drivers/rtc/rtc-pcf85063.c - linux - Git at Google

 /*
  * An I2C driver for the PCF85063 RTC
  * Copyright 2014 Rose Technology
  *
  * Author: Søren Andersen <san@rosetechnology.dk>
  * Maintainers: http://www.nslu2-linux.org/
  *
  * based on the other drivers in this same directory.
  *
  * 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/module.h>

 /*
  * Information for this driver was pulled from the following datasheets.
  *
  *  http://www.nxp.com/documents/data_sheet/PCF85063A.pdf
  *  http://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
  *
  *  PCF85063A -- Rev. 6 — 18 November 2015
  *  PCF85063TP -- Rev. 4 — 6 May 2015
 */

 #define PCF85063_REG_CTRL1		0x00 /* status */
 #define PCF85063_REG_CTRL1_CAP_SEL	BIT(0)
 #define PCF85063_REG_CTRL1_STOP		BIT(5)

 #define PCF85063_REG_SC			0x04 /* datetime */
 #define PCF85063_REG_SC_OS		0x80

 static struct i2c_driver pcf85063_driver;

 static int pcf85063_stop_clock(struct i2c_client *client, u8 *ctrl1)
 {
 	int rc;
 	u8 reg;

 	rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
 	if (rc < 0) {
 		dev_err(&client->dev, "Failing to stop the clock\n");
 		return -EIO;
 	}

 	/* stop the clock */
 	reg = rc | PCF85063_REG_CTRL1_STOP;

 	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);
 	if (rc < 0) {
 		dev_err(&client->dev, "Failing to stop the clock\n");
 		return -EIO;
 	}

 	*ctrl1 = reg;

 	return 0;
 }

 static int pcf85063_start_clock(struct i2c_client *client, u8 ctrl1)
 {
 	int rc;

 	/* start the clock */
 	ctrl1 &= ~PCF85063_REG_CTRL1_STOP;

 	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ctrl1);
 	if (rc < 0) {
 		dev_err(&client->dev, "Failing to start the clock\n");
 		return -EIO;
 	}

 	return 0;
 }

 static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	int rc;
 	u8 regs[7];

 	/*
 	 * while reading, the time/date registers are blocked and not updated
 	 * anymore until the access is finished. To not lose a second
 	 * event, the access must be finished within one second. So, read all
 	 * time/date registers in one turn.
 	 */
 	rc = i2c_smbus_read_i2c_block_data(client, PCF85063_REG_SC,
 					   sizeof(regs), regs);
 	if (rc != sizeof(regs)) {
 		dev_err(&client->dev, "date/time register read error\n");
 		return -EIO;
 	}

 	/* if the clock has lost its power it makes no sense to use its time */
 	if (regs[0] & PCF85063_REG_SC_OS) {
 		dev_warn(&client->dev, "Power loss detected, invalid time\n");
 		return -EINVAL;
 	}

 	tm->tm_sec = bcd2bin(regs[0] & 0x7F);
 	tm->tm_min = bcd2bin(regs[1] & 0x7F);
 	tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
 	tm->tm_mday = bcd2bin(regs[3] & 0x3F);
 	tm->tm_wday = regs[4] & 0x07;
 	tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
 	tm->tm_year = bcd2bin(regs[6]);
 	tm->tm_year += 100;

 	return 0;
 }

 static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	int rc;
 	u8 regs[7];
 	u8 ctrl1;

 	if ((tm->tm_year < 100) || (tm->tm_year > 199))
 		return -EINVAL;

 	/*
 	 * to accurately set the time, reset the divider chain and keep it in
 	 * reset state until all time/date registers are written
 	 */
 	rc = pcf85063_stop_clock(client, &ctrl1);
 	if (rc != 0)
 		return rc;

 	/* hours, minutes and seconds */
 	regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */

 	regs[1] = bin2bcd(tm->tm_min);
 	regs[2] = bin2bcd(tm->tm_hour);

 	/* Day of month, 1 - 31 */
 	regs[3] = bin2bcd(tm->tm_mday);

 	/* Day, 0 - 6 */
 	regs[4] = tm->tm_wday & 0x07;

 	/* month, 1 - 12 */
 	regs[5] = bin2bcd(tm->tm_mon + 1);

 	/* year and century */
 	regs[6] = bin2bcd(tm->tm_year - 100);

 	/* write all registers at once */
 	rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
 					    sizeof(regs), regs);
 	if (rc < 0) {
 		dev_err(&client->dev, "date/time register write error\n");
 		return rc;
 	}

