1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Ricoh RP5C01 RTC Driver
4 *
5 * Copyright 2009 Geert Uytterhoeven
6 *
7 * Based on the A3000 TOD code in arch/m68k/amiga/config.c
8 * Copyright (C) 1993 Hamish Macdonald
9 */
10
11 #include <linux/io.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/rtc.h>
16 #include <linux/slab.h>
17
18
19 enum {
20 RP5C01_1_SECOND = 0x0, /* MODE 00 */
21 RP5C01_10_SECOND = 0x1, /* MODE 00 */
22 RP5C01_1_MINUTE = 0x2, /* MODE 00 and MODE 01 */
23 RP5C01_10_MINUTE = 0x3, /* MODE 00 and MODE 01 */
24 RP5C01_1_HOUR = 0x4, /* MODE 00 and MODE 01 */
25 RP5C01_10_HOUR = 0x5, /* MODE 00 and MODE 01 */
26 RP5C01_DAY_OF_WEEK = 0x6, /* MODE 00 and MODE 01 */
27 RP5C01_1_DAY = 0x7, /* MODE 00 and MODE 01 */
28 RP5C01_10_DAY = 0x8, /* MODE 00 and MODE 01 */
29 RP5C01_1_MONTH = 0x9, /* MODE 00 */
30 RP5C01_10_MONTH = 0xa, /* MODE 00 */
31 RP5C01_1_YEAR = 0xb, /* MODE 00 */
32 RP5C01_10_YEAR = 0xc, /* MODE 00 */
33
34 RP5C01_12_24_SELECT = 0xa, /* MODE 01 */
35 RP5C01_LEAP_YEAR = 0xb, /* MODE 01 */
36
37 RP5C01_MODE = 0xd, /* all modes */
38 RP5C01_TEST = 0xe, /* all modes */
39 RP5C01_RESET = 0xf, /* all modes */
40 };
41
42 #define RP5C01_12_24_SELECT_12 (0 << 0)
43 #define RP5C01_12_24_SELECT_24 (1 << 0)
44
45 #define RP5C01_10_HOUR_AM (0 << 1)
46 #define RP5C01_10_HOUR_PM (1 << 1)
47
48 #define RP5C01_MODE_TIMER_EN (1 << 3) /* timer enable */
49 #define RP5C01_MODE_ALARM_EN (1 << 2) /* alarm enable */
50
51 #define RP5C01_MODE_MODE_MASK (3 << 0)
52 #define RP5C01_MODE_MODE00 (0 << 0) /* time */
53 #define RP5C01_MODE_MODE01 (1 << 0) /* alarm, 12h/24h, leap year */
54 #define RP5C01_MODE_RAM_BLOCK10 (2 << 0) /* RAM 4 bits x 13 */
55 #define RP5C01_MODE_RAM_BLOCK11 (3 << 0) /* RAM 4 bits x 13 */
56
57 #define RP5C01_RESET_1HZ_PULSE (1 << 3)
58 #define RP5C01_RESET_16HZ_PULSE (1 << 2)
59 #define RP5C01_RESET_SECOND (1 << 1) /* reset divider stages for */
60 /* seconds or smaller units */
61 #define RP5C01_RESET_ALARM (1 << 0) /* reset all alarm registers */
62
63
64 struct rp5c01_priv {
65 u32 __iomem *regs;
66 struct rtc_device *rtc;
67 spinlock_t lock; /* against concurrent RTC/NVRAM access */
68 };
69
rp5c01_read(struct rp5c01_priv * priv,unsigned int reg)70 static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
71 unsigned int reg)
72 {
73 return __raw_readl(&priv->regs[reg]) & 0xf;
74 }
75
rp5c01_write(struct rp5c01_priv * priv,unsigned int val,unsigned int reg)76 static inline void rp5c01_write(struct rp5c01_priv *priv, unsigned int val,
77 unsigned int reg)
78 {
79 __raw_writel(val, &priv->regs[reg]);
80 }
81
rp5c01_lock(struct rp5c01_priv * priv)82 static void rp5c01_lock(struct rp5c01_priv *priv)
83 {
84 rp5c01_write(priv, RP5C01_MODE_MODE00, RP5C01_MODE);
