drivers/rtc/rtc-ab3100.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2007-2009 ST-Ericsson AB
  * RTC clock driver for the AB3100 Analog Baseband Chip
  * Author: Linus Walleij <linus.walleij@stericsson.com>
  */
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 #include <linux/mfd/abx500.h>

 /* Clock rate in Hz */
 #define AB3100_RTC_CLOCK_RATE	32768

 /*
  * The AB3100 RTC registers. These are the same for
  * AB3000 and AB3100.
  * Control register:
  * Bit 0: RTC Monitor cleared=0, active=1, if you set it
  *        to 1 it remains active until RTC power is lost.
  * Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass
  * Bit 2: Alarm on, 0 = off, 1 = on
  * Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled
  */
 #define AB3100_RTC		0x53
 /* default setting, buffer disabled, alarm on */
 #define RTC_SETTING		0x30
 /* Alarm when AL0-AL3 == TI0-TI3  */
 #define AB3100_AL0		0x56
 #define AB3100_AL1		0x57
 #define AB3100_AL2		0x58
 #define AB3100_AL3		0x59
 /* This 48-bit register that counts up at 32768 Hz */
 #define AB3100_TI0		0x5a
 #define AB3100_TI1		0x5b
 #define AB3100_TI2		0x5c
 #define AB3100_TI3		0x5d
 #define AB3100_TI4		0x5e
 #define AB3100_TI5		0x5f

 /*
  * RTC clock functions and device struct declaration
  */
 static int ab3100_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2,
 		     AB3100_TI3, AB3100_TI4, AB3100_TI5};
 	unsigned char buf[6];
 	u64 hw_counter = rtc_tm_to_time64(tm) * AB3100_RTC_CLOCK_RATE * 2;
 	int err = 0;
 	int i;

 	buf[0] = (hw_counter) & 0xFF;
 	buf[1] = (hw_counter >> 8) & 0xFF;
 	buf[2] = (hw_counter >> 16) & 0xFF;
 	buf[3] = (hw_counter >> 24) & 0xFF;
 	buf[4] = (hw_counter >> 32) & 0xFF;
 	buf[5] = (hw_counter >> 40) & 0xFF;

 	for (i = 0; i < 6; i++) {
 		err = abx500_set_register_interruptible(dev, 0,
 							regs[i], buf[i]);
 		if (err)
 			return err;
 	}

 	/* Set the flag to mark that the clock is now set */
 	return abx500_mask_and_set_register_interruptible(dev, 0,
 							  AB3100_RTC,
 							  0x01, 0x01);

 }

 static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	time64_t time;
 	u8 rtcval;
 	int err;

 	err = abx500_get_register_interruptible(dev, 0,
 						AB3100_RTC, &rtcval);
 	if (err)
 		return err;

 	if (!(rtcval & 0x01)) {
 		dev_info(dev, "clock not set (lost power)");
 		return -EINVAL;
 	} else {
 		u64 hw_counter;
 		u8 buf[6];

 		/* Read out time registers */
 		err = abx500_get_register_page_interruptible(dev, 0,
 							     AB3100_TI0,
 							     buf, 6);
 		if (err != 0)
 			return err;

 		hw_counter = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) |
 			((u64) buf[3] << 24) | ((u64) buf[2] << 16) |
 			((u64) buf[1] << 8) | (u64) buf[0];
 		time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
 	}

 	rtc_time64_to_tm(time, tm);

 	return 0;
 }

 static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	time64_t time;
 	u64 hw_counter;
 	u8 buf[6];
 	u8 rtcval;
 	int err;

