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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * A SPI driver for the Ricoh RS5C348 RTC
4 *
5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 *
7 * The board specific init code should provide characteristics of this
8 * device:
9 * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS
10 */
11
12#include <linux/bcd.h>
13#include <linux/delay.h>
14#include <linux/device.h>
15#include <linux/errno.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/slab.h>
20#include <linux/rtc.h>
21#include <linux/workqueue.h>
22#include <linux/spi/spi.h>
23#include <linux/module.h>
24
25#define RS5C348_REG_SECS 0
26#define RS5C348_REG_MINS 1
27#define RS5C348_REG_HOURS 2
28#define RS5C348_REG_WDAY 3
29#define RS5C348_REG_DAY 4
30#define RS5C348_REG_MONTH 5
31#define RS5C348_REG_YEAR 6
32#define RS5C348_REG_CTL1 14
33#define RS5C348_REG_CTL2 15
34
35#define RS5C348_SECS_MASK 0x7f
36#define RS5C348_MINS_MASK 0x7f
37#define RS5C348_HOURS_MASK 0x3f
38#define RS5C348_WDAY_MASK 0x03
39#define RS5C348_DAY_MASK 0x3f
40#define RS5C348_MONTH_MASK 0x1f
41
42#define RS5C348_BIT_PM 0x20 /* REG_HOURS */
43#define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */
44#define RS5C348_BIT_24H 0x20 /* REG_CTL1 */
45#define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */
46#define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */
47
48#define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */
49#define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */
50#define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */
51#define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */
52
53struct rs5c348_plat_data {
54 struct rtc_device *rtc;
55 int rtc_24h;
56};
57
58static int
59rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm)
60{
61 struct spi_device *spi = to_spi_device(dev);
62 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);
63 u8 txbuf[5+7], *txp;
64 int ret;
65
66 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));
67 if (ret < 0)
68 return ret;
69 if (ret & RS5C348_BIT_XSTP) {
70 txbuf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);
71 txbuf[1] = 0;
72 ret = spi_write_then_read(spi, txbuf, 2, NULL, 0);
73 if (ret < 0)
74 return ret;
75 }
76
77 /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */
78 txp = txbuf;
79 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
80 txbuf[1] = 0; /* dummy */
81 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
82 txbuf[3] = 0; /* dummy */
83 txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */
84 txp = &txbuf[5];
85 txp[RS5C348_REG_SECS] = bin2bcd(tm->tm_sec);
86 txp[RS5C348_REG_MINS] = bin2bcd(tm->tm_min);
87 if (pdata->rtc_24h) {
88 txp[RS5C348_REG_HOURS] = bin2bcd(tm->tm_hour);
89 } else {
90 /* hour 0 is AM12, noon is PM12 */
91 txp[RS5C348_REG_HOURS] = bin2bcd((tm->tm_hour + 11) % 12 + 1) |
92 (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0);
93 }
94 txp[RS5C348_REG_WDAY] = bin2bcd(tm->tm_wday);
95 txp[RS5C348_REG_DAY] = bin2bcd(tm->tm_mday);
96 txp[RS5C348_REG_MONTH] = bin2bcd(tm->tm_mon + 1) |
97 (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0);
98 txp[RS5C348_REG_YEAR] = bin2bcd(tm->tm_year % 100);
99 /* write in one transfer to avoid data inconsistency */
100 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0);
101 udelay(62); /* Tcsr 62us */
102 return ret;
103}
104
105static int
106rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm)
107{
108 struct spi_device *spi = to_spi_device(dev);
109 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);
110 u8 txbuf[5], rxbuf[7];
111 int ret;
112
113 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));
114 if (ret < 0)
115 return ret;
116 if (ret & RS5C348_BIT_VDET)
117 dev_warn(&spi->dev, "voltage-low detected.\n");
118 if (ret & RS5C348_BIT_XSTP) {
119 dev_warn(&spi->dev, "oscillator-stop detected.\n");
120 return -EINVAL;
121 }
122
123 /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */
124 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
125 txbuf[1] = 0; /* dummy */
126 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
127 txbuf[3] = 0; /* dummy */
128 txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */
129
130 /* read in one transfer to avoid data inconsistency */
131 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
132 rxbuf, sizeof(rxbuf));
133 udelay(62); /* Tcsr 62us */
134 if (ret < 0)
135 return ret;
136
137 tm->tm_sec = bcd2bin(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK);
138 tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK);
