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1/*
2 * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC
3 *
4 * Copyright (C) 2008 Mercury IMC Ltd
5 * Written by Mark Jackson <mpfj@mimc.co.uk>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * NOTE: Currently this driver only supports the bare minimum for read
12 * and write the RTC. The extra features provided by the chip family
13 * (alarms, trickle charger, different control registers) are unavailable.
14 */
15
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/platform_device.h>
19#include <linux/rtc.h>
20#include <linux/spi/spi.h>
21#include <linux/bcd.h>
22#include <linux/slab.h>
23
24#define DS1390_REG_100THS 0x00
25#define DS1390_REG_SECONDS 0x01
26#define DS1390_REG_MINUTES 0x02
27#define DS1390_REG_HOURS 0x03
28#define DS1390_REG_DAY 0x04
29#define DS1390_REG_DATE 0x05
30#define DS1390_REG_MONTH_CENT 0x06
31#define DS1390_REG_YEAR 0x07
32
33#define DS1390_REG_ALARM_100THS 0x08
34#define DS1390_REG_ALARM_SECONDS 0x09
35#define DS1390_REG_ALARM_MINUTES 0x0A
36#define DS1390_REG_ALARM_HOURS 0x0B
37#define DS1390_REG_ALARM_DAY_DATE 0x0C
38
39#define DS1390_REG_CONTROL 0x0D
40#define DS1390_REG_STATUS 0x0E
41#define DS1390_REG_TRICKLE 0x0F
42
43struct ds1390 {
44 struct rtc_device *rtc;
45 u8 txrx_buf[9]; /* cmd + 8 registers */
46};
47
48static int ds1390_get_reg(struct device *dev, unsigned char address,
49 unsigned char *data)
50{
51 struct spi_device *spi = to_spi_device(dev);
52 struct ds1390 *chip = dev_get_drvdata(dev);
53 int status;
54
55 if (!data)
56 return -EINVAL;
57
58 /* Clear MSB to indicate read */
59 chip->txrx_buf[0] = address & 0x7f;
60 /* do the i/o */
61 status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
62 if (status != 0)
63 return status;
64
65 *data = chip->txrx_buf[1];
66
67 return 0;
68}
69
70static int ds1390_read_time(struct device *dev, struct rtc_time *dt)
71{
72 struct spi_device *spi = to_spi_device(dev);
73 struct ds1390 *chip = dev_get_drvdata(dev);
74 int status;
75
76 /* build the message */
77 chip->txrx_buf[0] = DS1390_REG_SECONDS;
78
79 /* do the i/o */
80 status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
81 if (status != 0)
82 return status;
83
84 /* The chip sends data in this order:
85 * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
86 dt->tm_sec = bcd2bin(chip->txrx_buf[0]);
87 dt->tm_min = bcd2bin(chip->txrx_buf[1]);
88 dt->tm_hour = bcd2bin(chip->txrx_buf[2]);
89 dt->tm_wday = bcd2bin(chip->txrx_buf[3]);
90 dt->tm_mday = bcd2bin(chip->txrx_buf[4]);
91 /* mask off century bit */
92 dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
93 /* adjust for century bit */
94 dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);
95
96 return rtc_valid_tm(dt);
97}
98
99static int ds1390_set_time(struct device *dev, struct rtc_time *dt)
100{
101 struct spi_device *spi = to_spi_device(dev);
102 struct ds1390 *chip = dev_get_drvdata(dev);
103
104 /* build the message */
105 chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80;
106 chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
107 chip->txrx_buf[2] = bin2bcd(dt->tm_min);
108 chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
109 chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
110 chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
111 chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) |
112 ((dt->tm_year > 99) ? 0x80 : 0x00);
113 chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);
114
115 /* do the i/o */
116 return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
117}
118
119static const struct rtc_class_ops ds1390_rtc_ops = {
120 .read_time = ds1390_read_time,
121 .set_time = ds1390_set_time,
122};
123
124static int __devinit ds1390_probe(struct spi_device *spi)
125{
126 unsigned char tmp;
127 struct ds1390 *chip;
128 int res;
129
130 spi->mode = SPI_MODE_3;
131 spi->bits_per_word = 8;
132 spi_setup(spi);
133
134 chip = kzalloc(sizeof *chip, GFP_KERNEL);
135 if (!chip) {
136 dev_err(&spi->dev, "unable to allocate device memory\n");
