1// SPDX-License-Identifier: GPL-2.0+
2//
3// Copyright 2022 NXP.
4
5#include <linux/init.h>
6#include <linux/io.h>
7#include <linux/kernel.h>
8#include <linux/mfd/syscon.h>
9#include <linux/module.h>
10#include <linux/of.h>
11#include <linux/platform_device.h>
12#include <linux/pm_wakeirq.h>
13#include <linux/regmap.h>
14#include <linux/rtc.h>
15
16#define BBNSM_CTRL	0x8
17#define BBNSM_INT_EN	0x10
18#define BBNSM_EVENTS	0x14
19#define BBNSM_RTC_LS	0x40
20#define BBNSM_RTC_MS	0x44
21#define BBNSM_TA	0x50
22
23#define RTC_EN		0x2
24#define RTC_EN_MSK	0x3
25#define TA_EN		(0x2 << 2)
26#define TA_DIS		(0x1 << 2)
27#define TA_EN_MSK	(0x3 << 2)
28#define RTC_INT_EN	0x2
29#define TA_INT_EN	(0x2 << 2)
30
31#define BBNSM_EVENT_TA	(0x2 << 2)
32
33#define CNTR_TO_SECS_SH	15
34
35struct bbnsm_rtc {
36	struct rtc_device *rtc;
37	struct regmap *regmap;
38	int irq;
39	struct clk *clk;
40};
41
42static u32 bbnsm_read_counter(struct bbnsm_rtc *bbnsm)
43{
44	u32 rtc_msb, rtc_lsb;
45	unsigned int timeout = 100;
46	u32 time;
47	u32 tmp = 0;
48
49	do {
50		time = tmp;
51		/* read the msb */
52		regmap_read(bbnsm->regmap, BBNSM_RTC_MS, &rtc_msb);
53		/* read the lsb */
54		regmap_read(bbnsm->regmap, BBNSM_RTC_LS, &rtc_lsb);
55		/* convert to seconds */
56		tmp = (rtc_msb << 17) | (rtc_lsb >> 15);
57	} while (tmp != time && --timeout);
58
59	return time;
60}
61
62static int bbnsm_rtc_read_time(struct device *dev, struct rtc_time *tm)
63{
64	struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
65	unsigned long time;
66	u32 val;
67
68	regmap_read(bbnsm->regmap, BBNSM_CTRL, &val);
69	if ((val & RTC_EN_MSK) != RTC_EN)
70		return -EINVAL;
71
72	time = bbnsm_read_counter(bbnsm);
73	rtc_time64_to_tm(time, tm);
74
75	return 0;
76}
77
78static int bbnsm_rtc_set_time(struct device *dev, struct rtc_time *tm)
79{
80	struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
81	unsigned long time = rtc_tm_to_time64(tm);
82
83	/* disable the RTC first */
84	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, 0);
85
86	/* write the 32bit sec time to 47 bit timer counter, leaving 15 LSBs blank */
87	regmap_write(bbnsm->regmap, BBNSM_RTC_LS, time << CNTR_TO_SECS_SH);
88	regmap_write(bbnsm->regmap, BBNSM_RTC_MS, time >> (32 - CNTR_TO_SECS_SH));
89
90	/* Enable the RTC again */
91	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, RTC_EN_MSK, RTC_EN);
92
93	return 0;
94}
95
96static int bbnsm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
97{
98	struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
99	u32 bbnsm_events, bbnsm_ta;
100
101	regmap_read(bbnsm->regmap, BBNSM_TA, &bbnsm_ta);
102	rtc_time64_to_tm(bbnsm_ta, &alrm->time);
103
104	regmap_read(bbnsm->regmap, BBNSM_EVENTS, &bbnsm_events);
105	alrm->pending = (bbnsm_events & BBNSM_EVENT_TA) ? 1 : 0;
106
107	return 0;
108}
109
110static int bbnsm_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
111{
112	struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
113
114	/* enable the alarm event */
115	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN_MSK, enable ? TA_EN : TA_DIS);
116	/* enable the alarm interrupt */
