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
28 struct ep93xx_rtc {
29 void __iomem *mmio_base;
30 struct rtc_device *rtc;
31 };
32
ep93xx_rtc_get_swcomp(struct device * dev,unsigned short * preload,unsigned short * delete)33 static 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
ep93xx_rtc_read_time(struct device * dev,struct rtc_time * tm)52 static 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
ep93xx_rtc_set_time(struct device * dev,struct rtc_time * tm)63 static 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
ep93xx_rtc_proc(struct device * dev,struct seq_file * seq)72 static 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
84 static 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
comp_preload_show(struct device * dev,struct device_attribute * attr,char * buf)90 static 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 }
99 static DEVICE_ATTR_RO(comp_preload);
100
comp_delete_show(struct device * dev,struct device_attribute * attr,char * buf)101 static 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 }
110 static DEVICE_ATTR_RO(comp_delete);
111
112 static struct attribute *ep93xx_rtc_attrs[] = {
113 &dev_attr_comp_preload.attr,
114 &dev_attr_comp_delete.attr,
115 NULL
116 };
117
118 static const struct attribute_group ep93xx_rtc_sysfs_files = {
119 .attrs = ep93xx_rtc_attrs,
120 };
121
ep93xx_rtc_probe(struct platform_device * pdev)122 static 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
151 static struct platform_driver ep93xx_rtc_driver = {
152 .driver = {
153 .name = "ep93xx-rtc",
154 },
155 .probe = ep93xx_rtc_probe,
156 };
157
158 module_platform_driver(ep93xx_rtc_driver);
159
160 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
161 MODULE_DESCRIPTION("EP93XX RTC driver");
162 MODULE_LICENSE("GPL");
163 MODULE_ALIAS("platform:ep93xx-rtc");
164