137 return -ENOMEM;
138 }
139 dev_set_drvdata(&spi->dev, chip);
140
141 res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
142 if (res != 0) {
143 dev_err(&spi->dev, "unable to read device\n");
144 kfree(chip);
145 return res;
146 }
147
148 chip->rtc = rtc_device_register("ds1390",
149 &spi->dev, &ds1390_rtc_ops, THIS_MODULE);
150 if (IS_ERR(chip->rtc)) {
151 dev_err(&spi->dev, "unable to register device\n");
152 res = PTR_ERR(chip->rtc);
153 kfree(chip);
154 }
155
156 return res;
157}
158
159static int __devexit ds1390_remove(struct spi_device *spi)
160{
161 struct ds1390 *chip = spi_get_drvdata(spi);
162
163 rtc_device_unregister(chip->rtc);
164 kfree(chip);
165
166 return 0;
167}
168
169static struct spi_driver ds1390_driver = {
170 .driver = {
171 .name = "rtc-ds1390",
172 .owner = THIS_MODULE,
173 },
174 .probe = ds1390_probe,
175 .remove = __devexit_p(ds1390_remove),
176};
177
178static __init int ds1390_init(void)
179{
180 return spi_register_driver(&ds1390_driver);
181}
182module_init(ds1390_init);
183
184static __exit void ds1390_exit(void)
185{
186 spi_unregister_driver(&ds1390_driver);
187}
188module_exit(ds1390_exit);
189
190MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
191MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
192MODULE_LICENSE("GPL");
193MODULE_ALIAS("spi:rtc-ds1390");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC
4 *
5 * Copyright (C) 2008 Mercury IMC Ltd
6 * Written by Mark Jackson <mpfj@mimc.co.uk>
7 *
8 * NOTE: Currently this driver only supports the bare minimum for read
9 * and write the RTC. The extra features provided by the chip family
10 * (alarms, trickle charger, different control registers) are unavailable.
11 */
12
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/platform_device.h>
16#include <linux/rtc.h>
17#include <linux/spi/spi.h>
18#include <linux/bcd.h>
19#include <linux/slab.h>
20#include <linux/of.h>
21
22#define DS1390_REG_100THS 0x00
23#define DS1390_REG_SECONDS 0x01
24#define DS1390_REG_MINUTES 0x02
25#define DS1390_REG_HOURS 0x03
26#define DS1390_REG_DAY 0x04
27#define DS1390_REG_DATE 0x05
28#define DS1390_REG_MONTH_CENT 0x06
29#define DS1390_REG_YEAR 0x07
30
31#define DS1390_REG_ALARM_100THS 0x08
32#define DS1390_REG_ALARM_SECONDS 0x09
33#define DS1390_REG_ALARM_MINUTES 0x0A
34#define DS1390_REG_ALARM_HOURS 0x0B
35#define DS1390_REG_ALARM_DAY_DATE 0x0C
36
37#define DS1390_REG_CONTROL 0x0D
38#define DS1390_REG_STATUS 0x0E
39#define DS1390_REG_TRICKLE 0x0F
40
41#define DS1390_TRICKLE_CHARGER_ENABLE 0xA0
42#define DS1390_TRICKLE_CHARGER_250_OHM 0x01
43#define DS1390_TRICKLE_CHARGER_2K_OHM 0x02
44#define DS1390_TRICKLE_CHARGER_4K_OHM 0x03
45#define DS1390_TRICKLE_CHARGER_NO_DIODE 0x04
46#define DS1390_TRICKLE_CHARGER_DIODE 0x08
47
48struct ds1390 {
49 struct rtc_device *rtc;
50 u8 txrx_buf[9]; /* cmd + 8 registers */
51};
52
53static void ds1390_set_reg(struct device *dev, unsigned char address,
54 unsigned char data)
55{
56 struct spi_device *spi = to_spi_device(dev);
57 unsigned char buf[2];
58
59 /* MSB must be '1' to write */
60 buf[0] = address | 0x80;
61 buf[1] = data;
62
63 spi_write(spi, buf, 2);
64}
65
66static int ds1390_get_reg(struct device *dev, unsigned char address,
67 unsigned char *data)
68{
69 struct spi_device *spi = to_spi_device(dev);
70 struct ds1390 *chip = dev_get_drvdata(dev);
71 int status;
72
73 if (!data)
74 return -EINVAL;
75
76 /* Clear MSB to indicate read */
77 chip->txrx_buf[0] = address & 0x7f;
78 /* do the i/o */
79 status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
80 if (status != 0)
81 return status;
82
83 *data = chip->txrx_buf[0];
84
85 return 0;
86}
87
88static void ds1390_trickle_of_init(struct spi_device *spi)
89{
90 u32 ohms = 0;
91 u8 value;
92
93 if (of_property_read_u32(spi->dev.of_node, "trickle-resistor-ohms",
94 &ohms))
95 goto out;
96
97 /* Enable charger */
98 value = DS1390_TRICKLE_CHARGER_ENABLE;
99 if (of_property_read_bool(spi->dev.of_node, "trickle-diode-disable"))
