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Release 4.11 drivers/rtc/rtc-rk808.c

Directory: drivers/rtc
/*
 * RTC driver for Rockchip RK808
 *
 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
 *
 * Author: Chris Zhong <zyw@rock-chips.com>
 * Author: Zhang Qing <zhangqing@rock-chips.com>
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/mfd/rk808.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>

/* RTC_CTRL_REG bitfields */

#define BIT_RTC_CTRL_REG_STOP_RTC_M		BIT(0)

/* RK808 has a shadowed register for saving a "frozen" RTC time.
 * When user setting "GET_TIME" to 1, the time will save in this shadowed
 * register. If set "READSEL" to 1, user read rtc time register, actually
 * get the time of that moment. If we need the real time, clr this bit.
 */

#define BIT_RTC_CTRL_REG_RTC_GET_TIME		BIT(6)

#define BIT_RTC_CTRL_REG_RTC_READSEL_M		BIT(7)

#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M	BIT(3)

#define RTC_STATUS_MASK		0xFE


#define SECONDS_REG_MSK		0x7F

#define MINUTES_REG_MAK		0x7F

#define HOURS_REG_MSK		0x3F

#define DAYS_REG_MSK		0x3F

#define MONTHS_REG_MSK		0x1F

#define YEARS_REG_MSK		0xFF

#define WEEKS_REG_MSK		0x7

/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */


#define NUM_TIME_REGS	(RK808_WEEKS_REG - RK808_SECONDS_REG + 1)

#define NUM_ALARM_REGS	(RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)


struct rk808_rtc {
	
struct rk808 *rk808;
	
struct rtc_device *rtc;
	
int irq;
};

/*
 * The Rockchip calendar used by the RK808 counts November with 31 days. We use
 * these translation functions to convert its dates to/from the Gregorian
 * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
 * as the day when both calendars were in sync, and treat all other dates
 * relative to that.
 * NOTE: Other system software (e.g. firmware) that reads the same hardware must
 * implement this exact same conversion algorithm, with the same anchor date.
 */

static time64_t nov2dec_transitions(struct rtc_time *tm) { return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0); }

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static void rockchip_to_gregorian(struct rtc_time *tm) { /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */ time64_t time = rtc_tm_to_time64(tm); rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm); }

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static void gregorian_to_rockchip(struct rtc_time *tm) { time64_t extra_days = nov2dec_transitions(tm); time64_t time = rtc_tm_to_time64(tm); rtc_time64_to_tm(time - extra_days * 86400, tm); /* Compensate if we went back over Nov 31st (will work up to 2381) */ if (nov2dec_transitions(tm) < extra_days) { if (tm->tm_mon + 1 == 11) tm->tm_mday++; /* This may result in 31! */ else rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm); } }

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/* Read current time and date in RTC */
static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm) { struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); struct rk808 *rk808 = rk808_rtc->rk808; u8 rtc_data[NUM_TIME_REGS]; int ret; /* Force an update of the shadowed registers right now */ ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, BIT_RTC_CTRL_REG_RTC_GET_TIME, BIT_RTC_CTRL_REG_RTC_GET_TIME); if (ret) { dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret); return ret; } /* * After we set the GET_TIME bit, the rtc time can't be read * immediately. So we should wait up to 31.25 us, about one cycle of * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency. */ ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, BIT_RTC_CTRL_REG_RTC_GET_TIME, 0); if (ret) { dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret); return ret; } ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG, rtc_data, NUM_TIME_REGS); if (ret) { dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret); return ret; } tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK); tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK); tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK); tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK); tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1; tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100; tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK); rockchip_to_gregorian(tm); dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec); return ret; }

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/* Set current time and date in RTC */
static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); struct rk808 *rk808 = rk808_rtc->rk808; u8 rtc_data[NUM_TIME_REGS]; int ret; dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec); gregorian_to_rockchip(tm); rtc_data[0] = bin2bcd(tm->tm_sec); rtc_data[1] = bin2bcd(tm->tm_min); rtc_data[2] = bin2bcd(tm->tm_hour); rtc_data[3] = bin2bcd(tm->tm_mday); rtc_data[4] = bin2bcd(tm->tm_mon + 1); rtc_data[5] = bin2bcd(tm->tm_year - 100); rtc_data[6] = bin2bcd(tm->tm_wday); /* Stop RTC while updating the RTC registers */ ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, BIT_RTC_CTRL_REG_STOP_RTC_M, BIT_RTC_CTRL_REG_STOP_RTC_M); if (ret) { dev_err(dev, "Failed to update RTC control: %d\n", ret); return ret; } ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG, rtc_data, NUM_TIME_REGS); if (ret) { dev_err(dev, "Failed to bull write rtc_data: %d\n", ret); return ret; } /* Start RTC again */ ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, BIT_RTC_CTRL_REG_STOP_RTC_M, 0); if (ret) { dev_err(dev, "Failed to update RTC control: %d\n", ret); return ret; } return 0; }

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/* Read alarm time and date in RTC */
static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); struct rk808 *rk808 = rk808_rtc->rk808; u8 alrm_data[NUM_ALARM_REGS]; uint32_t int_reg; int ret; ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG, alrm_data, NUM_ALARM_REGS); alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK); alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK); alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK); alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK); alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1; alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100; rockchip_to_gregorian(&alrm->time); ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg); if (ret) { dev_err(dev, "Failed to read RTC INT REG: %d\n", ret); return ret; } dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 1900 + alrm->time.tm_year, alrm->time.tm_mon + 1, alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour, alrm->time.tm_min, alrm->time.tm_sec); alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0; return 0; }

