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, &regs, 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, &regs, 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, &reg, BQ32K_CFG2, 1);
172	if (error)
173		return error;
174
175	reg = 0x20;
176	error = bq32k_write(dev, &reg, 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, &reg, 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, &reg, BQ32K_SECONDS, 1);
201	}
202	if (error)
203		return error;
204
205	/* Check Oscillator Failure flag */
206	error = bq32k_read(dev, &reg, 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, &reg, 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#define BQ32K_TCFE		BIT(6)	/* Trickle charge FET bypass */
 38
 39#define MAX_LEN			10	/* Maximum number of consecutive
 40					 * register for this particular RTC.
 41					 */
 42
 43struct bq32k_regs {
 44	uint8_t		seconds;
 45	uint8_t		minutes;
 46	uint8_t		cent_hours;
 47	uint8_t		day;
 48	uint8_t		date;
 49	uint8_t		month;
 50	uint8_t		years;
 51};
 52
 53static struct i2c_driver bq32k_driver;
 54
 55static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
 56{
 57	struct i2c_client *client = to_i2c_client(dev);
 58	struct i2c_msg msgs[] = {
 59		{
 60			.addr = client->addr,
 61			.flags = 0,
 62			.len = 1,
 63			.buf = &off,
 64		}, {
 65			.addr = client->addr,
 66			.flags = I2C_M_RD,
 67			.len = len,
 68			.buf = data,
 69		}
 70	};
 71
 72	if (i2c_transfer(client->adapter, msgs, 2) == 2)
 73		return 0;
 74
 75	return -EIO;
 76}
 77
 78static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
 79{
 80	struct i2c_client *client = to_i2c_client(dev);
 81	uint8_t buffer[MAX_LEN + 1];
 82
 83	buffer[0] = off;
 84	memcpy(&buffer[1], data, len);
 85
 86	if (i2c_master_send(client, buffer, len + 1) == len + 1)
 87		return 0;
 88
 89	return -EIO;
 90}
 91
 92static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
 93{
 94	struct bq32k_regs regs;
 95	int error;
 96
 97	error = bq32k_read(dev, &regs, 0, sizeof(regs));
 98	if (error)
 99		return error;
100
101	/*
102	 * In case of oscillator failure, the register contents should be
103	 * considered invalid. The flag is cleared the next time the RTC is set.
104	 */
105	if (regs.minutes & BQ32K_OF)
106		return -EINVAL;
107
108	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
109	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
110	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
111	tm->tm_mday = bcd2bin(regs.date);
112	tm->tm_wday = bcd2bin(regs.day) - 1;
113	tm->tm_mon = bcd2bin(regs.month) - 1;
114	tm->tm_year = bcd2bin(regs.years) +
115				((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
116
117	return 0;
118}
119
120static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
121{
122	struct bq32k_regs regs;
123
124	regs.seconds = bin2bcd(tm->tm_sec);
125	regs.minutes = bin2bcd(tm->tm_min);
126	regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
127	regs.day = bin2bcd(tm->tm_wday + 1);
128	regs.date = bin2bcd(tm->tm_mday);
129	regs.month = bin2bcd(tm->tm_mon + 1);
130
131	if (tm->tm_year >= 100) {
132		regs.cent_hours |= BQ32K_CENT;
133		regs.years = bin2bcd(tm->tm_year - 100);
134	} else
135		regs.years = bin2bcd(tm->tm_year);
136
137	return bq32k_write(dev, &regs, 0, sizeof(regs));
138}
139
140static const struct rtc_class_ops bq32k_rtc_ops = {
141	.read_time	= bq32k_rtc_read_time,
142	.set_time	= bq32k_rtc_set_time,
143};
144
145static int trickle_charger_of_init(struct device *dev, struct device_node *node)
146{
147	unsigned char reg;
148	int error;
149	u32 ohms = 0;
150
151	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
152		return 0;
153
154	switch (ohms) {
155	case 180+940:
156		/*
157		 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
158		 * over diode and 940ohm resistor)
159		 */
160
161		if (of_property_read_bool(node, "trickle-diode-disable")) {
162			dev_err(dev, "diode and resistor mismatch\n");
163			return -EINVAL;
164		}
165		reg = 0x05;
166		break;
167
168	case 180+20000:
169		/* diode disabled */
170
171		if (!of_property_read_bool(node, "trickle-diode-disable")) {
172			dev_err(dev, "bq32k: diode and resistor mismatch\n");
173			return -EINVAL;
174		}
175		reg = 0x45;
176		break;
177
178	default:
179		dev_err(dev, "invalid resistor value (%d)\n", ohms);
180		return -EINVAL;
181	}
182
183	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
184	if (error)
185		return error;
186
187	reg = 0x20;
188	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
189	if (error)
190		return error;
191
192	dev_info(dev, "Enabled trickle RTC battery charge.\n");
193	return 0;
194}
195
196static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
197					       struct device_attribute *attr,
198					       char *buf)
199{
200	int reg, error;
201
202	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
203	if (error)
204		return error;
205
206	return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
207}
208
209static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
210						struct device_attribute *attr,
211						const char *buf, size_t count)
212{
213	int reg, enable, error;
214
215	if (kstrtoint(buf, 0, &enable))
216		return -EINVAL;
217
218	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
219	if (error)
220		return error;
221
222	if (enable) {
223		reg |= BQ32K_TCFE;
224		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
225		if (error)
226			return error;
227
228		dev_info(dev, "Enabled trickle charge FET bypass.\n");
229	} else {
230		reg &= ~BQ32K_TCFE;
231		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
232		if (error)
233			return error;
234
235		dev_info(dev, "Disabled trickle charge FET bypass.\n");
236	}
237
238	return count;
239}
240
241static DEVICE_ATTR(trickle_charge_bypass, 0644,
242		   bq32k_sysfs_show_tricklecharge_bypass,
243		   bq32k_sysfs_store_tricklecharge_bypass);
244
245static int bq32k_sysfs_register(struct device *dev)
246{
247	return device_create_file(dev, &dev_attr_trickle_charge_bypass);
248}
249
250static void bq32k_sysfs_unregister(struct device *dev)
251{
252	device_remove_file(dev, &dev_attr_trickle_charge_bypass);
253}
254
255static int bq32k_probe(struct i2c_client *client,
256				const struct i2c_device_id *id)
257{
258	struct device *dev = &client->dev;
259	struct rtc_device *rtc;
260	uint8_t reg;
261	int error;
262
263	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
264		return -ENODEV;
265
266	/* Check Oscillator Stop flag */
267	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
268	if (!error && (reg & BQ32K_STOP)) {
269		dev_warn(dev, "Oscillator was halted. Restarting...\n");
270		reg &= ~BQ32K_STOP;
271		error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
272	}
273	if (error)
274		return error;
275
276	/* Check Oscillator Failure flag */
277	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
 
