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Commit 18cb6368 authored by Renaud Cerrato's avatar Renaud Cerrato Committed by Linus Torvalds
Browse files

rtc: add NXP PCF2127 support (i2c) 



Added support for NXP PCF2127 RTC (i2c).

[akpm@linux-foundation.org: fix typo, fix warnings]
Signed-off-by: default avatarRenaud Cerrato <r.cerrato@til-technologies.fr>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2c5a5b30

drivers/rtc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -313,6 +313,15 @@ config RTC_DRV_PALMAS 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-palma.



config RTC_DRV_PCF2127

	tristate "NXP PCF2127"

	help

	  If you say yes here you get support for the NXP PCF2127/29 RTC

	  chips.



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

	  will be called rtc-pcf2127.



config RTC_DRV_PCF8523

	tristate "NXP PCF8523"

	help

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -83,6 +83,7 @@ obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o 
obj-$(CONFIG_RTC_DRV_OMAP)	+= rtc-omap.o

obj-$(CONFIG_RTC_DRV_PALMAS)	+= rtc-palmas.o

obj-$(CONFIG_RTC_DRV_PCAP)	+= rtc-pcap.o

obj-$(CONFIG_RTC_DRV_PCF2127)	+= rtc-pcf2127.o

obj-$(CONFIG_RTC_DRV_PCF8523)	+= rtc-pcf8523.o

obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o

obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o

drivers/rtc/rtc-pcf2127.c

0 → 100644
+241 −0
Original line number Diff line number Diff line 
/*

 * An I2C driver for the NXP PCF2127 RTC

 * Copyright 2013 Til-Technologies

 *

 * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>

 *

 * based on the other drivers in this same directory.

 *

 * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf

 *

 * 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/i2c.h>

#include <linux/bcd.h>

#include <linux/rtc.h>

#include <linux/slab.h>

#include <linux/module.h>

#include <linux/of.h>



#define DRV_VERSION "0.0.1"



#define PCF2127_REG_CTRL1       (0x00)  /* Control Register 1 */

#define PCF2127_REG_CTRL2       (0x01)  /* Control Register 2 */

#define PCF2127_REG_CTRL3       (0x02)  /* Control Register 3 */

#define PCF2127_REG_SC          (0x03)  /* datetime */

#define PCF2127_REG_MN          (0x04)

#define PCF2127_REG_HR          (0x05)

#define PCF2127_REG_DM          (0x06)

#define PCF2127_REG_DW          (0x07)

#define PCF2127_REG_MO          (0x08)

#define PCF2127_REG_YR          (0x09)



static struct i2c_driver pcf2127_driver;



struct pcf2127 {

	struct rtc_device *rtc;

	int voltage_low; /* indicates if a low_voltage was detected */

};



/*

 * In the routines that deal directly with the pcf2127 hardware, we use

 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.

 */

static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	struct pcf2127 *pcf2127 = i2c_get_clientdata(client);

	unsigned char buf[10] = { PCF2127_REG_CTRL1 };



	/* read registers */

	if (i2c_master_send(client, buf, 1) != 1 ||

		i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {

		dev_err(&client->dev, "%s: read error\n", __func__);

		return -EIO;

	}



	if (buf[PCF2127_REG_CTRL3] & 0x04) {

		pcf2127->voltage_low = 1;

		dev_info(&client->dev,

			"low voltage detected, date/time is not reliable.\n");

	}



	dev_dbg(&client->dev,

		"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "

		"sec=%02x, min=%02x, hr=%02x, "

		"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",

		__func__,

		buf[0], buf[1], buf[2],

		buf[3], buf[4], buf[5],

		buf[6], buf[7], buf[8], buf[9]);





	tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);

	tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);

	tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */

	tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);

	tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;

	tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */

	tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);

	if (tm->tm_year < 70)

		tm->tm_year += 100;	/* assume we are in 1970...2069 */



	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "

		"mday=%d, mon=%d, year=%d, wday=%d\n",

		__func__,

		tm->tm_sec, tm->tm_min, tm->tm_hour,

		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



	/* the clock can give out invalid datetime, but we cannot return

	 * -EINVAL otherwise hwclock will refuse to set the time on bootup.

	 */

	if (rtc_valid_tm(tm) < 0)

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



	return 0;

}



static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	unsigned char buf[8];

	int i = 0, err;



	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "

		"mday=%d, mon=%d, year=%d, wday=%d\n",

		__func__,

		tm->tm_sec, tm->tm_min, tm->tm_hour,

		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



	/* start register address */

	buf[i++] = PCF2127_REG_SC;



	/* hours, minutes and seconds */

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

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

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

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

	buf[i++] = tm->tm_wday & 0x07;



	/* month, 1 - 12 */

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



	/* year */

	buf[i++] = bin2bcd(tm->tm_year % 100);



	/* write register's data */

	err = i2c_master_send(client, buf, i);

	if (err != i) {

		dev_err(&client->dev,

			"%s: err=%d", __func__, err);

		return -EIO;

	}



	return 0;

}



#ifdef CONFIG_RTC_INTF_DEV

static int pcf2127_rtc_ioctl(struct device *dev,

				unsigned int cmd, unsigned long arg)

{

	struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));



	switch (cmd) {

	case RTC_VL_READ:

		if (pcf2127->voltage_low)

			dev_info(dev, "low voltage detected, date/time is not reliable.\n");



		if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,

					sizeof(int)))

			return -EFAULT;

		return 0;

	default:

		return -ENOIOCTLCMD;

	}

}

#else

#define pcf2127_rtc_ioctl NULL

#endif



static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	return pcf2127_get_datetime(to_i2c_client(dev), tm);

}



static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	return pcf2127_set_datetime(to_i2c_client(dev), tm);

}



static const struct rtc_class_ops pcf2127_rtc_ops = {

	.ioctl		= pcf2127_rtc_ioctl,

	.read_time	= pcf2127_rtc_read_time,

	.set_time	= pcf2127_rtc_set_time,

};



static int pcf2127_probe(struct i2c_client *client,

				const struct i2c_device_id *id)

{

	struct pcf2127 *pcf2127;



	dev_dbg(&client->dev, "%s\n", __func__);



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

		return -ENODEV;



	pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),

				GFP_KERNEL);

	if (!pcf2127)

		return -ENOMEM;



	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");



	i2c_set_clientdata(client, pcf2127);



	pcf2127->rtc = devm_rtc_device_register(&client->dev,

				pcf2127_driver.driver.name,

				&pcf2127_rtc_ops, THIS_MODULE);



	if (IS_ERR(pcf2127->rtc))

		return PTR_ERR(pcf2127->rtc);



	return 0;

}



static int pcf2127_remove(struct i2c_client *client)

{

	return 0;

}



static const struct i2c_device_id pcf2127_id[] = {

	{ "pcf2127", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, pcf2127_id);



#ifdef CONFIG_OF

static const struct of_device_id pcf2127_of_match[] = {

	{ .compatible = "nxp,pcf2127" },

	{}

};

MODULE_DEVICE_TABLE(of, pcf2127_of_match);

#endif



static struct i2c_driver pcf2127_driver = {

	.driver		= {

		.name	= "rtc-pcf2127",

		.owner	= THIS_MODULE,

		.of_match_table = of_match_ptr(pcf2127_of_match),

	},

	.probe		= pcf2127_probe,

	.remove		= pcf2127_remove,

	.id_table	= pcf2127_id,

};



module_i2c_driver(pcf2127_driver);



MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");

MODULE_DESCRIPTION("NXP PCF2127 RTC driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(DRV_VERSION);