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1/*
2 * Driver for TI BQ32000 RTC.
3 *
4 * Copyright (C) 2009 Semihalf.
5 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
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 * You can get hardware description at
12 * http://www.ti.com/lit/ds/symlink/bq32000.pdf
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
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
38struct 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
48static struct i2c_driver bq32k_driver;
49
50static 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
73static 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
87static 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
96 tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
97 tm->tm_min = bcd2bin(regs.minutes & BQ32K_SECONDS_MASK);
98 tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
99 tm->tm_mday = bcd2bin(regs.date);
100 tm->tm_wday = bcd2bin(regs.day) - 1;
101 tm->tm_mon = bcd2bin(regs.month) - 1;
102 tm->tm_year = bcd2bin(regs.years) +
103 ((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
104
105 return rtc_valid_tm(tm);
106}
107
108static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
109{
110 struct bq32k_regs regs;
111
112 regs.seconds = bin2bcd(tm->tm_sec);
113 regs.minutes = bin2bcd(tm->tm_min);
114 regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
115 regs.day = bin2bcd(tm->tm_wday + 1);
116 regs.date = bin2bcd(tm->tm_mday);
117 regs.month = bin2bcd(tm->tm_mon + 1);
118
119 if (tm->tm_year >= 100) {
120 regs.cent_hours |= BQ32K_CENT;
121 regs.years = bin2bcd(tm->tm_year - 100);
122 } else
123 regs.years = bin2bcd(tm->tm_year);
124
125 return bq32k_write(dev, ®s, 0, sizeof(regs));
126}
127
128static const struct rtc_class_ops bq32k_rtc_ops = {
129 .read_time = bq32k_rtc_read_time,
130 .set_time = bq32k_rtc_set_time,
131};
132
133static int trickle_charger_of_init(struct device *dev, struct device_node *node)
134{
135 unsigned char reg;
136 int error;
137 u32 ohms = 0;
138
139 if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
140 return 0;
141
142 switch (ohms) {
143 case 180+940:
144 /*
145 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
146 * over diode and 940ohm resistor)
147 */
148
149 if (of_property_read_bool(node, "trickle-diode-disable")) {
150 dev_err(dev, "diode and resistor mismatch\n");
151 return -EINVAL;
152 }
153 reg = 0x05;
154 break;
155
156 case 180+20000:
157 /* diode disabled */
158
159 if (!of_property_read_bool(node, "trickle-diode-disable")) {
160 dev_err(dev, "bq32k: diode and resistor mismatch\n");
161 return -EINVAL;
162 }
163 reg = 0x45;
164 break;
165
166 default:
167 dev_err(dev, "invalid resistor value (%d)\n", ohms);
168 return -EINVAL;
169 }
170
171 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
172 if (error)
173 return error;
174
175 reg = 0x20;
176 error = bq32k_write(dev, ®, BQ32K_TCH2, 1);
177 if (error)
178 return error;
179
180 dev_info(dev, "Enabled trickle RTC battery charge.\n");
181 return 0;
182}
183
184static int bq32k_probe(struct i2c_client *client,
185 const struct i2c_device_id *id)
186{
187 struct device *dev = &client->dev;
188 struct rtc_device *rtc;
189 uint8_t reg;
190 int error;
191
192 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
193 return -ENODEV;
194
195 /* Check Oscillator Stop flag */
196 error = bq32k_read(dev, ®, BQ32K_SECONDS, 1);
197 if (!error && (reg & BQ32K_STOP)) {
198 dev_warn(dev, "Oscillator was halted. Restarting...\n");
199 reg &= ~BQ32K_STOP;
200 error = bq32k_write(dev, ®, BQ32K_SECONDS, 1);
201 }
202 if (error)
203 return error;
204
205 /* Check Oscillator Failure flag */
206 error = bq32k_read(dev, ®, BQ32K_MINUTES, 1);
207 if (!error && (reg & BQ32K_OF)) {
208 dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
209 reg &= ~BQ32K_OF;
210 error = bq32k_write(dev, ®, BQ32K_MINUTES, 1);
211 }
212 if (error)
213 return error;
214
215 if (client->dev.of_node)
216 trickle_charger_of_init(dev, client->dev.of_node);
217
218 rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
219 &bq32k_rtc_ops, THIS_MODULE);
220 if (IS_ERR(rtc))
221 return PTR_ERR(rtc);
222
223 i2c_set_clientdata(client, rtc);
224
225 return 0;
226}
227
228static const struct i2c_device_id bq32k_id[] = {
229 { "bq32000", 0 },
230 { }
231};
232MODULE_DEVICE_TABLE(i2c, bq32k_id);
233
234static struct i2c_driver bq32k_driver = {
235 .driver = {
236 .name = "bq32k",
237 },
238 .probe = bq32k_probe,
239 .id_table = bq32k_id,
240};
241
242module_i2c_driver(bq32k_driver);
243
244MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
245MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
246MODULE_LICENSE("GPL");
1/*
2 * Driver for TI BQ32000 RTC.
3 *
4 * Copyright (C) 2009 Semihalf.
5 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
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 * You can get hardware description at
12 * http://www.ti.com/lit/ds/symlink/bq32000.pdf
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
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
38struct 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
48static struct i2c_driver bq32k_driver;
49
50static 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
73static 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
87static 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
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
103 tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
104 tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
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
115static 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
135static const struct rtc_class_ops bq32k_rtc_ops = {
136 .read_time = bq32k_rtc_read_time,
137 .set_time = bq32k_rtc_set_time,
138};
139
140static 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 }
170 reg = 0x45;
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
191static 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);
214 if (error)
215 return error;
216 if (reg & BQ32K_OF)
217 dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
218
219 if (client->dev.of_node)
220 trickle_charger_of_init(dev, client->dev.of_node);
221
222 rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
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
232static const struct i2c_device_id bq32k_id[] = {
233 { "bq32000", 0 },
234 { }
235};
236MODULE_DEVICE_TABLE(i2c, bq32k_id);
237
238static struct i2c_driver bq32k_driver = {
239 .driver = {
240 .name = "bq32k",
241 },
242 .probe = bq32k_probe,
243 .id_table = bq32k_id,
244};
245
246module_i2c_driver(bq32k_driver);
247
248MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
249MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
250MODULE_LICENSE("GPL");