src/drivers/i2c/rv3028c7/rv3028c7.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <acpi/acpi_device.h>
   4 #include <acpi/acpigen.h>
   5 #include <commonlib/bsd/bcd.h>
   6 #include <console/console.h>
   7 #include <delay.h>
   8 #include <device/device.h>
   9 #include <device/i2c.h>
  10 #include <device/i2c_bus.h>
  11 #include <timer.h>
  12 #include <types.h>
  13 #include <version.h>
  14 #include "chip.h"
  15 #include "rv3028c7.h"
  16
  17 static enum cb_err rtc_eep_wait_ready(struct device *dev)
  18 {
  19         struct stopwatch sw;
  20         uint8_t status;
  21
  22         stopwatch_init_msecs_expire(&sw, EEP_SYNC_TIMEOUT_MS);
  23         do {
  24                 status = (uint8_t)i2c_dev_readb_at(dev, STATUS_REG);
  25                 mdelay(1);
  26         } while ((status & EE_BUSY_BIT) && !stopwatch_expired(&sw));
  27
  28         if (status & EE_BUSY_BIT) {
  29                 return CB_ERR;
  30         } else {
  31                 return CB_SUCCESS;
  32         }
  33 }
  34
  35 static enum cb_err rtc_eep_auto_refresh(struct device *dev, uint8_t state)
  36 {
  37         uint8_t reg;
  38
  39         reg = (uint8_t)i2c_dev_readb_at(dev, CTRL1_REG);
  40         reg &= ~EERD_BIT;
  41         if (state == EEP_REFRESH_DIS)
  42                 reg |= EERD_BIT;
  43         i2c_dev_writeb_at(dev, CTRL1_REG, reg);
  44         /* Wait until the EEPROM has finished a possible running operation. */
  45         if (rtc_eep_wait_ready(dev) != CB_SUCCESS) {
  46                 printk(BIOS_ERR, "%s: EEPROM access timed out (%d ms)!\n",
  47                         dev->chip_ops->name, EEP_SYNC_TIMEOUT_MS);
  48                 return CB_ERR;
  49         }
  50         return CB_SUCCESS;
  51 }
  52
  53 static enum cb_err rtc_eep_start_update(struct device *dev)
  54 {
  55         /* Disable EEPROM auto refresh before writing RAM to EEPROM
  56            to avoid race conditions. */
  57         if (rtc_eep_auto_refresh(dev, EEP_REFRESH_DIS))
  58                 return CB_ERR;
  59
  60         /* Now start the update cycle.*/
  61         i2c_dev_writeb_at(dev, EEP_CMD_REG, EEP_CMD_PREFIX);
  62         i2c_dev_writeb_at(dev, EEP_CMD_REG, EEP_CMD_UPDATE);
  63         return CB_SUCCESS;
  64 }
  65
  66 static void rtc_set_time_date(struct device *dev)
  67 {
  68         struct drivers_i2c_rv3028c7_config *config = dev->chip_info;
  69         uint8_t buf[7];
  70
  71         /* The buffer contains the seconds through years of the new time and date.
  72            Whenever a new date is set, the time is set to 00:00:00. */
  73         buf[0] = 0;     /* Entry for seconds. */
  74         buf[1] = 0;     /* Entry for minutes. */
  75         buf[2] = 0;     /* Entry for hours. */
  76         if (config->set_user_date) {
  77                 buf[3] = config->user_weekday;
  78                 buf[4] = bin2bcd(config->user_day);
  79                 buf[5] = bin2bcd(config->user_month);
  80                 buf[6] = bin2bcd(config->user_year);
  81                 printk(BIOS_DEBUG, "%s: Set to user date\n", dev->chip_ops->name);
  82         } else {
  83                 buf[3] = coreboot_build_date.weekday;
  84                 buf[4] = coreboot_build_date.day;
  85                 buf[5] = coreboot_build_date.month;
  86                 buf[6] = coreboot_build_date.year;
  87                 printk(BIOS_DEBUG, "%s: Set to coreboot build date\n", dev->chip_ops->name);
  88         }
  89         /* According to the datasheet, date and time should be transferred in "one go"
  90            in order to avoid value corruption. */
  91         if (i2c_dev_write_at(dev, buf, sizeof(buf), 0) != sizeof(buf)) {
  92                 printk(BIOS_ERR, "%s: Not able to set date and time!\n", dev->chip_ops->name);
  93         }
  94 }
  95
  96 static void rtc_final(struct device *dev)
  97 {
  98         uint8_t buf[7];
  99
 100         /* Read back current RTC date and time and print it to the console.
