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1ce7c83f PZ |
1 | /* |
2 | * Driver for TI BQ32000 RTC. | |
3 | * | |
4 | * Copyright (C) 2009 Semihalf. | |
765a98a6 | 5 | * Copyright (C) 2014 Pavel Machek <pavel@denx.de> |
1ce7c83f PZ |
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. | |
765a98a6 PM |
10 | * |
11 | * You can get hardware description at | |
12 | * http://www.ti.com/lit/ds/symlink/bq32000.pdf | |
1ce7c83f PZ |
13 | */ |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/rtc.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/bcd.h> | |
21 | ||
22 | #define BQ32K_SECONDS 0x00 /* Seconds register address */ | |
23 | #define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ | |
24 | #define BQ32K_STOP 0x80 /* Oscillator Stop flat */ | |
25 | ||
26 | #define BQ32K_MINUTES 0x01 /* Minutes register address */ | |
27 | #define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ | |
28 | #define BQ32K_OF 0x80 /* Oscillator Failure flag */ | |
29 | ||
30 | #define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ | |
31 | #define BQ32K_CENT 0x40 /* Century flag */ | |
32 | #define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ | |
33 | ||
765a98a6 PM |
34 | #define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */ |
35 | #define BQ32K_TCH2 0x08 /* Trickle charge enable */ | |
36 | #define BQ32K_CFG2 0x09 /* Trickle charger control */ | |
37 | ||
1ce7c83f PZ |
38 | struct bq32k_regs { |
39 | uint8_t seconds; | |
40 | uint8_t minutes; | |
41 | uint8_t cent_hours; | |
42 | uint8_t day; | |
43 | uint8_t date; | |
44 | uint8_t month; | |
45 | uint8_t years; | |
46 | }; | |
47 | ||
48 | static struct i2c_driver bq32k_driver; | |
49 | ||
50 | static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) | |
51 | { | |
52 | struct i2c_client *client = to_i2c_client(dev); | |
53 | struct i2c_msg msgs[] = { | |
54 | { | |
55 | .addr = client->addr, | |
56 | .flags = 0, | |
57 | .len = 1, | |
58 | .buf = &off, | |
59 | }, { | |
60 | .addr = client->addr, | |
61 | .flags = I2C_M_RD, | |
62 | .len = len, | |
63 | .buf = data, | |
64 | } | |
65 | }; | |
66 | ||
67 | if (i2c_transfer(client->adapter, msgs, 2) == 2) | |
68 | return 0; | |
69 | ||
70 | return -EIO; | |
71 | } | |
72 | ||
73 | static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) | |
74 | { | |
75 | struct i2c_client *client = to_i2c_client(dev); | |
76 | uint8_t buffer[len + 1]; | |
77 | ||
78 | buffer[0] = off; | |
79 | memcpy(&buffer[1], data, len); | |
80 | ||
81 | if (i2c_master_send(client, buffer, len + 1) == len + 1) | |
82 | return 0; | |
83 | ||
84 | return -EIO; | |
85 | } | |
86 | ||
87 | static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
88 | { | |
89 | struct bq32k_regs regs; | |
90 | int error; | |
91 | ||
92 | error = bq32k_read(dev, ®s, 0, sizeof(regs)); | |
93 | if (error) | |
94 | return error; | |
95 | ||
421a5ba2 JÖ |
96 | /* |
97 | * In case of oscillator failure, the register contents should be | |
98 | * considered invalid. The flag is cleared the next time the RTC is set. | |
99 | */ | |
100 | if (regs.minutes & BQ32K_OF) | |
101 | return -EINVAL; | |
102 | ||
1ce7c83f | 103 | tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); |
6ed1a51e | 104 | tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK); |
1ce7c83f PZ |
105 | tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); |
106 | tm->tm_mday = bcd2bin(regs.date); | |
107 | tm->tm_wday = bcd2bin(regs.day) - 1; | |
108 | tm->tm_mon = bcd2bin(regs.month) - 1; | |
109 | tm->tm_year = bcd2bin(regs.years) + | |
110 | ((regs.cent_hours & BQ32K_CENT) ? 100 : 0); | |
111 | ||
112 | return rtc_valid_tm(tm); | |
113 | } | |
114 | ||
115 | static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
116 | { | |
117 | struct bq32k_regs regs; | |
118 | ||
119 | regs.seconds = bin2bcd(tm->tm_sec); | |
120 | regs.minutes = bin2bcd(tm->tm_min); | |
121 | regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; | |
122 | regs.day = bin2bcd(tm->tm_wday + 1); | |
123 | regs.date = bin2bcd(tm->tm_mday); | |
124 | regs.month = bin2bcd(tm->tm_mon + 1); | |
