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35#include <linux/bcd.h>
36#include <linux/delay.h>
37#include <linux/device.h>
38#include <linux/errno.h>
39#include <linux/init.h>
40#include <linux/kernel.h>
41#include <linux/of.h>
42#include <linux/string.h>
43#include <linux/slab.h>
44#include <linux/rtc.h>
45#include <linux/spi/spi.h>
46#include <linux/module.h>
47#include <linux/sysfs.h>
48
49#define DRV_VERSION "0.6"
50
51#define PCF2123_REG_CTRL1 (0x00)
52#define PCF2123_REG_CTRL2 (0x01)
53#define PCF2123_REG_SC (0x02)
54#define PCF2123_REG_MN (0x03)
55#define PCF2123_REG_HR (0x04)
56#define PCF2123_REG_DM (0x05)
57#define PCF2123_REG_DW (0x06)
58#define PCF2123_REG_MO (0x07)
59#define PCF2123_REG_YR (0x08)
60
61#define PCF2123_SUBADDR (1 << 4)
62#define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR)
63#define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR)
64
65static struct spi_driver pcf2123_driver;
66
67struct pcf2123_sysfs_reg {
68 struct device_attribute attr;
69 char name[2];
70};
71
72struct pcf2123_plat_data {
73 struct rtc_device *rtc;
74 struct pcf2123_sysfs_reg regs[16];
75};
76
77
78
79
80
81
82static inline void pcf2123_delay_trec(void)
83{
84 ndelay(30);
85}
86
87static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr,
88 char *buffer)
89{
90 struct spi_device *spi = to_spi_device(dev);
91 struct pcf2123_sysfs_reg *r;
92 u8 txbuf[1], rxbuf[1];
93 unsigned long reg;
94 int ret;
95
96 r = container_of(attr, struct pcf2123_sysfs_reg, attr);
97
98 ret = kstrtoul(r->name, 16, ®);
99 if (ret)
100 return ret;
101
102 txbuf[0] = PCF2123_READ | reg;
103 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
104 if (ret < 0)
105 return -EIO;
106 pcf2123_delay_trec();
107 return sprintf(buffer, "0x%x\n", rxbuf[0]);
108}
109
110static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr,
111 const char *buffer, size_t count) {
112 struct spi_device *spi = to_spi_device(dev);
113 struct pcf2123_sysfs_reg *r;
114 u8 txbuf[2];
115 unsigned long reg;
116 unsigned long val;
117
118 int ret;
119
120 r = container_of(attr, struct pcf2123_sysfs_reg, attr);
121
122 ret = kstrtoul(r->name, 16, ®);
123 if (ret)
124 return ret;
125
126 ret = kstrtoul(buffer, 10, &val);
127 if (ret)
128 return ret;
129
130 txbuf[0] = PCF2123_WRITE | reg;
131 txbuf[1] = val;
132 ret = spi_write(spi, txbuf, sizeof(txbuf));
133 if (ret < 0)
134 return -EIO;
135 pcf2123_delay_trec();
136 return count;
137}
138
139static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm)
140{
141 struct spi_device *spi = to_spi_device(dev);
142 u8 txbuf[1], rxbuf[7];
143 int ret;
144
145 txbuf[0] = PCF2123_READ | PCF2123_REG_SC;
146 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
147 rxbuf, sizeof(rxbuf));
148 if (ret < 0)
149 return ret;
150 pcf2123_delay_trec();
151
152 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F);
153 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F);
154 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F);
155 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F);
156 tm->tm_wday = rxbuf[4] & 0x07;
157 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1;
158 tm->tm_year = bcd2bin(rxbuf[6]);
159 if (tm->tm_year < 70)
160 tm->tm_year += 100;
161
162 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
163 "mday=%d, mon=%d, year=%d, wday=%d\n",
164 __func__,
165 tm->tm_sec, tm->tm_min, tm->tm_hour,
166 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
167
168
169
170
171 if (rtc_valid_tm(tm) < 0)
172 dev_err(dev, "retrieved date/time is not valid.\n");
173
174 return 0;
175}
176
177static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm)
178{
179 struct spi_device *spi = to_spi_device(dev);
180 u8 txbuf[8];
181 int ret;
182
183 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
184 "mday=%d, mon=%d, year=%d, wday=%d\n",
185 __func__,
186 tm->tm_sec, tm->tm_min, tm->tm_hour,
187 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
188
189
190 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
191 txbuf[1] = 0x20;
192 ret = spi_write(spi, txbuf, 2);
193 if (ret < 0)
194 return ret;
195 pcf2123_delay_trec();
196
197
198 txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC;
199 txbuf[1] = bin2bcd(tm->tm_sec & 0x7F);
200 txbuf[2] = bin2bcd(tm->tm_min & 0x7F);
201 txbuf[3] = bin2bcd(tm->tm_hour & 0x3F);
202 txbuf[4] = bin2bcd(tm->tm_mday & 0x3F);
