1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for TI BQ32000 RTC.
  4 *
  5 * Copyright (C) 2009 Semihalf.
  6 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
  7 *
  8 * You can get hardware description at
  9 * https://www.ti.com/lit/ds/symlink/bq32000.pdf
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/i2c.h>
 14#include <linux/rtc.h>
 15#include <linux/init.h>
 16#include <linux/kstrtox.h>
 17#include <linux/errno.h>
 18#include <linux/bcd.h>
 19
 20#define BQ32K_SECONDS		0x00	/* Seconds register address */
 21#define BQ32K_SECONDS_MASK	0x7F	/* Mask over seconds value */
 22#define BQ32K_STOP		0x80	/* Oscillator Stop flat */
 23
 24#define BQ32K_MINUTES		0x01	/* Minutes register address */
 25#define BQ32K_MINUTES_MASK	0x7F	/* Mask over minutes value */
 26#define BQ32K_OF		0x80	/* Oscillator Failure flag */
 27
 28#define BQ32K_HOURS_MASK	0x3F	/* Mask over hours value */
 29#define BQ32K_CENT		0x40	/* Century flag */
 30#define BQ32K_CENT_EN		0x80	/* Century flag enable bit */
 31
 32#define BQ32K_CALIBRATION	0x07	/* CAL_CFG1, calibration and control */
 33#define BQ32K_TCH2		0x08	/* Trickle charge enable */
 34#define BQ32K_CFG2		0x09	/* Trickle charger control */
 35#define BQ32K_TCFE		BIT(6)	/* Trickle charge FET bypass */
 36
 37#define MAX_LEN			10	/* Maximum number of consecutive
 38					 * register for this particular RTC.
 39					 */
 40
 41struct bq32k_regs {
 42	uint8_t		seconds;
 43	uint8_t		minutes;
 44	uint8_t		cent_hours;
 45	uint8_t		day;
 46	uint8_t		date;
 47	uint8_t		month;
 48	uint8_t		years;
 49};
 50
 51static struct i2c_driver bq32k_driver;
 52
 53static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
 54{
 55	struct i2c_client *client = to_i2c_client(dev);
 56	struct i2c_msg msgs[] = {
 57		{
 58			.addr = client->addr,
 59			.flags = 0,
 60			.len = 1,
 61			.buf = &off,
 62		}, {
 63			.addr = client->addr,
 64			.flags = I2C_M_RD,
 65			.len = len,
 66			.buf = data,
 67		}
 68	};
 69
 70	if (i2c_transfer(client->adapter, msgs, 2) == 2)
 71		return 0;
 72
 73	return -EIO;
 74}
 75
 76static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
 77{
 78	struct i2c_client *client = to_i2c_client(dev);
 79	uint8_t buffer[MAX_LEN + 1];
 80
 81	buffer[0] = off;
 82	memcpy(&buffer[1], data, len);
 83
 84	if (i2c_master_send(client, buffer, len + 1) == len + 1)
 85		return 0;
 86
 87	return -EIO;
 88}
 89
 90static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
 91{
 92	struct bq32k_regs regs;
 93	int error;
 94
 95	error = bq32k_read(dev, &regs, 0, sizeof(regs));
 96	if (error)
 97		return error;
 98
 99	/*
100	 * In case of oscillator failure, the register contents should be
101	 * considered invalid. The flag is cleared the next time the RTC is set.
