drivers/rtc/s35392a.c - u-boot - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * SII Semiconductor Corporation S35392A RTC driver.
  *
  * Copyright (c) 2017, General Electric Company
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License 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 <command.h>
 #include <common.h>
 #include <dm.h>
 #include <i2c.h>
 #include <linux/bitrev.h>
 #include <rtc.h>
 #include <linux/delay.h>

 #define S35390A_CHIP_ADDR	0x30

 #define S35390A_CMD_STATUS1	0x0
 #define S35390A_CMD_STATUS2	0x1
 #define S35390A_CMD_TIME1	0x2
 #define S35390A_CMD_TIME2	0x3
 #define S35390A_CMD_INT2_REG1	0x5

 #define S35390A_BYTE_YEAR	0
 #define S35390A_BYTE_MONTH	1
 #define S35390A_BYTE_DAY	2
 #define S35390A_BYTE_WDAY	3
 #define S35390A_BYTE_HOURS	4
 #define S35390A_BYTE_MINS	5
 #define S35390A_BYTE_SECS	6

 /* flags for STATUS1 */
 #define S35390A_FLAG_POC	0x01
 #define S35390A_FLAG_BLD	0x02
 #define S35390A_FLAG_INT2	0x04
 #define S35390A_FLAG_24H	0x40
 #define S35390A_FLAG_RESET	0x80

 /*
  * If either BLD or POC is set, then the chip has lost power long enough for
  * the time value to become invalid.
  */
 #define S35390A_LOW_VOLTAGE (S35390A_FLAG_POC | S35390A_FLAG_BLD)

 /*---------------------------------------------------------------------*/
 #undef DEBUG_RTC

 #ifdef DEBUG_RTC
 #define DEBUGR(fmt, args...) printf(fmt, ##args)
 #else
 #define DEBUGR(fmt, args...)
 #endif
 /*---------------------------------------------------------------------*/

 #ifdef CONFIG_DM_RTC
 #define DEV_TYPE struct udevice
 #else
 /* Local udevice */
 struct ludevice {
 	u8 chip;
 };

 #define DEV_TYPE struct ludevice
 struct ludevice dev;

 #endif

 #define msleep(a) udelay(a * 1000)

 int lowvoltage;

 static int s35392a_rtc_reset(DEV_TYPE *dev);

 static int s35392a_rtc_read(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
 {
 	int ret;

 #ifdef CONFIG_DM_RTC
 	ret = dm_i2c_read(dev, reg, buf, len);
 #else
 	(void)dev;
 	ret = i2c_read(S35390A_CHIP_ADDR | reg, 0, -1, buf, len);
 #endif

 	return ret;
 }

 static int s35392a_rtc_write(DEV_TYPE *dev, u8 reg, u8 *buf, int len)
 {
 	int ret;

 #ifdef CONFIG_DM_RTC
 	ret = dm_i2c_write(dev, reg, buf, len);
 #else
 	(void)dev;
 	ret = i2c_write(S35390A_CHIP_ADDR | reg, 0, 0, buf, len);
 #endif

 	return ret;
 }

 static int s35392a_rtc_read8(DEV_TYPE *dev, unsigned int reg)
 {
 	u8 val;
 	int ret;

 	ret = s35392a_rtc_read(dev, reg, &val, sizeof(val));
 	return ret < 0 ? ret : val;
 }

 static int s35392a_rtc_write8(DEV_TYPE *dev, unsigned int reg, int val)
 {
 	int ret;
 	u8 lval = val;

 	ret = s35392a_rtc_write(dev, reg, &lval, sizeof(lval));
 	return ret < 0 ? ret : 0;
 }

 static int validate_time(const struct rtc_time *tm)
 {
 	if ((tm->tm_year < 2000) || (tm->tm_year > 2099))
 		return -EINVAL;

 	if ((tm->tm_mon < 1) || (tm->tm_mon > 12))
 		return -EINVAL;

 	if ((tm->tm_mday < 1) || (tm->tm_mday > 31))
 		return -EINVAL;

 	if ((tm->tm_wday < 0) || (tm->tm_wday > 6))
 		return -EINVAL;

 	if ((tm->tm_hour < 0) || (tm->tm_hour > 23))
 		return -EINVAL;

 	if ((tm->tm_min < 0) || (tm->tm_min > 59))
 		return -EINVAL;

 	if ((tm->tm_sec < 0) || (tm->tm_sec > 59))
 		return -EINVAL;

 	return 0;
 }

 void s35392a_rtc_init(DEV_TYPE *dev)
 {
 	int status;

 	status = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
 	if (status < 0)
 		goto error;