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static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc) { struct rk808 *rk808 = rk808_rtc->rk808; int ret; ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG, BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0); return ret; }

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static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc) { struct rk808 *rk808 = rk808_rtc->rk808; int ret; ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG, BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); return ret; }

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static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); struct rk808 *rk808 = rk808_rtc->rk808; u8 alrm_data[NUM_ALARM_REGS]; int ret; ret = rk808_rtc_stop_alarm(rk808_rtc); if (ret) { dev_err(dev, "Failed to stop alarm: %d\n", ret); return ret; } dev_dbg(dev, "alrm set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n", 1900 + alrm->time.tm_year, alrm->time.tm_mon + 1, alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour, alrm->time.tm_min, alrm->time.tm_sec); gregorian_to_rockchip(&alrm->time); alrm_data[0] = bin2bcd(alrm->time.tm_sec); alrm_data[1] = bin2bcd(alrm->time.tm_min); alrm_data[2] = bin2bcd(alrm->time.tm_hour); alrm_data[3] = bin2bcd(alrm->time.tm_mday); alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1); alrm_data[5] = bin2bcd(alrm->time.tm_year - 100); ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG, alrm_data, NUM_ALARM_REGS); if (ret) { dev_err(dev, "Failed to bulk write: %d\n", ret); return ret; } if (alrm->enabled) { ret = rk808_rtc_start_alarm(rk808_rtc); if (ret) { dev_err(dev, "Failed to start alarm: %d\n", ret); return ret; } } return 0; }

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static int rk808_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev); if (enabled) return rk808_rtc_start_alarm(rk808_rtc); return rk808_rtc_stop_alarm(rk808_rtc); }

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/* * We will just handle setting the frequency and make use the framework for * reading the periodic interupts. * * @freq: Current periodic IRQ freq: * bit 0: every second * bit 1: every minute * bit 2: every hour * bit 3: every day */
static irqreturn_t rk808_alarm_irq(int irq, void *data) { struct rk808_rtc *rk808_rtc = data; struct rk808 *rk808 = rk808_rtc->rk808; struct i2c_client *client = rk808->i2c; int ret; ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG, RTC_STATUS_MASK); if (ret) { dev_err(&client->dev, "%s:Failed to update RTC status: %d\n", __func__, ret); return ret; } rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF); dev_dbg(&client->dev, "%s:irq=%d\n", __func__, irq); return IRQ_HANDLED; }

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static const struct rtc_class_ops rk808_rtc_ops = { .read_time = rk808_rtc_readtime, .set_time = rk808_rtc_set_time, .read_alarm = rk808_rtc_readalarm, .set_alarm = rk808_rtc_setalarm, .alarm_irq_enable = rk808_rtc_alarm_irq_enable, }; #ifdef CONFIG_PM_SLEEP /* Turn off the alarm if it should not be a wake source. */
static int rk808_rtc_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev); if (device_may_wakeup(dev)) enable_irq_wake(rk808_rtc->irq); return 0; }

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/* Enable the alarm if it should be enabled (in case it was disabled to * prevent use as a wake source). */
static int rk808_rtc_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev); if (device_may_wakeup(dev)) disable_irq_wake(rk808_rtc->irq); return 0; }

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#endif static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops, rk808_rtc_suspend, rk808_rtc_resume);
static int rk808_rtc_probe(struct platform_device *pdev) { struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent); struct rk808_rtc *rk808_rtc; struct rtc_time tm; int ret; rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL); if (rk808_rtc == NULL) return -ENOMEM; platform_set_drvdata(pdev, rk808_rtc); rk808_rtc->rk808 = rk808; /* start rtc running by default, and use shadowed timer. */ ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG, BIT_RTC_CTRL_REG_STOP_RTC_M | BIT_RTC_CTRL_REG_RTC_READSEL_M, BIT_RTC_CTRL_REG_RTC_READSEL_M); if (ret) { dev_err(&pdev->dev, "Failed to update RTC control: %d\n", ret); return ret; } ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG, RTC_STATUS_MASK); if (ret) { dev_err(&pdev->dev, "Failed to write RTC status: %d\n", ret); return ret; } /* set init time */ ret = rk808_rtc_readtime(&pdev->dev, &tm); if (ret) { dev_err(&pdev->dev, "Failed to read RTC time\n"); return ret; } ret = rtc_valid_tm(&tm); if (ret) dev_warn(&pdev->dev, "invalid date/time\n"); device_init_wakeup(&pdev->dev, 1); rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc", &rk808_rtc_ops, THIS_MODULE); if (IS_ERR(rk808_rtc->rtc)) { ret = PTR_ERR(rk808_rtc->rtc); return ret; } rk808_rtc->irq = platform_get_irq(pdev, 0); if (rk808_rtc->irq < 0) { if (rk808_rtc->irq != -EPROBE_DEFER) dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n", rk808_rtc->irq); return rk808_rtc->irq; } /* request alarm irq of rk808 */ ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL, rk808_alarm_irq, 0, "RTC alarm", rk808_rtc); if (ret) { dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", rk808_rtc->irq, ret); } return ret; }

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static struct platform_driver rk808_rtc_driver = { .probe = rk808_rtc_probe, .driver = { .name = "rk808-rtc", .pm = &rk808_rtc_pm_ops, }, }; module_platform_driver(rk808_rtc_driver); MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs"); MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>"); MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:rk808-rtc");

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Directory: drivers/rtc
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