1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * TX4939 internal RTC driver
4 * Based on RBTX49xx patch from CELF patch archive.
5 *
6 * (C) Copyright TOSHIBA CORPORATION 2005-2007
7 */
8 #include <linux/rtc.h>
9 #include <linux/platform_device.h>
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
12 #include <linux/io.h>
13 #include <linux/gfp.h>
14
15 #define TX4939_RTCCTL_ALME 0x00000080
16 #define TX4939_RTCCTL_ALMD 0x00000040
17 #define TX4939_RTCCTL_BUSY 0x00000020
18
19 #define TX4939_RTCCTL_COMMAND 0x00000007
20 #define TX4939_RTCCTL_COMMAND_NOP 0x00000000
21 #define TX4939_RTCCTL_COMMAND_GETTIME 0x00000001
22 #define TX4939_RTCCTL_COMMAND_SETTIME 0x00000002
23 #define TX4939_RTCCTL_COMMAND_GETALARM 0x00000003
24 #define TX4939_RTCCTL_COMMAND_SETALARM 0x00000004
25
26 #define TX4939_RTCTBC_PM 0x00000080
27 #define TX4939_RTCTBC_COMP 0x0000007f
28
29 #define TX4939_RTC_REG_RAMSIZE 0x00000100
30 #define TX4939_RTC_REG_RWBSIZE 0x00000006
31
32 struct tx4939_rtc_reg {
33 __u32 ctl;
34 __u32 adr;
35 __u32 dat;
36 __u32 tbc;
37 };
38
39 struct tx4939rtc_plat_data {
40 struct rtc_device *rtc;
41 struct tx4939_rtc_reg __iomem *rtcreg;
42 spinlock_t lock;
43 };
44
tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem * rtcreg,int cmd)45 static int tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem *rtcreg, int cmd)
46 {
47 int i = 0;
48
49 __raw_writel(cmd, &rtcreg->ctl);
50 /* This might take 30us (next 32.768KHz clock) */
51 while (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_BUSY) {
52 /* timeout on approx. 100us (@ GBUS200MHz) */
53 if (i++ > 200 * 100)
54 return -EBUSY;
55 cpu_relax();
56 }
57 return 0;
58 }
59
tx4939_rtc_set_time(struct device * dev,struct rtc_time * tm)60 static int tx4939_rtc_set_time(struct device *dev, struct rtc_time *tm)
61 {
62 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
63 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
64 unsigned long secs = rtc_tm_to_time64(tm);
65 int i, ret;
66 unsigned char buf[6];
67
68 buf[0] = 0;
69 buf[1] = 0;
70 buf[2] = secs;
71 buf[3] = secs >> 8;
72 buf[4] = secs >> 16;
73 buf[5] = secs >> 24;
74 spin_lock_irq(&pdata->lock);
75 __raw_writel(0, &rtcreg->adr);
76 for (i = 0; i < 6; i++)
77 __raw_writel(buf[i], &rtcreg->dat);
78 ret = tx4939_rtc_cmd(rtcreg,
79 TX4939_RTCCTL_COMMAND_SETTIME |
80 (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
81 spin_unlock_irq(&pdata->lock);
82 return ret;
83 }
84
tx4939_rtc_read_time(struct device * dev,struct rtc_time * tm)85 static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
86 {
87 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
88 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
89 int i, ret;
90 unsigned long sec;
91 unsigned char buf[6];
92
93 spin_lock_irq(&pdata->lock);
94 ret = tx4939_rtc_cmd(rtcreg,
95 TX4939_RTCCTL_COMMAND_GETTIME |
96 (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
97 if (ret) {
98 spin_unlock_irq(&pdata->lock);
99 return ret;
100 }
101 __raw_writel(2, &rtcreg->adr);
102 for (i = 2; i < 6; i++)
103 buf[i] = __raw_readl(&rtcreg->dat);
104 spin_unlock_irq(&pdata->lock);
105 sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
106 (buf[3] << 8) | buf[2];
107 rtc_time64_to_tm(sec, tm);
108 return 0;
109 }
110
tx4939_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)111 static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
112 {
113 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
114 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
115 int i, ret;
116 unsigned long sec;
117 unsigned char buf[6];
118
119 sec = rtc_tm_to_time64(&alrm->time);
120 buf[0] = 0;
121 buf[1] = 0;
122 buf[2] = sec;
123 buf[3] = sec >> 8;
124 buf[4] = sec >> 16;
125 buf[5] = sec >> 24;
126 spin_lock_irq(&pdata->lock);
127 __raw_writel(0, &rtcreg->adr);
128 for (i = 0; i < 6; i++)
129 __raw_writel(buf[i], &rtcreg->dat);
130 ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
131 (alrm->enabled ? TX4939_RTCCTL_ALME : 0));
132 spin_unlock_irq(&pdata->lock);
133 return ret;
134 }
135
tx4939_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)136 static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
137 {
138 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
139 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
140 int i, ret;
141 unsigned long sec;
142 unsigned char buf[6];
143 u32 ctl;
144
145 spin_lock_irq(&pdata->lock);
146 ret = tx4939_rtc_cmd(rtcreg,
147 TX4939_RTCCTL_COMMAND_GETALARM |
148 (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
149 if (ret) {
150 spin_unlock_irq(&pdata->lock);
151 return ret;
152 }
153 __raw_writel(2, &rtcreg->adr);
154 for (i = 2; i < 6; i++)
155 buf[i] = __raw_readl(&rtcreg->dat);