 101            Date and time are read in "one go", the buffer contains seconds (byte 0)
 102            through years (byte 6) after this read. */
 103         if (i2c_dev_read_at(dev, buf, sizeof(buf), 0) != sizeof(buf)) {
 104                 printk(BIOS_ERR, "%s: Not able to read current date and time!\n",
 105                         dev->chip_ops->name);
 106         } else {
 107                 printk(BIOS_INFO, "%s: Current date %02d.%02d.%02d %02d:%02d:%02d\n",
 108                                 dev->chip_ops->name, bcd2bin(buf[5]), bcd2bin(buf[4]),
 109                                 bcd2bin(buf[6]), bcd2bin(buf[2]), bcd2bin(buf[1]),
 110                                 bcd2bin(buf[0]));
 111         }
 112         /* Make sure the EEPROM automatic refresh is enabled. */
 113         if (rtc_eep_auto_refresh(dev, EEP_REFRESH_EN) != CB_SUCCESS) {
 114                 printk(BIOS_ERR, "%s: Not able to enable EEPROM auto refresh!\n",
 115                         dev->chip_ops->name);
 116         }
 117 }
 118
 119 static void rtc_init(struct device *dev)
 120 {
 121         struct drivers_i2c_rv3028c7_config *config = dev->chip_info;
 122         uint8_t reg, backup_reg, eep_update_needed = 0;
 123
 124         /* On every startup, the RTC synchronizes the internal EEPROM with RAM.
 125          * During this time no operation shall modify RAM registers. Ensure this
 126          * sync is finished before starting the initialization. */
 127         if (rtc_eep_wait_ready(dev) != CB_SUCCESS) {
 128                 printk(BIOS_WARNING, "%s: Timeout on EEPROM sync after power on!\n",
 129                         dev->chip_ops->name);
 130                 return;
 131         }
 132         reg = backup_reg = (uint8_t)i2c_dev_readb_at(dev, EEP_BACKUP_REG);
 133         /* Configure the switch-over setting according to devicetree. */
 134         if (config->bckup_sw_mode) {
 135                 reg &= ~BSM_MASK;
 136                 reg |= config->bckup_sw_mode << BSM_BIT;
 137         }
 138         /* Configure the VBACKUP charging mode. */
 139         if (config->cap_charge) {
 140                 reg &= ~TCR_MASK;
 141                 reg |= ((config->cap_charge - 1) << TCR_BIT);
 142                 reg |= TCE_BIT;
 143         } else {
 144                 reg &= ~TCE_BIT;
 145         }
 146         /* According to the datasheet the Fast Edge Detection Enable (FEDE) bit
 147            should always be set. */
 148         reg |= FEDE_BIT;
 149         if (reg != backup_reg) {
 150                 /* Write new register value into shadow RAM and request an EEPROM update. */
 151                 i2c_dev_writeb_at(dev, EEP_BACKUP_REG, reg);
 152                 eep_update_needed = 1;
 153         }
 154         /* Make sure the hour register is in 24h format.*/
 155         reg = (uint8_t)i2c_dev_readb_at(dev, CTRL2_REG);
 156         if (reg & HOUR_12_24_BIT) {
 157                 reg &= ~HOUR_12_24_BIT;
 158                 i2c_dev_writeb_at(dev, CTRL2_REG, reg);
 159         }
 160         /* Check for a possible voltage drop event. */
 161         reg = (uint8_t)i2c_dev_readb_at(dev, STATUS_REG);
 162         if (reg & PORF_BIT) {
 163                 /* Voltage drop was detected, date and time needs to be set properly. */
 164                 rtc_set_time_date(dev);
 165                 /* Clear the PORF bit to mark that the event was handled. */
 166                 reg &= ~PORF_BIT;
 167                 i2c_dev_writeb_at(dev, STATUS_REG, reg);
 168         }
 169         /*
 170          * Finally, trigger the EEPROM update procedure if needed.
