[linux-2.6-block.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_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);
}

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

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 = rtc_device_register(DRIVER_NAME, &client->dev,
				       &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)
{
	struct pcf8523 *pcf = i2c_get_clientdata(client);

	rtc_device_unregister(pcf->rtc);

	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
	26
	27	#define REG_SECONDS 0x03
	28	#define REG_SECONDS_OS (1 << 7)
	29
	30	#define REG_MINUTES 0x04
	31	#define REG_HOURS 0x05
	32	#define REG_DAYS 0x06
	33	#define REG_WEEKDAYS 0x07
	34	#define REG_MONTHS 0x08
	35	#define REG_YEARS 0x09
	36
	37	struct pcf8523 {
	38	struct rtc_device *rtc;
	39	};
	40
	41	static int pcf8523_read(struct i2c_client client, u8 reg, u8 valuep)
	42	{
	43	struct i2c_msg msgs[2];
	44	u8 value = 0;
	45	int err;
	46
	47	msgs[0].addr = client->addr;
	48	msgs[0].flags = 0;
	49	msgs[0].len = sizeof(reg);
	50	msgs[0].buf = ®
	51
	52	msgs[1].addr = client->addr;
	53	msgs[1].flags = I2C_M_RD;
	54	msgs[1].len = sizeof(value);
	55	msgs[1].buf = &value;
	56
	57	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	58	if (err < 0)
	59	return err;
	60
	61	*valuep = value;
	62
	63	return 0;
	64	}
65
66	static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
67	{
68	u8 buffer[2] = { reg, value };
69	struct i2c_msg msg;
70	int err;
71
72	msg.addr = client->addr;
73	msg.flags = 0;
74	msg.len = sizeof(buffer);
75	msg.buf = buffer;
76
77	err = i2c_transfer(client->adapter, &msg, 1);
78	if (err < 0)
79	return err;
80
81	return 0;
82	}
83
84	static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
85	{
86	u8 value;
87	int err;
88
89	err = pcf8523_read(client, REG_CONTROL1, &value);
90	if (err < 0)
91	return err;
92
93	if (!high)
94	value &= ~REG_CONTROL1_CAP_SEL;
95	else
96	value \|= REG_CONTROL1_CAP_SEL;
97
98	err = pcf8523_write(client, REG_CONTROL1, value);
99	if (err < 0)
100	return err;
101
102	return err;
103	}
104
105	static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
106	{
107	u8 value;
108	int err;
109
110	err = pcf8523_read(client, REG_CONTROL3, &value);
111	if (err < 0)
112	return err;
113
114	value = (value & ~REG_CONTROL3_PM_MASK) \| pm;
115
116	err = pcf8523_write(client, REG_CONTROL3, value);
117	if (err < 0)
118	return err;
119
120	return 0;
121	}
122
123	static int pcf8523_stop_rtc(struct i2c_client *client)
124	{
125	u8 value;
126	int err;
127
128	err = pcf8523_read(client, REG_CONTROL1, &value);
129	if (err < 0)
130	return err;
131
132	value \|= REG_CONTROL1_STOP;
133
134	err = pcf8523_write(client, REG_CONTROL1, value);
135	if (err < 0)
136	return err;
137
138	return 0;
139	}
140
141	static int pcf8523_start_rtc(struct i2c_client *client)
142	{
143	u8 value;
144	int err;
145
146	err = pcf8523_read(client, REG_CONTROL1, &value);
147	if (err < 0)
148	return err;
149
150	value &= ~REG_CONTROL1_STOP;
151
152	err = pcf8523_write(client, REG_CONTROL1, value);
153	if (err < 0)
154	return err;
155
156	return 0;
157	}
158
159	static int pcf8523_rtc_read_time(struct device dev, struct rtc_time tm)
160	{
161	struct i2c_client *client = to_i2c_client(dev);
162	u8 start = REG_SECONDS, regs[7];
163	struct i2c_msg msgs[2];
164	int err;
165
166	msgs[0].addr = client->addr;
167	msgs[0].flags = 0;
168	msgs[0].len = 1;
169	msgs[0].buf = &start;
170
171	msgs[1].addr = client->addr;
172	msgs[1].flags = I2C_M_RD;
173	msgs[1].len = sizeof(regs);
174	msgs[1].buf = regs;
175
176	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
177	if (err < 0)
178	return err;
179
180	if (regs[0] & REG_SECONDS_OS) {
181	/*
182	* If the oscillator was stopped, try to clear the flag. Upon