102	 */
103	if (regs.minutes & BQ32K_OF)
104		return -EINVAL;
105
106	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
107	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
108	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
109	tm->tm_mday = bcd2bin(regs.date);
110	tm->tm_wday = bcd2bin(regs.day) - 1;
111	tm->tm_mon = bcd2bin(regs.month) - 1;
112	tm->tm_year = bcd2bin(regs.years) +
113				((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
114
115	return 0;
116}
117
118static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
119{
120	struct bq32k_regs regs;
121
122	regs.seconds = bin2bcd(tm->tm_sec);
123	regs.minutes = bin2bcd(tm->tm_min);
124	regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
125	regs.day = bin2bcd(tm->tm_wday + 1);
126	regs.date = bin2bcd(tm->tm_mday);
127	regs.month = bin2bcd(tm->tm_mon + 1);
128
129	if (tm->tm_year >= 100) {
130		regs.cent_hours |= BQ32K_CENT;
131		regs.years = bin2bcd(tm->tm_year - 100);
132	} else
133		regs.years = bin2bcd(tm->tm_year);
134
135	return bq32k_write(dev, &regs, 0, sizeof(regs));
136}
137
138static const struct rtc_class_ops bq32k_rtc_ops = {
139	.read_time	= bq32k_rtc_read_time,
140	.set_time	= bq32k_rtc_set_time,
141};
142
143static int trickle_charger_of_init(struct device *dev, struct device_node *node)
144{
145	unsigned char reg;
146	int error;
147	u32 ohms = 0;
148
149	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
150		return 0;
151
152	switch (ohms) {
153	case 180+940:
154		/*
155		 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
156		 * over diode and 940ohm resistor)
157		 */
158
159		if (of_property_read_bool(node, "trickle-diode-disable")) {
160			dev_err(dev, "diode and resistor mismatch\n");
161			return -EINVAL;
162		}
163		reg = 0x05;
164		break;
165
166	case 180+20000:
167		/* diode disabled */
168
169		if (!of_property_read_bool(node, "trickle-diode-disable")) {
170			dev_err(dev, "bq32k: diode and resistor mismatch\n");
171			return -EINVAL;
172		}
173		reg = 0x45;
174		break;
175
176	default:
177		dev_err(dev, "invalid resistor value (%d)\n", ohms);
178		return -EINVAL;
179	}
180
181	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
182	if (error)
183		return error;
184
185	reg = 0x20;
186	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
187	if (error)
188		return error;
189
190	dev_info(dev, "Enabled trickle RTC battery charge.\n");
191	return 0;
192}
193
194static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
195					       struct device_attribute *attr,
196					       char *buf)
197{
198	int reg, error;
199
200	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
201	if (error)
202		return error;
203
204	return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
205}
206
207static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
208						struct device_attribute *attr,
209						const char *buf, size_t count)
210{
211	int reg, enable, error;
212
213	if (kstrtoint(buf, 0, &enable))
214		return -EINVAL;
215
216	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
217	if (error)
218		return error;
219
220	if (enable) {
221		reg |= BQ32K_TCFE;
222		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
223		if (error)
224			return error;
225
226		dev_info(dev, "Enabled trickle charge FET bypass.\n");
227	} else {
228		reg &= ~BQ32K_TCFE;
229		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
230		if (error)
231			return error;
232
233		dev_info(dev, "Disabled trickle charge FET bypass.\n");
234	}
235
236	return count;
237}
238
239static DEVICE_ATTR(trickle_charge_bypass, 0644,
240		   bq32k_sysfs_show_tricklecharge_bypass,
241		   bq32k_sysfs_store_tricklecharge_bypass);
242
243static int bq32k_sysfs_register(struct device *dev)
