Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
06de1808 | 2 | /* |
7b9b2ef1 | 3 | * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC |
06de1808 MJ |
4 | * |
5 | * Copyright (C) 2008 Mercury IMC Ltd | |
6 | * Written by Mark Jackson <mpfj@mimc.co.uk> | |
7 | * | |
7b9b2ef1 AZ |
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 | |
06de1808 MJ |
10 | * (alarms, trickle charger, different control registers) are unavailable. |
11 | */ | |
12 | ||
7b9b2ef1 AZ |
13 | #include <linux/init.h> |
14 | #include <linux/module.h> | |
06de1808 MJ |
15 | #include <linux/platform_device.h> |
16 | #include <linux/rtc.h> | |
17 | #include <linux/spi/spi.h> | |
18 | #include <linux/bcd.h> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
fa395fb8 | 20 | #include <linux/of.h> |
06de1808 MJ |
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 | ||
fa395fb8 IG |
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 | ||
06de1808 MJ |
48 | struct ds1390 { |
49 | struct rtc_device *rtc; | |
50 | u8 txrx_buf[9]; /* cmd + 8 registers */ | |
51 | }; | |
52 | ||
fa395fb8 IG |
53 | static 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 | ||
06de1808 MJ |
66 | static 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 | ||
2ec68825 | 83 | *data = chip->txrx_buf[0]; |
06de1808 MJ |
84 | |
85 | return 0; | |
86 | } | |
87 | ||
fa395fb8 IG |
88 | static 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 | ||
123 | out: | |
124 | return; | |
125 | } | |
126 | ||
7b9b2ef1 | 127 | static int ds1390_read_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
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 | ||
22652ba7 | 153 | return 0; |
06de1808 MJ |
154 | } |
155 | ||
7b9b2ef1 | 156 | static int ds1390_set_time(struct device *dev, struct rtc_time *dt) |
06de1808 MJ |
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 | ||
06de1808 MJ |
176 | static const struct rtc_class_ops ds1390_rtc_ops = { |
177 | .read_time = ds1390_read_time, | |
178 | .set_time = ds1390_set_time, | |
179 | }; | |
180 | ||
5a167f45 | 181 | static int ds1390_probe(struct spi_device *spi) |
06de1808 | 182 | { |
06de1808 MJ |
183 | unsigned char tmp; |
184 | struct ds1390 *chip; | |
185 | int res; | |
186 | ||
06de1808 MJ |
187 | spi->mode = SPI_MODE_3; |
188 | spi->bits_per_word = 8; | |
189 | spi_setup(spi); | |
190 | ||
1ce95ba7 | 191 | chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL); |
7841fe53 | 192 | if (!chip) |
06de1808 | 193 | return -ENOMEM; |
7841fe53 | 194 | |
ccbc20f9 | 195 | spi_set_drvdata(spi, chip); |
06de1808 MJ |
196 | |
197 | res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp); | |
7b9b2ef1 AZ |
198 | if (res != 0) { |
199 | dev_err(&spi->dev, "unable to read device\n"); | |
06de1808 MJ |
200 | return res; |
201 | } | |
202 | ||
fa395fb8 IG |
203 | if (spi->dev.of_node) |
204 | ds1390_trickle_of_init(spi); | |
205 | ||
1ce95ba7 JH |
206 | chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390", |
207 | &ds1390_rtc_ops, THIS_MODULE); | |
7b9b2ef1 AZ |
208 | if (IS_ERR(chip->rtc)) { |
209 | dev_err(&spi->dev, "unable to register device\n"); | |
210 | res = PTR_ERR(chip->rtc); | |
7b9b2ef1 AZ |
211 | } |
212 | ||
213 | return res; | |
06de1808 MJ |
214 | } |
215 | ||
3ba2c76a AB |
216 | static const struct of_device_id ds1390_of_match[] = { |
217 | { .compatible = "dallas,ds1390" }, | |
218 | {} | |
219 | }; | |
220 | MODULE_DEVICE_TABLE(of, ds1390_of_match); | |
221 | ||
da87639d MB |
222 | static const struct spi_device_id ds1390_spi_ids[] = { |
223 | { .name = "ds1390" }, | |
224 | {} | |
225 | }; | |
226 | MODULE_DEVICE_TABLE(spi, ds1390_spi_ids); | |
227 | ||
06de1808 MJ |
228 | static struct spi_driver ds1390_driver = { |
229 | .driver = { | |
230 | .name = "rtc-ds1390", | |
3ba2c76a | 231 | .of_match_table = of_match_ptr(ds1390_of_match), |
06de1808 MJ |
232 | }, |
233 | .probe = ds1390_probe, | |
da87639d | 234 | .id_table = ds1390_spi_ids, |
06de1808 MJ |
235 | }; |
236 | ||
109e9418 | 237 | module_spi_driver(ds1390_driver); |
06de1808 | 238 | |
7b9b2ef1 | 239 | MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver"); |
06de1808 MJ |
240 | MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>"); |
241 | MODULE_LICENSE("GPL"); | |
e0626e38 | 242 | MODULE_ALIAS("spi:rtc-ds1390"); |