125 | ||
126 | if (tm->tm_year >= 100) { | |
127 | regs.cent_hours |= BQ32K_CENT; | |
128 | regs.years = bin2bcd(tm->tm_year - 100); | |
129 | } else | |
130 | regs.years = bin2bcd(tm->tm_year); | |
131 | ||
132 | return bq32k_write(dev, ®s, 0, sizeof(regs)); | |
133 | } | |
134 | ||
135 | static const struct rtc_class_ops bq32k_rtc_ops = { | |
136 | .read_time = bq32k_rtc_read_time, | |
137 | .set_time = bq32k_rtc_set_time, | |
138 | }; | |
139 | ||
765a98a6 PM |
140 | static int trickle_charger_of_init(struct device *dev, struct device_node *node) |
141 | { | |
142 | unsigned char reg; | |
143 | int error; | |
144 | u32 ohms = 0; | |
145 | ||
146 | if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms)) | |
147 | return 0; | |
148 | ||
149 | switch (ohms) { | |
150 | case 180+940: | |
151 | /* | |
152 | * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging | |
153 | * over diode and 940ohm resistor) | |
154 | */ | |
155 | ||
156 | if (of_property_read_bool(node, "trickle-diode-disable")) { | |
157 | dev_err(dev, "diode and resistor mismatch\n"); | |
158 | return -EINVAL; | |
159 | } | |
160 | reg = 0x05; | |
161 | break; | |
162 | ||
163 | case 180+20000: | |
164 | /* diode disabled */ | |
165 | ||
166 | if (!of_property_read_bool(node, "trickle-diode-disable")) { | |
167 | dev_err(dev, "bq32k: diode and resistor mismatch\n"); | |
168 | return -EINVAL; | |
169 | } | |
5a6e7599 | 170 | reg = 0x45; |
765a98a6 PM |
171 | break; |
172 | ||
173 | default: | |
174 | dev_err(dev, "invalid resistor value (%d)\n", ohms); | |
175 | return -EINVAL; | |
176 | } | |
177 | ||
178 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
179 | if (error) | |
180 | return error; | |
181 | ||
182 | reg = 0x20; | |
183 | error = bq32k_write(dev, ®, BQ32K_TCH2, 1); | |
184 | if (error) | |
185 | return error; | |
186 | ||
187 | dev_info(dev, "Enabled trickle RTC battery charge.\n"); | |
188 | return 0; | |
189 | } | |
190 | ||
1ce7c83f PZ |
191 | static int bq32k_probe(struct i2c_client *client, |
192 | const struct i2c_device_id *id) | |
193 | { | |
194 | struct device *dev = &client->dev; | |
195 | struct rtc_device *rtc; | |
196 | uint8_t reg; | |
197 | int error; | |
198 | ||
199 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
200 | return -ENODEV; | |
201 | ||
202 | /* Check Oscillator Stop flag */ | |
203 | error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); | |
204 | if (!error && (reg & BQ32K_STOP)) { | |
205 | dev_warn(dev, "Oscillator was halted. Restarting...\n"); | |
206 | reg &= ~BQ32K_STOP; | |
207 | error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); | |
208 | } | |
209 | if (error) | |
210 | return error; | |
211 | ||
212 | /* Check Oscillator Failure flag */ | |
213 | error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); | |
1ce7c83f PZ |
214 | if (error) |
215 | return error; | |
421a5ba2 JÖ |
216 | if (reg & BQ32K_OF) |
217 | dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); | |
1ce7c83f | 218 | |
617f6f7e | 219 | if (client->dev.of_node) |
765a98a6 PM |
220 | trickle_charger_of_init(dev, client->dev.of_node); |
221 | ||
4e440681 | 222 | rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name, |
1ce7c83f PZ |
223 | &bq32k_rtc_ops, THIS_MODULE); |
224 | if (IS_ERR(rtc)) | |
225 | return PTR_ERR(rtc); | |
226 | ||
227 | i2c_set_clientdata(client, rtc); | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
1ce7c83f PZ |
232 | static const struct i2c_device_id bq32k_id[] = { |
233 | { "bq32000", 0 }, | |
234 | { } | |
235 | }; | |
236 | MODULE_DEVICE_TABLE(i2c, bq32k_id); | |
237 | ||
238 | static struct i2c_driver bq32k_driver = { | |
239 | .driver = { | |
240 | .name = "bq32k", | |
1ce7c83f PZ |
241 | }, |
242 | .probe = bq32k_probe, | |
1ce7c83f PZ |
243 | .id_table = bq32k_id, |
244 | }; | |
245 | ||
0abc9201 | 246 | module_i2c_driver(bq32k_driver); |
1ce7c83f PZ |
247 | |
248 | MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>"); | |
249 | MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); | |
250 | MODULE_LICENSE("GPL"); |