/*

   * An I2C and SPI driver for the NXP PCF2127/29 RTC

   * Copyright 2013 Til-Technologies
   *
   * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
   *
   * based on the other drivers in this same directory.
   *

   * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.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/spi/spi.h>

  #include <linux/bcd.h>
  #include <linux/rtc.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/of.h>

  #include <linux/regmap.h>

  #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_CTRL3_BLF		BIT(2)

  #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)

  #define PCF2127_OSF             BIT(7)  /* Oscillator Fail flag */

  struct pcf2127 {
  	struct rtc_device *rtc;

  	struct regmap *regmap;

  };
  
  /*
   * 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_rtc_read_time(struct device *dev, struct rtc_time *tm)

  {

  	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
  	unsigned char buf[10];
  	int ret;

  	int i;

  	for (i = 0; i <= PCF2127_REG_CTRL3; i++) {
  		ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1 + i,
  				  (unsigned int *)(buf + i));
  		if (ret) {
  			dev_err(dev, "%s: read error
  ", __func__);
  			return ret;
  		}
  	}
  
  	ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_SC,
  			       (buf + PCF2127_REG_SC),
  			       ARRAY_SIZE(buf) - PCF2127_REG_SC);

  	if (ret) {
  		dev_err(dev, "%s: read error
  ", __func__);
  		return ret;

  	}

  	if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)

  		dev_info(dev,

  			"low voltage detected, check/replace RTC battery.
  ");

  
  	if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
  		/*
  		 * no need clear the flag here,
  		 * it will be cleared once the new date is saved
  		 */

  		dev_warn(dev,

  			 "oscillator stop detected, date/time is not reliable
  ");
  		return -EINVAL;

  	}

  	dev_dbg(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
  ",
  		__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(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "

  		"mday=%d, mon=%d, year=%d, wday=%d
  ",
  		__func__,
  		tm->tm_sec, tm->tm_min, tm->tm_hour,
  		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

  	return rtc_valid_tm(tm);

  }

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

  {

  	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
  	unsigned char buf[7];

  	int i = 0, err;

  	dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "

  		"mday=%d, mon=%d, year=%d, wday=%d
  ",
  		__func__,
  		tm->tm_sec, tm->tm_min, tm->tm_hour,
  		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

  	/* hours, minutes and seconds */

  	buf[i++] = bin2bcd(tm->tm_sec);	/* this will also clear OSF flag */

  	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 = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
  	if (err) {
  		dev_err(dev,

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

  		return err;

  	}
  
  	return 0;
  }
  
  #ifdef CONFIG_RTC_INTF_DEV
  static int pcf2127_rtc_ioctl(struct device *dev,
  				unsigned int cmd, unsigned long arg)
  {

  	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);

  	int touser;
  	int ret;

  
  	switch (cmd) {
  	case RTC_VL_READ:

  		ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
  		if (ret)

  			return ret;

  		touser = touser & PCF2127_REG_CTRL3_BLF ? 1 : 0;

  		if (copy_to_user((void __user *)arg, &touser, sizeof(int)))

  			return -EFAULT;
  		return 0;
  	default:
  		return -ENOIOCTLCMD;
  	}
  }
  #else
  #define pcf2127_rtc_ioctl NULL
  #endif

  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 device *dev, struct regmap *regmap,
  			const char *name)

  {
  	struct pcf2127 *pcf2127;

  	dev_dbg(dev, "%s
  ", __func__);

  	pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);

  	if (!pcf2127)
  		return -ENOMEM;

  	pcf2127->regmap = regmap;

  	dev_set_drvdata(dev, pcf2127);
  
  	pcf2127->rtc = devm_rtc_device_register(dev, name, &pcf2127_rtc_ops,
  						THIS_MODULE);

  	return PTR_ERR_OR_ZERO(pcf2127->rtc);

  }

  #ifdef CONFIG_OF
  static const struct of_device_id pcf2127_of_match[] = {
  	{ .compatible = "nxp,pcf2127" },

  	{ .compatible = "nxp,pcf2129" },

  	{}
  };
  MODULE_DEVICE_TABLE(of, pcf2127_of_match);
  #endif

  #if IS_ENABLED(CONFIG_I2C)

  static int pcf2127_i2c_write(void *context, const void *data, size_t count)
  {
  	struct device *dev = context;
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret;
  
  	ret = i2c_master_send(client, data, count);
  	if (ret != count)
  		return ret < 0 ? ret : -EIO;
  
  	return 0;
  }
  
  static int pcf2127_i2c_gather_write(void *context,
  				const void *reg, size_t reg_size,
  				const void *val, size_t val_size)
  {
  	struct device *dev = context;
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret;
  	void *buf;
  
  	if (WARN_ON(reg_size != 1))
  		return -EINVAL;
  
  	buf = kmalloc(val_size + 1, GFP_KERNEL);
  	if (!buf)
  		return -ENOMEM;
  
  	memcpy(buf, reg, 1);
  	memcpy(buf + 1, val, val_size);
  
  	ret = i2c_master_send(client, buf, val_size + 1);

  
  	kfree(buf);

  	if (ret != val_size + 1)
  		return ret < 0 ? ret : -EIO;
  