203 txbuf[5] = tm->tm_wday & 0x07;
204 txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F);
205 txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100);
206
207 ret = spi_write(spi, txbuf, sizeof(txbuf));
208 if (ret < 0)
209 return ret;
210 pcf2123_delay_trec();
211
212
213 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
214 txbuf[1] = 0x00;
215 ret = spi_write(spi, txbuf, 2);
216 if (ret < 0)
217 return ret;
218 pcf2123_delay_trec();
219
220 return 0;
221}
222
223static const struct rtc_class_ops pcf2123_rtc_ops = {
224 .read_time = pcf2123_rtc_read_time,
225 .set_time = pcf2123_rtc_set_time,
226};
227
228static int pcf2123_probe(struct spi_device *spi)
229{
230 struct rtc_device *rtc;
231 struct pcf2123_plat_data *pdata;
232 u8 txbuf[2], rxbuf[2];
233 int ret, i;
234
235 pdata = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data),
236 GFP_KERNEL);
237 if (!pdata)
238 return -ENOMEM;
239 spi->dev.platform_data = pdata;
240
241
242 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
243 txbuf[1] = 0x58;
244 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n",
245 txbuf[0], txbuf[1]);
246 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
247 if (ret < 0)
248 goto kfree_exit;
249 pcf2123_delay_trec();
250
251
252 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
253 txbuf[1] = 0x20;
254 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n",
255 txbuf[0], txbuf[1]);
256 ret = spi_write(spi, txbuf, 2 * sizeof(u8));
257 if (ret < 0)
258 goto kfree_exit;
259 pcf2123_delay_trec();
260
261
262 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1;
263 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n",
264 txbuf[0]);
265 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8),
266 rxbuf, 2 * sizeof(u8));
267 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n",
268 rxbuf[0], rxbuf[1]);
269 if (ret < 0)
270 goto kfree_exit;
271 pcf2123_delay_trec();
272
273 if (!(rxbuf[0] & 0x20)) {
274 dev_err(&spi->dev, "chip not found\n");
275 ret = -ENODEV;
276 goto kfree_exit;
277 }
278
279 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
280 dev_info(&spi->dev, "spiclk %u KHz.\n",
281 (spi->max_speed_hz + 500) / 1000);
282
283
284 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1;
285 txbuf[1] = 0x00;
286 ret = spi_write(spi, txbuf, sizeof(txbuf));
287 if (ret < 0)
288 goto kfree_exit;
289 pcf2123_delay_trec();
290
291
292 rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name,
293 &pcf2123_rtc_ops, THIS_MODULE);
294
295 if (IS_ERR(rtc)) {
296 dev_err(&spi->dev, "failed to register.\n");
297 ret = PTR_ERR(rtc);
298 goto kfree_exit;
299 }
300
301 pdata->rtc = rtc;
302
303 for (i = 0; i < 16; i++) {
304 sysfs_attr_init(&pdata->regs[i].attr.attr);
305 sprintf(pdata->regs[i].name, "%1x", i);
306 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
307 pdata->regs[i].attr.attr.name = pdata->regs[i].name;
308 pdata->regs[i].attr.show = pcf2123_show;
309 pdata->regs[i].attr.store = pcf2123_store;
310 ret = device_create_file(&spi->dev, &pdata->regs[i].attr);
311 if (ret) {
312 dev_err(&spi->dev, "Unable to create sysfs %s\n",
313 pdata->regs[i].name);
314 goto sysfs_exit;
315 }
316 }
317
318 return 0;
319
320sysfs_exit:
321 for (i--; i >= 0; i--)
322 device_remove_file(&spi->dev, &pdata->regs[i].attr);
323
324kfree_exit:
325 spi->dev.platform_data = NULL;
326 return ret;
327}
328
329static int pcf2123_remove(struct spi_device *spi)
330{
331 struct pcf2123_plat_data *pdata = dev_get_platdata(&spi->dev);
332 int i;
333
334 if (pdata) {
335 for (i = 0; i < 16; i++)
336 if (pdata->regs[i].name[0])
337 device_remove_file(&spi->dev,
338 &pdata->regs[i].attr);
339 }
340
341 return 0;
342}
343
344#ifdef CONFIG_OF
345static const struct of_device_id pcf2123_dt_ids[] = {
346 { .compatible = "nxp,rtc-pcf2123", },
347 { }
348};
349MODULE_DEVICE_TABLE(of, pcf2123_dt_ids);
350#endif
351
352static struct spi_driver pcf2123_driver = {
353 .driver = {
354 .name = "rtc-pcf2123",
355 .owner = THIS_MODULE,
356 .of_match_table = of_match_ptr(pcf2123_dt_ids),
357 },
358 .probe = pcf2123_probe,
359 .remove = pcf2123_remove,
360};
361
362module_spi_driver(pcf2123_driver);
363
364MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>");
365MODULE_DESCRIPTION("NXP PCF2123 RTC driver");
366MODULE_LICENSE("GPL");
367MODULE_VERSION(DRV_VERSION);
368