xref: /openbmc/linux/drivers/rtc/rtc-ftrtc010.c (revision 43eeb707)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Faraday Technology FTRTC010 driver
4  *
5  *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
6  *
7  * Original code for older kernel 2.6.15 are from Stormlinksemi
8  * first update from Janos Laube for > 2.6.29 kernels
9  *
10  * checkpatch fixes and usage of rtc-lib code
11  * Hans Ulli Kroll <ulli.kroll@googlemail.com>
12  */
13 
14 #include <linux/rtc.h>
15 #include <linux/io.h>
16 #include <linux/slab.h>
17 #include <linux/platform_device.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/mod_devicetable.h>
21 #include <linux/clk.h>
22 
23 #define DRV_NAME        "rtc-ftrtc010"
24 
25 MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
26 MODULE_DESCRIPTION("RTC driver for Gemini SoC");
27 MODULE_LICENSE("GPL");
28 MODULE_ALIAS("platform:" DRV_NAME);
29 
30 struct ftrtc010_rtc {
31 	struct rtc_device	*rtc_dev;
32 	void __iomem		*rtc_base;
33 	int			rtc_irq;
34 	struct clk		*pclk;
35 	struct clk		*extclk;
36 };
37 
38 enum ftrtc010_rtc_offsets {
39 	FTRTC010_RTC_SECOND		= 0x00,
40 	FTRTC010_RTC_MINUTE		= 0x04,
41 	FTRTC010_RTC_HOUR		= 0x08,
42 	FTRTC010_RTC_DAYS		= 0x0C,
43 	FTRTC010_RTC_ALARM_SECOND	= 0x10,
44 	FTRTC010_RTC_ALARM_MINUTE	= 0x14,
45 	FTRTC010_RTC_ALARM_HOUR		= 0x18,
46 	FTRTC010_RTC_RECORD		= 0x1C,
47 	FTRTC010_RTC_CR			= 0x20,
48 };
49 
ftrtc010_rtc_interrupt(int irq,void * dev)50 static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
51 {
52 	return IRQ_HANDLED;
53 }
54 
55 /*
56  * Looks like the RTC in the Gemini SoC is (totaly) broken
57  * We can't read/write directly the time from RTC registers.
58  * We must do some "offset" calculation to get the real time
59  *
60  * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
61  * the same thing, without the rtc-lib.c calls.
62  */
63 
ftrtc010_rtc_read_time(struct device * dev,struct rtc_time * tm)64 static int ftrtc010_rtc_read_time(struct device *dev, struct rtc_time *tm)
65 {
66 	struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
67 
68 	u32 days, hour, min, sec, offset;
69 	timeu64_t time;
70 
71 	sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
72 	min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
73 	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
74 	days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
75 	offset = readl(rtc->rtc_base + FTRTC010_RTC_RECORD);
76 
77 	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
78 
79 	rtc_time64_to_tm(time, tm);
80 
81 	return 0;
82 }
83 
ftrtc010_rtc_set_time(struct device * dev,struct rtc_time * tm)84 static int ftrtc010_rtc_set_time(struct device *dev, struct rtc_time *tm)
85 {
86 	struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
87 	u32 sec, min, hour, day, offset;
88 	timeu64_t time;
89 
90 	time = rtc_tm_to_time64(tm);
91 
92 	sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
93 	min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
94 	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
95 	day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
96 
97 	offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
98 
99 	writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
100 	writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
101 
102 	return 0;
103 }
104 
105 static const struct rtc_class_ops ftrtc010_rtc_ops = {
