Commit 4d61ff6b authored by Philippe De Muyter's avatar Philippe De Muyter Committed by Linus Torvalds
Browse files

rtc: add rtc-abx80x, a driver for the Abracon AB x80x i2c rtc 



This is a basic driver for the ultra-low-power Abracon AB x80x series of RTC
chips. It supports in particular, the supersets AB0805 and AB1805.
It allows reading and writing the time, and enables the supercapacitor/
battery charger.

[arnd@arndb.de: abx805 depends on i2c]
[alexandre.belloni@free-electrons.com: renam buffer from date to buf in abx80x_rtc_read_time()]
Signed-off-by: default avatarPhilippe De Muyter <phdm@macqel.be>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c71f1e05

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -164,6 +164,16 @@ config RTC_DRV_ABB5ZES3 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-ab-b5ze-s3.



config RTC_DRV_ABX80X

	tristate "Abracon ABx80x"

	help

	  If you say yes here you get support for Abracon AB080X and AB180X

	  families of ultra-low-power  battery- and capacitor-backed real-time

	  clock chips.



	  This driver can also be built as a module. If so, the module

	  will be called rtc-abx80x.



config RTC_DRV_AS3722

	tristate "ams AS3722 RTC driver"

	depends on MFD_AS3722

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ obj-$(CONFIG_RTC_DRV_88PM80X) += rtc-88pm80x.o 
obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o

obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o

obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o

obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o

obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o

obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o

obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o

drivers/rtc/rtc-abx80x.c

0 → 100644
+307 −0
Original line number Diff line number Diff line 
/*

 * A driver for the I2C members of the Abracon AB x8xx RTC family,

 * and compatible: AB 1805 and AB 0805

 *

 * Copyright 2014-2015 Macq S.A.

 *

 * Author: Philippe De Muyter <phdm@macqel.be>

 * Author: Alexandre Belloni <alexandre.belloni@free-electrons.com>

 *

 * 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>



#define ABX8XX_REG_HTH		0x00

#define ABX8XX_REG_SC		0x01

#define ABX8XX_REG_MN		0x02

#define ABX8XX_REG_HR		0x03

#define ABX8XX_REG_DA		0x04

#define ABX8XX_REG_MO		0x05

#define ABX8XX_REG_YR		0x06

#define ABX8XX_REG_WD		0x07



#define ABX8XX_REG_CTRL1	0x10

#define ABX8XX_CTRL_WRITE	BIT(1)

#define ABX8XX_CTRL_12_24	BIT(6)



#define ABX8XX_REG_CFG_KEY	0x1f

#define ABX8XX_CFG_KEY_MISC	0x9d



#define ABX8XX_REG_ID0		0x28



#define ABX8XX_REG_TRICKLE	0x20

#define ABX8XX_TRICKLE_CHARGE_ENABLE	0xa0

#define ABX8XX_TRICKLE_STANDARD_DIODE	0x8

#define ABX8XX_TRICKLE_SCHOTTKY_DIODE	0x4



static u8 trickle_resistors[] = {0, 3, 6, 11};



enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,

	AB1801, AB1803, AB1804, AB1805, ABX80X};



struct abx80x_cap {

	u16 pn;

	bool has_tc;

};



static struct abx80x_cap abx80x_caps[] = {

	[AB0801] = {.pn = 0x0801},

	[AB0803] = {.pn = 0x0803},

	[AB0804] = {.pn = 0x0804, .has_tc = true},

	[AB0805] = {.pn = 0x0805, .has_tc = true},

	[AB1801] = {.pn = 0x1801},

	[AB1803] = {.pn = 0x1803},

	[AB1804] = {.pn = 0x1804, .has_tc = true},

	[AB1805] = {.pn = 0x1805, .has_tc = true},

	[ABX80X] = {.pn = 0}

};



static struct i2c_driver abx80x_driver;



static int abx80x_enable_trickle_charger(struct i2c_client *client,

					 u8 trickle_cfg)

{

	int err;



	/*

	 * Write the configuration key register to enable access to the Trickle

	 * register

	 */

	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,

					ABX8XX_CFG_KEY_MISC);

	if (err < 0) {

		dev_err(&client->dev, "Unable to write configuration key\n");

		return -EIO;

	}



	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE,

					ABX8XX_TRICKLE_CHARGE_ENABLE |

					trickle_cfg);

	if (err < 0) {

		dev_err(&client->dev, "Unable to write trickle register\n");

		return -EIO;

	}



	return 0;

}



static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct i2c_client *client = to_i2c_client(dev);

	unsigned char buf[8];

	int err;



	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,

					    sizeof(buf), buf);

	if (err < 0) {

		dev_err(&client->dev, "Unable to read date\n");

		return -EIO;

	}



	tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F);

	tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F);

	tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F);

	tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7;

	tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F);

	tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1;

	tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100;



	err = rtc_valid_tm(tm);

	if (err < 0)

		dev_err(&client->dev, "retrieved date/time is not valid.\n");



	return err;