100 value |= DS1390_TRICKLE_CHARGER_NO_DIODE;
101 else
102 value |= DS1390_TRICKLE_CHARGER_DIODE;
103
104 /* Resistor select */
105 switch (ohms) {
106 case 250:
107 value |= DS1390_TRICKLE_CHARGER_250_OHM;
108 break;
109 case 2000:
110 value |= DS1390_TRICKLE_CHARGER_2K_OHM;
111 break;
112 case 4000:
113 value |= DS1390_TRICKLE_CHARGER_4K_OHM;
114 break;
115 default:
116 dev_warn(&spi->dev,
117 "Unsupported ohm value %02ux in dt\n", ohms);
118 return;
119 }
120
121 ds1390_set_reg(&spi->dev, DS1390_REG_TRICKLE, value);
122
123out:
124 return;
125}
126
127static int ds1390_read_time(struct device *dev, struct rtc_time *dt)
128{
129 struct spi_device *spi = to_spi_device(dev);
130 struct ds1390 *chip = dev_get_drvdata(dev);
131 int status;
132
133 /* build the message */
134 chip->txrx_buf[0] = DS1390_REG_SECONDS;
135
136 /* do the i/o */
137 status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
138 if (status != 0)
139 return status;
140
141 /* The chip sends data in this order:
142 * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
143 dt->tm_sec = bcd2bin(chip->txrx_buf[0]);
144 dt->tm_min = bcd2bin(chip->txrx_buf[1]);
145 dt->tm_hour = bcd2bin(chip->txrx_buf[2]);
146 dt->tm_wday = bcd2bin(chip->txrx_buf[3]);
147 dt->tm_mday = bcd2bin(chip->txrx_buf[4]);
148 /* mask off century bit */
149 dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
150 /* adjust for century bit */
151 dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);
152
153 return 0;
154}
155
156static int ds1390_set_time(struct device *dev, struct rtc_time *dt)
157{
158 struct spi_device *spi = to_spi_device(dev);
159 struct ds1390 *chip = dev_get_drvdata(dev);
160
161 /* build the message */
162 chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80;
163 chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
164 chip->txrx_buf[2] = bin2bcd(dt->tm_min);
165 chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
166 chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
167 chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
168 chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) |
169 ((dt->tm_year > 99) ? 0x80 : 0x00);
170 chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);
171
172 /* do the i/o */
173 return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
174}
175
176static const struct rtc_class_ops ds1390_rtc_ops = {
177 .read_time = ds1390_read_time,
178 .set_time = ds1390_set_time,
179};
180
181static int ds1390_probe(struct spi_device *spi)
182{
183 unsigned char tmp;
184 struct ds1390 *chip;
185 int res;
186
187 spi->mode = SPI_MODE_3;
188 spi->bits_per_word = 8;
189 spi_setup(spi);
190
191 chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
192 if (!chip)
193 return -ENOMEM;
194
195 spi_set_drvdata(spi, chip);
196
197 res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
198 if (res != 0) {
199 dev_err(&spi->dev, "unable to read device\n");
200 return res;
201 }
202
203 if (spi->dev.of_node)
204 ds1390_trickle_of_init(spi);
205
206 chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390",
207 &ds1390_rtc_ops, THIS_MODULE);
208 if (IS_ERR(chip->rtc)) {
209 dev_err(&spi->dev, "unable to register device\n");
210 res = PTR_ERR(chip->rtc);
211 }
212
213 return res;
214}
215
216static const struct of_device_id ds1390_of_match[] __maybe_unused = {
217 { .compatible = "dallas,ds1390" },
218 {}
219};
220MODULE_DEVICE_TABLE(of, ds1390_of_match);
221
222static const struct spi_device_id ds1390_spi_ids[] = {
223 { .name = "ds1390" },
224 {}
225};
226MODULE_DEVICE_TABLE(spi, ds1390_spi_ids);
227
228static struct spi_driver ds1390_driver = {
229 .driver = {
230 .name = "rtc-ds1390",
231 .of_match_table = of_match_ptr(ds1390_of_match),
232 },
233 .probe = ds1390_probe,
234 .id_table = ds1390_spi_ids,
235};
236
237module_spi_driver(ds1390_driver);
238
239MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
240MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
241MODULE_LICENSE("GPL");
242MODULE_ALIAS("spi:rtc-ds1390");