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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
4 *
5 * Copyright (C) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
6 */
7
8/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
9 * crystal. Counter 0, which keeps counting during sleep/powerdown, is
10 * used to count seconds since the beginning of the unix epoch.
11 *
12 * The counters must be configured and enabled by bootloader/board code;
13 * no checks as to whether they really get a proper 32.768kHz clock are
14 * made as this would take far too long.
15 */
16
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/rtc.h>
20#include <linux/init.h>
21#include <linux/platform_device.h>
22#include <linux/io.h>
23#include <asm/mach-au1x00/au1000.h>
24
25/* 32kHz clock enabled and detected */
26#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
27
28static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
29{
30 unsigned long t;
31
32 t = alchemy_rdsys(AU1000_SYS_TOYREAD);
33
34 rtc_time64_to_tm(t, tm);
35
36 return 0;
37}
38
39static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
40{
41 unsigned long t;
42
43 t = rtc_tm_to_time64(tm);
44
45 alchemy_wrsys(t, AU1000_SYS_TOYWRITE);
46
47 /* wait for the pending register write to succeed. This can
48 * take up to 6 seconds...
49 */
50 while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
51 msleep(1);
52
53 return 0;
54}
55
56static const struct rtc_class_ops au1xtoy_rtc_ops = {
57 .read_time = au1xtoy_rtc_read_time,
58 .set_time = au1xtoy_rtc_set_time,
59};
60
61static int au1xtoy_rtc_probe(struct platform_device *pdev)
62{
63 struct rtc_device *rtcdev;
64 unsigned long t;
65
66 t = alchemy_rdsys(AU1000_SYS_CNTRCTRL);
67 if (!(t & CNTR_OK)) {
68 dev_err(&pdev->dev, "counters not working; aborting.\n");
69 return -ENODEV;
70 }
71
72 /* set counter0 tickrate to 1Hz if necessary */
73 if (alchemy_rdsys(AU1000_SYS_TOYTRIM) != 32767) {
74 /* wait until hardware gives access to TRIM register */
75 t = 0x00100000;
76 while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T0S) && --t)
77 msleep(1);
78
79 if (!t) {
80 /* timed out waiting for register access; assume
81 * counters are unusable.
82 */
83 dev_err(&pdev->dev, "timeout waiting for access\n");
84 return -ETIMEDOUT;
85 }
86
87 /* set 1Hz TOY tick rate */
88 alchemy_wrsys(32767, AU1000_SYS_TOYTRIM);
89 }
90
91 /* wait until the hardware allows writes to the counter reg */
92 while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
93 msleep(1);
94
95 rtcdev = devm_rtc_allocate_device(&pdev->dev);
96 if (IS_ERR(rtcdev))
97 return PTR_ERR(rtcdev);
98
99 rtcdev->ops = &au1xtoy_rtc_ops;
100 rtcdev->range_max = U32_MAX;
101
102 platform_set_drvdata(pdev, rtcdev);
103
104 return devm_rtc_register_device(rtcdev);
105}
106
107static struct platform_driver au1xrtc_driver = {
108 .driver = {
109 .name = "rtc-au1xxx",
110 },
111};
112
113module_platform_driver_probe(au1xrtc_driver, au1xtoy_rtc_probe);
114
115MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
116MODULE_AUTHOR("Manuel Lauss <manuel.lauss@gmail.com>");
117MODULE_LICENSE("GPL");
118MODULE_ALIAS("platform:rtc-au1xxx");
1/*
2 * Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
3 *
4 * Copyright (C) 2008 Manuel Lauss <mano@roarinelk.homelinux.net>
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
12 * crystal. Counter 0, which keeps counting during sleep/powerdown, is
13 * used to count seconds since the beginning of the unix epoch.
14 *
15 * The counters must be configured and enabled by bootloader/board code;
16 * no checks as to whether they really get a proper 32.768kHz clock are
17 * made as this would take far too long.
18 */
19
20#include <linux/module.h>
21#include <linux/kernel.h>
22#include <linux/rtc.h>
23#include <linux/init.h>
24#include <linux/platform_device.h>
25#include <linux/io.h>
26#include <asm/mach-au1x00/au1000.h>
27
28/* 32kHz clock enabled and detected */
29#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
30
31static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
32{
33 unsigned long t;
34
35 t = alchemy_rdsys(AU1000_SYS_TOYREAD);
36
37 rtc_time_to_tm(t, tm);
38
39 return 0;
40}
41
42static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
43{
44 unsigned long t;
45
46 rtc_tm_to_time(tm, &t);
47
48 alchemy_wrsys(t, AU1000_SYS_TOYWRITE);
49
50 /* wait for the pending register write to succeed. This can
51 * take up to 6 seconds...
52 */
53 while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
54 msleep(1);
55
56 return 0;
57}
58
59static const struct rtc_class_ops au1xtoy_rtc_ops = {
60 .read_time = au1xtoy_rtc_read_time,
61 .set_time = au1xtoy_rtc_set_time,
62};
63
64static int au1xtoy_rtc_probe(struct platform_device *pdev)
65{
66 struct rtc_device *rtcdev;
67 unsigned long t;
68 int ret;
69
70 t = alchemy_rdsys(AU1000_SYS_CNTRCTRL);
71 if (!(t & CNTR_OK)) {
72 dev_err(&pdev->dev, "counters not working; aborting.\n");
73 ret = -ENODEV;
74 goto out_err;
75 }
76
77 ret = -ETIMEDOUT;
78
79 /* set counter0 tickrate to 1Hz if necessary */
80 if (alchemy_rdsys(AU1000_SYS_TOYTRIM) != 32767) {
81 /* wait until hardware gives access to TRIM register */
82 t = 0x00100000;
83 while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T0S) && --t)
84 msleep(1);
85
86 if (!t) {
87 /* timed out waiting for register access; assume
88 * counters are unusable.
89 */
90 dev_err(&pdev->dev, "timeout waiting for access\n");
91 goto out_err;
92 }
93
94 /* set 1Hz TOY tick rate */
95 alchemy_wrsys(32767, AU1000_SYS_TOYTRIM);
96 }
97
98 /* wait until the hardware allows writes to the counter reg */
99 while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
100 msleep(1);
101
102 rtcdev = devm_rtc_device_register(&pdev->dev, "rtc-au1xxx",
103 &au1xtoy_rtc_ops, THIS_MODULE);
104 if (IS_ERR(rtcdev)) {
105 ret = PTR_ERR(rtcdev);
106 goto out_err;
107 }
108
109 platform_set_drvdata(pdev, rtcdev);
110
111 return 0;
112
113out_err:
114 return ret;
115}
116
117static struct platform_driver au1xrtc_driver = {
118 .driver = {
119 .name = "rtc-au1xxx",
120 },
121};
122
123module_platform_driver_probe(au1xrtc_driver, au1xtoy_rtc_probe);
124
125MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
126MODULE_AUTHOR("Manuel Lauss <manuel.lauss@gmail.com>");
127MODULE_LICENSE("GPL");
128MODULE_ALIAS("platform:rtc-au1xxx");