 	/* Figure out if alarm is enabled or not */
 	err = abx500_get_register_interruptible(dev, 0,
 						AB3100_RTC, &rtcval);
 	if (err)
 		return err;
 	if (rtcval & 0x04)
 		alarm->enabled = 1;
 	else
 		alarm->enabled = 0;
 	/* No idea how this could be represented */
 	alarm->pending = 0;
 	/* Read out alarm registers, only 4 bytes */
 	err = abx500_get_register_page_interruptible(dev, 0,
 						     AB3100_AL0, buf, 4);
 	if (err)
 		return err;
 	hw_counter = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) |
 		((u64) buf[1] << 24) | ((u64) buf[0] << 16);
 	time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);

 	rtc_time64_to_tm(time, &alarm->time);

 	return rtc_valid_tm(&alarm->time);
 }

 static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3};
 	unsigned char buf[4];
 	time64_t secs;
 	u64 hw_counter;
 	int err;
 	int i;

 	secs = rtc_tm_to_time64(&alarm->time);
 	hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
 	buf[0] = (hw_counter >> 16) & 0xFF;
 	buf[1] = (hw_counter >> 24) & 0xFF;
 	buf[2] = (hw_counter >> 32) & 0xFF;
 	buf[3] = (hw_counter >> 40) & 0xFF;

 	/* Set the alarm */
 	for (i = 0; i < 4; i++) {
 		err = abx500_set_register_interruptible(dev, 0,
 							regs[i], buf[i]);
 		if (err)
 			return err;
 	}
 	/* Then enable the alarm */
 	return abx500_mask_and_set_register_interruptible(dev, 0,
 							  AB3100_RTC, (1 << 2),
 							  alarm->enabled << 2);
 }

 static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled)
 {
 	/*
 	 * It's not possible to enable/disable the alarm IRQ for this RTC.
 	 * It does not actually trigger any IRQ: instead its only function is
 	 * to power up the system, if it wasn't on. This will manifest as
 	 * a "power up cause" in the AB3100 power driver (battery charging etc)
 	 * and need to be handled there instead.
 	 */
 	if (enabled)
 		return abx500_mask_and_set_register_interruptible(dev, 0,
 						    AB3100_RTC, (1 << 2),
 						    1 << 2);
 	else
 		return abx500_mask_and_set_register_interruptible(dev, 0,
 						    AB3100_RTC, (1 << 2),
 						    0);
 }

 static const struct rtc_class_ops ab3100_rtc_ops = {
 	.read_time	= ab3100_rtc_read_time,
 	.set_time	= ab3100_rtc_set_time,
 	.read_alarm	= ab3100_rtc_read_alarm,
 	.set_alarm	= ab3100_rtc_set_alarm,
 	.alarm_irq_enable = ab3100_rtc_irq_enable,
 };

 static int __init ab3100_rtc_probe(struct platform_device *pdev)
 {
 	int err;
 	u8 regval;
 	struct rtc_device *rtc;

 	/* The first RTC register needs special treatment */
 	err = abx500_get_register_interruptible(&pdev->dev, 0,
 						AB3100_RTC, &regval);
 	if (err) {
 		dev_err(&pdev->dev, "unable to read RTC register\n");
 		return -ENODEV;
 	}

 	if ((regval & 0xFE) != RTC_SETTING) {
 		dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n",
 			 regval);
 	}

 	if ((regval & 1) == 0) {
 		/*
 		 * Set bit to detect power loss.
 		 * This bit remains until RTC power is lost.
 		 */
 		regval = 1 | RTC_SETTING;
 		err = abx500_set_register_interruptible(&pdev->dev, 0,
 							AB3100_RTC, regval);
 		/* Ignore any error on this write */
 	}

 	rtc = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);

 	rtc->ops = &ab3100_rtc_ops;
 	/* 48bit counter at (AB3100_RTC_CLOCK_RATE * 2) */
 	rtc->range_max = U32_MAX;

 	platform_set_drvdata(pdev, rtc);

 	return devm_rtc_register_device(rtc);
 }

 static struct platform_driver ab3100_rtc_driver = {
 	.driver = {
 		.name = "ab3100-rtc",
 	},
 };

 module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe);

