tps65913rtc.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <commonlib/bsd/bcd.h>
#include <console/console.h>
#include <device/i2c_simple.h>
#include <rtc.h>
#include <stdint.h>
 
enum TPS65913_RTC_REG {
        TPS65913_SECONDS_REG            = 0x00,
        TPS65913_MINUTES_REG            = 0x01,
        TPS65913_HOURS_REG              = 0x02,
        TPS65913_DAYS_REG               = 0x03,
        TPS65913_MONTHS_REG             = 0x04,
        TPS65913_YEARS_REG              = 0x05,
        TPS65913_WEEKS_REG              = 0x06,
        TPS65913_RTC_CTRL_REG           = 0x10,
        TPS65913_RTC_STATUS_REG = 0x11,
        TPS65913_RTC_INTERRUPTS_REG     = 0x12,
};
 
enum {
        TPS65913_RTC_CTRL_STOP          = (1 << 0),
        TPS65913_RTC_CTRL_GET_TIME      = (1 << 6),
 
        TPS65913_RTC_STATUS_RUN = (1 << 1),
        TPS65913_RTC_RUNNING            = (1 << 1),
        TPS65913_RTC_FROZEN             = (0 << 1),
};
 
static inline uint8_t tps65913_read(enum TPS65913_RTC_REG reg)
{
        uint8_t val;
        i2c_readb(CONFIG_DRIVERS_TI_TPS65913_RTC_BUS,
                  CONFIG_DRIVERS_TI_TPS65913_RTC_ADDR, reg, &val);
        return val;
}
 
static inline void tps65913_write(enum TPS65913_RTC_REG reg, uint8_t val)
{
        i2c_writeb(CONFIG_DRIVERS_TI_TPS65913_RTC_BUS,
                   CONFIG_DRIVERS_TI_TPS65913_RTC_ADDR, reg, val);
}
 
static void tps65913_rtc_ctrl_clear(uint8_t bit)
{
        uint8_t control = tps65913_read(TPS65913_RTC_CTRL_REG);
 
        control &= ~bit;
        tps65913_write(TPS65913_RTC_CTRL_REG, control);
}
 
static void tps65913_rtc_ctrl_set(uint8_t bit)
{
        uint8_t control = tps65913_read(TPS65913_RTC_CTRL_REG);
 
        control |= TPS65913_RTC_CTRL_GET_TIME;
        tps65913_write(TPS65913_RTC_CTRL_REG, control);
}
 
static int tps65913_is_rtc_running(void)
{
        uint8_t status = tps65913_read(TPS65913_RTC_STATUS_REG);
        return ((status & TPS65913_RTC_STATUS_RUN) == TPS65913_RTC_RUNNING);
}
 
/*
 * This function ensures that current time is copied to shadow registers. Then a
 * normal read on TC registers reads from the shadow instead of current TC
 * registers. This helps prevent the accidental change in counters while
 * reading. In order to ensure that the current TC registers are copied into
 * shadow registers, GET_TIME bit needs to be set to 0 and then to 1.
 */
static void tps65913_rtc_shadow(void)
{
        tps65913_rtc_ctrl_clear(TPS65913_RTC_CTRL_GET_TIME);
        tps65913_rtc_ctrl_set(TPS65913_RTC_CTRL_GET_TIME);
}
 
static int tps65913_rtc_stop(void)
{
        /* Clearing stop bit freezes RTC */
        tps65913_rtc_ctrl_clear(TPS65913_RTC_CTRL_STOP);
 
        if (tps65913_is_rtc_running()) {
                printk(BIOS_ERR, "Could not stop RTC\n");
                return 1;
        }
 
        return 0;
}
 
static int tps65913_rtc_start(void)
{
        /* Setting stop bit starts RTC */
        tps65913_rtc_ctrl_set(TPS65913_RTC_CTRL_STOP);
 
        if (!tps65913_is_rtc_running()) {
                printk(BIOS_ERR, "Could not start RTC\n");
                return 1;
        }
 
        return 0;
}
 
int rtc_set(const struct rtc_time *time)
{
        /* Before setting the time, ensure that rtc is stopped */
        if (tps65913_rtc_stop())
                return 1;
 
        tps65913_write(TPS65913_SECONDS_REG, bin2bcd(time->sec));
        tps65913_write(TPS65913_MINUTES_REG, bin2bcd(time->min));
        tps65913_write(TPS65913_HOURS_REG, bin2bcd(time->hour));
        tps65913_write(TPS65913_DAYS_REG, bin2bcd(time->mday));
        tps65913_write(TPS65913_MONTHS_REG, bin2bcd(time->mon));
        tps65913_write(TPS65913_YEARS_REG, bin2bcd(time->year));
 
        /* Re-start rtc */
        if (tps65913_rtc_start())
                return 1;
 
        return 0;
}
 
int rtc_get(struct rtc_time *time)
{
        tps65913_rtc_shadow();
 
        time->sec = bcd2bin(tps65913_read(TPS65913_SECONDS_REG) & 0x7f);
        time->min = bcd2bin(tps65913_read(TPS65913_MINUTES_REG) & 0x7f);
        time->hour = bcd2bin(tps65913_read(TPS65913_HOURS_REG) & 0x3f);
        time->mday = bcd2bin(tps65913_read(TPS65913_DAYS_REG) & 0x3f);
        time->mon = bcd2bin(tps65913_read(TPS65913_MONTHS_REG) & 0x1f);
        time->year = bcd2bin(tps65913_read(TPS65913_YEARS_REG) & 0xff);
 
        return 0;
}