[linux-2.6-block.git] / drivers / rtc / rtc-rx6110.c

/*
 * Driver for the Epson RTC module RX-6110 SA
 *
 * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
 * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
 *
 * This driver software is distributed as is, without any warranty of any kind,
 * either express or implied as further specified in the GNU Public License.
 * This software may be used and distributed according to the terms of the GNU
 * Public License, version 2 as published by the Free Software Foundation.
 * See the file COPYING in the main directory of this archive for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/spi/spi.h>

/* RX-6110 Register definitions */
#define RX6110_REG_SEC		0x10
#define RX6110_REG_MIN		0x11
#define RX6110_REG_HOUR		0x12
#define RX6110_REG_WDAY		0x13
#define RX6110_REG_MDAY		0x14
#define RX6110_REG_MONTH	0x15
#define RX6110_REG_YEAR		0x16
#define RX6110_REG_RES1		0x17
#define RX6110_REG_ALMIN	0x18
#define RX6110_REG_ALHOUR	0x19
#define RX6110_REG_ALWDAY	0x1A
#define RX6110_REG_TCOUNT0	0x1B
#define RX6110_REG_TCOUNT1	0x1C
#define RX6110_REG_EXT		0x1D
#define RX6110_REG_FLAG		0x1E
#define RX6110_REG_CTRL		0x1F
#define RX6110_REG_USER0	0x20
#define RX6110_REG_USER1	0x21
#define RX6110_REG_USER2	0x22
#define RX6110_REG_USER3	0x23
#define RX6110_REG_USER4	0x24
#define RX6110_REG_USER5	0x25
#define RX6110_REG_USER6	0x26
#define RX6110_REG_USER7	0x27
#define RX6110_REG_USER8	0x28
#define RX6110_REG_USER9	0x29
#define RX6110_REG_USERA	0x2A
#define RX6110_REG_USERB	0x2B
#define RX6110_REG_USERC	0x2C
#define RX6110_REG_USERD	0x2D
#define RX6110_REG_USERE	0x2E
#define RX6110_REG_USERF	0x2F
#define RX6110_REG_RES2		0x30
#define RX6110_REG_RES3		0x31
#define RX6110_REG_IRQ		0x32

#define RX6110_BIT_ALARM_EN		BIT(7)

/* Extension Register (1Dh) bit positions */
#define RX6110_BIT_EXT_TSEL0		BIT(0)
#define RX6110_BIT_EXT_TSEL1		BIT(1)
#define RX6110_BIT_EXT_TSEL2		BIT(2)
#define RX6110_BIT_EXT_WADA		BIT(3)
#define RX6110_BIT_EXT_TE		BIT(4)
#define RX6110_BIT_EXT_USEL		BIT(5)
#define RX6110_BIT_EXT_FSEL0		BIT(6)
#define RX6110_BIT_EXT_FSEL1		BIT(7)

/* Flag Register (1Eh) bit positions */
#define RX6110_BIT_FLAG_VLF		BIT(1)
#define RX6110_BIT_FLAG_AF		BIT(3)
#define RX6110_BIT_FLAG_TF		BIT(4)
#define RX6110_BIT_FLAG_UF		BIT(5)

/* Control Register (1Fh) bit positions */
#define RX6110_BIT_CTRL_TBKE		BIT(0)
#define RX6110_BIT_CTRL_TBKON		BIT(1)
#define RX6110_BIT_CTRL_TSTP		BIT(2)
#define RX6110_BIT_CTRL_AIE		BIT(3)
#define RX6110_BIT_CTRL_TIE		BIT(4)
#define RX6110_BIT_CTRL_UIE		BIT(5)
#define RX6110_BIT_CTRL_STOP		BIT(6)
#define RX6110_BIT_CTRL_TEST		BIT(7)

enum {
	RTC_SEC = 0,
	RTC_MIN,
	RTC_HOUR,
	RTC_WDAY,
	RTC_MDAY,
	RTC_MONTH,
	RTC_YEAR,
	RTC_NR_TIME
};

#define RX6110_DRIVER_NAME		"rx6110"

struct rx6110_data {
	struct rtc_device *rtc;
	struct regmap *regmap;
};