106 	.read_time     = ftrtc010_rtc_read_time,
107 	.set_time      = ftrtc010_rtc_set_time,
108 };
109 
ftrtc010_rtc_probe(struct platform_device * pdev)110 static int ftrtc010_rtc_probe(struct platform_device *pdev)
111 {
112 	u32 days, hour, min, sec;
113 	struct ftrtc010_rtc *rtc;
114 	struct device *dev = &pdev->dev;
115 	struct resource *res;
116 	int ret;
117 
118 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
119 	if (unlikely(!rtc))
120 		return -ENOMEM;
121 	platform_set_drvdata(pdev, rtc);
122 
123 	rtc->pclk = devm_clk_get(dev, "PCLK");
124 	if (IS_ERR(rtc->pclk)) {
125 		dev_err(dev, "could not get PCLK\n");
126 	} else {
127 		ret = clk_prepare_enable(rtc->pclk);
128 		if (ret) {
129 			dev_err(dev, "failed to enable PCLK\n");
130 			return ret;
131 		}
132 	}
133 	rtc->extclk = devm_clk_get(dev, "EXTCLK");
134 	if (IS_ERR(rtc->extclk)) {
135 		dev_err(dev, "could not get EXTCLK\n");
136 	} else {
137 		ret = clk_prepare_enable(rtc->extclk);
138 		if (ret) {
139 			dev_err(dev, "failed to enable EXTCLK\n");
140 			goto err_disable_pclk;
141 		}
142 	}
143 
144 	rtc->rtc_irq = platform_get_irq(pdev, 0);
145 	if (rtc->rtc_irq < 0) {
146 		ret = rtc->rtc_irq;
147 		goto err_disable_extclk;
148 	}
149 
150 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151 	if (!res) {
152 		ret = -ENODEV;
153 		goto err_disable_extclk;
154 	}
155 
156 	rtc->rtc_base = devm_ioremap(dev, res->start,
157 				     resource_size(res));
158 	if (!rtc->rtc_base) {
159 		ret = -ENOMEM;
160 		goto err_disable_extclk;
161 	}
162 
163 	rtc->rtc_dev = devm_rtc_allocate_device(dev);
164 	if (IS_ERR(rtc->rtc_dev)) {
165 		ret = PTR_ERR(rtc->rtc_dev);
166 		goto err_disable_extclk;
167 	}
168 
169 	rtc->rtc_dev->ops = &ftrtc010_rtc_ops;
170 
171 	sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
172 	min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
173 	hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
174 	days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
175 
176 	rtc->rtc_dev->range_min = (u64)days * 86400 + hour * 3600 +
177 				  min * 60 + sec;
178 	rtc->rtc_dev->range_max = U32_MAX + rtc->rtc_dev->range_min;
179 
180 	ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
181 			       IRQF_SHARED, pdev->name, dev);
182 	if (unlikely(ret))
183 		goto err_disable_extclk;
184 
185 	return devm_rtc_register_device(rtc->rtc_dev);
186 
187 err_disable_extclk:
188 	clk_disable_unprepare(rtc->extclk);
189 err_disable_pclk:
190 	clk_disable_unprepare(rtc->pclk);
191 	return ret;
192 }
193 
ftrtc010_rtc_remove(struct platform_device * pdev)194 static void ftrtc010_rtc_remove(struct platform_device *pdev)
195 {
196 	struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
197 
198 	if (!IS_ERR(rtc->extclk))
199 		clk_disable_unprepare(rtc->extclk);
200 	if (!IS_ERR(rtc->pclk))
201 		clk_disable_unprepare(rtc->pclk);
202 }
203 
204 static const struct of_device_id ftrtc010_rtc_dt_match[] = {
205 	{ .compatible = "cortina,gemini-rtc" },
206 	{ .compatible = "faraday,ftrtc010" },
207 	{ }
208 };
209 MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
210 
211 static struct platform_driver ftrtc010_rtc_driver = {
212 	.driver		= {
213 		.name	= DRV_NAME,
214 		.of_match_table = ftrtc010_rtc_dt_match,
215 	},
216 	.probe		= ftrtc010_rtc_probe,
217 	.remove_new	= ftrtc010_rtc_remove,
218 };
219 
220 module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);
221