244{
245	return device_create_file(dev, &dev_attr_trickle_charge_bypass);
246}
247
248static void bq32k_sysfs_unregister(struct device *dev)
249{
250	device_remove_file(dev, &dev_attr_trickle_charge_bypass);
251}
252
253static int bq32k_probe(struct i2c_client *client)
 
254{
255	struct device *dev = &client->dev;
256	struct rtc_device *rtc;
257	uint8_t reg;
258	int error;
259
260	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
261		return -ENODEV;
262
263	/* Check Oscillator Stop flag */
264	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
265	if (!error && (reg & BQ32K_STOP)) {
266		dev_warn(dev, "Oscillator was halted. Restarting...\n");
267		reg &= ~BQ32K_STOP;
268		error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
269	}
270	if (error)
271		return error;
272
273	/* Check Oscillator Failure flag */
274	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
275	if (error)
276		return error;
277	if (reg & BQ32K_OF)
278		dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
279
280	if (client->dev.of_node)
281		trickle_charger_of_init(dev, client->dev.of_node);
282
283	rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
284						&bq32k_rtc_ops, THIS_MODULE);
285	if (IS_ERR(rtc))
286		return PTR_ERR(rtc);
287
288	error = bq32k_sysfs_register(&client->dev);
289	if (error) {
290		dev_err(&client->dev,
291			"Unable to create sysfs entries for rtc bq32000\n");
292		return error;
293	}
294
295
296	i2c_set_clientdata(client, rtc);
297
298	return 0;
299}
300
301static void bq32k_remove(struct i2c_client *client)
302{
303	bq32k_sysfs_unregister(&client->dev);
 
 
304}
305
306static const struct i2c_device_id bq32k_id[] = {
307	{ "bq32000", 0 },
308	{ }
309};
310MODULE_DEVICE_TABLE(i2c, bq32k_id);
311
312static const __maybe_unused struct of_device_id bq32k_of_match[] = {
313	{ .compatible = "ti,bq32000" },
314	{ }
315};
316MODULE_DEVICE_TABLE(of, bq32k_of_match);
317
318static struct i2c_driver bq32k_driver = {
319	.driver = {
320		.name	= "bq32k",
321		.of_match_table = of_match_ptr(bq32k_of_match),
322	},
323	.probe_new	= bq32k_probe,
324	.remove		= bq32k_remove,
325	.id_table	= bq32k_id,
326};
327
328module_i2c_driver(bq32k_driver);
329
330MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
331MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
332MODULE_LICENSE("GPL");

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for TI BQ32000 RTC.
  4 *
  5 * Copyright (C) 2009 Semihalf.
  6 * Copyright (C) 2014 Pavel Machek <pavel@denx.de>
  7 *
  8 * You can get hardware description at
  9 * http://www.ti.com/lit/ds/symlink/bq32000.pdf
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/i2c.h>
 14#include <linux/rtc.h>
 15#include <linux/init.h>
 
 16#include <linux/errno.h>
 17#include <linux/bcd.h>
 18
 19#define BQ32K_SECONDS		0x00	/* Seconds register address */
 20#define BQ32K_SECONDS_MASK	0x7F	/* Mask over seconds value */
 21#define BQ32K_STOP		0x80	/* Oscillator Stop flat */
 22
 23#define BQ32K_MINUTES		0x01	/* Minutes register address */
 24#define BQ32K_MINUTES_MASK	0x7F	/* Mask over minutes value */
 25#define BQ32K_OF		0x80	/* Oscillator Failure flag */
 26
 27#define BQ32K_HOURS_MASK	0x3F	/* Mask over hours value */
 28#define BQ32K_CENT		0x40	/* Century flag */
 29#define BQ32K_CENT_EN		0x80	/* Century flag enable bit */
 30
 31#define BQ32K_CALIBRATION	0x07	/* CAL_CFG1, calibration and control */
 32#define BQ32K_TCH2		0x08	/* Trickle charge enable */
 33#define BQ32K_CFG2		0x09	/* Trickle charger control */
 34#define BQ32K_TCFE		BIT(6)	/* Trickle charge FET bypass */
 35
 36#define MAX_LEN			10	/* Maximum number of consecutive
 37					 * register for this particular RTC.