/**
 * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
 *
 * @tm: holds date and time
 * @data: holds the encoding in rx6110 native form
 */
static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
{
	pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
		 tm->tm_sec, tm->tm_min, tm->tm_hour,
		 tm->tm_mday, tm->tm_mon, tm->tm_year);

	/*
	 * The year in the RTC is a value between 0 and 99.
	 * Assume that this represents the current century
	 * and disregard all other values.
	 */
	if (tm->tm_year < 100 || tm->tm_year >= 200)
		return -EINVAL;

	data[RTC_SEC] = bin2bcd(tm->tm_sec);
	data[RTC_MIN] = bin2bcd(tm->tm_min);
	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
	data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
	data[RTC_MDAY] = bin2bcd(tm->tm_mday);
	data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
	data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);

	return 0;
}

/**
 * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
 *
 * @data: holds the encoding in rx6110 native form
 * @tm: holds date and time
 */
static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
{
	tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
	tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
	/* only 24-hour clock */
	tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
	tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
	tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
	tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
	tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;

	pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
		 tm->tm_sec, tm->tm_min, tm->tm_hour,
		 tm->tm_mday, tm->tm_mon, tm->tm_year);

	/*
	 * The year in the RTC is a value between 0 and 99.
	 * Assume that this represents the current century
	 * and disregard all other values.
	 */
	if (tm->tm_year < 100 || tm->tm_year >= 200)
		return -EINVAL;

	return 0;
}

/**
 * rx6110_set_time - set the current time in the rx6110 registers
 *
 * @dev: the rtc device in use
 * @tm: holds date and time
 *
 * BUG: The HW assumes every year that is a multiple of 4 to be a leap
 * year. Next time this is wrong is 2100, which will not be a leap year
 *
 * Note: If STOP is not set/cleared, the clock will start when the seconds
 *       register is written
 *
 */
static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
{
	struct rx6110_data *rx6110 = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int ret;

	ret = rx6110_rtc_tm_to_data(tm, data);
	if (ret < 0)
		return ret;

	/* set STOP bit before changing clock/calendar */
	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
				 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
	if (ret)
		return ret;

	ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
				RTC_NR_TIME);
	if (ret)
		return ret;

	/* The time in the RTC is valid. Be sure to have VLF cleared. */
	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
				 RX6110_BIT_FLAG_VLF, 0);
	if (ret)
		return ret;

	/* clear STOP bit after changing clock/calendar */
	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
				 RX6110_BIT_CTRL_STOP, 0);

	return ret;
}

/**
 * rx6110_get_time - get the current time from the rx6110 registers
 * @dev: the rtc device in use
 * @tm: holds date and time
 */
static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
{
	struct rx6110_data *rx6110 = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int flags;
	int ret;

	ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
	if (ret)
		return -EINVAL;

	/* check for VLF Flag (set at power-on) */
	if ((flags & RX6110_BIT_FLAG_VLF)) {
		dev_warn(dev, "Voltage low, data is invalid.\n");
		return -EINVAL;
	}

	/* read registers to date */
	ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
			       RTC_NR_TIME);
	if (ret)
		return ret;

	ret = rx6110_data_to_rtc_tm(data, tm);
	if (ret)
		return ret;

	dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
		tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year);

	return rtc_valid_tm(tm);
}

static const struct reg_sequence rx6110_default_regs[] = {
	{ RX6110_REG_RES1,   0xB8 },
	{ RX6110_REG_RES2,   0x00 },
	{ RX6110_REG_RES3,   0x10 },
	{ RX6110_REG_IRQ,    0x00 },
	{ RX6110_REG_ALMIN,  0x00 },
	{ RX6110_REG_ALHOUR, 0x00 },
	{ RX6110_REG_ALWDAY, 0x00 },
};

/**
 * rx6110_init - initialize the rx6110 registers
 *
 * @rx6110: pointer to the rx6110 struct in use
 *
 */
static int rx6110_init(struct rx6110_data *rx6110)
{
	struct rtc_device *rtc = rx6110->rtc;
	int flags;
	int ret;

	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
				 RX6110_BIT_EXT_TE, 0);
	if (ret)
		return ret;

	ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
				    ARRAY_SIZE(rx6110_default_regs));
	if (ret)
		return ret;

	ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
	if (ret)
		return ret;

	/* check for VLF Flag (set at power-on) */
	if ((flags & RX6110_BIT_FLAG_VLF))
		dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");