 
 
 
 
278	if (error)
279		return error;
280	if (reg & BQ32K_OF)
281		dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
282
283	if (client->dev.of_node)
284		trickle_charger_of_init(dev, client->dev.of_node);
285
286	rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
287						&bq32k_rtc_ops, THIS_MODULE);
288	if (IS_ERR(rtc))
289		return PTR_ERR(rtc);
290
291	error = bq32k_sysfs_register(&client->dev);
292	if (error) {
293		dev_err(&client->dev,
294			"Unable to create sysfs entries for rtc bq32000\n");
295		return error;
296	}
297
298
299	i2c_set_clientdata(client, rtc);
300
301	return 0;
302}
303
304static int bq32k_remove(struct i2c_client *client)
305{
306	bq32k_sysfs_unregister(&client->dev);
307
308	return 0;
309}
310
311static const struct i2c_device_id bq32k_id[] = {
312	{ "bq32000", 0 },
313	{ }
314};
315MODULE_DEVICE_TABLE(i2c, bq32k_id);
316
317static const struct of_device_id bq32k_of_match[] = {
318	{ .compatible = "ti,bq32000" },
319	{ }
320};
321MODULE_DEVICE_TABLE(of, bq32k_of_match);
322
323static struct i2c_driver bq32k_driver = {
324	.driver = {
325		.name	= "bq32k",
326		.of_match_table = of_match_ptr(bq32k_of_match),
327	},
328	.probe		= bq32k_probe,
329	.remove		= bq32k_remove,
330	.id_table	= bq32k_id,
331};
332
333module_i2c_driver(bq32k_driver);
334
335MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
336MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
337MODULE_LICENSE("GPL");