85 }
86
rp5c01_unlock(struct rp5c01_priv * priv)87 static void rp5c01_unlock(struct rp5c01_priv *priv)
88 {
89 rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
90 RP5C01_MODE);
91 }
92
rp5c01_read_time(struct device * dev,struct rtc_time * tm)93 static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
94 {
95 struct rp5c01_priv *priv = dev_get_drvdata(dev);
96
97 spin_lock_irq(&priv->lock);
98 rp5c01_lock(priv);
99
100 tm->tm_sec = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
101 rp5c01_read(priv, RP5C01_1_SECOND);
102 tm->tm_min = rp5c01_read(priv, RP5C01_10_MINUTE) * 10 +
103 rp5c01_read(priv, RP5C01_1_MINUTE);
104 tm->tm_hour = rp5c01_read(priv, RP5C01_10_HOUR) * 10 +
105 rp5c01_read(priv, RP5C01_1_HOUR);
106 tm->tm_mday = rp5c01_read(priv, RP5C01_10_DAY) * 10 +
107 rp5c01_read(priv, RP5C01_1_DAY);
108 tm->tm_wday = rp5c01_read(priv, RP5C01_DAY_OF_WEEK);
109 tm->tm_mon = rp5c01_read(priv, RP5C01_10_MONTH) * 10 +
110 rp5c01_read(priv, RP5C01_1_MONTH) - 1;
111 tm->tm_year = rp5c01_read(priv, RP5C01_10_YEAR) * 10 +
112 rp5c01_read(priv, RP5C01_1_YEAR);
113 if (tm->tm_year <= 69)
114 tm->tm_year += 100;
115
116 rp5c01_unlock(priv);
117 spin_unlock_irq(&priv->lock);
118
119 return 0;
120 }
121
rp5c01_set_time(struct device * dev,struct rtc_time * tm)122 static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
123 {
124 struct rp5c01_priv *priv = dev_get_drvdata(dev);
125
126 spin_lock_irq(&priv->lock);
127 rp5c01_lock(priv);
128
129 rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
130 rp5c01_write(priv, tm->tm_sec % 10, RP5C01_1_SECOND);
131 rp5c01_write(priv, tm->tm_min / 10, RP5C01_10_MINUTE);
132 rp5c01_write(priv, tm->tm_min % 10, RP5C01_1_MINUTE);
133 rp5c01_write(priv, tm->tm_hour / 10, RP5C01_10_HOUR);
134 rp5c01_write(priv, tm->tm_hour % 10, RP5C01_1_HOUR);
135 rp5c01_write(priv, tm->tm_mday / 10, RP5C01_10_DAY);
136 rp5c01_write(priv, tm->tm_mday % 10, RP5C01_1_DAY);
137 if (tm->tm_wday != -1)
138 rp5c01_write(priv, tm->tm_wday, RP5C01_DAY_OF_WEEK);
139 rp5c01_write(priv, (tm->tm_mon + 1) / 10, RP5C01_10_MONTH);
140 rp5c01_write(priv, (tm->tm_mon + 1) % 10, RP5C01_1_MONTH);
141 if (tm->tm_year >= 100)
142 tm->tm_year -= 100;
143 rp5c01_write(priv, tm->tm_year / 10, RP5C01_10_YEAR);
144 rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
145
146 rp5c01_unlock(priv);
147 spin_unlock_irq(&priv->lock);
148 return 0;
149 }
150
151 static const struct rtc_class_ops rp5c01_rtc_ops = {
152 .read_time = rp5c01_read_time,
153 .set_time = rp5c01_set_time,
154 };
155
156
157 /*
158 * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
159 * We provide access to them like AmigaOS does: the high nibble of each 8-bit
160 * byte is stored in BLOCK10, the low nibble in BLOCK11.
