diff options
Diffstat (limited to 'drivers/rtc/rtc-rk808.c')
| -rw-r--r-- | drivers/rtc/rtc-rk808.c | 449 |
1 files changed, 449 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rk808.c b/drivers/rtc/rtc-rk808.c new file mode 100644 index 000000000..739c0d42e --- /dev/null +++ b/drivers/rtc/rtc-rk808.c @@ -0,0 +1,449 @@ +/* + * 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); +} + +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); +} + +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); + } +} + +/* 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; +} + +/* 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; +} + +/* 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; +} + +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; +} + +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; +} + +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; +} + +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); +} + +/* + * 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; +} + +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; +} + +/* 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; +} +#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; + 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; + } + + device_init_wakeup(&pdev->dev, 1); + + rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rk808_rtc->rtc)) + return PTR_ERR(rk808_rtc->rtc); + + rk808_rtc->rtc->ops = &rk808_rtc_ops; + + 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; + } + + return rtc_register_device(rk808_rtc->rtc); +} + +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"); |