 	DEBUGR("init: S35390A_CMD_STATUS1: 0x%x\n", status);

 	lowvoltage = status & S35390A_LOW_VOLTAGE ? 1 : 0;

 	if (status & S35390A_FLAG_POC)
 		/*
 		 * Do not communicate for 0.5 seconds since the power-on
 		 * detection circuit is in operation.
 		 */
 		msleep(500);

 	else if (!lowvoltage)
 		/*
 		 * If both POC and BLD are unset everything is fine.
 		 */
 		return;

 	if (lowvoltage)
 		printf("RTC low voltage detected\n");

 	if (!s35392a_rtc_reset(dev))
 		return;

 error:
 	printf("Error RTC init.\n");
 }

 /* Get the current time from the RTC */
 static int s35392a_rtc_get(DEV_TYPE *dev, struct rtc_time *tm)
 {
 	u8 date[7];
 	int ret, i;

 	if (lowvoltage) {
 		DEBUGR("RTC low voltage detected\n");
 		return -EINVAL;
 	}

 	ret = s35392a_rtc_read(dev, S35390A_CMD_TIME1, date, sizeof(date));
 	if (ret < 0) {
 		DEBUGR("Error reading date from RTC\n");
 		return -EIO;
 	}

 	/* This chip returns the bits of each byte in reverse order */
 	for (i = 0; i < 7; ++i)
 		date[i] = bitrev8(date[i]);

 	tm->tm_sec  = bcd2bin(date[S35390A_BYTE_SECS]);
 	tm->tm_min  = bcd2bin(date[S35390A_BYTE_MINS]);
 	tm->tm_hour = bcd2bin(date[S35390A_BYTE_HOURS] & ~S35390A_FLAG_24H);
 	tm->tm_wday = bcd2bin(date[S35390A_BYTE_WDAY]);
 	tm->tm_mday = bcd2bin(date[S35390A_BYTE_DAY]);
 	tm->tm_mon  = bcd2bin(date[S35390A_BYTE_MONTH]);
 	tm->tm_year = bcd2bin(date[S35390A_BYTE_YEAR]) + 2000;

 	DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 	       tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 	       tm->tm_hour, tm->tm_min, tm->tm_sec);

 	return 0;
 }

 /* Set the RTC */
 static int s35392a_rtc_set(DEV_TYPE *dev, const struct rtc_time *tm)
 {
 	int i, ret;
 	int status;
 	u8 date[7];

 	DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 	       tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
 	       tm->tm_hour, tm->tm_min, tm->tm_sec);

 	ret = validate_time(tm);
 	if (ret < 0)
 		return -EINVAL;

 	/* We support only 24h mode */
 	ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
 	if (ret < 0)
 		return -EIO;
 	status = ret;

 	ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1,
 				 status | S35390A_FLAG_24H);
 	if (ret < 0)
 		return -EIO;

 	date[S35390A_BYTE_YEAR]  = bin2bcd(tm->tm_year - 2000);
 	date[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon);
 	date[S35390A_BYTE_DAY]   = bin2bcd(tm->tm_mday);
 	date[S35390A_BYTE_WDAY]  = bin2bcd(tm->tm_wday);
 	date[S35390A_BYTE_HOURS] = bin2bcd(tm->tm_hour);
 	date[S35390A_BYTE_MINS]  = bin2bcd(tm->tm_min);
 	date[S35390A_BYTE_SECS]  = bin2bcd(tm->tm_sec);

 	/* This chip expects the bits of each byte to be in reverse order */
 	for (i = 0; i < 7; ++i)
 		date[i] = bitrev8(date[i]);

 	ret = s35392a_rtc_write(dev, S35390A_CMD_TIME1, date, sizeof(date));
 	if (ret < 0) {
 		DEBUGR("Error writing date to RTC\n");
 		return -EIO;
 	}

