1 /*
2 * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
3 *
4 * Copyright (C) 2015 Xilinx, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program. If not, see <http://www.gnu.org/licenses/>.
17 *
18 */
19
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/io.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/platform_device.h>
26 #include <linux/rtc.h>
27
28 /* RTC Registers */
29 #define RTC_SET_TM_WR 0x00
30 #define RTC_SET_TM_RD 0x04
31 #define RTC_CALIB_WR 0x08
32 #define RTC_CALIB_RD 0x0C
33 #define RTC_CUR_TM 0x10
34 #define RTC_CUR_TICK 0x14
35 #define RTC_ALRM 0x18
36 #define RTC_INT_STS 0x20
37 #define RTC_INT_MASK 0x24
38 #define RTC_INT_EN 0x28
39 #define RTC_INT_DIS 0x2C
40 #define RTC_CTRL 0x40
41
42 #define RTC_FR_EN BIT(20)
43 #define RTC_FR_DATSHIFT 16
44 #define RTC_TICK_MASK 0xFFFF
45 #define RTC_INT_SEC BIT(0)
46 #define RTC_INT_ALRM BIT(1)
47 #define RTC_OSC_EN BIT(24)
48
49 #define RTC_CALIB_DEF 0x198233
50 #define RTC_CALIB_MASK 0x1FFFFF
51 #define RTC_SEC_MAX_VAL 0xFFFFFFFF
52
53 struct xlnx_rtc_dev {
54 struct rtc_device *rtc;
55 void __iomem *reg_base;
56 int alarm_irq;
57 int sec_irq;
58 };
59
xlnx_rtc_set_time(struct device * dev,struct rtc_time * tm)60 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
61 {
62 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
63 unsigned long new_time;
64
65 new_time = rtc_tm_to_time64(tm);
66
67 if (new_time > RTC_SEC_MAX_VAL)
68 return -EINVAL;
69
70 writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
71
72 return 0;
73 }
74
xlnx_rtc_read_time(struct device * dev,struct rtc_time * tm)75 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
76 {
77 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
78
79 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
80
81 return rtc_valid_tm(tm);
82 }
83
xlnx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)84 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
85 {
86 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
87
88 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
89 alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
90
91 return 0;
92 }
93
xlnx_rtc_alarm_irq_enable(struct device * dev,u32 enabled)94 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
95 {
96 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
97
98 if (enabled)
99 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
100 else
101 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
102
103 return 0;
104 }
105
xlnx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)106 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
107 {
108 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
109 unsigned long alarm_time;
110
111 alarm_time = rtc_tm_to_time64(&alrm->time);
112
113 if (alarm_time > RTC_SEC_MAX_VAL)
114 return -EINVAL;
115
116 writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
117
118 xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
119
120 return 0;
121 }
122
xlnx_init_rtc(struct xlnx_rtc_dev * xrtcdev,u32 calibval)123 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev, u32 calibval)
124 {
125 /*
126 * Based on crystal freq of 33.330 KHz
127 * set the seconds counter and enable, set fractions counter
128 * to default value suggested as per design spec
129 * to correct RTC delay in frequency over period of time.