 38					 */
 39
 40struct bq32k_regs {
 41	uint8_t		seconds;
 42	uint8_t		minutes;
 43	uint8_t		cent_hours;
 44	uint8_t		day;
 45	uint8_t		date;
 46	uint8_t		month;
 47	uint8_t		years;
 48};
 49
 50static struct i2c_driver bq32k_driver;
 51
 52static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
 53{
 54	struct i2c_client *client = to_i2c_client(dev);
 55	struct i2c_msg msgs[] = {
 56		{
 57			.addr = client->addr,
 58			.flags = 0,
 59			.len = 1,
 60			.buf = &off,
 61		}, {
 62			.addr = client->addr,
 63			.flags = I2C_M_RD,
 64			.len = len,
 65			.buf = data,
 66		}
 67	};
 68
 69	if (i2c_transfer(client->adapter, msgs, 2) == 2)
 70		return 0;
 71
 72	return -EIO;
 73}
 74
 75static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
 76{
 77	struct i2c_client *client = to_i2c_client(dev);
 78	uint8_t buffer[MAX_LEN + 1];
 79
 80	buffer[0] = off;
 81	memcpy(&buffer[1], data, len);
 82
 83	if (i2c_master_send(client, buffer, len + 1) == len + 1)
 84		return 0;
 85
 86	return -EIO;
 87}
 88
 89static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
 90{
 91	struct bq32k_regs regs;
 92	int error;
 93
 94	error = bq32k_read(dev, &regs, 0, sizeof(regs));
 95	if (error)
 96		return error;
 97
 98	/*
 99	 * In case of oscillator failure, the register contents should be
100	 * considered invalid. The flag is cleared the next time the RTC is set.
101	 */
102	if (regs.minutes & BQ32K_OF)
103		return -EINVAL;
104
105	tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
106	tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
107	tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
108	tm->tm_mday = bcd2bin(regs.date);
109	tm->tm_wday = bcd2bin(regs.day) - 1;
110	tm->tm_mon = bcd2bin(regs.month) - 1;
111	tm->tm_year = bcd2bin(regs.years) +
112				((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
113
114	return 0;
115}
116
117static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
118{
119	struct bq32k_regs regs;
120
121	regs.seconds = bin2bcd(tm->tm_sec);
122	regs.minutes = bin2bcd(tm->tm_min);
123	regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
124	regs.day = bin2bcd(tm->tm_wday + 1);
125	regs.date = bin2bcd(tm->tm_mday);
126	regs.month = bin2bcd(tm->tm_mon + 1);
127
128	if (tm->tm_year >= 100) {
129		regs.cent_hours |= BQ32K_CENT;
130		regs.years = bin2bcd(tm->tm_year - 100);
131	} else
132		regs.years = bin2bcd(tm->tm_year);
133
134	return bq32k_write(dev, &regs, 0, sizeof(regs));
135}
136
137static const struct rtc_class_ops bq32k_rtc_ops = {
138	.read_time	= bq32k_rtc_read_time,
139	.set_time	= bq32k_rtc_set_time,
140};
141
142static int trickle_charger_of_init(struct device *dev, struct device_node *node)
143{
144	unsigned char reg;
145	int error;
146	u32 ohms = 0;
147
148	if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
149		return 0;
150
151	switch (ohms) {
152	case 180+940:
153		/*
154		 * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging
155		 * over diode and 940ohm resistor)
156		 */
157
158		if (of_property_read_bool(node, "trickle-diode-disable")) {
159			dev_err(dev, "diode and resistor mismatch\n");
160			return -EINVAL;
161		}
162		reg = 0x05;
163		break;
164
165	case 180+20000:
166		/* diode disabled */
167
168		if (!of_property_read_bool(node, "trickle-diode-disable")) {
169			dev_err(dev, "bq32k: diode and resistor mismatch\n");
170			return -EINVAL;
171		}
172		reg = 0x45;
173		break;
174
175	default:
176		dev_err(dev, "invalid resistor value (%d)\n", ohms);
177		return -EINVAL;
178	}
179
180	error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
181	if (error)
182		return error;
183
184	reg = 0x20;
185	error = bq32k_write(dev, &reg, BQ32K_TCH2, 1);
186	if (error)
187		return error;
188
