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