[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / drivers / rtc / rtc-pcf8523.c

/*
 * Copyright (C) 2012 Avionic Design GmbH
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/bcd.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/of.h>

#define DRIVER_NAME "rtc-pcf8523"

#define REG_CONTROL1 0x00
#define REG_CONTROL1_CAP_SEL (1 << 7)
#define REG_CONTROL1_STOP    (1 << 5)

#define REG_CONTROL3 0x02
#define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */
#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
#define REG_CONTROL3_PM_MASK 0xe0
#define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */

#define REG_SECONDS  0x03
#define REG_SECONDS_OS (1 << 7)

#define REG_MINUTES  0x04
#define REG_HOURS    0x05
#define REG_DAYS     0x06
#define REG_WEEKDAYS 0x07
#define REG_MONTHS   0x08
#define REG_YEARS    0x09

struct pcf8523 {
	struct rtc_device *rtc;
};

static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
{
	struct i2c_msg msgs[2];
	u8 value = 0;
	int err;

	msgs[0].addr = client->addr;
	msgs[0].flags = 0;
	msgs[0].len = sizeof(reg);
	msgs[0].buf = &reg;

	msgs[1].addr = client->addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = sizeof(value);
	msgs[1].buf = &value;

	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (err < 0)
		return err;

	*valuep = value;

	return 0;
}

static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
{
	u8 buffer[2] = { reg, value };
	struct i2c_msg msg;
	int err;

	msg.addr = client->addr;
	msg.flags = 0;
	msg.len = sizeof(buffer);
	msg.buf = buffer;

	err = i2c_transfer(client->adapter, &msg, 1);
	if (err < 0)
		return err;

	return 0;
}

static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
{
	u8 value;
	int err;

	err = pcf8523_read(client, REG_CONTROL1, &value);
	if (err < 0)
		return err;

	if (!high)
		value &= ~REG_CONTROL1_CAP_SEL;
	else
		value |= REG_CONTROL1_CAP_SEL;

	err = pcf8523_write(client, REG_CONTROL1, value);
	if (err < 0)
		return err;

	return err;
}

static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
{
	u8 value;
	int err;

	err = pcf8523_read(client, REG_CONTROL3, &value);
	if (err < 0)
		return err;

	value = (value & ~REG_CONTROL3_PM_MASK) | pm;

	err = pcf8523_write(client, REG_CONTROL3, value);
	if (err < 0)
		return err;

	return 0;
}

static int pcf8523_stop_rtc(struct i2c_client *client)
{
	u8 value;
	int err;

	err = pcf8523_read(client, REG_CONTROL1, &value);
	if (err < 0)
		return err;

	value |= REG_CONTROL1_STOP;

	err = pcf8523_write(client, REG_CONTROL1, value);
	if (err < 0)
		return err;

	return 0;
}

static int pcf8523_start_rtc(struct i2c_client *client)
{
	u8 value;
	int err;

	err = pcf8523_read(client, REG_CONTROL1, &value);
	if (err < 0)
		return err;

	value &= ~REG_CONTROL1_STOP;

	err = pcf8523_write(client, REG_CONTROL1, value);
	if (err < 0)
		return err;

	return 0;
}

static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 start = REG_SECONDS, regs[7];
	struct i2c_msg msgs[2];
	int err;

	msgs[0].addr = client->addr;
	msgs[0].flags = 0;
	msgs[0].len = 1;
	msgs[0].buf = &start;

	msgs[1].addr = client->addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = sizeof(regs);
	msgs[1].buf = regs;

	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (err < 0)
		return err;

	if (regs[0] & REG_SECONDS_OS) {
		/*
		 * If the oscillator was stopped, try to clear the flag. Upon
		 * power-up the flag is always set, but if we cannot clear it
		 * the oscillator isn't running properly for some reason. The
		 * sensible thing therefore is to return an error, signalling
		 * that the clock cannot be assumed to be correct.
		 */

		regs[0] &= ~REG_SECONDS_OS;

		err = pcf8523_write(client, REG_SECONDS, regs[0]);
		if (err < 0)
			return err;

		err = pcf8523_read(client, REG_SECONDS, &regs[0]);
		if (err < 0)
			return err;

		if (regs[0] & REG_SECONDS_OS)
			return -EAGAIN;
	}

	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
	tm->tm_min = bcd2bin(regs[1] & 0x7f);
	tm->tm_hour = bcd2bin(regs[2] & 0x3f);
	tm->tm_mday = bcd2bin(regs[3] & 0x3f);
	tm->tm_wday = regs[4] & 0x7;
	tm->tm_mon = bcd2bin(regs[5] & 0x1f);
	tm->tm_year = bcd2bin(regs[6]) + 100;

