1// SPDX-License-Identifier: GPL-2.0
2/*
3 * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
4 * Copyright (c) 2006 Tower Technologies
5 *
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 */
8
9#include <linux/module.h>
10#include <linux/rtc.h>
11#include <linux/platform_device.h>
12#include <linux/io.h>
13#include <linux/gfp.h>
14
15#define EP93XX_RTC_DATA			0x000
16#define EP93XX_RTC_MATCH		0x004
17#define EP93XX_RTC_STATUS		0x008
18#define  EP93XX_RTC_STATUS_INTR		 BIT(0)
19#define EP93XX_RTC_LOAD			0x00C
20#define EP93XX_RTC_CONTROL		0x010
21#define  EP93XX_RTC_CONTROL_MIE		 BIT(0)
22#define EP93XX_RTC_SWCOMP		0x108
23#define  EP93XX_RTC_SWCOMP_DEL_MASK	 0x001f0000
24#define  EP93XX_RTC_SWCOMP_DEL_SHIFT	 16
25#define  EP93XX_RTC_SWCOMP_INT_MASK	 0x0000ffff
26#define  EP93XX_RTC_SWCOMP_INT_SHIFT	 0
27
28struct ep93xx_rtc {
29	void __iomem	*mmio_base;
30	struct rtc_device *rtc;
31};
32
33static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
34				 unsigned short *delete)
35{
36	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
37	unsigned long comp;
38
39	comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
40
41	if (preload)
42		*preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
43				>> EP93XX_RTC_SWCOMP_INT_SHIFT;
44
45	if (delete)
46		*delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
47				>> EP93XX_RTC_SWCOMP_DEL_SHIFT;
48
49	return 0;
50}
51
52static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
53{
54	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
55	unsigned long time;
56
57	time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
58
59	rtc_time64_to_tm(time, tm);
60	return 0;
61}
62
63static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
64{
65	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
66	unsigned long secs = rtc_tm_to_time64(tm);
67
68	writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
69	return 0;
70}
71
72static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
73{
74	unsigned short preload, delete;
75
76	ep93xx_rtc_get_swcomp(dev, &preload, &delete);
77
78	seq_printf(seq, "preload\t\t: %d\n", preload);
79	seq_printf(seq, "delete\t\t: %d\n", delete);
80
81	return 0;
82}
83
84static const struct rtc_class_ops ep93xx_rtc_ops = {
85	.read_time	= ep93xx_rtc_read_time,
86	.set_time	= ep93xx_rtc_set_time,
87	.proc		= ep93xx_rtc_proc,
88};
89
90static ssize_t comp_preload_show(struct device *dev,
91				 struct device_attribute *attr, char *buf)
92{
93	unsigned short preload;
94
95	ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
96
97	return sprintf(buf, "%d\n", preload);
98}
99static DEVICE_ATTR_RO(comp_preload);
100
101static ssize_t comp_delete_show(struct device *dev,
102				struct device_attribute *attr, char *buf)
103{
104	unsigned short delete;
105
106	ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
107
108	return sprintf(buf, "%d\n", delete);
109}
110static DEVICE_ATTR_RO(comp_delete);
111
112static struct attribute *ep93xx_rtc_attrs[] = {
113	&dev_attr_comp_preload.attr,
114	&dev_attr_comp_delete.attr,
115	NULL
116};
117
118static const struct attribute_group ep93xx_rtc_sysfs_files = {
119	.attrs	= ep93xx_rtc_attrs,
120};
121
122static int ep93xx_rtc_probe(struct platform_device *pdev)
123{
124	struct ep93xx_rtc *ep93xx_rtc;
125	int err;
126
127	ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
128	if (!ep93xx_rtc)
129		return -ENOMEM;
130
131	ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
132	if (IS_ERR(ep93xx_rtc->mmio_base))
133		return PTR_ERR(ep93xx_rtc->mmio_base);
134
135	platform_set_drvdata(pdev, ep93xx_rtc);
136
137	ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
138	if (IS_ERR(ep93xx_rtc->rtc))
139		return PTR_ERR(ep93xx_rtc->rtc);
140
141	ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
142	ep93xx_rtc->rtc->range_max = U32_MAX;
143
144	err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
145	if (err)
146		return err;
147
148	return devm_rtc_register_device(ep93xx_rtc->rtc);
149}
150
151static struct platform_driver ep93xx_rtc_driver = {
152	.driver		= {
153		.name	= "ep93xx-rtc",
154	},
155	.probe		= ep93xx_rtc_probe,
156};
157
158module_platform_driver(ep93xx_rtc_driver);
159
160MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
161MODULE_DESCRIPTION("EP93XX RTC driver");
162MODULE_LICENSE("GPL");
163MODULE_ALIAS("platform:ep93xx-rtc");
164