[mirror_ubuntu-bionic-kernel.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

#define REG_OFFSET   0x0e
#define REG_OFFSET_MODE BIT(7)

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

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

	return !!(value & REG_CONTROL3_BLF);
}

static int pcf8523_load_capacitance(struct i2c_client *client)
{
	u32 load;
	u8 value;
	int err;

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

	load = 12500;
	of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
			     &load);

	switch (load) {
	default:
		dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
			 load);
		/* fall through */
	case 12500:
		value |= REG_CONTROL1_CAP_SEL;
		break;
	case 7000:
		value &= ~REG_CONTROL1_CAP_SEL;
		break;
	}

	err = pcf8523_write(client, REG_CONTROL1, value);

	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;

	err = pcf8523_voltage_low(client);
	if (err < 0) {
		return err;
	} else if (err > 0) {
		dev_err(dev, "low voltage detected, time is unreliable\n");
		return -EINVAL;
	}

	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);
	int ret;

	switch (cmd) {
	case RTC_VL_READ:
		ret = pcf8523_voltage_low(client);
		if (ret < 0)
			return ret;

		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 int pcf8523_rtc_read_offset(struct device *dev, long *offset)
{
	struct i2c_client *client = to_i2c_client(dev);
	int err;
	u8 value;
	s8 val;

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

	/* sign extend the 7-bit offset value */
	val = value << 1;
	*offset = (value & REG_OFFSET_MODE ? 4069 : 4340) * (val >> 1);

	return 0;
}

static int pcf8523_rtc_set_offset(struct device *dev, long offset)
{
	struct i2c_client *client = to_i2c_client(dev);
	long reg_m0, reg_m1;
	u8 value;

	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);

	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
		value = reg_m0 & 0x7f;
	else
		value = (reg_m1 & 0x7f) | REG_OFFSET_MODE;

	return pcf8523_write(client, REG_OFFSET, value);
}

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,
	.read_offset = pcf8523_rtc_read_offset,
	.set_offset = pcf8523_rtc_set_offset,
};