	return rtc_valid_tm(tm);
}

static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct i2c_msg msg;
	u8 regs[8];
	int err;

	err = pcf8523_stop_rtc(client);
	if (err < 0)
		return err;

	regs[0] = REG_SECONDS;
	regs[1] = bin2bcd(tm->tm_sec);
	regs[2] = bin2bcd(tm->tm_min);
	regs[3] = bin2bcd(tm->tm_hour);
	regs[4] = bin2bcd(tm->tm_mday);
	regs[5] = tm->tm_wday;
	regs[6] = bin2bcd(tm->tm_mon);
	regs[7] = bin2bcd(tm->tm_year - 100);

	msg.addr = client->addr;
	msg.flags = 0;
	msg.len = sizeof(regs);
	msg.buf = regs;

	err = i2c_transfer(client->adapter, &msg, 1);
	if (err < 0) {
		/*
		 * If the time cannot be set, restart the RTC anyway. Note
		 * that errors are ignored if the RTC cannot be started so
		 * that we have a chance to propagate the original error.
		 */
		pcf8523_start_rtc(client);
		return err;
	}

	return pcf8523_start_rtc(client);
}

#ifdef CONFIG_RTC_INTF_DEV
static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
			     unsigned long arg)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 value;
	int ret = 0, err;

	switch (cmd) {
	case RTC_VL_READ:
		err = pcf8523_read(client, REG_CONTROL3, &value);
		if (err < 0)
			return err;

		if (value & REG_CONTROL3_BLF)
			ret = 1;

		if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
			return -EFAULT;

		return 0;
	default:
		return -ENOIOCTLCMD;
	}
}
#else
#define pcf8523_rtc_ioctl NULL
#endif

static const struct rtc_class_ops pcf8523_rtc_ops = {
	.read_time = pcf8523_rtc_read_time,
	.set_time = pcf8523_rtc_set_time,
	.ioctl = pcf8523_rtc_ioctl,
};

static int pcf8523_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct pcf8523 *pcf;
	int err;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
	if (!pcf)
		return -ENOMEM;

	err = pcf8523_select_capacitance(client, true);
	if (err < 0)
		return err;

	err = pcf8523_set_pm(client, 0);
	if (err < 0)
		return err;

	pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
				       &pcf8523_rtc_ops, THIS_MODULE);
	if (IS_ERR(pcf->rtc))
		return PTR_ERR(pcf->rtc);

	i2c_set_clientdata(client, pcf);

	return 0;
}

static int pcf8523_remove(struct i2c_client *client)
{
	return 0;
}

static const struct i2c_device_id pcf8523_id[] = {
	{ "pcf8523", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8523_id);

#ifdef CONFIG_OF
static const struct of_device_id pcf8523_of_match[] = {
	{ .compatible = "nxp,pcf8523" },
	{ }
};
MODULE_DEVICE_TABLE(of, pcf8523_of_match);
#endif

static struct i2c_driver pcf8523_driver = {
	.driver = {
		.name = DRIVER_NAME,
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(pcf8523_of_match),
	},
	.probe = pcf8523_probe,
	.remove = pcf8523_remove,
	.id_table = pcf8523_id,
};
module_i2c_driver(pcf8523_driver);

MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
f803f0d0 TR	1	/*
	2	* Copyright (C) 2012 Avionic Design GmbH
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/bcd.h>
	10	#include <linux/i2c.h>
	11	#include <linux/module.h>
	12	#include <linux/rtc.h>
	13	#include <linux/of.h>
	14
	15	#define DRIVER_NAME "rtc-pcf8523"
	16
	17	#define REG_CONTROL1 0x00
	18	#define REG_CONTROL1_CAP_SEL (1 << 7)
	19	#define REG_CONTROL1_STOP (1 << 5)
	20
	21	#define REG_CONTROL3 0x02
	22	#define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */
	23	#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
	24	#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
	25	#define REG_CONTROL3_PM_MASK 0xe0
f32bc70d	26	#define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */
f803f0d0 TR	27
	28	#define REG_SECONDS 0x03
	29	#define REG_SECONDS_OS (1 << 7)
	30
	31	#define REG_MINUTES 0x04
	32	#define REG_HOURS 0x05
	33	#define REG_DAYS 0x06
	34	#define REG_WEEKDAYS 0x07
	35	#define REG_MONTHS 0x08
	36	#define REG_YEARS 0x09
	37
	38	struct pcf8523 {
	39	struct rtc_device *rtc;
	40	};
	41
	42	static int pcf8523_read(struct i2c_client client, u8 reg, u8 valuep)
	43	{
	44	struct i2c_msg msgs[2];
	45	u8 value = 0;
	46	int err;
	47
	48	msgs[0].addr = client->addr;
	49	msgs[0].flags = 0;
	50	msgs[0].len = sizeof(reg);
	51	msgs[0].buf = ®
	52
	53	msgs[1].addr = client->addr;
	54	msgs[1].flags = I2C_M_RD;
	55	msgs[1].len = sizeof(value);
	56	msgs[1].buf = &value;
	57
	58	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	59	if (err < 0)
	60	return err;
	61
	62	*valuep = value;
	63
	64	return 0;
	65	}
	66
	67	static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
	68	{
	69	u8 buffer[2] = { reg, value };
	70	struct i2c_msg msg;
	71	int err;
	72
	73	msg.addr = client->addr;
	74	msg.flags = 0;
	75	msg.len = sizeof(buffer);
	76	msg.buf = buffer;
	77
	78	err = i2c_transfer(client->adapter, &msg, 1);
	79	if (err < 0)
	80	return err;
	81
	82	return 0;
	83	}
	84
	85	static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
	86	{
	87	u8 value;
	88	int err;
	89
	90	err = pcf8523_read(client, REG_CONTROL1, &value);
91	if (err < 0)
92	return err;
93
94	if (!high)
95	value &= ~REG_CONTROL1_CAP_SEL;
96	else
97	value \|= REG_CONTROL1_CAP_SEL;
98
99	err = pcf8523_write(client, REG_CONTROL1, value);
100	if (err < 0)
101	return err;
102
103	return err;
104	}
105
106	static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
107	{
108	u8 value;
109	int err;
110
111	err = pcf8523_read(client, REG_CONTROL3, &value);
112	if (err < 0)
113	return err;
114
115	value = (value & ~REG_CONTROL3_PM_MASK) \| pm;
116
117	err = pcf8523_write(client, REG_CONTROL3, value);
118	if (err < 0)
119	return err;
120
121	return 0;
122	}
123
124	static int pcf8523_stop_rtc(struct i2c_client *client)
125	{
126	u8 value;
127	int err;
128
129	err = pcf8523_read(client, REG_CONTROL1, &value);
130	if (err < 0)
131	return err;
132
133	value \|= REG_CONTROL1_STOP;
134
135	err = pcf8523_write(client, REG_CONTROL1, value);
136	if (err < 0)
137	return err;
138
139	return 0;
140	}
141
142	static int pcf8523_start_rtc(struct i2c_client *client)
143	{
144	u8 value;
145	int err;
146
147	err = pcf8523_read(client, REG_CONTROL1, &value);
148	if (err < 0)
149	return err;
150
151	value &= ~REG_CONTROL1_STOP;
152
153	err = pcf8523_write(client, REG_CONTROL1, value);
154	if (err < 0)
155	return err;
156
157	return 0;
158	}
159
160	static int pcf8523_rtc_read_time(struct device dev, struct rtc_time tm)
161	{
162	struct i2c_client *client = to_i2c_client(dev);
163	u8 start = REG_SECONDS, regs[7];
164	struct i2c_msg msgs[2];
165	int err;
166
167	msgs[0].addr = client->addr;
168	msgs[0].flags = 0;
169	msgs[0].len = 1;
170	msgs[0].buf = &start;
171
172	msgs[1].addr = client->addr;
173	msgs[1].flags = I2C_M_RD;
174	msgs[1].len = sizeof(regs);
175	msgs[1].buf = regs;
176
177	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
178	if (err < 0)
179	return err;
180
181	if (regs[0] & REG_SECONDS_OS) {
182	/*
183	* If the oscillator was stopped, try to clear the flag. Upon
184	* power-up the flag is always set, but if we cannot clear it
185	* the oscillator isn't running properly for some reason. The
186	* sensible thing therefore is to return an error, signalling