156 ctl = __raw_readl(&rtcreg->ctl);
157 alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
158 alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
159 spin_unlock_irq(&pdata->lock);
160 sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
161 (buf[3] << 8) | buf[2];
162 rtc_time64_to_tm(sec, &alrm->time);
163 return rtc_valid_tm(&alrm->time);
164 }
165
tx4939_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)166 static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
167 {
168 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
169
170 spin_lock_irq(&pdata->lock);
171 tx4939_rtc_cmd(pdata->rtcreg,
172 TX4939_RTCCTL_COMMAND_NOP |
173 (enabled ? TX4939_RTCCTL_ALME : 0));
174 spin_unlock_irq(&pdata->lock);
175 return 0;
176 }
177
tx4939_rtc_interrupt(int irq,void * dev_id)178 static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
179 {
180 struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev_id);
181 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
182 unsigned long events = RTC_IRQF;
183
184 spin_lock(&pdata->lock);
185 if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
186 events |= RTC_AF;
187 tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
188 }
189 spin_unlock(&pdata->lock);
190 rtc_update_irq(pdata->rtc, 1, events);
191
192 return IRQ_HANDLED;
193 }
194
195 static const struct rtc_class_ops tx4939_rtc_ops = {
196 .read_time = tx4939_rtc_read_time,
197 .read_alarm = tx4939_rtc_read_alarm,
198 .set_alarm = tx4939_rtc_set_alarm,
199 .set_time = tx4939_rtc_set_time,
200 .alarm_irq_enable = tx4939_rtc_alarm_irq_enable,
201 };
202
tx4939_nvram_read(void * priv,unsigned int pos,void * val,size_t bytes)203 static int tx4939_nvram_read(void *priv, unsigned int pos, void *val,
204 size_t bytes)
205 {
206 struct tx4939rtc_plat_data *pdata = priv;
207 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
208 u8 *buf = val;
209
210 spin_lock_irq(&pdata->lock);
211 for (; bytes; bytes--) {
212 __raw_writel(pos++, &rtcreg->adr);
213 *buf++ = __raw_readl(&rtcreg->dat);
214 }
215 spin_unlock_irq(&pdata->lock);
216 return 0;
217 }
218
tx4939_nvram_write(void * priv,unsigned int pos,void * val,size_t bytes)219 static int tx4939_nvram_write(void *priv, unsigned int pos, void *val,
220 size_t bytes)
221 {
222 struct tx4939rtc_plat_data *pdata = priv;
223 struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
224 u8 *buf = val;
225
226 spin_lock_irq(&pdata->lock);
227 for (; bytes; bytes--) {
228 __raw_writel(pos++, &rtcreg->adr);
229 __raw_writel(*buf++, &rtcreg->dat);
230 }
231 spin_unlock_irq(&pdata->lock);
232 return 0;
233 }
234
tx4939_rtc_probe(struct platform_device * pdev)235 static int __init tx4939_rtc_probe(struct platform_device *pdev)
236 {
237 struct rtc_device *rtc;
238 struct tx4939rtc_plat_data *pdata;
239 int irq, ret;
240 struct nvmem_config nvmem_cfg = {
241 .name = "tx4939_nvram",
242 .size = TX4939_RTC_REG_RAMSIZE,
243 .reg_read = tx4939_nvram_read,
244 .reg_write = tx4939_nvram_write,
245 };
246
247 irq = platform_get_irq(pdev, 0);
248 if (irq < 0)
249 return -ENODEV;
250 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
251 if (!pdata)
252 return -ENOMEM;
253 platform_set_drvdata(pdev, pdata);
254
255 pdata->rtcreg = devm_platform_ioremap_resource(pdev, 0);
256 if (IS_ERR(pdata->rtcreg))
257 return PTR_ERR(pdata->rtcreg);
258
259 spin_lock_init(&pdata->lock);
260 tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
261 if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
262 0, pdev->name, &pdev->dev) < 0)
263 return -EBUSY;
264 rtc = devm_rtc_allocate_device(&pdev->dev);
265 if (IS_ERR(rtc))
266 return PTR_ERR(rtc);
267
268 rtc->ops = &tx4939_rtc_ops;
269 rtc->nvram_old_abi = true;
270 rtc->range_max = U32_MAX;
271
272 pdata->rtc = rtc;
273
274 nvmem_cfg.priv = pdata;
275 ret = rtc_nvmem_register(rtc, &nvmem_cfg);
276 if (ret)
277 return ret;
278
279 return rtc_register_device(rtc);
280 }
281
tx4939_rtc_remove(struct platform_device * pdev)282 static int __exit tx4939_rtc_remove(struct platform_device *pdev)
283 {
284 struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
285
286 spin_lock_irq(&pdata->lock);
287 tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
288 spin_unlock_irq(&pdata->lock);
289 return 0;
290 }
291
292 static struct platform_driver tx4939_rtc_driver = {
293 .remove = __exit_p(tx4939_rtc_remove),
294 .driver = {
295 .name = "tx4939rtc",
296 },
297 };
298
299 module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
300
301 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
302 MODULE_DESCRIPTION("TX4939 internal RTC driver");
303 MODULE_LICENSE("GPL v2");
304 MODULE_ALIAS("platform:tx4939rtc");
305