139 tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK);
140 if (!pdata->rtc_24h) {
141 if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) {
142 tm->tm_hour -= 20;
143 tm->tm_hour %= 12;
144 tm->tm_hour += 12;
145 } else
146 tm->tm_hour %= 12;
147 }
148 tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK);
149 tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);
150 tm->tm_mon =
151 bcd2bin(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1;
152 /* year is 1900 + tm->tm_year */
153 tm->tm_year = bcd2bin(rxbuf[RS5C348_REG_YEAR]) +
154 ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0);
155
156 return 0;
157}
158
159static const struct rtc_class_ops rs5c348_rtc_ops = {
160 .read_time = rs5c348_rtc_read_time,
161 .set_time = rs5c348_rtc_set_time,
162};
163
164static int rs5c348_probe(struct spi_device *spi)
165{
166 int ret;
167 struct rtc_device *rtc;
168 struct rs5c348_plat_data *pdata;
169
170 pdata = devm_kzalloc(&spi->dev, sizeof(struct rs5c348_plat_data),
171 GFP_KERNEL);
172 if (!pdata)
173 return -ENOMEM;
174 spi->dev.platform_data = pdata;
175
176 /* Check D7 of SECOND register */
177 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS));
178 if (ret < 0 || (ret & 0x80)) {
179 dev_err(&spi->dev, "not found.\n");
180 return ret;
181 }
182
183 dev_info(&spi->dev, "spiclk %u KHz.\n",
184 (spi->max_speed_hz + 500) / 1000);
185
186 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));
187 if (ret < 0)
188 return ret;
189 if (ret & RS5C348_BIT_24H)
190 pdata->rtc_24h = 1;
191
192 rtc = devm_rtc_allocate_device(&spi->dev);
193 if (IS_ERR(rtc))
194 return PTR_ERR(rtc);
195
196 pdata->rtc = rtc;
197
198 rtc->ops = &rs5c348_rtc_ops;
199
200 return rtc_register_device(rtc);
201}
202
203static struct spi_driver rs5c348_driver = {
204 .driver = {
205 .name = "rtc-rs5c348",
206 },
207 .probe = rs5c348_probe,
208};
209
210module_spi_driver(rs5c348_driver);
211
212MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
213MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver");
214MODULE_LICENSE("GPL");
215MODULE_ALIAS("spi:rtc-rs5c348");
1/*
2 * A SPI driver for the Ricoh RS5C348 RTC
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * The board specific init code should provide characteristics of this
11 * device:
12 * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS
13 */
14
15#include <linux/bcd.h>
16#include <linux/delay.h>
17#include <linux/device.h>
18#include <linux/errno.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/string.h>
22#include <linux/slab.h>
23#include <linux/rtc.h>
24#include <linux/workqueue.h>
25#include <linux/spi/spi.h>
26#include <linux/module.h>
27
28#define DRV_VERSION "0.2"
29
30#define RS5C348_REG_SECS 0
31#define RS5C348_REG_MINS 1
32#define RS5C348_REG_HOURS 2
33#define RS5C348_REG_WDAY 3
34#define RS5C348_REG_DAY 4
35#define RS5C348_REG_MONTH 5
36#define RS5C348_REG_YEAR 6
37#define RS5C348_REG_CTL1 14
38#define RS5C348_REG_CTL2 15
39
40#define RS5C348_SECS_MASK 0x7f
41#define RS5C348_MINS_MASK 0x7f
42#define RS5C348_HOURS_MASK 0x3f
43#define RS5C348_WDAY_MASK 0x03
44#define RS5C348_DAY_MASK 0x3f
45#define RS5C348_MONTH_MASK 0x1f
46
47#define RS5C348_BIT_PM 0x20 /* REG_HOURS */
48#define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */
49#define RS5C348_BIT_24H 0x20 /* REG_CTL1 */
50#define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */
51#define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */
52
53#define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */
54#define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */
55#define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */
56#define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */
57
58struct rs5c348_plat_data {
59 struct rtc_device *rtc;
60 int rtc_24h;
61};
62
63static int
64rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm)
65{
66 struct spi_device *spi = to_spi_device(dev);
67 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);
68 u8 txbuf[5+7], *txp;
69 int ret;
70
71 /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */
72 txp = txbuf;
73 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
74 txbuf[1] = 0; /* dummy */
75 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
76 txbuf[3] = 0; /* dummy */
77 txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */
78 txp = &txbuf[5];
79 txp[RS5C348_REG_SECS] = bin2bcd(tm->tm_sec);
80 txp[RS5C348_REG_MINS] = bin2bcd(tm->tm_min);
81 if (pdata->rtc_24h) {
82 txp[RS5C348_REG_HOURS] = bin2bcd(tm->tm_hour);
83 } else {
84 /* hour 0 is AM12, noon is PM12 */
85 txp[RS5C348_REG_HOURS] = bin2bcd((tm->tm_hour + 11) % 12 + 1) |
