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Arnaud Ebalard70e12332013-12-19 23:27:28 +01001/*
2 * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock
3 *
4 * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org>
5 *
6 * This work is largely based on Intersil ISL1208 driver developed by
7 * Hebert Valerio Riedel <hvr@gnu.org>.
8 *
9 * Detailed datasheet on which this development is based is available here:
10 *
11 * http://natisbad.org/NAS2/refs/ISL12057.pdf
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 */
23
24#include <linux/module.h>
25#include <linux/mutex.h>
26#include <linux/rtc.h>
27#include <linux/i2c.h>
28#include <linux/bcd.h>
Arnaud Ebalard70e12332013-12-19 23:27:28 +010029#include <linux/of.h>
30#include <linux/of_device.h>
31#include <linux/regmap.h>
32
33#define DRV_NAME "rtc-isl12057"
34
35/* RTC section */
36#define ISL12057_REG_RTC_SC 0x00 /* Seconds */
37#define ISL12057_REG_RTC_MN 0x01 /* Minutes */
38#define ISL12057_REG_RTC_HR 0x02 /* Hours */
39#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */
40#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */
41#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */
42#define ISL12057_REG_RTC_DT 0x04 /* Date */
43#define ISL12057_REG_RTC_MO 0x05 /* Month */
Arnaud Ebalardb5f41842014-12-10 15:54:05 -080044#define ISL12057_REG_RTC_MO_CEN BIT(7) /* Century bit */
Arnaud Ebalard70e12332013-12-19 23:27:28 +010045#define ISL12057_REG_RTC_YR 0x06 /* Year */
46#define ISL12057_RTC_SEC_LEN 7
47
48/* Alarm 1 section */
49#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */
50#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */
51#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */
52#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */
53#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */
54#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */
55#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */
56#define ISL12057_A1_SEC_LEN 4
57
58/* Alarm 2 section */
59#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */
60#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */
61#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */
62#define ISL12057_A2_SEC_LEN 3
63
64/* Control/Status registers */
65#define ISL12057_REG_INT 0x0E
66#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */
67#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */
68#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */
69#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */
70#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */
71#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */
72
73#define ISL12057_REG_SR 0x0F
74#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */
75#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */
76#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */
77
78/* Register memory map length */
79#define ISL12057_MEM_MAP_LEN 0x10
80
81struct isl12057_rtc_data {
82 struct regmap *regmap;
83 struct mutex lock;
84};
85
86static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs)
87{
88 tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]);
89 tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]);
90
91 if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */
Arnaud Ebalard5945b282014-12-10 15:54:02 -080092 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x1f);
Arnaud Ebalard70e12332013-12-19 23:27:28 +010093 if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM)
94 tm->tm_hour += 12;
95 } else { /* 24 hour mode */
96 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f);
97 }
98
99 tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]);
100 tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */
Arnaud Ebalard5945b282014-12-10 15:54:02 -0800101 tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100102 tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100;
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800103
104 /* Check if years register has overflown from 99 to 00 */
105 if (regs[ISL12057_REG_RTC_MO] & ISL12057_REG_RTC_MO_CEN)
106 tm->tm_year += 100;
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100107}
108
109static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm)
110{
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800111 u8 century_bit;
112
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100113 /*
114 * The clock has an 8 bit wide bcd-coded register for the year.
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800115 * It also has a century bit encoded in MO flag which provides
116 * information about overflow of year register from 99 to 00.
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100117 * tm_year is an offset from 1900 and we are interested in the
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800118 * 2000-2199 range, so any value less than 100 or larger than
119 * 299 is invalid.
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100120 */
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800121 if (tm->tm_year < 100 || tm->tm_year > 299)
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100122 return -EINVAL;
123
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800124 century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0;
125
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100126 regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec);
127 regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min);
128 regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
129 regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday);
Arnaud Ebalardb5f41842014-12-10 15:54:05 -0800130 regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit;
131 regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100);
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100132 regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1);
133
134 return 0;
135}
136
137/*
138 * Try and match register bits w/ fixed null values to see whether we
139 * are dealing with an ISL12057. Note: this function is called early
140 * during init and hence does need mutex protection.