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_load_capacitance(client);
	if (err < 0)
		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
			 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
bc3bee02 RK	38	#define REG_OFFSET 0x0e
	39	#define REG_OFFSET_MODE BIT(7)
	40
f803f0d0 TR	41	struct pcf8523 {
	42	struct rtc_device *rtc;
	43	};
	44
	45	static int pcf8523_read(struct i2c_client client, u8 reg, u8 valuep)
	46	{
	47	struct i2c_msg msgs[2];
	48	u8 value = 0;
	49	int err;
	50
	51	msgs[0].addr = client->addr;
	52	msgs[0].flags = 0;
	53	msgs[0].len = sizeof(reg);
	54	msgs[0].buf = ®
	55
	56	msgs[1].addr = client->addr;
	57	msgs[1].flags = I2C_M_RD;
	58	msgs[1].len = sizeof(value);
	59	msgs[1].buf = &value;
	60
	61	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	62	if (err < 0)
	63	return err;
	64
	65	*valuep = value;
	66
	67	return 0;
	68	}
	69
	70	static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
	71	{
	72	u8 buffer[2] = { reg, value };
	73	struct i2c_msg msg;
	74	int err;
	75
	76	msg.addr = client->addr;
	77	msg.flags = 0;
	78	msg.len = sizeof(buffer);
	79	msg.buf = buffer;
	80
	81	err = i2c_transfer(client->adapter, &msg, 1);
	82	if (err < 0)
	83	return err;
	84
	85	return 0;
	86	}
	87
80447f7e BS	88	static int pcf8523_voltage_low(struct i2c_client *client)
	89	{
	90	u8 value;
	91	int err;
	92
	93	err = pcf8523_read(client, REG_CONTROL3, &value);
	94	if (err < 0)
	95	return err;
	96
	97	return !!(value & REG_CONTROL3_BLF);
	98	}
	99
cf806a5b	100	static int pcf8523_load_capacitance(struct i2c_client *client)
f803f0d0	101	{
cf806a5b	102	u32 load;
f803f0d0 TR	103	u8 value;
	104	int err;
	105
	106	err = pcf8523_read(client, REG_CONTROL1, &value);
	107	if (err < 0)
	108	return err;
	109
cf806a5b SR	110	load = 12500;
	111	of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
	112	&load);
	113
	114	switch (load) {
	115	default:
	116	dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
	117	load);
	118	/* fall through */
	119	case 12500:
f803f0d0	120	value \|= REG_CONTROL1_CAP_SEL;
cf806a5b SR	121	break;
	122	case 7000:
	123	value &= ~REG_CONTROL1_CAP_SEL;
	124	break;
	125	}
f803f0d0 TR	126
f803f0d0 TR	127	err = pcf8523_write(client, REG_CONTROL1, value);
f803f0d0 TR	128
	129	return err;
	130	}
	131
	132	static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
	133	{
	134	u8 value;
	135	int err;
	136
	137	err = pcf8523_read(client, REG_CONTROL3, &value);
	138	if (err < 0)
	139	return err;
	140
	141	value = (value & ~REG_CONTROL3_PM_MASK) \| pm;
	142
	143	err = pcf8523_write(client, REG_CONTROL3, value);
	144	if (err < 0)
	145	return err;
	146
	147	return 0;
	148	}
	149
	150	static int pcf8523_stop_rtc(struct i2c_client *client)
	151	{
	152	u8 value;
	153	int err;
	154
	155	err = pcf8523_read(client, REG_CONTROL1, &value);
	156	if (err < 0)
	157	return err;
	158
	159	value \|= REG_CONTROL1_STOP;
	160
	161	err = pcf8523_write(client, REG_CONTROL1, value);
	162	if (err < 0)
	163	return err;
	164
	165	return 0;
	166	}
	167
	168	static int pcf8523_start_rtc(struct i2c_client *client)
	169	{
	170	u8 value;
	171	int err;
	172
	173	err = pcf8523_read(client, REG_CONTROL1, &value);
	174	if (err < 0)
	175	return err;
	176
	177	value &= ~REG_CONTROL1_STOP;
	178
	179	err = pcf8523_write(client, REG_CONTROL1, value);
	180	if (err < 0)
	181	return err;
	182
	183	return 0;
	184	}
	185
	186	static int pcf8523_rtc_read_time(struct device dev, struct rtc_time tm)
	187	{
	188	struct i2c_client *client = to_i2c_client(dev);
	189	u8 start = REG_SECONDS, regs[7];
	190	struct i2c_msg msgs[2];
	191	int err;
192
80447f7e BS	193	err = pcf8523_voltage_low(client);
	194	if (err < 0) {
	195	return err;
	196	} else if (err > 0) {
	197	dev_err(dev, "low voltage detected, time is unreliable\n");
	198	return -EINVAL;
	199	}
	200
f803f0d0 TR	201	msgs[0].addr = client->addr;
	202	msgs[0].flags = 0;
	203	msgs[0].len = 1;
	204	msgs[0].buf = &start;
	205
	206	msgs[1].addr = client->addr;
	207	msgs[1].flags = I2C_M_RD;
	208	msgs[1].len = sizeof(regs);
	209	msgs[1].buf = regs;
	210
	211	err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	212	if (err < 0)
	213	return err;
	214
ede44c90 AB	215	if (regs[0] & REG_SECONDS_OS)
ede44c90 AB	216	return -EINVAL;
f803f0d0 TR	217
	218	tm->tm_sec = bcd2bin(regs[0] & 0x7f);
	219	tm->tm_min = bcd2bin(regs[1] & 0x7f);
	220	tm->tm_hour = bcd2bin(regs[2] & 0x3f);
	221	tm->tm_mday = bcd2bin(regs[3] & 0x3f);
	222	tm->tm_wday = regs[4] & 0x7;
35738392	223	tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
f803f0d0 TR	224	tm->tm_year = bcd2bin(regs[6]) + 100;
	225
	226	return rtc_valid_tm(tm);
	227	}
	228
	229	static int pcf8523_rtc_set_time(struct device dev, struct rtc_time tm)
	230	{
	231	struct i2c_client *client = to_i2c_client(dev);
	232	struct i2c_msg msg;
	233	u8 regs[8];
	234	int err;
	235
fbbf53f7 UKK	236	/*
	237	* The hardware can only store values between 0 and 99 in it's YEAR