161 */
162
rp5c01_nvram_read(void * _priv,unsigned int pos,void * val,size_t bytes)163 static int rp5c01_nvram_read(void *_priv, unsigned int pos, void *val,
164 size_t bytes)
165 {
166 struct rp5c01_priv *priv = _priv;
167 u8 *buf = val;
168
169 spin_lock_irq(&priv->lock);
170
171 for (; bytes; bytes--) {
172 u8 data;
173
174 rp5c01_write(priv,
175 RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
176 RP5C01_MODE);
177 data = rp5c01_read(priv, pos) << 4;
178 rp5c01_write(priv,
179 RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
180 RP5C01_MODE);
181 data |= rp5c01_read(priv, pos++);
182 rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
183 RP5C01_MODE);
184 *buf++ = data;
185 }
186
187 spin_unlock_irq(&priv->lock);
188 return 0;
189 }
190
rp5c01_nvram_write(void * _priv,unsigned int pos,void * val,size_t bytes)191 static int rp5c01_nvram_write(void *_priv, unsigned int pos, void *val,
192 size_t bytes)
193 {
194 struct rp5c01_priv *priv = _priv;
195 u8 *buf = val;
196
197 spin_lock_irq(&priv->lock);
198
199 for (; bytes; bytes--) {
200 u8 data = *buf++;
201
202 rp5c01_write(priv,
203 RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
204 RP5C01_MODE);
205 rp5c01_write(priv, data >> 4, pos);
206 rp5c01_write(priv,
207 RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
208 RP5C01_MODE);
209 rp5c01_write(priv, data & 0xf, pos++);
210 rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
211 RP5C01_MODE);
212 }
213
214 spin_unlock_irq(&priv->lock);
215 return 0;
216 }
217
rp5c01_rtc_probe(struct platform_device * dev)218 static int __init rp5c01_rtc_probe(struct platform_device *dev)
219 {
220 struct resource *res;
221 struct rp5c01_priv *priv;
222 struct rtc_device *rtc;
223 int error;
224 struct nvmem_config nvmem_cfg = {
225 .name = "rp5c01_nvram",
226 .word_size = 1,
227 .stride = 1,
228 .size = RP5C01_MODE,
229 .reg_read = rp5c01_nvram_read,
230 .reg_write = rp5c01_nvram_write,
231 };
232
233 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
234 if (!res)
235 return -ENODEV;
236
237 priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
238 if (!priv)
239 return -ENOMEM;
240
241 priv->regs = devm_ioremap(&dev->dev, res->start, resource_size(res));
242 if (!priv->regs)
243 return -ENOMEM;
244
245 spin_lock_init(&priv->lock);
246
247 platform_set_drvdata(dev, priv);
248
249 rtc = devm_rtc_allocate_device(&dev->dev);
250 if (IS_ERR(rtc))
251 return PTR_ERR(rtc);
252
253 rtc->ops = &rp5c01_rtc_ops;
254
255 priv->rtc = rtc;
256
257 nvmem_cfg.priv = priv;
258 error = devm_rtc_nvmem_register(rtc, &nvmem_cfg);
259 if (error)
260 return error;
261
262 return devm_rtc_register_device(rtc);
263 }
264
265 static struct platform_driver rp5c01_rtc_driver = {
266 .driver = {
267 .name = "rtc-rp5c01",
268 },
269 };
270
271 module_platform_driver_probe(rp5c01_rtc_driver, rp5c01_rtc_probe);
272
273 MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
274 MODULE_LICENSE("GPL");
275 MODULE_DESCRIPTION("Ricoh RP5C01 RTC driver");
276 MODULE_ALIAS("platform:rtc-rp5c01");
277