130 */
131 calibval &= RTC_CALIB_MASK;
132 writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
133 }
134
135 static const struct rtc_class_ops xlnx_rtc_ops = {
136 .set_time = xlnx_rtc_set_time,
137 .read_time = xlnx_rtc_read_time,
138 .read_alarm = xlnx_rtc_read_alarm,
139 .set_alarm = xlnx_rtc_set_alarm,
140 .alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
141 };
142
xlnx_rtc_interrupt(int irq,void * id)143 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
144 {
145 struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
146 unsigned int status;
147
148 status = readl(xrtcdev->reg_base + RTC_INT_STS);
149 /* Check if interrupt asserted */
150 if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
151 return IRQ_NONE;
152
153 /* Clear interrupt */
154 writel(status, xrtcdev->reg_base + RTC_INT_STS);
155
156 if (status & RTC_INT_SEC)
157 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_UF);
158 if (status & RTC_INT_ALRM)
159 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
160
161 return IRQ_HANDLED;
162 }
163
xlnx_rtc_probe(struct platform_device * pdev)164 static int xlnx_rtc_probe(struct platform_device *pdev)
165 {
166 struct xlnx_rtc_dev *xrtcdev;
167 struct resource *res;
168 int ret;
169 unsigned int calibvalue;
170
171 xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
172 if (!xrtcdev)
173 return -ENOMEM;
174
175 platform_set_drvdata(pdev, xrtcdev);
176
177 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
178
179 xrtcdev->reg_base = devm_ioremap_resource(&pdev->dev, res);
180 if (IS_ERR(xrtcdev->reg_base))
181 return PTR_ERR(xrtcdev->reg_base);
182
183 xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
184 if (xrtcdev->alarm_irq < 0) {
185 dev_err(&pdev->dev, "no irq resource\n");
186 return xrtcdev->alarm_irq;
187 }
188 ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
189 xlnx_rtc_interrupt, 0,
190 dev_name(&pdev->dev), xrtcdev);
191 if (ret) {
192 dev_err(&pdev->dev, "request irq failed\n");
193 return ret;
194 }
195
196 xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
197 if (xrtcdev->sec_irq < 0) {
198 dev_err(&pdev->dev, "no irq resource\n");
199 return xrtcdev->sec_irq;
200 }
201 ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
202 xlnx_rtc_interrupt, 0,
203 dev_name(&pdev->dev), xrtcdev);
204 if (ret) {
205 dev_err(&pdev->dev, "request irq failed\n");
206 return ret;
207 }
208
209 ret = of_property_read_u32(pdev->dev.of_node, "calibration",
210 &calibvalue);
211 if (ret)
212 calibvalue = RTC_CALIB_DEF;
213
214 xlnx_init_rtc(xrtcdev, calibvalue);
215
216 device_init_wakeup(&pdev->dev, 1);
217
218 xrtcdev->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
219 &xlnx_rtc_ops, THIS_MODULE);
220 return PTR_ERR_OR_ZERO(xrtcdev->rtc);
221 }
222
xlnx_rtc_remove(struct platform_device * pdev)223 static int xlnx_rtc_remove(struct platform_device *pdev)
224 {
225 xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
226 device_init_wakeup(&pdev->dev, 0);
227
228 return 0;
229 }
230
xlnx_rtc_suspend(struct device * dev)231 static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
232 {
233 struct platform_device *pdev = to_platform_device(dev);
234 struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
235
236 if (device_may_wakeup(&pdev->dev))
237 enable_irq_wake(xrtcdev->alarm_irq);
238 else
239 xlnx_rtc_alarm_irq_enable(dev, 0);
240
241 return 0;
242 }
243
xlnx_rtc_resume(struct device * dev)244 static int __maybe_unused xlnx_rtc_resume(struct device *dev)
245 {
246 struct platform_device *pdev = to_platform_device(dev);
247 struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
248
249 if (device_may_wakeup(&pdev->dev))
250 disable_irq_wake(xrtcdev->alarm_irq);
251 else
252 xlnx_rtc_alarm_irq_enable(dev, 1);
253
254 return 0;
255 }
256
257 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
258
259 static const struct of_device_id xlnx_rtc_of_match[] = {
260 {.compatible = "xlnx,zynqmp-rtc" },
261 { }
262 };
263 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
264
265 static struct platform_driver xlnx_rtc_driver = {
266 .probe = xlnx_rtc_probe,
267 .remove = xlnx_rtc_remove,
268 .driver = {
269 .name = KBUILD_MODNAME,
270 .pm = &xlnx_rtc_pm_ops,
271 .of_match_table = xlnx_rtc_of_match,
272 },
273 };
274
275 module_platform_driver(xlnx_rtc_driver);
276
277 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
278 MODULE_AUTHOR("Xilinx Inc.");
279 MODULE_LICENSE("GPL v2");
280