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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* Real Time Clock driver for Conexant Digicolor
*
* Copyright (C) 2015 Paradox Innovation Ltd.
*
* Author: Baruch Siach <baruch@tkos.co.il>
*/
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/of.h>
#define DC_RTC_CONTROL 0x0
#define DC_RTC_TIME 0x8
#define DC_RTC_REFERENCE 0xc
#define DC_RTC_ALARM 0x10
#define DC_RTC_INTFLAG_CLEAR 0x14
#define DC_RTC_INTENABLE 0x16
#define DC_RTC_CMD_MASK 0xf
#define DC_RTC_GO_BUSY BIT(7)
#define CMD_NOP 0
#define CMD_RESET 1
#define CMD_WRITE 3
#define CMD_READ 4
#define CMD_DELAY_US (10*1000)
#define CMD_TIMEOUT_US (500*CMD_DELAY_US)
struct dc_rtc {
struct rtc_device *rtc_dev;
void __iomem *regs;
};
static int dc_rtc_cmds(struct dc_rtc *rtc, const u8 *cmds, int len)
{
u8 val;
int i, ret;
for (i = 0; i < len; i++) {
writeb_relaxed((cmds[i] & DC_RTC_CMD_MASK) | DC_RTC_GO_BUSY,
rtc->regs + DC_RTC_CONTROL);
ret = readb_relaxed_poll_timeout(
rtc->regs + DC_RTC_CONTROL, val,
!(val & DC_RTC_GO_BUSY), CMD_DELAY_US, CMD_TIMEOUT_US);
if (ret < 0)
return ret;
}
return 0;
}
static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val)
{
static const u8 read_cmds[] = {CMD_READ, CMD_NOP};
u32 reference, time1, time2;
int ret;
ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds));
if (ret < 0)
return ret;
reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
time1 = readl_relaxed(rtc->regs + DC_RTC_TIME);
/* Read twice to ensure consistency */
while (1) {
time2 = readl_relaxed(rtc->regs + DC_RTC_TIME);
if (time1 == time2)
break;
time1 = time2;
}
*val = reference + time1;
return 0;
}
static int dc_rtc_write(struct dc_rtc *rtc, u32 val)
{
static const u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP};
writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE);
return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds));
}
static int dc_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct dc_rtc *rtc = dev_get_drvdata(dev);
unsigned long now;
int ret;
ret = dc_rtc_read(rtc, &now);
if (ret < 0)
return ret;
rtc_time64_to_tm(now, tm);
return 0;
}
static int dc_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct dc_rtc *rtc = dev_get_drvdata(dev);
return dc_rtc_write(rtc, rtc_tm_to_time64(tm));
}
static int dc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct dc_rtc *rtc = dev_get_drvdata(dev);
u32 alarm_reg, reference;
unsigned long now;
int ret;
alarm_reg = readl_relaxed(rtc->regs + DC_RTC_ALARM);
reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
rtc_time64_to_tm(reference + alarm_reg, &alarm->time);
ret = dc_rtc_read(rtc, &now);
if (ret < 0)
return ret;
alarm->pending = alarm_reg + reference > now;
alarm->enabled = readl_relaxed(rtc->regs + DC_RTC_INTENABLE);
return 0;
}
static int dc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct dc_rtc *rtc = dev_get_drvdata(dev);
time64_t alarm_time;
u32 reference;
alarm_time = rtc_tm_to_time64(&alarm->time);
reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
writel_relaxed(alarm_time - reference, rtc->regs + DC_RTC_ALARM);
writeb_relaxed(!!alarm->enabled, rtc->regs + DC_RTC_INTENABLE);
return 0;
}
static int dc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct dc_rtc *rtc = dev_get_drvdata(dev);
writeb_relaxed(!!enabled, rtc->regs + DC_RTC_INTENABLE);
return 0;
}
static const struct rtc_class_ops dc_rtc_ops = {
.read_time = dc_rtc_read_time,
.set_time = dc_rtc_set_time,
.read_alarm = dc_rtc_read_alarm,
.set_alarm = dc_rtc_set_alarm,
.alarm_irq_enable = dc_rtc_alarm_irq_enable,
};
static irqreturn_t dc_rtc_irq(int irq, void *dev_id)
{
struct dc_rtc *rtc = dev_id;
writeb_relaxed(1, rtc->regs + DC_RTC_INTFLAG_CLEAR);
rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
return IRQ_HANDLED;
}
static int __init dc_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct dc_rtc *rtc;
int irq, ret;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rtc->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtc->regs))
return PTR_ERR(rtc->regs);
rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
ret = devm_request_irq(&pdev->dev, irq, dc_rtc_irq, 0, pdev->name, rtc);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev->ops = &dc_rtc_ops;
rtc->rtc_dev->range_max = U32_MAX;
return rtc_register_device(rtc->rtc_dev);
}
static const struct of_device_id dc_dt_ids[] = {
{ .compatible = "cnxt,cx92755-rtc" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, dc_dt_ids);
static struct platform_driver dc_rtc_driver = {
.driver = {
.name = "digicolor_rtc",
.of_match_table = of_match_ptr(dc_dt_ids),
},
};
module_platform_driver_probe(dc_rtc_driver, dc_rtc_probe);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Conexant Digicolor Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
|
