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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
32struct tx4939_rtc_reg {
33 __u32 ctl;
34 __u32 adr;
35 __u32 dat;
36 __u32 tbc;
37};
38
39struct tx4939rtc_plat_data {
40 struct rtc_device *rtc;
41 struct tx4939_rtc_reg __iomem *rtcreg;
42 spinlock_t lock;
43};
44
45static 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
60static 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
85static 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
111static 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
136static 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
166static 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
178static 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
195static 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
203static 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
219static 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
235static int __init tx4939_rtc_probe(struct platform_device *pdev)
236{
237 struct rtc_device *rtc;
238 struct tx4939rtc_plat_data *pdata;
239 struct resource *res;
240 int irq, ret;
241 struct nvmem_config nvmem_cfg = {
242 .name = "tx4939_nvram",
243 .size = TX4939_RTC_REG_RAMSIZE,
244 .reg_read = tx4939_nvram_read,
245 .reg_write = tx4939_nvram_write,
246 };
247
248 irq = platform_get_irq(pdev, 0);
249 if (irq < 0)
250 return -ENODEV;
251 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
252 if (!pdata)
253 return -ENOMEM;
254 platform_set_drvdata(pdev, pdata);
255
256 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
257 pdata->rtcreg = devm_ioremap_resource(&pdev->dev, res);
258 if (IS_ERR(pdata->rtcreg))
259 return PTR_ERR(pdata->rtcreg);
260
261 spin_lock_init(&pdata->lock);
262 tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
263 if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
264 0, pdev->name, &pdev->dev) < 0)
265 return -EBUSY;
266 rtc = devm_rtc_allocate_device(&pdev->dev);
267 if (IS_ERR(rtc))
268 return PTR_ERR(rtc);
269
270 rtc->ops = &tx4939_rtc_ops;
271 rtc->nvram_old_abi = true;
272 rtc->range_max = U32_MAX;
273
274 pdata->rtc = rtc;
275
276 nvmem_cfg.priv = pdata;
277 ret = rtc_nvmem_register(rtc, &nvmem_cfg);
278 if (ret)
279 return ret;
280
281 return rtc_register_device(rtc);
282}
283
284static int __exit tx4939_rtc_remove(struct platform_device *pdev)
285{
286 struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
287
288 spin_lock_irq(&pdata->lock);
289 tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
290 spin_unlock_irq(&pdata->lock);
291 return 0;
292}
293
294static struct platform_driver tx4939_rtc_driver = {
295 .remove = __exit_p(tx4939_rtc_remove),
296 .driver = {
297 .name = "tx4939rtc",
298 },
299};
300
301module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
302
303MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
304MODULE_DESCRIPTION("TX4939 internal RTC driver");
305MODULE_LICENSE("GPL v2");
306MODULE_ALIAS("platform:tx4939rtc");