	238	* register (with 99 overflowing to 0 on increment).
	239	* After 2100-02-28 we could start interpreting the year to be in the
	240	* interval [2100, 2199], but there is no path to switch in a smooth way
	241	* because the chip handles YEAR=0x00 (and the out-of-spec
	242	* YEAR=0xa0) as a leap year, but 2100 isn't.
	243	*/
	244	if (tm->tm_year < 100 \|\| tm->tm_year >= 200)
	245	return -EINVAL;
	246
f803f0d0 TR	247	err = pcf8523_stop_rtc(client);
	248	if (err < 0)
	249	return err;
	250
	251	regs[0] = REG_SECONDS;
ede44c90	252	/* This will purposely overwrite REG_SECONDS_OS */
f803f0d0 TR	253	regs[1] = bin2bcd(tm->tm_sec);
	254	regs[2] = bin2bcd(tm->tm_min);
	255	regs[3] = bin2bcd(tm->tm_hour);
	256	regs[4] = bin2bcd(tm->tm_mday);
	257	regs[5] = tm->tm_wday;
35738392	258	regs[6] = bin2bcd(tm->tm_mon + 1);
f803f0d0 TR	259	regs[7] = bin2bcd(tm->tm_year - 100);
	260
	261	msg.addr = client->addr;
	262	msg.flags = 0;
	263	msg.len = sizeof(regs);
	264	msg.buf = regs;
	265
	266	err = i2c_transfer(client->adapter, &msg, 1);
	267	if (err < 0) {
	268	/*
	269	* If the time cannot be set, restart the RTC anyway. Note
	270	* that errors are ignored if the RTC cannot be started so
	271	* that we have a chance to propagate the original error.
	272	*/
	273	pcf8523_start_rtc(client);
	274	return err;
	275	}
	276
	277	return pcf8523_start_rtc(client);
	278	}
	279
f32bc70d JN	280	#ifdef CONFIG_RTC_INTF_DEV
	281	static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
	282	unsigned long arg)
	283	{
	284	struct i2c_client *client = to_i2c_client(dev);
80447f7e	285	int ret;
f32bc70d JN	286
	287	switch (cmd) {
	288	case RTC_VL_READ:
80447f7e BS	289	ret = pcf8523_voltage_low(client);
	290	if (ret < 0)
	291	return ret;
f32bc70d JN	292
	293	if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
	294	return -EFAULT;
	295
	296	return 0;
	297	default:
	298	return -ENOIOCTLCMD;
	299	}
	300	}
	301	#else
	302	#define pcf8523_rtc_ioctl NULL
	303	#endif
	304
bc3bee02 RK	305	static int pcf8523_rtc_read_offset(struct device dev, long offset)
	306	{
	307	struct i2c_client *client = to_i2c_client(dev);
	308	int err;
	309	u8 value;
	310	s8 val;
	311
	312	err = pcf8523_read(client, REG_OFFSET, &value);
	313	if (err < 0)
	314	return err;
	315
	316	/* sign extend the 7-bit offset value */
	317	val = value << 1;
	318	offset = (value & REG_OFFSET_MODE ? 4069 : 4340) (val >> 1);
	319
	320	return 0;
	321	}
	322
	323	static int pcf8523_rtc_set_offset(struct device *dev, long offset)
	324	{
	325	struct i2c_client *client = to_i2c_client(dev);
	326	long reg_m0, reg_m1;
	327	u8 value;
	328
	329	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
	330	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
	331
	332	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
	333	value = reg_m0 & 0x7f;
	334	else
	335	value = (reg_m1 & 0x7f) \| REG_OFFSET_MODE;
	336
	337	return pcf8523_write(client, REG_OFFSET, value);
	338	}
	339
f803f0d0 TR	340	static const struct rtc_class_ops pcf8523_rtc_ops = {
	341	.read_time = pcf8523_rtc_read_time,
	342	.set_time = pcf8523_rtc_set_time,
f32bc70d	343	.ioctl = pcf8523_rtc_ioctl,
bc3bee02 RK	344	.read_offset = pcf8523_rtc_read_offset,
bc3bee02 RK	345	.set_offset = pcf8523_rtc_set_offset,
f803f0d0 TR	346	};
	347
	348	static int pcf8523_probe(struct i2c_client *client,
	349	const struct i2c_device_id *id)
	350	{
	351	struct pcf8523 *pcf;
	352	int err;
	353
	354	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	355	return -ENODEV;
	356
	357	pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
	358	if (!pcf)
	359	return -ENOMEM;
	360
cf806a5b	361	err = pcf8523_load_capacitance(client);
f803f0d0	362	if (err < 0)
cf806a5b SR	363	dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
cf806a5b SR	364	err);
f803f0d0 TR	365
	366	err = pcf8523_set_pm(client, 0);
	367	if (err < 0)
	368	return err;
	369
288031bf	370	pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME,
f803f0d0 TR	371	&pcf8523_rtc_ops, THIS_MODULE);
	372	if (IS_ERR(pcf->rtc))
	373	return PTR_ERR(pcf->rtc);
	374
	375	i2c_set_clientdata(client, pcf);
	376
	377	return 0;
	378	}
	379
f803f0d0 TR	380	static const struct i2c_device_id pcf8523_id[] = {
	381	{ "pcf8523", 0 },
	382	{ }
	383	};
	384	MODULE_DEVICE_TABLE(i2c, pcf8523_id);
	385
	386	#ifdef CONFIG_OF
	387	static const struct of_device_id pcf8523_of_match[] = {
	388	{ .compatible = "nxp,pcf8523" },
	389	{ }
	390	};
	391	MODULE_DEVICE_TABLE(of, pcf8523_of_match);
	392	#endif
	393
	394	static struct i2c_driver pcf8523_driver = {
	395	.driver = {
	396	.name = DRIVER_NAME,
f803f0d0 TR	397	.of_match_table = of_match_ptr(pcf8523_of_match),
	398	},
	399	.probe = pcf8523_probe,
f803f0d0 TR	400	.id_table = pcf8523_id,
	401	};
	402	module_i2c_driver(pcf8523_driver);
	403
	404	MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
	405	MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
	406	MODULE_LICENSE("GPL v2");