183	* power-up the flag is always set, but if we cannot clear it
184	* the oscillator isn't running properly for some reason. The
185	* sensible thing therefore is to return an error, signalling
186	* that the clock cannot be assumed to be correct.
187	*/
188
189	regs[0] &= ~REG_SECONDS_OS;
190
191	err = pcf8523_write(client, REG_SECONDS, regs[0]);
192	if (err < 0)
193	return err;
194
195	err = pcf8523_read(client, REG_SECONDS, &regs[0]);
196	if (err < 0)
197	return err;
198
199	if (regs[0] & REG_SECONDS_OS)
200	return -EAGAIN;
201	}
202
203	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
204	tm->tm_min = bcd2bin(regs[1] & 0x7f);
205	tm->tm_hour = bcd2bin(regs[2] & 0x3f);
206	tm->tm_mday = bcd2bin(regs[3] & 0x3f);
207	tm->tm_wday = regs[4] & 0x7;
208	tm->tm_mon = bcd2bin(regs[5] & 0x1f);
209	tm->tm_year = bcd2bin(regs[6]) + 100;
210
211	return rtc_valid_tm(tm);
212	}
213
214	static int pcf8523_rtc_set_time(struct device dev, struct rtc_time tm)
215	{
216	struct i2c_client *client = to_i2c_client(dev);
217	struct i2c_msg msg;
218	u8 regs[8];
219	int err;
220
221	err = pcf8523_stop_rtc(client);
222	if (err < 0)
223	return err;
224
225	regs[0] = REG_SECONDS;
226	regs[1] = bin2bcd(tm->tm_sec);
227	regs[2] = bin2bcd(tm->tm_min);
228	regs[3] = bin2bcd(tm->tm_hour);
229	regs[4] = bin2bcd(tm->tm_mday);
230	regs[5] = tm->tm_wday;
231	regs[6] = bin2bcd(tm->tm_mon);
232	regs[7] = bin2bcd(tm->tm_year - 100);
233
234	msg.addr = client->addr;
235	msg.flags = 0;
236	msg.len = sizeof(regs);
237	msg.buf = regs;
238
239	err = i2c_transfer(client->adapter, &msg, 1);
240	if (err < 0) {
241	/*
242	* If the time cannot be set, restart the RTC anyway. Note
243	* that errors are ignored if the RTC cannot be started so
244	* that we have a chance to propagate the original error.
245	*/
246	pcf8523_start_rtc(client);
247	return err;
248	}
249
250	return pcf8523_start_rtc(client);
251	}
252
253	static const struct rtc_class_ops pcf8523_rtc_ops = {
254	.read_time = pcf8523_rtc_read_time,
255	.set_time = pcf8523_rtc_set_time,
256	};
257
258	static int pcf8523_probe(struct i2c_client *client,
259	const struct i2c_device_id *id)
260	{
261	struct pcf8523 *pcf;
262	int err;
263
264	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
265	return -ENODEV;
266
267	pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
268	if (!pcf)
269	return -ENOMEM;
270
271	err = pcf8523_select_capacitance(client, true);
272	if (err < 0)
273	return err;
274
275	err = pcf8523_set_pm(client, 0);
276	if (err < 0)
277	return err;
278
279	pcf->rtc = rtc_device_register(DRIVER_NAME, &client->dev,
280	&pcf8523_rtc_ops, THIS_MODULE);
281	if (IS_ERR(pcf->rtc))
282	return PTR_ERR(pcf->rtc);
283
284	i2c_set_clientdata(client, pcf);
285
286	return 0;
287	}
288
289	static int pcf8523_remove(struct i2c_client *client)
290	{
291	struct pcf8523 *pcf = i2c_get_clientdata(client);
292
293	rtc_device_unregister(pcf->rtc);
294
295	return 0;
296	}
297
298	static const struct i2c_device_id pcf8523_id[] = {
299	{ "pcf8523", 0 },
300	{ }
301	};
302	MODULE_DEVICE_TABLE(i2c, pcf8523_id);
303
304	#ifdef CONFIG_OF
305	static const struct of_device_id pcf8523_of_match[] = {
306	{ .compatible = "nxp,pcf8523" },
307	{ }
308	};
309	MODULE_DEVICE_TABLE(of, pcf8523_of_match);
310	#endif
311
312	static struct i2c_driver pcf8523_driver = {
313	.driver = {
314	.name = DRIVER_NAME,
315	.owner = THIS_MODULE,
316	.of_match_table = of_match_ptr(pcf8523_of_match),
317	},
318	.probe = pcf8523_probe,
319	.remove = pcf8523_remove,
320	.id_table = pcf8523_id,
321	};
322	module_i2c_driver(pcf8523_driver);
323
324	MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
325	MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
326	MODULE_LICENSE("GPL v2");