 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 MODULE_DESCRIPTION("AB3100 RTC Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright (C) 2007-2009 ST-Ericsson AB
	* RTC clock driver for the AB3100 Analog Baseband Chip
	* Author: Linus Walleij <linus.walleij@stericsson.com>
	*/
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/platform_device.h>
	#include <linux/rtc.h>
	#include <linux/mfd/abx500.h>

	/* Clock rate in Hz */
	#define AB3100_RTC_CLOCK_RATE 32768

	/*
	* The AB3100 RTC registers. These are the same for
	* AB3000 and AB3100.
	* Control register:
	* Bit 0: RTC Monitor cleared=0, active=1, if you set it
	* to 1 it remains active until RTC power is lost.
	* Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass
	* Bit 2: Alarm on, 0 = off, 1 = on
	* Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled
	*/
	#define AB3100_RTC 0x53
	/* default setting, buffer disabled, alarm on */
	#define RTC_SETTING 0x30
	/* Alarm when AL0-AL3 == TI0-TI3 */
	#define AB3100_AL0 0x56
	#define AB3100_AL1 0x57
	#define AB3100_AL2 0x58
	#define AB3100_AL3 0x59
	/* This 48-bit register that counts up at 32768 Hz */
	#define AB3100_TI0 0x5a
	#define AB3100_TI1 0x5b
	#define AB3100_TI2 0x5c
	#define AB3100_TI3 0x5d
	#define AB3100_TI4 0x5e
	#define AB3100_TI5 0x5f

	/*
	* RTC clock functions and device struct declaration
	*/
	static int ab3100_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2,
	AB3100_TI3, AB3100_TI4, AB3100_TI5};
	unsigned char buf[6];
	u64 hw_counter = rtc_tm_to_time64(tm) * AB3100_RTC_CLOCK_RATE * 2;
	int err = 0;
	int i;

	buf[0] = (hw_counter) & 0xFF;
	buf[1] = (hw_counter >> 8) & 0xFF;
	buf[2] = (hw_counter >> 16) & 0xFF;
	buf[3] = (hw_counter >> 24) & 0xFF;
	buf[4] = (hw_counter >> 32) & 0xFF;
	buf[5] = (hw_counter >> 40) & 0xFF;

	for (i = 0; i < 6; i++) {
	err = abx500_set_register_interruptible(dev, 0,
	regs[i], buf[i]);
	if (err)
	return err;
	}

	/* Set the flag to mark that the clock is now set */
	return abx500_mask_and_set_register_interruptible(dev, 0,
	AB3100_RTC,
	0x01, 0x01);

	}

	static int ab3100_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	time64_t time;
	u8 rtcval;
	int err;

	err = abx500_get_register_interruptible(dev, 0,
	AB3100_RTC, &rtcval);
	if (err)
	return err;

	if (!(rtcval & 0x01)) {
	dev_info(dev, "clock not set (lost power)");
	return -EINVAL;
	} else {
	u64 hw_counter;
	u8 buf[6];

	/* Read out time registers */
	err = abx500_get_register_page_interruptible(dev, 0,
	AB3100_TI0,
	buf, 6);
	if (err != 0)
	return err;

	hw_counter = ((u64) buf[5] << 40) \| ((u64) buf[4] << 32) \|
	((u64) buf[3] << 24) \| ((u64) buf[2] << 16) \|
	((u64) buf[1] << 8) \| (u64) buf[0];
	time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
	}

	rtc_time64_to_tm(time, tm);

	return 0;
	}

	static int ab3100_rtc_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	time64_t time;
	u64 hw_counter;
	u8 buf[6];
	u8 rtcval;
	int err;