 	/* Now we have time. Reset the low voltage status */
 	lowvoltage = 0;

 	return 0;
 }

 /* Reset the RTC. */
 static int s35392a_rtc_reset(DEV_TYPE *dev)
 {
 	int buf;
 	int ret;
 	unsigned int initcount = 0;

 	buf = S35390A_FLAG_RESET;

 initialize:
 	ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, buf);
 	if (ret < 0)
 		return -EIO;

 	ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
 	if (ret < 0)
 		return -EIO;
 	buf = ret;

 	if (!lowvoltage)
 		lowvoltage = buf & S35390A_LOW_VOLTAGE ? 1 : 0;

 	if (buf & S35390A_LOW_VOLTAGE) {
 		/* Try up to five times to reset the chip */
 		if (initcount < 5) {
 			++initcount;
 			goto initialize;
 		} else {
 			return -EIO;
 		}
 	}

 	return 0;
 }

 #ifndef CONFIG_DM_RTC

 int rtc_get(struct rtc_time *tm)
 {
 	return s35392a_rtc_get(&dev, tm);
 }

 int rtc_set(struct rtc_time *tm)
 {
 	return s35392a_rtc_set(&dev, tm);
 }

 void rtc_reset(void)
 {
 	s35392a_rtc_reset(&dev);
 }

 void rtc_init(void)
 {
 	s35392a_rtc_init(&dev);
 }

 #else

 static int s35392a_probe(struct udevice *dev)
 {
 #if defined(CONFIG_DM_RTC)
 	/* 3-bit "command", or register, is encoded within the device address.
 	 */
 	i2c_set_chip_offset_len(dev, 0);
 	i2c_set_chip_addr_offset_mask(dev, 0x7);
 #endif

 	s35392a_rtc_init(dev);
 	return 0;
 }

 static const struct rtc_ops s35392a_rtc_ops = {
 	.get = s35392a_rtc_get,
 	.set = s35392a_rtc_set,
 	.read8 = s35392a_rtc_read8,
 	.write8 = s35392a_rtc_write8,
 	.reset = s35392a_rtc_reset,
 };

 static const struct udevice_id s35392a_rtc_ids[] = {
 	{ .compatible = "sii,s35392a-rtc" },
 	{ .compatible = "sii,s35392a" },
 	{ .compatible = "s35392a" },
 	{ }
 };

 U_BOOT_DRIVER(s35392a_rtc) = {
 	.name	  = "s35392a_rtc",
 	.id	      = UCLASS_RTC,
 	.probe    = s35392a_probe,
 	.of_match = s35392a_rtc_ids,
 	.ops	  = &s35392a_rtc_ops,
 };

 #endif
	// SPDX-License-Identifier: GPL-2.0
	/*
	* SII Semiconductor Corporation S35392A RTC driver.
	*
	* Copyright (c) 2017, General Electric Company
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 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 <command.h>
	#include <common.h>
	#include <dm.h>
	#include <i2c.h>
	#include <linux/bitrev.h>
	#include <rtc.h>
	#include <linux/delay.h>

	#define S35390A_CHIP_ADDR 0x30

	#define S35390A_CMD_STATUS1 0x0
	#define S35390A_CMD_STATUS2 0x1
	#define S35390A_CMD_TIME1 0x2
	#define S35390A_CMD_TIME2 0x3
	#define S35390A_CMD_INT2_REG1 0x5

	#define S35390A_BYTE_YEAR 0
	#define S35390A_BYTE_MONTH 1
	#define S35390A_BYTE_DAY 2
	#define S35390A_BYTE_WDAY 3
	#define S35390A_BYTE_HOURS 4
	#define S35390A_BYTE_MINS 5
	#define S35390A_BYTE_SECS 6

	/* flags for STATUS1 */
	#define S35390A_FLAG_POC 0x01
	#define S35390A_FLAG_BLD 0x02
	#define S35390A_FLAG_INT2 0x04
	#define S35390A_FLAG_24H 0x40
	#define S35390A_FLAG_RESET 0x80

	/*
	* If either BLD or POC is set, then the chip has lost power long enough for
	* the time value to become invalid.
	*/
	#define S35390A_LOW_VOLTAGE (S35390A_FLAG_POC \| S35390A_FLAG_BLD)

	/---------------------------------------------------------------------/
	#undef DEBUG_RTC

