[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_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)
		return -EINVAL;

	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) - 1;
	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;

	/*
	 * The hardware can only store values between 0 and 99 in it's YEAR
	 * register (with 99 overflowing to 0 on increment).
	 * After 2100-02-28 we could start interpreting the year to be in the
	 * interval [2100, 2199], but there is no path to switch in a smooth way
	 * because the chip handles YEAR=0x00 (and the out-of-spec
	 * YEAR=0xa0) as a leap year, but 2100 isn't.
	 */
	if (tm->tm_year < 100 || tm->tm_year >= 200)
		return -EINVAL;

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

	regs[0] = REG_SECONDS;
	/* This will purposely overwrite REG_SECONDS_OS */
	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 + 1);
	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 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,
		.of_match_table = of_match_ptr(pcf8523_of_match),
	},
	.probe = pcf8523_probe,
	.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
ede44c90 AB	181	if (regs[0] & REG_SECONDS_OS)
ede44c90 AB	182	return -EINVAL;
f803f0d0 TR	183
	184	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
	185	tm->tm_min = bcd2bin(regs[1] & 0x7f);
	186	tm->tm_hour = bcd2bin(regs[2] & 0x3f);
	187	tm->tm_mday = bcd2bin(regs[3] & 0x3f);
	188	tm->tm_wday = regs[4] & 0x7;
35738392	189	tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
f803f0d0 TR	190	tm->tm_year = bcd2bin(regs[6]) + 100;
	191
	192	return rtc_valid_tm(tm);
	193	}
	194
	195	static int pcf8523_rtc_set_time(struct device dev, struct rtc_time tm)
	196	{
	197	struct i2c_client *client = to_i2c_client(dev);
	198	struct i2c_msg msg;
	199	u8 regs[8];
	200	int err;
	201
fbbf53f7 UKK	202	/*
	203	* The hardware can only store values between 0 and 99 in it's YEAR
	204	* register (with 99 overflowing to 0 on increment).
	205	* After 2100-02-28 we could start interpreting the year to be in the
	206	* interval [2100, 2199], but there is no path to switch in a smooth way
	207	* because the chip handles YEAR=0x00 (and the out-of-spec
	208	* YEAR=0xa0) as a leap year, but 2100 isn't.
	209	*/
	210	if (tm->tm_year < 100 \|\| tm->tm_year >= 200)
	211	return -EINVAL;
	212
f803f0d0 TR	213	err = pcf8523_stop_rtc(client);
	214	if (err < 0)
	215	return err;
	216
	217	regs[0] = REG_SECONDS;
ede44c90	218	/* This will purposely overwrite REG_SECONDS_OS */
f803f0d0 TR	219	regs[1] = bin2bcd(tm->tm_sec);
	220	regs[2] = bin2bcd(tm->tm_min);
	221	regs[3] = bin2bcd(tm->tm_hour);
	222	regs[4] = bin2bcd(tm->tm_mday);
	223	regs[5] = tm->tm_wday;
35738392	224	regs[6] = bin2bcd(tm->tm_mon + 1);
f803f0d0 TR	225	regs[7] = bin2bcd(tm->tm_year - 100);
	226
	227	msg.addr = client->addr;
	228	msg.flags = 0;
	229	msg.len = sizeof(regs);
	230	msg.buf = regs;
	231
	232	err = i2c_transfer(client->adapter, &msg, 1);
	233	if (err < 0) {
	234	/*
	235	* If the time cannot be set, restart the RTC anyway. Note
	236	* that errors are ignored if the RTC cannot be started so
	237	* that we have a chance to propagate the original error.
	238	*/
	239	pcf8523_start_rtc(client);
	240	return err;
	241	}
	242
	243	return pcf8523_start_rtc(client);
	244	}
	245
f32bc70d JN	246	#ifdef CONFIG_RTC_INTF_DEV
	247	static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
	248	unsigned long arg)
	249	{
	250	struct i2c_client *client = to_i2c_client(dev);
	251	u8 value;
	252	int ret = 0, err;
	253
	254	switch (cmd) {
	255	case RTC_VL_READ:
	256	err = pcf8523_read(client, REG_CONTROL3, &value);
	257	if (err < 0)
	258	return err;
	259
	260	if (value & REG_CONTROL3_BLF)
	261	ret = 1;
	262
	263	if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
	264	return -EFAULT;
	265
	266	return 0;
	267	default:
	268	return -ENOIOCTLCMD;
	269	}
	270	}
	271	#else
	272	#define pcf8523_rtc_ioctl NULL
	273	#endif
	274
f803f0d0 TR	275	static const struct rtc_class_ops pcf8523_rtc_ops = {
	276	.read_time = pcf8523_rtc_read_time,
	277	.set_time = pcf8523_rtc_set_time,
f32bc70d	278	.ioctl = pcf8523_rtc_ioctl,
f803f0d0 TR	279	};
	280
	281	static int pcf8523_probe(struct i2c_client *client,
	282	const struct i2c_device_id *id)
	283	{
	284	struct pcf8523 *pcf;
	285	int err;
	286
	287	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	288	return -ENODEV;
	289
	290	pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
	291	if (!pcf)
	292	return -ENOMEM;
	293
	294	err = pcf8523_select_capacitance(client, true);
	295	if (err < 0)
	296	return err;
	297
	298	err = pcf8523_set_pm(client, 0);
	299	if (err < 0)
	300	return err;
	301
288031bf	302	pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
f803f0d0 TR	303	&pcf8523_rtc_ops, THIS_MODULE);
	304	if (IS_ERR(pcf->rtc))
	305	return PTR_ERR(pcf->rtc);
	306
	307	i2c_set_clientdata(client, pcf);
	308
	309	return 0;
	310	}
	311
f803f0d0 TR	312	static const struct i2c_device_id pcf8523_id[] = {
	313	{ "pcf8523", 0 },
	314	{ }
	315	};
	316	MODULE_DEVICE_TABLE(i2c, pcf8523_id);
	317
	318	#ifdef CONFIG_OF
	319	static const struct of_device_id pcf8523_of_match[] = {
	320	{ .compatible = "nxp,pcf8523" },
	321	{ }
	322	};
	323	MODULE_DEVICE_TABLE(of, pcf8523_of_match);
	324	#endif
	325
	326	static struct i2c_driver pcf8523_driver = {
	327	.driver = {
	328	.name = DRIVER_NAME,
f803f0d0 TR	329	.of_match_table = of_match_ptr(pcf8523_of_match),
	330	},
	331	.probe = pcf8523_probe,
f803f0d0 TR	332	.id_table = pcf8523_id,
	333	};
	334	module_i2c_driver(pcf8523_driver);
	335
	336	MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
	337	MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
	338	MODULE_LICENSE("GPL v2");