 	/*
 	 * Write the control register as a separate action since the size of
 	 * the register space is different between the PCF85063TP and
 	 * PCF85063A devices.  The rollover point can not be used.
 	 */
 	rc = pcf85063_start_clock(client, ctrl1);
 	if (rc != 0)
 		return rc;

 	return 0;
 }

 static const struct rtc_class_ops pcf85063_rtc_ops = {
 	.read_time	= pcf85063_rtc_read_time,
 	.set_time	= pcf85063_rtc_set_time
 };

 static int pcf85063_load_capacitance(struct i2c_client *client)
 {
 	u32 load;
 	int rc;
 	u8 reg;

 	rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
 	if (rc < 0)
 		return rc;

 	reg = rc;
 	load = 7000;
 	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 7000",
 			 load);
 		/* fall through */
 	case 7000:
 		reg &= ~PCF85063_REG_CTRL1_CAP_SEL;
 		break;
 	case 12500:
 		reg |= PCF85063_REG_CTRL1_CAP_SEL;
 		break;
 	}

 	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);

 	return rc;
 }

 static int pcf85063_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
 	struct rtc_device *rtc;
 	int err;

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

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 		return -ENODEV;

 	err = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
 	if (err < 0) {
 		dev_err(&client->dev, "RTC chip is not present\n");
 		return err;
 	}

 	err = pcf85063_load_capacitance(client);
 	if (err < 0)
 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
 			 err);

 	rtc = devm_rtc_device_register(&client->dev,
 				       pcf85063_driver.driver.name,
 				       &pcf85063_rtc_ops, THIS_MODULE);

 	return PTR_ERR_OR_ZERO(rtc);
 }

 static const struct i2c_device_id pcf85063_id[] = {
 	{ "pcf85063", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pcf85063_id);

 #ifdef CONFIG_OF
 static const struct of_device_id pcf85063_of_match[] = {
 	{ .compatible = "nxp,pcf85063" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, pcf85063_of_match);
 #endif

 static struct i2c_driver pcf85063_driver = {
 	.driver		= {
 		.name	= "rtc-pcf85063",
 		.of_match_table = of_match_ptr(pcf85063_of_match),
 	},
 	.probe		= pcf85063_probe,
 	.id_table	= pcf85063_id,
 };

 module_i2c_driver(pcf85063_driver);

 MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
 MODULE_DESCRIPTION("PCF85063 RTC driver");
 MODULE_LICENSE("GPL");
	/*
	* An I2C driver for the PCF85063 RTC
	* Copyright 2014 Rose Technology
	*
	* Author: Søren Andersen <san@rosetechnology.dk>
	* Maintainers: http://www.nslu2-linux.org/
	*
	* based on the other drivers in this same directory.
	*
	* 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/module.h>

	/*
	* Information for this driver was pulled from the following datasheets.
	*
	* http://www.nxp.com/documents/data_sheet/PCF85063A.pdf
	* http://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
	*
	* PCF85063A -- Rev. 6 — 18 November 2015
	* PCF85063TP -- Rev. 4 — 6 May 2015
	*/

	#define PCF85063_REG_CTRL1 0x00 /* status */
	#define PCF85063_REG_CTRL1_CAP_SEL BIT(0)
	#define PCF85063_REG_CTRL1_STOP BIT(5)

	#define PCF85063_REG_SC 0x04 /* datetime */
	#define PCF85063_REG_SC_OS 0x80

	static struct i2c_driver pcf85063_driver;

	static int pcf85063_stop_clock(struct i2c_client client, u8 ctrl1)
	{
	int rc;
	u8 reg;

	rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
	if (rc < 0) {
	dev_err(&client->dev, "Failing to stop the clock\n");
	return -EIO;
	}

	/* stop the clock */
	reg = rc \| PCF85063_REG_CTRL1_STOP;

	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);
	if (rc < 0) {
	dev_err(&client->dev, "Failing to stop the clock\n");
	return -EIO;
	}

	*ctrl1 = reg;

	return 0;
	}

	static int pcf85063_start_clock(struct i2c_client *client, u8 ctrl1)
	{
	int rc;

	/* start the clock */
	ctrl1 &= ~PCF85063_REG_CTRL1_STOP;

	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ctrl1);
	if (rc < 0) {
	dev_err(&client->dev, "Failing to start the clock\n");
	return -EIO;
	}

	return 0;
	}

	static int pcf85063_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	int rc;
	u8 regs[7];