}



static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct i2c_client *client = to_i2c_client(dev);

	unsigned char buf[8];

	int err;



	if (tm->tm_year < 100)

		return -EINVAL;



	buf[ABX8XX_REG_HTH] = 0;

	buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec);

	buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min);

	buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour);

	buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday);

	buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1);

	buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100);

	buf[ABX8XX_REG_WD] = tm->tm_wday;



	err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH,

					     sizeof(buf), buf);

	if (err < 0) {

		dev_err(&client->dev, "Unable to write to date registers\n");

		return -EIO;

	}



	return 0;

}



static const struct rtc_class_ops abx80x_rtc_ops = {

	.read_time	= abx80x_rtc_read_time,

	.set_time	= abx80x_rtc_set_time,

};



static int abx80x_dt_trickle_cfg(struct device_node *np)

{

	const char *diode;

	int trickle_cfg = 0;

	int i, ret;

	u32 tmp;



	ret = of_property_read_string(np, "abracon,tc-diode", &diode);

	if (ret)

		return ret;



	if (!strcmp(diode, "standard"))

		trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;

	else if (!strcmp(diode, "schottky"))

		trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;

	else

		return -EINVAL;



	ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);

	if (ret)

		return ret;



	for (i = 0; i < sizeof(trickle_resistors); i++)

		if (trickle_resistors[i] == tmp)

			break;



	if (i == sizeof(trickle_resistors))

		return -EINVAL;



	return (trickle_cfg | i);

}



static int abx80x_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	struct device_node *np = client->dev.of_node;

	struct rtc_device *rtc;

	int i, data, err, trickle_cfg = -EINVAL;

	char buf[7];

	unsigned int part = id->driver_data;

	unsigned int partnumber;

	unsigned int majrev, minrev;

	unsigned int lot;

	unsigned int wafer;

	unsigned int uid;



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))

		return -ENODEV;



	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,

					    sizeof(buf), buf);

	if (err < 0) {

		dev_err(&client->dev, "Unable to read partnumber\n");

		return -EIO;

	}



	partnumber = (buf[0] << 8) | buf[1];

	majrev = buf[2] >> 3;

	minrev = buf[2] & 0x7;

	lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];

	uid = ((buf[4] & 0x7f) << 8) | buf[5];

	wafer = (buf[6] & 0x7c) >> 2;

	dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",

		 partnumber, majrev, minrev, lot, wafer, uid);



	data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);

	if (data < 0) {

		dev_err(&client->dev, "Unable to read control register\n");

		return -EIO;

	}



	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,

					((data & ~ABX8XX_CTRL_12_24) |

					 ABX8XX_CTRL_WRITE));

	if (err < 0) {

		dev_err(&client->dev, "Unable to write control register\n");

		return -EIO;

	}



	/* part autodetection */

	if (part == ABX80X) {

		for (i = 0; abx80x_caps[i].pn; i++)

			if (partnumber == abx80x_caps[i].pn)

				break;

		if (abx80x_caps[i].pn == 0) {

			dev_err(&client->dev, "Unknown part: %04x\n",

				partnumber);

			return -EINVAL;

		}

		part = i;

	}



	if (partnumber != abx80x_caps[part].pn) {

		dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",

			partnumber, abx80x_caps[part].pn);

		return -EINVAL;

	}



	if (np && abx80x_caps[part].has_tc)

		trickle_cfg = abx80x_dt_trickle_cfg(np);



	if (trickle_cfg > 0) {

		dev_info(&client->dev, "Enabling trickle charger: %02x\n",

			 trickle_cfg);

		abx80x_enable_trickle_charger(client, trickle_cfg);

	}



	rtc = devm_rtc_device_register(&client->dev, abx80x_driver.driver.name,

				       &abx80x_rtc_ops, THIS_MODULE);



	if (IS_ERR(rtc))

		return PTR_ERR(rtc);



	i2c_set_clientdata(client, rtc);



	return 0;

}



static int abx80x_remove(struct i2c_client *client)

{

	return 0;

}



static const struct i2c_device_id abx80x_id[] = {

	{ "abx80x", ABX80X },

	{ "ab0801", AB0801 },

	{ "ab0803", AB0803 },

	{ "ab0804", AB0804 },

	{ "ab0805", AB0805 },

	{ "ab1801", AB1801 },

	{ "ab1803", AB1803 },

	{ "ab1804", AB1804 },

	{ "ab1805", AB1805 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, abx80x_id);



static struct i2c_driver abx80x_driver = {

	.driver		= {

		.name	= "rtc-abx80x",

	},

	.probe		= abx80x_probe,

	.remove		= abx80x_remove,

	.id_table	= abx80x_id,

};



module_i2c_driver(abx80x_driver);



MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");

MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");

MODULE_DESCRIPTION("Abracon ABX80X RTC driver");

MODULE_LICENSE("GPL v2");

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