  	return 0;
  }
  
  static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
  				void *val, size_t val_size)
  {
  	struct device *dev = context;
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret;
  
  	if (WARN_ON(reg_size != 1))
  		return -EINVAL;
  
  	ret = i2c_master_send(client, reg, 1);
  	if (ret != 1)
  		return ret < 0 ? ret : -EIO;
  
  	ret = i2c_master_recv(client, val, val_size);
  	if (ret != val_size)
  		return ret < 0 ? ret : -EIO;
  
  	return 0;
  }
  
  /*
   * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
   * is that the STOP condition is required between set register address and
   * read register data when reading from registers.
   */
  static const struct regmap_bus pcf2127_i2c_regmap = {
  	.write = pcf2127_i2c_write,
  	.gather_write = pcf2127_i2c_gather_write,
  	.read = pcf2127_i2c_read,
  };
  
  static struct i2c_driver pcf2127_i2c_driver;
  
  static int pcf2127_i2c_probe(struct i2c_client *client,
  				const struct i2c_device_id *id)
  {
  	struct regmap *regmap;
  	static const struct regmap_config config = {
  		.reg_bits = 8,
  		.val_bits = 8,
  	};
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
  		return -ENODEV;
  
  	regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
  					&client->dev, &config);
  	if (IS_ERR(regmap)) {
  		dev_err(&client->dev, "%s: regmap allocation failed: %ld
  ",
  			__func__, PTR_ERR(regmap));
  		return PTR_ERR(regmap);
  	}
  
  	return pcf2127_probe(&client->dev, regmap,
  				pcf2127_i2c_driver.driver.name);
  }
  
  static const struct i2c_device_id pcf2127_i2c_id[] = {
  	{ "pcf2127", 0 },

  	{ "pcf2129", 0 },

  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
  
  static struct i2c_driver pcf2127_i2c_driver = {

  	.driver		= {

  		.name	= "rtc-pcf2127-i2c",

  		.of_match_table = of_match_ptr(pcf2127_of_match),
  	},

  	.probe		= pcf2127_i2c_probe,
  	.id_table	= pcf2127_i2c_id,

  };

  
  static int pcf2127_i2c_register_driver(void)
  {
  	return i2c_add_driver(&pcf2127_i2c_driver);
  }
  
  static void pcf2127_i2c_unregister_driver(void)
  {
  	i2c_del_driver(&pcf2127_i2c_driver);
  }
  
  #else
  
  static int pcf2127_i2c_register_driver(void)
  {
  	return 0;
  }
  
  static void pcf2127_i2c_unregister_driver(void)
  {
  }
  
  #endif
  
  #if IS_ENABLED(CONFIG_SPI_MASTER)
  
  static struct spi_driver pcf2127_spi_driver;
  
  static int pcf2127_spi_probe(struct spi_device *spi)
  {
  	static const struct regmap_config config = {
  		.reg_bits = 8,
  		.val_bits = 8,
  		.read_flag_mask = 0xa0,
  		.write_flag_mask = 0x20,
  	};
  	struct regmap *regmap;
  
  	regmap = devm_regmap_init_spi(spi, &config);
  	if (IS_ERR(regmap)) {
  		dev_err(&spi->dev, "%s: regmap allocation failed: %ld
  ",
  			__func__, PTR_ERR(regmap));
  		return PTR_ERR(regmap);
  	}
  
  	return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name);
  }
  
  static const struct spi_device_id pcf2127_spi_id[] = {
  	{ "pcf2127", 0 },

  	{ "pcf2129", 0 },

  	{ }
  };
  MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
  
  static struct spi_driver pcf2127_spi_driver = {
  	.driver		= {
  		.name	= "rtc-pcf2127-spi",
  		.of_match_table = of_match_ptr(pcf2127_of_match),
  	},
  	.probe		= pcf2127_spi_probe,
  	.id_table	= pcf2127_spi_id,
  };
  
  static int pcf2127_spi_register_driver(void)
  {
  	return spi_register_driver(&pcf2127_spi_driver);
  }
  
  static void pcf2127_spi_unregister_driver(void)
  {
  	spi_unregister_driver(&pcf2127_spi_driver);
  }
  
  #else
  
  static int pcf2127_spi_register_driver(void)
  {
  	return 0;
  }
  
  static void pcf2127_spi_unregister_driver(void)
  {
  }
  
  #endif
  
  static int __init pcf2127_init(void)
  {
  	int ret;
  
  	ret = pcf2127_i2c_register_driver();
  	if (ret) {
  		pr_err("Failed to register pcf2127 i2c driver: %d
  ", ret);
  		return ret;
  	}
  
  	ret = pcf2127_spi_register_driver();
  	if (ret) {
  		pr_err("Failed to register pcf2127 spi driver: %d
  ", ret);
  		pcf2127_i2c_unregister_driver();
  	}
  
  	return ret;
  }
  module_init(pcf2127_init)
  
  static void __exit pcf2127_exit(void)
  {
  	pcf2127_spi_unregister_driver();
  	pcf2127_i2c_unregister_driver();
  }
  module_exit(pcf2127_exit)

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

  MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");

  MODULE_LICENSE("GPL v2");