	/*
	* while reading, the time/date registers are blocked and not updated
	* anymore until the access is finished. To not lose a second
	* event, the access must be finished within one second. So, read all
	* time/date registers in one turn.
	*/
	rc = i2c_smbus_read_i2c_block_data(client, PCF85063_REG_SC,
	sizeof(regs), regs);
	if (rc != sizeof(regs)) {
	dev_err(&client->dev, "date/time register read error\n");
	return -EIO;
	}

	/* if the clock has lost its power it makes no sense to use its time */
	if (regs[0] & PCF85063_REG_SC_OS) {
	dev_warn(&client->dev, "Power loss detected, invalid time\n");
	return -EINVAL;
	}

	tm->tm_sec = bcd2bin(regs[0] & 0x7F);
	tm->tm_min = bcd2bin(regs[1] & 0x7F);
	tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
	tm->tm_mday = bcd2bin(regs[3] & 0x3F);
	tm->tm_wday = regs[4] & 0x07;
	tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
	tm->tm_year = bcd2bin(regs[6]);
	tm->tm_year += 100;

	return 0;
	}

	static int pcf85063_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct i2c_client *client = to_i2c_client(dev);
	int rc;
	u8 regs[7];
	u8 ctrl1;

	if ((tm->tm_year < 100) \|\| (tm->tm_year > 199))
	return -EINVAL;

	/*
	* to accurately set the time, reset the divider chain and keep it in
	* reset state until all time/date registers are written
	*/
	rc = pcf85063_stop_clock(client, &ctrl1);
	if (rc != 0)
	return rc;

	/* hours, minutes and seconds */
	regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */

	regs[1] = bin2bcd(tm->tm_min);
	regs[2] = bin2bcd(tm->tm_hour);

	/* Day of month, 1 - 31 */
	regs[3] = bin2bcd(tm->tm_mday);

	/* Day, 0 - 6 */
	regs[4] = tm->tm_wday & 0x07;

	/* month, 1 - 12 */
	regs[5] = bin2bcd(tm->tm_mon + 1);

	/* year and century */
	regs[6] = bin2bcd(tm->tm_year - 100);

	/* write all registers at once */
	rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
	sizeof(regs), regs);
	if (rc < 0) {
	dev_err(&client->dev, "date/time register write error\n");
	return rc;
	}

	/*
	* Write the control register as a separate action since the size of
	* the register space is different between the PCF85063TP and
	* PCF85063A devices. The rollover point can not be used.
	*/
	rc = pcf85063_start_clock(client, ctrl1);
	if (rc != 0)
	return rc;

	return 0;
	}

	static const struct rtc_class_ops pcf85063_rtc_ops = {
	.read_time = pcf85063_rtc_read_time,
	.set_time = pcf85063_rtc_set_time
	};

	static int pcf85063_load_capacitance(struct i2c_client *client)
	{
	u32 load;
	int rc;
	u8 reg;

	rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
	if (rc < 0)
	return rc;

	reg = rc;
	load = 7000;
	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 7000",
	load);
	/* fall through */
	case 7000:
	reg &= ~PCF85063_REG_CTRL1_CAP_SEL;
	break;
	case 12500:
	reg \|= PCF85063_REG_CTRL1_CAP_SEL;
	break;
	}

	rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);

	return rc;
	}

	static int pcf85063_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct rtc_device *rtc;
	int err;

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

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	return -ENODEV;

	err = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
	if (err < 0) {
	dev_err(&client->dev, "RTC chip is not present\n");
	return err;
	}

	err = pcf85063_load_capacitance(client);
	if (err < 0)
	dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
	err);

	rtc = devm_rtc_device_register(&client->dev,
	pcf85063_driver.driver.name,
	&pcf85063_rtc_ops, THIS_MODULE);

	return PTR_ERR_OR_ZERO(rtc);
	}

	static const struct i2c_device_id pcf85063_id[] = {
	{ "pcf85063", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, pcf85063_id);

	#ifdef CONFIG_OF
	static const struct of_device_id pcf85063_of_match[] = {
	{ .compatible = "nxp,pcf85063" },
	{}
	};
	MODULE_DEVICE_TABLE(of, pcf85063_of_match);
	#endif

	static struct i2c_driver pcf85063_driver = {
	.driver = {
	.name = "rtc-pcf85063",
	.of_match_table = of_match_ptr(pcf85063_of_match),
	},
	.probe = pcf85063_probe,
	.id_table = pcf85063_id,
	};

	module_i2c_driver(pcf85063_driver);

	MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
	MODULE_DESCRIPTION("PCF85063 RTC driver");
	MODULE_LICENSE("GPL");