	/* check for Alarm Flag */
	if (flags & RX6110_BIT_FLAG_AF)
		dev_warn(&rtc->dev, "An alarm may have been missed.\n");

	/* check for Periodic Timer Flag */
	if (flags & RX6110_BIT_FLAG_TF)
		dev_warn(&rtc->dev, "Periodic timer was detected\n");

	/* check for Update Timer Flag */
	if (flags & RX6110_BIT_FLAG_UF)
		dev_warn(&rtc->dev, "Update timer was detected\n");

	/* clear all flags BUT VLF */
	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
				 RX6110_BIT_FLAG_AF |
				 RX6110_BIT_FLAG_UF |
				 RX6110_BIT_FLAG_TF,
				 0);

	return ret;
}

static struct rtc_class_ops rx6110_rtc_ops = {
	.read_time = rx6110_get_time,
	.set_time = rx6110_set_time,
};

static struct regmap_config regmap_spi_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = RX6110_REG_IRQ,
	.read_flag_mask = 0x80,
};

/**
 * rx6110_probe - initialize rtc driver
 * @spi: pointer to spi device
 */
static int rx6110_probe(struct spi_device *spi)
{
	struct rx6110_data *rx6110;
	int err;

	if ((spi->bits_per_word && spi->bits_per_word != 8) ||
	    (spi->max_speed_hz > 2000000) ||
	    (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
		dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
			 spi->bits_per_word, spi->max_speed_hz, spi->mode);
		dev_warn(&spi->dev, "driving device in an unsupported mode");
	}

	rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
	if (!rx6110)
		return -ENOMEM;

	rx6110->regmap = devm_regmap_init_spi(spi, &regmap_spi_config);
	if (IS_ERR(rx6110->regmap)) {
		dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
		return PTR_ERR(rx6110->regmap);
	}

	spi_set_drvdata(spi, rx6110);

	rx6110->rtc = devm_rtc_device_register(&spi->dev,
					       RX6110_DRIVER_NAME,
					       &rx6110_rtc_ops, THIS_MODULE);

	if (IS_ERR(rx6110->rtc))
		return PTR_ERR(rx6110->rtc);

	err = rx6110_init(rx6110);
	if (err)
		return err;

	rx6110->rtc->max_user_freq = 1;

	return 0;
}

static int rx6110_remove(struct spi_device *spi)
{
	return 0;
}

static const struct spi_device_id rx6110_id[] = {
	{ "rx6110", 0 },
	{ }
};
MODULE_DEVICE_TABLE(spi, rx6110_id);

static struct spi_driver rx6110_driver = {
	.driver = {
		.name = RX6110_DRIVER_NAME,
		.owner = THIS_MODULE,
	},
	.probe		= rx6110_probe,
	.remove		= rx6110_remove,
	.id_table	= rx6110_id,
};

module_spi_driver(rx6110_driver);

MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
MODULE_DESCRIPTION("RX-6110 SA RTC driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
68298c2d ST	1	/*
	2	* Driver for the Epson RTC module RX-6110 SA
	3	*
	4	* Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
	5	* Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
	6	*
	7	* This driver software is distributed as is, without any warranty of any kind,
	8	* either express or implied as further specified in the GNU Public License.
	9	* This software may be used and distributed according to the terms of the GNU
	10	* Public License, version 2 as published by the Free Software Foundation.
	11	* See the file COPYING in the main directory of this archive for more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along with
	14	* this program. If not, see <http://www.gnu.org/licenses/>.
	15	*/
	16
	17	#include <linux/bcd.h>
	18	#include <linux/init.h>
	19	#include <linux/kernel.h>
	20	#include <linux/module.h>
	21	#include <linux/of_gpio.h>
	22	#include <linux/regmap.h>
	23	#include <linux/rtc.h>
	24	#include <linux/spi/spi.h>
	25
	26	/* RX-6110 Register definitions */
	27	#define RX6110_REG_SEC 0x10
	28	#define RX6110_REG_MIN 0x11
	29	#define RX6110_REG_HOUR 0x12
	30	#define RX6110_REG_WDAY 0x13
	31	#define RX6110_REG_MDAY 0x14
	32	#define RX6110_REG_MONTH 0x15
	33	#define RX6110_REG_YEAR 0x16
	34	#define RX6110_REG_RES1 0x17
	35	#define RX6110_REG_ALMIN 0x18
	36	#define RX6110_REG_ALHOUR 0x19
	37	#define RX6110_REG_ALWDAY 0x1A
	38	#define RX6110_REG_TCOUNT0 0x1B
	39	#define RX6110_REG_TCOUNT1 0x1C
	40	#define RX6110_REG_EXT 0x1D
	41	#define RX6110_REG_FLAG 0x1E
	42	#define RX6110_REG_CTRL 0x1F
	43	#define RX6110_REG_USER0 0x20
	44	#define RX6110_REG_USER1 0x21
	45	#define RX6110_REG_USER2 0x22
	46	#define RX6110_REG_USER3 0x23
	47	#define RX6110_REG_USER4 0x24
	48	#define RX6110_REG_USER5 0x25
	49	#define RX6110_REG_USER6 0x26
	50	#define RX6110_REG_USER7 0x27
	51	#define RX6110_REG_USER8 0x28
	52	#define RX6110_REG_USER9 0x29
	53	#define RX6110_REG_USERA 0x2A
	54	#define RX6110_REG_USERB 0x2B
	55	#define RX6110_REG_USERC 0x2C
	56	#define RX6110_REG_USERD 0x2D
	57	#define RX6110_REG_USERE 0x2E
	58	#define RX6110_REG_USERF 0x2F
	59	#define RX6110_REG_RES2 0x30
	60	#define RX6110_REG_RES3 0x31
	61	#define RX6110_REG_IRQ 0x32
	62
	63	#define RX6110_BIT_ALARM_EN BIT(7)
	64
65	/* Extension Register (1Dh) bit positions */
66	#define RX6110_BIT_EXT_TSEL0 BIT(0)
67	#define RX6110_BIT_EXT_TSEL1 BIT(1)
68	#define RX6110_BIT_EXT_TSEL2 BIT(2)
69	#define RX6110_BIT_EXT_WADA BIT(3)
70	#define RX6110_BIT_EXT_TE BIT(4)
71	#define RX6110_BIT_EXT_USEL BIT(5)
72	#define RX6110_BIT_EXT_FSEL0 BIT(6)
73	#define RX6110_BIT_EXT_FSEL1 BIT(7)
74
75	/* Flag Register (1Eh) bit positions */
76	#define RX6110_BIT_FLAG_VLF BIT(1)
77	#define RX6110_BIT_FLAG_AF BIT(3)
78	#define RX6110_BIT_FLAG_TF BIT(4)
79	#define RX6110_BIT_FLAG_UF BIT(5)
80
81	/* Control Register (1Fh) bit positions */
82	#define RX6110_BIT_CTRL_TBKE BIT(0)
83	#define RX6110_BIT_CTRL_TBKON BIT(1)
84	#define RX6110_BIT_CTRL_TSTP BIT(2)
85	#define RX6110_BIT_CTRL_AIE BIT(3)
86	#define RX6110_BIT_CTRL_TIE BIT(4)
87	#define RX6110_BIT_CTRL_UIE BIT(5)
88	#define RX6110_BIT_CTRL_STOP BIT(6)
89	#define RX6110_BIT_CTRL_TEST BIT(7)
90
91	enum {
92	RTC_SEC = 0,
93	RTC_MIN,
94	RTC_HOUR,
95	RTC_WDAY,
96	RTC_MDAY,
97	RTC_MONTH,
98	RTC_YEAR,
99	RTC_NR_TIME
100	};
101
102	#define RX6110_DRIVER_NAME "rx6110"
103
104	struct rx6110_data {
105	struct rtc_device *rtc;
106	struct regmap *regmap;
107	};
108
109	/**
110	* rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
111	*
112	* @tm: holds date and time
113	* @data: holds the encoding in rx6110 native form
114	*/
115	static int rx6110_rtc_tm_to_data(struct rtc_time tm, u8 data)
116	{
117	pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
118	tm->tm_sec, tm->tm_min, tm->tm_hour,
119	tm->tm_mday, tm->tm_mon, tm->tm_year);
120