	#ifdef DEBUG_RTC
	#define DEBUGR(fmt, args...) printf(fmt, ##args)
	#else
	#define DEBUGR(fmt, args...)
	#endif
	/---------------------------------------------------------------------/

	#ifdef CONFIG_DM_RTC
	#define DEV_TYPE struct udevice
	#else
	/* Local udevice */
	struct ludevice {
	u8 chip;
	};

	#define DEV_TYPE struct ludevice
	struct ludevice dev;

	#endif

	#define msleep(a) udelay(a * 1000)

	int lowvoltage;

	static int s35392a_rtc_reset(DEV_TYPE *dev);

	static int s35392a_rtc_read(DEV_TYPE dev, u8 reg, u8 buf, int len)
	{
	int ret;

	#ifdef CONFIG_DM_RTC
	ret = dm_i2c_read(dev, reg, buf, len);
	#else
	(void)dev;
	ret = i2c_read(S35390A_CHIP_ADDR \| reg, 0, -1, buf, len);
	#endif

	return ret;
	}

	static int s35392a_rtc_write(DEV_TYPE dev, u8 reg, u8 buf, int len)
	{
	int ret;

	#ifdef CONFIG_DM_RTC
	ret = dm_i2c_write(dev, reg, buf, len);
	#else
	(void)dev;
	ret = i2c_write(S35390A_CHIP_ADDR \| reg, 0, 0, buf, len);
	#endif

	return ret;
	}

	static int s35392a_rtc_read8(DEV_TYPE *dev, unsigned int reg)
	{
	u8 val;
	int ret;

	ret = s35392a_rtc_read(dev, reg, &val, sizeof(val));
	return ret < 0 ? ret : val;
	}

	static int s35392a_rtc_write8(DEV_TYPE *dev, unsigned int reg, int val)
	{
	int ret;
	u8 lval = val;

	ret = s35392a_rtc_write(dev, reg, &lval, sizeof(lval));
	return ret < 0 ? ret : 0;
	}

	static int validate_time(const struct rtc_time *tm)
	{
	if ((tm->tm_year < 2000) \|\| (tm->tm_year > 2099))
	return -EINVAL;

	if ((tm->tm_mon < 1) \|\| (tm->tm_mon > 12))
	return -EINVAL;

	if ((tm->tm_mday < 1) \|\| (tm->tm_mday > 31))
	return -EINVAL;

	if ((tm->tm_wday < 0) \|\| (tm->tm_wday > 6))
	return -EINVAL;

	if ((tm->tm_hour < 0) \|\| (tm->tm_hour > 23))
	return -EINVAL;

	if ((tm->tm_min < 0) \|\| (tm->tm_min > 59))
	return -EINVAL;

	if ((tm->tm_sec < 0) \|\| (tm->tm_sec > 59))
	return -EINVAL;

	return 0;
	}

	void s35392a_rtc_init(DEV_TYPE *dev)
	{
	int status;

	status = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
	if (status < 0)
	goto error;

	DEBUGR("init: S35390A_CMD_STATUS1: 0x%x\n", status);

	lowvoltage = status & S35390A_LOW_VOLTAGE ? 1 : 0;

	if (status & S35390A_FLAG_POC)
	/*
	* Do not communicate for 0.5 seconds since the power-on
	* detection circuit is in operation.
	*/
	msleep(500);

	else if (!lowvoltage)
	/*
	* If both POC and BLD are unset everything is fine.
	*/
	return;

	if (lowvoltage)
	printf("RTC low voltage detected\n");

	if (!s35392a_rtc_reset(dev))
	return;

	error:
	printf("Error RTC init.\n");
	}

	/* Get the current time from the RTC */
	static int s35392a_rtc_get(DEV_TYPE dev, struct rtc_time tm)
	{
	u8 date[7];
	int ret, i;

	if (lowvoltage) {
	DEBUGR("RTC low voltage detected\n");
	return -EINVAL;
	}

	ret = s35392a_rtc_read(dev, S35390A_CMD_TIME1, date, sizeof(date));
	if (ret < 0) {
	DEBUGR("Error reading date from RTC\n");
	return -EIO;
	}