187	* that the clock cannot be assumed to be correct.
188	*/
189
190	regs[0] &= ~REG_SECONDS_OS;
191
192	err = pcf8523_write(client, REG_SECONDS, regs[0]);
193	if (err < 0)
194	return err;
195
196	err = pcf8523_read(client, REG_SECONDS, &regs[0]);
197	if (err < 0)
198	return err;
199
200	if (regs[0] & REG_SECONDS_OS)
201	return -EAGAIN;
202	}
203
204	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
205	tm->tm_min = bcd2bin(regs[1] & 0x7f);
206	tm->tm_hour = bcd2bin(regs[2] & 0x3f);
207	tm->tm_mday = bcd2bin(regs[3] & 0x3f);
208	tm->tm_wday = regs[4] & 0x7;
209	tm->tm_mon = bcd2bin(regs[5] & 0x1f);
210	tm->tm_year = bcd2bin(regs[6]) + 100;
211
212	return rtc_valid_tm(tm);
213	}
214
215	static int pcf8523_rtc_set_time(struct device dev, struct rtc_time tm)
216	{
217	struct i2c_client *client = to_i2c_client(dev);
218	struct i2c_msg msg;
219	u8 regs[8];
220	int err;
221
222	err = pcf8523_stop_rtc(client);
223	if (err < 0)
224	return err;
225
226	regs[0] = REG_SECONDS;
227	regs[1] = bin2bcd(tm->tm_sec);
228	regs[2] = bin2bcd(tm->tm_min);
229	regs[3] = bin2bcd(tm->tm_hour);
230	regs[4] = bin2bcd(tm->tm_mday);
231	regs[5] = tm->tm_wday;
232	regs[6] = bin2bcd(tm->tm_mon);
233	regs[7] = bin2bcd(tm->tm_year - 100);
234
235	msg.addr = client->addr;
236	msg.flags = 0;
237	msg.len = sizeof(regs);
238	msg.buf = regs;
239
240	err = i2c_transfer(client->adapter, &msg, 1);
241	if (err < 0) {
242	/*
243	* If the time cannot be set, restart the RTC anyway. Note
244	* that errors are ignored if the RTC cannot be started so
245	* that we have a chance to propagate the original error.
246	*/
247	pcf8523_start_rtc(client);
248	return err;
249	}
250
251	return pcf8523_start_rtc(client);
252	}
253
f32bc70d JN	254	#ifdef CONFIG_RTC_INTF_DEV
	255	static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
	256	unsigned long arg)
	257	{
	258	struct i2c_client *client = to_i2c_client(dev);
	259	u8 value;
	260	int ret = 0, err;
	261
	262	switch (cmd) {
	263	case RTC_VL_READ:
	264	err = pcf8523_read(client, REG_CONTROL3, &value);
	265	if (err < 0)
	266	return err;
	267
	268	if (value & REG_CONTROL3_BLF)
	269	ret = 1;
	270
	271	if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
	272	return -EFAULT;
	273
	274	return 0;
	275	default:
	276	return -ENOIOCTLCMD;
	277	}
	278	}
	279	#else
	280	#define pcf8523_rtc_ioctl NULL
	281	#endif
	282
f803f0d0 TR	283	static const struct rtc_class_ops pcf8523_rtc_ops = {
	284	.read_time = pcf8523_rtc_read_time,
	285	.set_time = pcf8523_rtc_set_time,
f32bc70d	286	.ioctl = pcf8523_rtc_ioctl,
f803f0d0 TR	287	};
	288
	289	static int pcf8523_probe(struct i2c_client *client,
	290	const struct i2c_device_id *id)
	291	{
	292	struct pcf8523 *pcf;
	293	int err;
	294
	295	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	296	return -ENODEV;
	297
	298	pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
	299	if (!pcf)
	300	return -ENOMEM;
	301
	302	err = pcf8523_select_capacitance(client, true);
	303	if (err < 0)
	304	return err;
	305
	306	err = pcf8523_set_pm(client, 0);
	307	if (err < 0)
	308	return err;
	309
288031bf	310	pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
f803f0d0 TR	311	&pcf8523_rtc_ops, THIS_MODULE);
	312	if (IS_ERR(pcf->rtc))
	313	return PTR_ERR(pcf->rtc);
	314
	315	i2c_set_clientdata(client, pcf);
	316
	317	return 0;
	318	}
	319
	320	static int pcf8523_remove(struct i2c_client *client)
	321	{
f803f0d0 TR	322	return 0;
	323	}
	324
	325	static const struct i2c_device_id pcf8523_id[] = {
	326	{ "pcf8523", 0 },
	327	{ }
	328	};
	329	MODULE_DEVICE_TABLE(i2c, pcf8523_id);
	330
	331	#ifdef CONFIG_OF
	332	static const struct of_device_id pcf8523_of_match[] = {
	333	{ .compatible = "nxp,pcf8523" },
	334	{ }
	335	};
	336	MODULE_DEVICE_TABLE(of, pcf8523_of_match);
	337	#endif
	338
	339	static struct i2c_driver pcf8523_driver = {
	340	.driver = {
	341	.name = DRIVER_NAME,
	342	.owner = THIS_MODULE,
	343	.of_match_table = of_match_ptr(pcf8523_of_match),
	344	},
	345	.probe = pcf8523_probe,
	346	.remove = pcf8523_remove,
	347	.id_table = pcf8523_id,
	348	};
	349	module_i2c_driver(pcf8523_driver);
	350
	351	MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
	352	MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
	353	MODULE_LICENSE("GPL v2");