121	/*
122	* The year in the RTC is a value between 0 and 99.
123	* Assume that this represents the current century
124	* and disregard all other values.
125	*/
126	if (tm->tm_year < 100 \|\| tm->tm_year >= 200)
127	return -EINVAL;
128
129	data[RTC_SEC] = bin2bcd(tm->tm_sec);
130	data[RTC_MIN] = bin2bcd(tm->tm_min);
131	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
132	data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
133	data[RTC_MDAY] = bin2bcd(tm->tm_mday);
134	data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
135	data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
136
137	return 0;
138	}
139
140	/**
141	* rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
142	*
143	* @data: holds the encoding in rx6110 native form
144	* @tm: holds date and time
145	*/
146	static int rx6110_data_to_rtc_tm(u8 data, struct rtc_time tm)
147	{
148	tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
149	tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
150	/* only 24-hour clock */
151	tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
152	tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
153	tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
154	tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
155	tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
156
157	pr_debug("%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
158	tm->tm_sec, tm->tm_min, tm->tm_hour,
159	tm->tm_mday, tm->tm_mon, tm->tm_year);
160
161	/*
162	* The year in the RTC is a value between 0 and 99.
163	* Assume that this represents the current century
164	* and disregard all other values.
165	*/
166	if (tm->tm_year < 100 \|\| tm->tm_year >= 200)
167	return -EINVAL;
168
169	return 0;
170	}
171
172	/**
173	* rx6110_set_time - set the current time in the rx6110 registers
174	*
175	* @dev: the rtc device in use
176	* @tm: holds date and time
177	*
178	* BUG: The HW assumes every year that is a multiple of 4 to be a leap
179	* year. Next time this is wrong is 2100, which will not be a leap year
180	*
181	* Note: If STOP is not set/cleared, the clock will start when the seconds
182	* register is written
183	*
184	*/
185	static int rx6110_set_time(struct device dev, struct rtc_time tm)
186	{
187	struct rx6110_data *rx6110 = dev_get_drvdata(dev);
188	u8 data[RTC_NR_TIME];
189	int ret;
190
191	ret = rx6110_rtc_tm_to_data(tm, data);
192	if (ret < 0)
193	return ret;
194
195	/* set STOP bit before changing clock/calendar */
196	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
197	RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
198	if (ret)
199	return ret;
200
201	ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
202	RTC_NR_TIME);
203	if (ret)
204	return ret;
205
206	/* The time in the RTC is valid. Be sure to have VLF cleared. */
207	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
208	RX6110_BIT_FLAG_VLF, 0);
209	if (ret)
210	return ret;
211
212	/* clear STOP bit after changing clock/calendar */
213	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
214	RX6110_BIT_CTRL_STOP, 0);
215
216	return ret;
217	}
218
219	/**
220	* rx6110_get_time - get the current time from the rx6110 registers
221	* @dev: the rtc device in use
222	* @tm: holds date and time
223	*/
224	static int rx6110_get_time(struct device dev, struct rtc_time tm)
225	{
226	struct rx6110_data *rx6110 = dev_get_drvdata(dev);
227	u8 data[RTC_NR_TIME];
228	int flags;
229	int ret;
230
231	ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
232	if (ret)
233	return -EINVAL;
234
235	/* check for VLF Flag (set at power-on) */
236	if ((flags & RX6110_BIT_FLAG_VLF)) {
237	dev_warn(dev, "Voltage low, data is invalid.\n");
238	return -EINVAL;
239	}
240
241	/* read registers to date */
242	ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
243	RTC_NR_TIME);
244	if (ret)
245	return ret;
246
247	ret = rx6110_data_to_rtc_tm(data, tm);
248	if (ret)
249	return ret;
250