86 (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0);
87 }
88 txp[RS5C348_REG_WDAY] = bin2bcd(tm->tm_wday);
89 txp[RS5C348_REG_DAY] = bin2bcd(tm->tm_mday);
90 txp[RS5C348_REG_MONTH] = bin2bcd(tm->tm_mon + 1) |
91 (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0);
92 txp[RS5C348_REG_YEAR] = bin2bcd(tm->tm_year % 100);
93 /* write in one transfer to avoid data inconsistency */
94 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0);
95 udelay(62); /* Tcsr 62us */
96 return ret;
97}
98
99static int
100rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm)
101{
102 struct spi_device *spi = to_spi_device(dev);
103 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev);
104 u8 txbuf[5], rxbuf[7];
105 int ret;
106
107 /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */
108 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
109 txbuf[1] = 0; /* dummy */
110 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */
111 txbuf[3] = 0; /* dummy */
112 txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */
113
114 /* read in one transfer to avoid data inconsistency */
115 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf),
116 rxbuf, sizeof(rxbuf));
117 udelay(62); /* Tcsr 62us */
118 if (ret < 0)
119 return ret;
120
121 tm->tm_sec = bcd2bin(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK);
122 tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK);
123 tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK);
124 if (!pdata->rtc_24h) {
125 if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) {
126 tm->tm_hour -= 20;
127 tm->tm_hour %= 12;
128 tm->tm_hour += 12;
129 } else
130 tm->tm_hour %= 12;
131 }
132 tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK);
133 tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);
134 tm->tm_mon =
135 bcd2bin(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1;
136 /* year is 1900 + tm->tm_year */
137 tm->tm_year = bcd2bin(rxbuf[RS5C348_REG_YEAR]) +
138 ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0);
139
140 if (rtc_valid_tm(tm) < 0) {
141 dev_err(&spi->dev, "retrieved date/time is not valid.\n");
142 rtc_time_to_tm(0, tm);
143 }
144
145 return 0;
146}
147
148static const struct rtc_class_ops rs5c348_rtc_ops = {
149 .read_time = rs5c348_rtc_read_time,
150 .set_time = rs5c348_rtc_set_time,
151};
152
153static struct spi_driver rs5c348_driver;
154
155static int rs5c348_probe(struct spi_device *spi)
156{
157 int ret;
158 struct rtc_device *rtc;
159 struct rs5c348_plat_data *pdata;
160
161 pdata = devm_kzalloc(&spi->dev, sizeof(struct rs5c348_plat_data),
162 GFP_KERNEL);
163 if (!pdata)
164 return -ENOMEM;
165 spi->dev.platform_data = pdata;
166
167 /* Check D7 of SECOND register */
168 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS));
169 if (ret < 0 || (ret & 0x80)) {
170 dev_err(&spi->dev, "not found.\n");
171 goto kfree_exit;
172 }
173
174 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n");
175 dev_info(&spi->dev, "spiclk %u KHz.\n",
176 (spi->max_speed_hz + 500) / 1000);
177
178 /* turn RTC on if it was not on */
179 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2));
180 if (ret < 0)
181 goto kfree_exit;
182 if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) {
183 u8 buf[2];
184 struct rtc_time tm;
185 if (ret & RS5C348_BIT_VDET)
186 dev_warn(&spi->dev, "voltage-low detected.\n");
187 if (ret & RS5C348_BIT_XSTP)
188 dev_warn(&spi->dev, "oscillator-stop detected.\n");
189 rtc_time_to_tm(0, &tm); /* 1970/1/1 */
190 ret = rs5c348_rtc_set_time(&spi->dev, &tm);
191 if (ret < 0)
192 goto kfree_exit;
193 buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2);
194 buf[1] = 0;
195 ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0);
196 if (ret < 0)
197 goto kfree_exit;
198 }
199
200 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1));
201 if (ret < 0)
202 goto kfree_exit;
203 if (ret & RS5C348_BIT_24H)
204 pdata->rtc_24h = 1;
205
206 rtc = devm_rtc_device_register(&spi->dev, rs5c348_driver.driver.name,
207 &rs5c348_rtc_ops, THIS_MODULE);
208
209 if (IS_ERR(rtc)) {
210 ret = PTR_ERR(rtc);
211 goto kfree_exit;
212 }
213
214 pdata->rtc = rtc;
215
216 return 0;
217 kfree_exit:
218 return ret;
219}
220
221static struct spi_driver rs5c348_driver = {
222 .driver = {
223 .name = "rtc-rs5c348",
224 .owner = THIS_MODULE,
225 },
226 .probe = rs5c348_probe,
227};
228
229module_spi_driver(rs5c348_driver);
230
231MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
232MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver");
233MODULE_LICENSE("GPL");
234MODULE_VERSION(DRV_VERSION);
235MODULE_ALIAS("spi:rtc-rs5c348");