189	dev_info(dev, "Enabled trickle RTC battery charge.\n");
190	return 0;
191}
192
193static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
194					       struct device_attribute *attr,
195					       char *buf)
196{
197	int reg, error;
198
199	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
200	if (error)
201		return error;
202
203	return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
204}
205
206static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
207						struct device_attribute *attr,
208						const char *buf, size_t count)
209{
210	int reg, enable, error;
211
212	if (kstrtoint(buf, 0, &enable))
213		return -EINVAL;
214
215	error = bq32k_read(dev, &reg, BQ32K_CFG2, 1);
216	if (error)
217		return error;
218
219	if (enable) {
220		reg |= BQ32K_TCFE;
221		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
222		if (error)
223			return error;
224
225		dev_info(dev, "Enabled trickle charge FET bypass.\n");
226	} else {
227		reg &= ~BQ32K_TCFE;
228		error = bq32k_write(dev, &reg, BQ32K_CFG2, 1);
229		if (error)
230			return error;
231
232		dev_info(dev, "Disabled trickle charge FET bypass.\n");
233	}
234
235	return count;
236}
237
238static DEVICE_ATTR(trickle_charge_bypass, 0644,
239		   bq32k_sysfs_show_tricklecharge_bypass,
240		   bq32k_sysfs_store_tricklecharge_bypass);
241
242static int bq32k_sysfs_register(struct device *dev)
243{
244	return device_create_file(dev, &dev_attr_trickle_charge_bypass);
245}
246
247static void bq32k_sysfs_unregister(struct device *dev)
248{
249	device_remove_file(dev, &dev_attr_trickle_charge_bypass);
250}
251
252static int bq32k_probe(struct i2c_client *client,
253				const struct i2c_device_id *id)
254{
255	struct device *dev = &client->dev;
256	struct rtc_device *rtc;
257	uint8_t reg;
258	int error;
259
260	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
261		return -ENODEV;
262
263	/* Check Oscillator Stop flag */
264	error = bq32k_read(dev, &reg, BQ32K_SECONDS, 1);
265	if (!error && (reg & BQ32K_STOP)) {
266		dev_warn(dev, "Oscillator was halted. Restarting...\n");
267		reg &= ~BQ32K_STOP;
268		error = bq32k_write(dev, &reg, BQ32K_SECONDS, 1);
269	}
270	if (error)
271		return error;
272
273	/* Check Oscillator Failure flag */
274	error = bq32k_read(dev, &reg, BQ32K_MINUTES, 1);
275	if (error)
276		return error;
277	if (reg & BQ32K_OF)
278		dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
279
280	if (client->dev.of_node)
281		trickle_charger_of_init(dev, client->dev.of_node);
282
283	rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
284						&bq32k_rtc_ops, THIS_MODULE);
285	if (IS_ERR(rtc))
286		return PTR_ERR(rtc);
287
288	error = bq32k_sysfs_register(&client->dev);
289	if (error) {
290		dev_err(&client->dev,
291			"Unable to create sysfs entries for rtc bq32000\n");
292		return error;
293	}
294
295
296	i2c_set_clientdata(client, rtc);
297
298	return 0;
299}
300
301static int bq32k_remove(struct i2c_client *client)
302{
303	bq32k_sysfs_unregister(&client->dev);
304
305	return 0;
306}
307
308static const struct i2c_device_id bq32k_id[] = {
309	{ "bq32000", 0 },
310	{ }
311};
312MODULE_DEVICE_TABLE(i2c, bq32k_id);
313
314static const struct of_device_id bq32k_of_match[] = {
315	{ .compatible = "ti,bq32000" },
316	{ }
317};
318MODULE_DEVICE_TABLE(of, bq32k_of_match);
319
320static struct i2c_driver bq32k_driver = {
321	.driver = {
322		.name	= "bq32k",
323		.of_match_table = of_match_ptr(bq32k_of_match),
324	},
325	.probe		= bq32k_probe,
326	.remove		= bq32k_remove,
327	.id_table	= bq32k_id,
328};
329
330module_i2c_driver(bq32k_driver);
331
332MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
333MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
334MODULE_LICENSE("GPL");