141 */
142static int isl12057_i2c_validate_chip(struct regmap *regmap)
143{
144 u8 regs[ISL12057_MEM_MAP_LEN];
145 static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8,
146 0xc0, 0x60, 0x00, 0x00,
147 0x00, 0x00, 0x00, 0x00,
148 0x00, 0x00, 0x60, 0x7c };
149 int ret, i;
150
151 ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN);
152 if (ret)
153 return ret;
154
155 for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) {
156 if (regs[i] & mask[i]) /* check if bits are cleared */
157 return -ENODEV;
158 }
159
160 return 0;
161}
162
163static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm)
164{
165 struct isl12057_rtc_data *data = dev_get_drvdata(dev);
166 u8 regs[ISL12057_RTC_SEC_LEN];
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800167 unsigned int sr;
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100168 int ret;
169
170 mutex_lock(&data->lock);
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800171 ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr);
172 if (ret) {
173 dev_err(dev, "%s: unable to read oscillator status flag\n",
174 __func__);
175 goto out;
176 } else {
177 if (sr & ISL12057_REG_SR_OSF) {
178 ret = -ENODATA;
179 goto out;
180 }
181 }
182
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100183 ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs,
184 ISL12057_RTC_SEC_LEN);
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800185 if (ret)
186 dev_err(dev, "%s: unable to read RTC time\n", __func__);
187
188out:
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100189 mutex_unlock(&data->lock);
190
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800191 if (ret)
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100192 return ret;
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100193
194 isl12057_rtc_regs_to_tm(tm, regs);
195
196 return rtc_valid_tm(tm);
197}
198
199static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm)
200{
201 struct isl12057_rtc_data *data = dev_get_drvdata(dev);
202 u8 regs[ISL12057_RTC_SEC_LEN];
203 int ret;
204
205 ret = isl12057_rtc_tm_to_regs(regs, tm);
206 if (ret)
207 return ret;
208
209 mutex_lock(&data->lock);
210 ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs,
211 ISL12057_RTC_SEC_LEN);
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800212 if (ret) {
213 dev_err(dev, "%s: writing RTC time failed\n", __func__);
214 goto out;
215 }
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100216
Arnaud Ebalard10df1e62014-12-10 15:54:08 -0800217 /*
218 * Now that RTC time has been updated, let's clear oscillator
219 * failure flag, if needed.
220 */
221 ret = regmap_update_bits(data->regmap, ISL12057_REG_SR,
222 ISL12057_REG_SR_OSF, 0);
223 if (ret < 0)
224 dev_err(dev, "Unable to clear oscillator failure bit\n");
225
226out:
227 mutex_unlock(&data->lock);
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100228
229 return ret;
230}
231
232/*
233 * Check current RTC status and enable/disable what needs to be. Return 0 if
234 * everything went ok and a negative value upon error. Note: this function
235 * is called early during init and hence does need mutex protection.
236 */
237static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap)
238{
239 int ret;
240
241 /* Enable oscillator if not already running */
242 ret = regmap_update_bits(regmap, ISL12057_REG_INT,
243 ISL12057_REG_INT_EOSC, 0);
244 if (ret < 0) {
245 dev_err(dev, "Unable to enable oscillator\n");
246 return ret;
247 }
248
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100249 /* Clear alarm bit if needed */
250 ret = regmap_update_bits(regmap, ISL12057_REG_SR,
251 ISL12057_REG_SR_A1F, 0);
252 if (ret < 0) {
253 dev_err(dev, "Unable to clear alarm bit\n");
254 return ret;
255 }
256
257 return 0;
258}
259
260static const struct rtc_class_ops rtc_ops = {
261 .read_time = isl12057_rtc_read_time,
262 .set_time = isl12057_rtc_set_time,
263};
264
265static struct regmap_config isl12057_rtc_regmap_config = {
266 .reg_bits = 8,
267 .val_bits = 8,
268};
269
270static int isl12057_probe(struct i2c_client *client,
271 const struct i2c_device_id *id)
272{
273 struct device *dev = &client->dev;
274 struct isl12057_rtc_data *data;
275 struct rtc_device *rtc;
276 struct regmap *regmap;
277 int ret;
278
279 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
280 I2C_FUNC_SMBUS_BYTE_DATA |
281 I2C_FUNC_SMBUS_I2C_BLOCK))
282 return -ENODEV;
283
284 regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config);
285 if (IS_ERR(regmap)) {
286 ret = PTR_ERR(regmap);
287 dev_err(dev, "regmap allocation failed: %d\n", ret);
288 return ret;
289 }
290
291 ret = isl12057_i2c_validate_chip(regmap);
292 if (ret)
293 return ret;
294
295 ret = isl12057_check_rtc_status(dev, regmap);
296 if (ret)
297 return ret;
298
299 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
300 if (!data)
301 return -ENOMEM;
302
303 mutex_init(&data->lock);
304 data->regmap = regmap;
305 dev_set_drvdata(dev, data);
306
307 rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE);
Fengguang Wu00b281842014-02-18 18:00:21 +0000308 return PTR_ERR_OR_ZERO(rtc);
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100309}
310
311#ifdef CONFIG_OF
Jingoo Han8c5bfac2014-06-06 14:35:56 -0700312static const struct of_device_id isl12057_dt_match[] = {
Arnaud Ebalard70e12332013-12-19 23:27:28 +0100313 { .compatible = "isl,isl12057" },
314 { },
315};
316#endif
317
318static const struct i2c_device_id isl12057_id[] = {
319 { "isl12057", 0 },
320 { }
321};
322MODULE_DEVICE_TABLE(i2c, isl12057_id);
323
324static struct i2c_driver isl12057_driver = {
325 .driver = {
326 .name = DRV_NAME,
327 .owner = THIS_MODULE,
328 .of_match_table = of_match_ptr(isl12057_dt_match),
329 },
330 .probe = isl12057_probe,
331 .id_table = isl12057_id,
332};
333module_i2c_driver(isl12057_driver);
334
335MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
336MODULE_DESCRIPTION("Intersil ISL12057 RTC driver");
337MODULE_LICENSE("GPL");