 171          * According to the datasheet, this update will consume ~63 ms.
 172          * In order to not block the boot process here waiting for this update being finished,
 173          * trigger the update now and check for readiness in the final hook.
 174          */
 175         if (eep_update_needed && rtc_eep_start_update(dev) != CB_SUCCESS) {
 176                 printk(BIOS_ERR, "%s: Not able to trigger EEPROM update!\n",
 177                         dev->chip_ops->name);
 178         }
 179 }
 180
 181 #if CONFIG(HAVE_ACPI_TABLES)
 182 static void rv3028c7_fill_ssdt(const struct device *dev)
 183 {
 184         const char *scope = acpi_device_scope(dev);
 185         struct drivers_i2c_rv3028c7_config *config = dev->chip_info;
 186         enum i2c_speed bus_speed;
 187
 188         if (!scope)
 189                 return;
 190
 191         switch (config->bus_speed) {
 192         case I2C_SPEED_STANDARD:
 193         case I2C_SPEED_FAST:
 194                 bus_speed = config->bus_speed;
 195                 break;
 196         default:
 197                 bus_speed = I2C_SPEED_STANDARD;
 198                 printk(BIOS_INFO, "%s: Bus speed unsupported, fall back to %d kHz!\n",
 199                         dev->chip_ops->name, bus_speed / 1000);
 200                 break;
 201         }
 202
 203         struct acpi_i2c i2c = {
 204                 .address = dev->path.i2c.device,
 205                 .mode_10bit = dev->path.i2c.mode_10bit,
 206                 .speed = bus_speed,
 207                 .resource = scope,
 208         };
 209
 210         /* Device */
 211         acpigen_write_scope(scope);
 212         acpigen_write_device(acpi_device_name(dev));
 213         acpigen_write_name_string("_HID", RV3028C7_HID_NAME);
 214         acpigen_write_name_string("_DDN", RV3028C7_HID_DESC);
 215         acpigen_write_STA(acpi_device_status(dev));
 216
 217         /* Resources */
 218         acpigen_write_name("_CRS");
 219
 220         acpigen_write_resourcetemplate_header();
 221         acpi_device_write_i2c(&i2c);
 222         acpigen_write_resourcetemplate_footer();
 223
 224         acpigen_pop_len(); /* Device */
 225         acpigen_pop_len(); /* Scope */
 226
 227         printk(BIOS_INFO, "%s: %s at %s\n", acpi_device_path(dev), dev->chip_ops->name,
 228                         dev_path(dev));
 229 }
 230
 231 static const char *rv3028c7_acpi_name(const struct device *dev)
 232 {
 233         return RV3028C7_ACPI_NAME;
 234 }
 235 #endif
 236
 237 static struct device_operations rv3028c7_ops = {
 238         .read_resources         = noop_read_resources,
 239         .set_resources          = noop_set_resources,
 240         .init                   = rtc_init,
 241         .final                  = rtc_final,
 242 #if CONFIG(HAVE_ACPI_TABLES)
 243         .acpi_name              = rv3028c7_acpi_name,
 244         .acpi_fill_ssdt         = rv3028c7_fill_ssdt,
 245 #endif
 246 };
 247
 248 static void rtc_enable(struct device *dev)
 249 {
 250         dev->ops = &rv3028c7_ops;
 251 }
 252
 253 struct chip_operations drivers_i2c_rv3028c7_ops = {
 254         .name = "RV-3028-C7",
 255         .enable_dev = rtc_enable
 256 };