	/* This chip returns the bits of each byte in reverse order */
	for (i = 0; i < 7; ++i)
	date[i] = bitrev8(date[i]);

	tm->tm_sec = bcd2bin(date[S35390A_BYTE_SECS]);
	tm->tm_min = bcd2bin(date[S35390A_BYTE_MINS]);
	tm->tm_hour = bcd2bin(date[S35390A_BYTE_HOURS] & ~S35390A_FLAG_24H);
	tm->tm_wday = bcd2bin(date[S35390A_BYTE_WDAY]);
	tm->tm_mday = bcd2bin(date[S35390A_BYTE_DAY]);
	tm->tm_mon = bcd2bin(date[S35390A_BYTE_MONTH]);
	tm->tm_year = bcd2bin(date[S35390A_BYTE_YEAR]) + 2000;

	DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
	tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);

	return 0;
	}

	/* Set the RTC */
	static int s35392a_rtc_set(DEV_TYPE dev, const struct rtc_time tm)
	{
	int i, ret;
	int status;
	u8 date[7];

	DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
	tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);

	ret = validate_time(tm);
	if (ret < 0)
	return -EINVAL;

	/* We support only 24h mode */
	ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
	if (ret < 0)
	return -EIO;
	status = ret;

	ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1,
	status \| S35390A_FLAG_24H);
	if (ret < 0)
	return -EIO;

	date[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 2000);
	date[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon);
	date[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
	date[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
	date[S35390A_BYTE_HOURS] = bin2bcd(tm->tm_hour);
	date[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
	date[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);

	/* This chip expects the bits of each byte to be in reverse order */
	for (i = 0; i < 7; ++i)
	date[i] = bitrev8(date[i]);

	ret = s35392a_rtc_write(dev, S35390A_CMD_TIME1, date, sizeof(date));
	if (ret < 0) {
	DEBUGR("Error writing date to RTC\n");
	return -EIO;
	}

	/* Now we have time. Reset the low voltage status */
	lowvoltage = 0;

	return 0;
	}

	/* Reset the RTC. */
	static int s35392a_rtc_reset(DEV_TYPE *dev)
	{
	int buf;
	int ret;
	unsigned int initcount = 0;

	buf = S35390A_FLAG_RESET;

	initialize:
	ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, buf);
	if (ret < 0)
	return -EIO;

	ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1);
	if (ret < 0)
	return -EIO;
	buf = ret;

	if (!lowvoltage)
	lowvoltage = buf & S35390A_LOW_VOLTAGE ? 1 : 0;

	if (buf & S35390A_LOW_VOLTAGE) {
	/* Try up to five times to reset the chip */
	if (initcount < 5) {
	++initcount;
	goto initialize;
	} else {
	return -EIO;
	}
	}

	return 0;
	}

	#ifndef CONFIG_DM_RTC

	int rtc_get(struct rtc_time *tm)
	{
	return s35392a_rtc_get(&dev, tm);
	}

	int rtc_set(struct rtc_time *tm)
	{
	return s35392a_rtc_set(&dev, tm);
	}

	void rtc_reset(void)
	{
	s35392a_rtc_reset(&dev);
	}

	void rtc_init(void)
	{
	s35392a_rtc_init(&dev);
	}

	#else

	static int s35392a_probe(struct udevice *dev)
	{
	#if defined(CONFIG_DM_RTC)
	/* 3-bit "command", or register, is encoded within the device address.
	*/
	i2c_set_chip_offset_len(dev, 0);
	i2c_set_chip_addr_offset_mask(dev, 0x7);
	#endif

	s35392a_rtc_init(dev);
	return 0;
	}

	static const struct rtc_ops s35392a_rtc_ops = {
	.get = s35392a_rtc_get,
	.set = s35392a_rtc_set,
	.read8 = s35392a_rtc_read8,
	.write8 = s35392a_rtc_write8,
	.reset = s35392a_rtc_reset,
	};

	static const struct udevice_id s35392a_rtc_ids[] = {
	{ .compatible = "sii,s35392a-rtc" },
	{ .compatible = "sii,s35392a" },
	{ .compatible = "s35392a" },
	{ }
	};

	U_BOOT_DRIVER(s35392a_rtc) = {
	.name = "s35392a_rtc",
	.id = UCLASS_RTC,
	.probe = s35392a_probe,
	.of_match = s35392a_rtc_ids,
	.ops = &s35392a_rtc_ops,
	};

	#endif