1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
|
// SPDX-License-Identifier: GPL-2.0+
/*
* 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>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.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;
void __iomem *csr_base;
struct clk *clk;
unsigned int irq_wake;
unsigned int irq_enabled;
};
static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
rtc_time64_to_tm(readl(pdata->csr_base + RTC_CCVR), tm);
return 0;
}
static int xgene_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
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)rtc_tm_to_time64(tm), pdata->csr_base + RTC_CLR);
readl(pdata->csr_base + RTC_CLR); /* Force a barrier */
return 0;
}
static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
/* If possible, CMR should be read here */
rtc_time64_to_tm(0, &alrm->time);
alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE;
return 0;
}
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;
}
static int xgene_rtc_alarm_irq_enabled(struct device *dev)
{
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
return readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE ? 1 : 0;
}
static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
writel((u32)rtc_tm_to_time64(&alrm->time), pdata->csr_base + RTC_CMR);
xgene_rtc_alarm_irq_enable(dev, alrm->enabled);
return 0;
}
static const struct rtc_class_ops xgene_rtc_ops = {
.read_time = xgene_rtc_read_time,
.set_time = xgene_rtc_set_time,
.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 = 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;
}
static int xgene_rtc_probe(struct platform_device *pdev)
{
struct xgene_rtc_dev *pdata;
int ret;
int irq;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
platform_set_drvdata(pdev, pdata);
pdata->csr_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pdata->csr_base))
return PTR_ERR(pdata->csr_base);
pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(pdata->rtc))
return PTR_ERR(pdata->rtc);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
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;
}
ret = clk_prepare_enable(pdata->clk);
if (ret)
return ret;
/* Turn on the clock and the crystal */
writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
ret = device_init_wakeup(&pdev->dev, 1);
if (ret) {
clk_disable_unprepare(pdata->clk);
return ret;
}
pdata->rtc->ops = &xgene_rtc_ops;
pdata->rtc->range_max = U32_MAX;
ret = devm_rtc_register_device(pdata->rtc);
if (ret) {
clk_disable_unprepare(pdata->clk);
return ret;
}
return 0;
}
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;
}
static int __maybe_unused 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 this RTC alarm will be used for waking the system up,
* don't disable it of course. Else we just disable the alarm
* and await suspension.
*/
if (device_may_wakeup(&pdev->dev)) {
if (!enable_irq_wake(irq))
pdata->irq_wake = 1;
} else {
pdata->irq_enabled = xgene_rtc_alarm_irq_enabled(dev);
xgene_rtc_alarm_irq_enable(dev, 0);
clk_disable_unprepare(pdata->clk);
}
return 0;
}
static int __maybe_unused 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;
int rc;
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 {
rc = clk_prepare_enable(pdata->clk);
if (rc) {
dev_err(dev, "Unable to enable clock error %d\n", rc);
return rc;
}
xgene_rtc_alarm_irq_enable(dev, pdata->irq_enabled);
}
return 0;
}
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");
|
