pcf8523.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <commonlib/bsd/bcd.h>
#include <console/console.h>
#include <device/smbus.h>
#include <version.h>
#include "chip.h"
 
/* Set RTC date from coreboot build date. */
static void pcf8523_set_build_date(struct device *dev)
{
        smbus_write_byte(dev, YEAR_REG, coreboot_build_date.year);
        smbus_write_byte(dev, MONTH_REG, coreboot_build_date.month);
        smbus_write_byte(dev, WEEKDAY_REG, coreboot_build_date.weekday);
        smbus_write_byte(dev, DAY_REG, coreboot_build_date.day);
}
 
/* Set RTC date from user defined date (available in e.g. device tree). */
static void pcf8523_set_user_date(struct device *dev)
{
        struct drivers_i2c_pcf8523_config *config = dev->chip_info;
        smbus_write_byte(dev, YEAR_REG, bin2bcd(config->user_year));
        smbus_write_byte(dev, MONTH_REG, bin2bcd(config->user_month));
        smbus_write_byte(dev, DAY_REG, bin2bcd(config->user_day));
        smbus_write_byte(dev, WEEKDAY_REG, bin2bcd(config->user_weekday));
}
 
static void pcf8523_final(struct device *dev)
{
        /* Read back current RTC date and time and print it to the console. */
        printk(BIOS_INFO, "%s: Current date %02d.%02d.%02d %02d:%02d:%02d\n",
                dev->chip_ops->name,
                bcd2bin(smbus_read_byte(dev, MONTH_REG)),
                bcd2bin(smbus_read_byte(dev, DAY_REG)),
                bcd2bin(smbus_read_byte(dev, YEAR_REG)),
                bcd2bin(smbus_read_byte(dev, HOUR_REG)),
                bcd2bin(smbus_read_byte(dev, MINUTE_REG)),
                bcd2bin(smbus_read_byte(dev, SECOND_REG)) & ~OS_BIT);
}
 
static void pcf8523_init(struct device *dev)
{
        struct drivers_i2c_pcf8523_config *config = dev->chip_info;
        uint8_t reg = 0;
 
        if (!(smbus_read_byte(dev, SECOND_REG) & OS_BIT)) {
                /* Set control registers to a known good value even if no
                 * power loss event was recognized. There were issues with
                 * this RTC in the past where control registers were
                 * corrupted and OS bit was not set. */
                reg = smbus_read_byte(dev, CTRL_REG_1);
                reg &= ~(STOP_BIT | CAP_SEL);
                reg |= ((!!config->cap_sel) << 7);
                smbus_write_byte(dev, CTRL_REG_1, reg);
                reg = smbus_read_byte(dev, CTRL_REG_3);
                reg &= ~PM_MASK;
                reg |= ((config->power_mode & 0x07) << 5);
                smbus_write_byte(dev, CTRL_REG_3, reg);
                reg = smbus_read_byte(dev, TMR_CLKOUT_REG);
                reg &= ~COF_MASK;
                reg |= ((config->cof_selection & 0x07) << 3);
                smbus_write_byte(dev, TMR_CLKOUT_REG, reg);
                return;
        }
 
        /* Initialize the RTC fully only if a power-loss event was recognized.
         * In this case RTC will be set up with default date and time. */
        smbus_write_byte(dev, CTRL_REG_1, ((!!config->cap_sel) << 7) |
                                          ((!!config->second_int_en) << 2) |
                                          ((!!config->alarm_int_en) << 1) |
                                          (!!config->correction_int_en));
 
        smbus_write_byte(dev, CTRL_REG_2, ((!!config->wdt_int_en) << 2) |
                                          ((!!config->tmrA_int_en) << 1) |
                                          (!!config->tmrB_int_en));
 
        smbus_write_byte(dev, CTRL_REG_3, ((config->power_mode & 0x07) << 5) |
                                          ((!!config->bat_switch_int_en) << 1) |
                                          (!!config->bat_low_int_en));
 
        smbus_write_byte(dev, OFFSET_REG, ((!!config->offset_mode) << 7) |
                                          (config->offset_val & 0x7f));
 
        smbus_write_byte(dev, TMR_CLKOUT_REG, ((!!config->tmrA_int_mode) << 7) |
                                        ((!!config->tmrB_int_mode) << 6) |
                                        ((config->cof_selection & 0x07) << 3) |
                                        ((config->tmrA_mode & 0x03) << 1) |
                                        (!!config->tmrB_mode));
 
        smbus_write_byte(dev, TMR_A_FREQ_REG, (config->tmrA_prescaler & 0x7));
 
        smbus_write_byte(dev, TMR_B_FREQ_REG,  (config->tmrB_prescaler & 0x7) |
                                        ((config->tmrB_pulse_cfg & 0x7) << 4));
 
        /* Before setting the clock stop oscillator. */
        reg = smbus_read_byte(dev, CTRL_REG_1);
        reg |= STOP_BIT;
        smbus_write_byte(dev, CTRL_REG_1, reg);
        if (config->set_user_date) {
                /* Set user date defined in device tree. */
                printk(BIOS_DEBUG, "%s: Set to user date\n",
                        dev->chip_ops->name);
                pcf8523_set_user_date(dev);
        } else {
                /* Set date from coreboot build. */
                printk(BIOS_DEBUG, "%s: Set to coreboot build date\n",
                        dev->chip_ops->name);
                pcf8523_set_build_date(dev);
        }
        /* Set time to 01:00:00 */
        smbus_write_byte(dev, HOUR_REG, 1);
        smbus_write_byte(dev, MINUTE_REG, 0);
        smbus_write_byte(dev, SECOND_REG, 0);
        /* Start oscillator again as the clock is set up now */
        reg &= ~STOP_BIT;
        smbus_write_byte(dev, CTRL_REG_1, reg);
}
 
static struct device_operations pcf8523c_ops = {
        .read_resources         = noop_read_resources,
        .set_resources          = noop_set_resources,
        .init                   = pcf8523_init,
        .final                  = pcf8523_final
};
 
static void pcf8523_enable(struct device *dev)
{
        dev->ops = &pcf8523c_ops;
}
 
struct chip_operations drivers_i2c_pcf8523_ops = {
        CHIP_NAME("PCF8523")
        .enable_dev = pcf8523_enable
};