struct pl030_rtc *rtc = dev_get_drvdata(dev);
 71
 72	writel(rtc_tm_to_time64(tm) + 1, rtc->base + RTC_LR);
 73
 74	return 0;
 75}
 76
 77static const struct rtc_class_ops pl030_ops = {
 78	.read_time	= pl030_read_time,
 79	.set_time	= pl030_set_time,
 80	.read_alarm	= pl030_read_alarm,
 81	.set_alarm	= pl030_set_alarm,
 82};
 83
 84static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
 85{
 86	struct pl030_rtc *rtc;
 87	int ret;
 88	struct rtc_device *rtc_dev;
 89
 90	ret = amba_request_regions(dev, NULL);
 91	if (ret)
 92		goto err_req;
 93
 94	rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL);
 95	if (!rtc) {
 96		ret = -ENOMEM;
 97		goto err_rtc;
 98	}
 99
100	rtc_dev = devm_rtc_allocate_device(&dev->dev);
101	if (IS_ERR(rtc_dev)) {
102		ret = PTR_ERR(rtc_dev);
103		goto err_rtc;
104	}
105
106	rtc_dev->ops = &pl030_ops;
107	rtc_dev->range_max = U32_MAX;
108	rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
109	if (!rtc->base) {
110		ret = -ENOMEM;
111		goto err_rtc;
112	}
113
114	__raw_writel(0, rtc->base + RTC_CR);
115	__raw_writel(0, rtc->base + RTC_EOI);
116
117	amba_set_drvdata(dev, rtc);
118
119	ret = request_irq(dev->irq[0], pl030_interrupt, 0,
120			  "rtc-pl030", rtc);
121	if (ret)
122		goto err_irq;
123
124	ret = devm_rtc_register_device(rtc_dev);
125	if (ret)
126		goto err_reg;
127
128	return 0;
129
130 err_reg:
131	free_irq(dev->irq[0], rtc);
132 err_irq:
133	iounmap(rtc->base);
134 err_rtc:
135	amba_release_regions(dev);
136 err_req:
137	return ret;
138}
139
140static void pl030_remove(struct amba_device *dev)
141{
142	struct pl030_rtc *rtc = amba_get_drvdata(dev);
143
144	writel(0, rtc->base + RTC_CR);
145
146	free_irq(dev->irq[0], rtc);
147	iounmap(rtc->base);
148	amba_release_regions(dev);
149}
150
151static const struct amba_id pl030_ids[] = {
152	{
153		.id	= 0x00041030,
154		.mask	= 0x000fffff,
155	},
156	{ 0, 0 },
157};
158
159MODULE_DEVICE_TABLE(amba, pl030_ids);
160
161static struct amba_driver pl030_driver = {
162	.drv		= {
163		.name	= "rtc-pl030",
164	},
165	.probe		= pl030_probe,
166	.remove		= pl030_remove,
167	.id_table	= pl030_ids,
168};
169
170module_amba_driver(pl030_driver);
171
172MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
173MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
174MODULE_LICENSE("GPL");