117	regmap_update_bits(bbnsm->regmap, BBNSM_INT_EN, TA_EN_MSK, enable ? TA_EN : TA_DIS);
118
119	return 0;
120}
121
122static int bbnsm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
123{
124	struct bbnsm_rtc *bbnsm = dev_get_drvdata(dev);
125	unsigned long time = rtc_tm_to_time64(&alrm->time);
126
127	/* disable the alarm */
128	regmap_update_bits(bbnsm->regmap, BBNSM_CTRL, TA_EN, TA_EN);
129
130	/* write the seconds to TA */
131	regmap_write(bbnsm->regmap, BBNSM_TA, time);
132
133	return bbnsm_rtc_alarm_irq_enable(dev, alrm->enabled);
134}
135
136static const struct rtc_class_ops bbnsm_rtc_ops = {
137	.read_time = bbnsm_rtc_read_time,
138	.set_time = bbnsm_rtc_set_time,
139	.read_alarm = bbnsm_rtc_read_alarm,
140	.set_alarm = bbnsm_rtc_set_alarm,
141	.alarm_irq_enable = bbnsm_rtc_alarm_irq_enable,
142};
143
144static irqreturn_t bbnsm_rtc_irq_handler(int irq, void *dev_id)
145{
146	struct device *dev = dev_id;
147	struct bbnsm_rtc  *bbnsm = dev_get_drvdata(dev);
148	u32 val;
149
150	regmap_read(bbnsm->regmap, BBNSM_EVENTS, &val);
151	if (val & BBNSM_EVENT_TA) {
152		bbnsm_rtc_alarm_irq_enable(dev, false);
153		/* clear the alarm event */
154		regmap_write_bits(bbnsm->regmap, BBNSM_EVENTS, TA_EN_MSK, BBNSM_EVENT_TA);
155		rtc_update_irq(bbnsm->rtc, 1, RTC_AF | RTC_IRQF);
156
157		return IRQ_HANDLED;
158	}
159
160	return IRQ_NONE;
161}
162
163static int bbnsm_rtc_probe(struct platform_device *pdev)
164{
165	struct device_node *np = pdev->dev.of_node;
166	struct bbnsm_rtc *bbnsm;
167	int ret;
168
169	bbnsm = devm_kzalloc(&pdev->dev, sizeof(*bbnsm), GFP_KERNEL);
170	if (!bbnsm)
171		return -ENOMEM;
172
173	bbnsm->rtc = devm_rtc_allocate_device(&pdev->dev);
174	if (IS_ERR(bbnsm->rtc))
175		return PTR_ERR(bbnsm->rtc);
176
177	bbnsm->regmap = syscon_node_to_regmap(np->parent);
178	if (IS_ERR(bbnsm->regmap)) {
179		dev_dbg(&pdev->dev, "bbnsm get regmap failed\n");
180		return PTR_ERR(bbnsm->regmap);
181	}
182
183	bbnsm->irq = platform_get_irq(pdev, 0);
184	if (bbnsm->irq < 0)
185		return bbnsm->irq;
186
187	platform_set_drvdata(pdev, bbnsm);
188
189	/* clear all the pending events */
190	regmap_write(bbnsm->regmap, BBNSM_EVENTS, 0x7A);
191
192	device_init_wakeup(&pdev->dev, true);
193	dev_pm_set_wake_irq(&pdev->dev, bbnsm->irq);
194
195	ret = devm_request_irq(&pdev->dev, bbnsm->irq, bbnsm_rtc_irq_handler,
196			       IRQF_SHARED, "rtc alarm", &pdev->dev);
197	if (ret) {
198		dev_err(&pdev->dev, "failed to request irq %d: %d\n",
199			bbnsm->irq, ret);
200		return ret;
201	}
202
203	bbnsm->rtc->ops = &bbnsm_rtc_ops;
204	bbnsm->rtc->range_max = U32_MAX;
205
206	return devm_rtc_register_device(bbnsm->rtc);
207}
208
209static const struct of_device_id bbnsm_dt_ids[] = {
210	{ .compatible = "nxp,imx93-bbnsm-rtc" },
211	{ /* sentinel */ },
212};
213MODULE_DEVICE_TABLE(of, bbnsm_dt_ids);
214
215static struct platform_driver bbnsm_rtc_driver = {
216	.driver = {
217		.name = "bbnsm_rtc",
218		.of_match_table = bbnsm_dt_ids,
219	},
220	.probe = bbnsm_rtc_probe,
221};
222module_platform_driver(bbnsm_rtc_driver);
223
224MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
225MODULE_DESCRIPTION("NXP BBNSM RTC Driver");
226MODULE_LICENSE("GPL");
227