251	dev_dbg(dev, "%s: date %ds %dm %dh %dmd %dm %dy\n", __func__,
252	tm->tm_sec, tm->tm_min, tm->tm_hour,
253	tm->tm_mday, tm->tm_mon, tm->tm_year);
254
255	return rtc_valid_tm(tm);
256	}
257
258	static const struct reg_sequence rx6110_default_regs[] = {
259	{ RX6110_REG_RES1, 0xB8 },
260	{ RX6110_REG_RES2, 0x00 },
261	{ RX6110_REG_RES3, 0x10 },
262	{ RX6110_REG_IRQ, 0x00 },
263	{ RX6110_REG_ALMIN, 0x00 },
264	{ RX6110_REG_ALHOUR, 0x00 },
265	{ RX6110_REG_ALWDAY, 0x00 },
266	};
267
268	/**
269	* rx6110_init - initialize the rx6110 registers
270	*
271	* @rx6110: pointer to the rx6110 struct in use
272	*
273	*/
274	static int rx6110_init(struct rx6110_data *rx6110)
275	{
276	struct rtc_device *rtc = rx6110->rtc;
277	int flags;
278	int ret;
279
280	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
281	RX6110_BIT_EXT_TE, 0);
282	if (ret)
283	return ret;
284
285	ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
286	ARRAY_SIZE(rx6110_default_regs));
287	if (ret)
288	return ret;
289
290	ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
291	if (ret)
292	return ret;
293
294	/* check for VLF Flag (set at power-on) */
295	if ((flags & RX6110_BIT_FLAG_VLF))
296	dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
297
298	/* check for Alarm Flag */
299	if (flags & RX6110_BIT_FLAG_AF)
300	dev_warn(&rtc->dev, "An alarm may have been missed.\n");
301
302	/* check for Periodic Timer Flag */
303	if (flags & RX6110_BIT_FLAG_TF)
304	dev_warn(&rtc->dev, "Periodic timer was detected\n");
305
306	/* check for Update Timer Flag */
307	if (flags & RX6110_BIT_FLAG_UF)
308	dev_warn(&rtc->dev, "Update timer was detected\n");
309
310	/* clear all flags BUT VLF */
311	ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
312	RX6110_BIT_FLAG_AF \|
313	RX6110_BIT_FLAG_UF \|
314	RX6110_BIT_FLAG_TF,
315	0);
316
317	return ret;
318	}
319
320	static struct rtc_class_ops rx6110_rtc_ops = {
321	.read_time = rx6110_get_time,
322	.set_time = rx6110_set_time,
323	};
324
325	static struct regmap_config regmap_spi_config = {
326	.reg_bits = 8,
327	.val_bits = 8,
328	.max_register = RX6110_REG_IRQ,
329	.read_flag_mask = 0x80,
330	};
331
332	/**
333	* rx6110_probe - initialize rtc driver
334	* @spi: pointer to spi device
335	*/
336	static int rx6110_probe(struct spi_device *spi)
337	{
338	struct rx6110_data *rx6110;
339	int err;
340
341	if ((spi->bits_per_word && spi->bits_per_word != 8) \|\|
342	(spi->max_speed_hz > 2000000) \|\|
343	(spi->mode != (SPI_CS_HIGH \| SPI_CPOL \| SPI_CPHA))) {
344	dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
345	spi->bits_per_word, spi->max_speed_hz, spi->mode);
346	dev_warn(&spi->dev, "driving device in an unsupported mode");
347	}
348
349	rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
350	if (!rx6110)
351	return -ENOMEM;
352
353	rx6110->regmap = devm_regmap_init_spi(spi, &regmap_spi_config);
354	if (IS_ERR(rx6110->regmap)) {
355	dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
356	return PTR_ERR(rx6110->regmap);
357	}
358
359	spi_set_drvdata(spi, rx6110);
360
361	rx6110->rtc = devm_rtc_device_register(&spi->dev,
362	RX6110_DRIVER_NAME,
363	&rx6110_rtc_ops, THIS_MODULE);
364
365	if (IS_ERR(rx6110->rtc))
366	return PTR_ERR(rx6110->rtc);
367
368	err = rx6110_init(rx6110);
369	if (err)
370	return err;
371
372	rx6110->rtc->max_user_freq = 1;
373
374	return 0;
375	}
376
377	static int rx6110_remove(struct spi_device *spi)
378	{
379	return 0;
380	}
381
382	static const struct spi_device_id rx6110_id[] = {
383	{ "rx6110", 0 },
384	{ }
385	};
386	MODULE_DEVICE_TABLE(spi, rx6110_id);
387
388	static struct spi_driver rx6110_driver = {
389	.driver = {
390	.name = RX6110_DRIVER_NAME,
391	.owner = THIS_MODULE,
392	},
393	.probe = rx6110_probe,
394	.remove = rx6110_remove,
395	.id_table = rx6110_id,
396	};
397
398	module_spi_driver(rx6110_driver);
399
400	MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
401	MODULE_DESCRIPTION("RX-6110 SA RTC driver");
402	MODULE_LICENSE("GPL");