	/* Figure out if alarm is enabled or not */
	err = abx500_get_register_interruptible(dev, 0,
	AB3100_RTC, &rtcval);
	if (err)
	return err;
	if (rtcval & 0x04)
	alarm->enabled = 1;
	else
	alarm->enabled = 0;
	/* No idea how this could be represented */
	alarm->pending = 0;
	/* Read out alarm registers, only 4 bytes */
	err = abx500_get_register_page_interruptible(dev, 0,
	AB3100_AL0, buf, 4);
	if (err)
	return err;
	hw_counter = ((u64) buf[3] << 40) \| ((u64) buf[2] << 32) \|
	((u64) buf[1] << 24) \| ((u64) buf[0] << 16);
	time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);

	rtc_time64_to_tm(time, &alarm->time);

	return rtc_valid_tm(&alarm->time);
	}

	static int ab3100_rtc_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3};
	unsigned char buf[4];
	time64_t secs;
	u64 hw_counter;
	int err;
	int i;

	secs = rtc_tm_to_time64(&alarm->time);
	hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
	buf[0] = (hw_counter >> 16) & 0xFF;
	buf[1] = (hw_counter >> 24) & 0xFF;
	buf[2] = (hw_counter >> 32) & 0xFF;
	buf[3] = (hw_counter >> 40) & 0xFF;

	/* Set the alarm */
	for (i = 0; i < 4; i++) {
	err = abx500_set_register_interruptible(dev, 0,
	regs[i], buf[i]);
	if (err)
	return err;
	}
	/* Then enable the alarm */
	return abx500_mask_and_set_register_interruptible(dev, 0,
	AB3100_RTC, (1 << 2),
	alarm->enabled << 2);
	}

	static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled)
	{
	/*
	* It's not possible to enable/disable the alarm IRQ for this RTC.
	* It does not actually trigger any IRQ: instead its only function is
	* to power up the system, if it wasn't on. This will manifest as
	* a "power up cause" in the AB3100 power driver (battery charging etc)
	* and need to be handled there instead.
	*/
	if (enabled)
	return abx500_mask_and_set_register_interruptible(dev, 0,
	AB3100_RTC, (1 << 2),
	1 << 2);
	else
	return abx500_mask_and_set_register_interruptible(dev, 0,
	AB3100_RTC, (1 << 2),
	0);
	}

	static const struct rtc_class_ops ab3100_rtc_ops = {
	.read_time = ab3100_rtc_read_time,
	.set_time = ab3100_rtc_set_time,
	.read_alarm = ab3100_rtc_read_alarm,
	.set_alarm = ab3100_rtc_set_alarm,
	.alarm_irq_enable = ab3100_rtc_irq_enable,
	};

	static int __init ab3100_rtc_probe(struct platform_device *pdev)
	{
	int err;
	u8 regval;
	struct rtc_device *rtc;

	/* The first RTC register needs special treatment */
	err = abx500_get_register_interruptible(&pdev->dev, 0,
	AB3100_RTC, &regval);
	if (err) {
	dev_err(&pdev->dev, "unable to read RTC register\n");
	return -ENODEV;
	}

	if ((regval & 0xFE) != RTC_SETTING) {
	dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n",
	regval);
	}

	if ((regval & 1) == 0) {
	/*
	* Set bit to detect power loss.
	* This bit remains until RTC power is lost.
	*/
	regval = 1 \| RTC_SETTING;
	err = abx500_set_register_interruptible(&pdev->dev, 0,
	AB3100_RTC, regval);
	/* Ignore any error on this write */
	}

	rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc))
	return PTR_ERR(rtc);

	rtc->ops = &ab3100_rtc_ops;
	/* 48bit counter at (AB3100_RTC_CLOCK_RATE * 2) */
	rtc->range_max = U32_MAX;

	platform_set_drvdata(pdev, rtc);

	return devm_rtc_register_device(rtc);
	}

	static struct platform_driver ab3100_rtc_driver = {
	.driver = {
	.name = "ab3100-rtc",
	},
	};

	module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe);

	MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
	MODULE_DESCRIPTION("AB3100 RTC Driver");
	MODULE_LICENSE("GPL");