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
35 struct bbnsm_rtc {
36 struct rtc_device *rtc;
37 struct regmap *regmap;
38 int irq;
39 struct clk *clk;
40 };
41
bbnsm_read_counter(struct bbnsm_rtc * bbnsm)42 static 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
bbnsm_rtc_read_time(struct device * dev,struct rtc_time * tm)62 static 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
bbnsm_rtc_set_time(struct device * dev,struct rtc_time * tm)78 static 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
bbnsm_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)96 static 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
bbnsm_rtc_alarm_irq_enable(struct device * dev,unsigned int enable)110 static 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
bbnsm_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)122 static 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
136 static 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
bbnsm_rtc_irq_handler(int irq,void * dev_id)144 static 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
bbnsm_rtc_probe(struct platform_device * pdev)163 static 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
209 static const struct of_device_id bbnsm_dt_ids[] = {
210 { .compatible = "nxp,imx93-bbnsm-rtc" },
211 { /* sentinel */ },
212 };
213 MODULE_DEVICE_TABLE(of, bbnsm_dt_ids);
214
215 static 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 };
222 module_platform_driver(bbnsm_rtc_driver);
223
224 MODULE_AUTHOR("Jacky Bai <ping.bai@nxp.com>");
225 MODULE_DESCRIPTION("NXP BBNSM RTC Driver");
226 MODULE_LICENSE("GPL");
227