Commit | Line | Data |
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06de1808 | 1 | /* |
7b9b2ef1 | 2 | * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC |
06de1808 MJ |
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 | * | |
7b9b2ef1 AZ |
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 | |
06de1808 MJ |
13 | * (alarms, trickle charger, different control registers) are unavailable. |
14 | */ | |
15 | ||
7b9b2ef1 AZ |
16 | #include <linux/init.h> |
17 | #include <linux/module.h> | |
06de1808 MJ |
18 | #include <linux/platform_device.h> |
19 | #include <linux/rtc.h> | |
20 | #include <linux/spi/spi.h> | |
21 | #include <linux/bcd.h> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
fa395fb8 | 23 | #include <linux/of.h> |
06de1808 MJ |
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 | ||
fa395fb8 IG |
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 | ||
06de1808 MJ |
51 | struct ds1390 { |
52 | struct rtc_device *rtc; | |
53 | u8 txrx_buf[9]; /* cmd + 8 registers */ | |
54 | }; | |
55 | ||
fa395fb8 IG |
56 | static 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 | ||
06de1808 MJ |
69 | static 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 | ||
2ec68825 | 86 | *data = chip->txrx_buf[0]; |
06de1808 MJ |
87 | |
88 | return 0; | |
89 | } | |
90 | ||
fa395fb8 IG |
91 | static 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 | ||
126 | out: | |
127 | return; | |
128 | } | |
129 | ||
7b9b2ef1 | 130 | static int ds1390_read_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
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 rtc_valid_tm(dt); | |
157 | } | |
158 | ||
7b9b2ef1 | 159 | static int ds1390_set_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
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 | ||
06de1808 MJ |
179 | static const struct rtc_class_ops ds1390_rtc_ops = { |
180 | .read_time = ds1390_read_time, | |
181 | .set_time = ds1390_set_time, | |
182 | }; | |
183 | ||
5a167f45 | 184 | static int ds1390_probe(struct spi_device *spi) |
06de1808 | 185 | { |
06de1808 MJ |
186 | unsigned char tmp; |
187 | struct ds1390 *chip; | |
188 | int res; | |
189 | ||
06de1808 MJ |
190 | spi->mode = SPI_MODE_3; |
191 | spi->bits_per_word = 8; | |
192 | spi_setup(spi); | |
193 | ||
1ce95ba7 | 194 | chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); |
7841fe53 | 195 | if (!chip) |
06de1808 | 196 | return -ENOMEM; |
7841fe53 | 197 | |
ccbc20f9 | 198 | spi_set_drvdata(spi, chip); |
06de1808 MJ |
199 | |
200 | res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); | |
7b9b2ef1 AZ |
201 | if (res != 0) { |
202 | dev_err(&spi->dev, "unable to read device\n"); | |
06de1808 MJ |
203 | return res; |
204 | } | |
205 | ||
fa395fb8 IG |
206 | if (spi->dev.of_node) |
207 | ds1390_trickle_of_init(spi); | |
208 | ||
1ce95ba7 JH |
209 | chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390", |
210 | &ds1390_rtc_ops, THIS_MODULE); | |
7b9b2ef1 AZ |
211 | if (IS_ERR(chip->rtc)) { |
212 | dev_err(&spi->dev, "unable to register device\n"); | |
213 | res = PTR_ERR(chip->rtc); | |
7b9b2ef1 AZ |
214 | } |
215 | ||
216 | return res; | |
06de1808 MJ |
217 | } |
218 | ||
06de1808 MJ |
219 | static struct spi_driver ds1390_driver = { |
220 | .driver = { | |
221 | .name = "rtc-ds1390", | |
06de1808 MJ |
222 | }, |
223 | .probe = ds1390_probe, | |
06de1808 MJ |
224 | }; |
225 | ||
109e9418 | 226 | module_spi_driver(ds1390_driver); |
06de1808 | 227 | |
7b9b2ef1 | 228 | MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver"); |
06de1808 MJ |
229 | MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); |
230 | MODULE_LICENSE("GPL"); | |
e0626e38 | 231 | MODULE_ALIAS("spi:rtc-ds1390"); |