Re: [RFC PATCH edk2-platforms 1/3] Silicon/NXP: add RTC support library for PCF8563 I2C IP

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 8 November 2017 at 16:43, Leif Lindholm <leif.lindholm@linaro.org> wrote:
> On Fri, Nov 03, 2017 at 10:16:52AM +0000, Ard Biesheuvel wrote:
>> Add a RealTimeClockLib implementation for the NXP PCF8563 as used on
>> the Socionext Developer Box board. Note that the standard I2C protocol
>> stack does not support runtime use, so this driver invokes the I2C master
>> protocol directly. This requires support from the platform side as well,
>> and so this driver will only attach to a I2C master that has the
>> gPcf8563RealTimeClockLibI2cMasterProtolGuid protocol installed on its
>> handle. It is up to the platform to ensure that the driver producing
>> the I2C master protocol in question is runtime capable, and is not
>> shared with the I2C protocol stack (i.e., it should not have the I2C
>> Bus Configuration Management protocol installed as well).
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>>  Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c   | 385 ++++++++++++++++++++
>>  Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.dec |  29 ++
>>  Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.inf |  52 +++
>>  3 files changed, 466 insertions(+)
>>
>> diff --git a/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c
>> new file mode 100644
>> index 000000000000..fea65a225d7f
>> --- /dev/null
>> +++ b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.c
>> @@ -0,0 +1,385 @@
>> +/** @file
>> +
>> +  Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>
>> +
>> +  This program and the accompanying materials
>> +  are licensed and made available under the terms and conditions of the BSD License
>> +  which accompanies this distribution.  The full text of the license may be found at
>> +  http://opensource.org/licenses/bsd-license.php
>> +
>> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
>> +  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>> +
>> +**/
>> +
>> +#include <PiDxe.h>
>> +#include <Library/DebugLib.h>
>> +#include <Library/IoLib.h>
>> +#include <Library/RealTimeClockLib.h>
>> +#include <Library/UefiBootServicesTableLib.h>
>> +#include <Library/UefiLib.h>
>> +#include <Library/UefiRuntimeLib.h>
>> +#include <Protocol/I2cMaster.h>
>> +
>> +#define SLAVE_ADDRESS             (FixedPcdGet8 (PcdI2cSlaveAddress))
>> +#define PCF8563_DATA_REG_OFFSET   0x2
>> +
>> +#define PCF8563_SECONDS_MASK      0x7f
>> +#define PCF8563_MINUTES_MASK      0x7f
>> +#define PCF8563_HOURS_MASK        0x3f
>> +#define PCF8563_DAYS_MASK         0x3f
>> +#define PCF8563_WEEKDAYS_MASK     0x07
>> +#define PCF8563_MONTHS_MASK       0x1f
>> +#define PCF8563_CENTURY_MASK      0x80
>> +
>> +#define EPOCH_BASE                2000
>> +
>> +STATIC EFI_HANDLE                 mI2cMasterHandle;
>> +STATIC VOID                       *mDriverEventRegistration;
>> +STATIC EFI_I2C_MASTER_PROTOCOL    *mI2cMaster;
>> +STATIC EFI_EVENT                  mRtcVirtualAddrChangeEvent;
>> +
>> +typedef struct {
>> +  UINTN                           OperationCount;
>> +  EFI_I2C_OPERATION               SetAddressOp;
>> +  EFI_I2C_OPERATION               GetSetDateTimeOp;
>> +} RTC_I2C_REQUEST;
>> +
>> +#pragma pack(1)
>> +typedef struct {
>> +  UINT8     VL_seconds;
>> +  UINT8     Minutes;
>> +  UINT8     Hours;
>> +  UINT8     Days;
>> +  UINT8     Weekdays;
>> +  UINT8     Century_months;
>> +  UINT8     Years;
>> +} RTC_DATETIME;
>> +#pragma pack()
>> +
>> +/**
>> +  Returns the current time and date information, and the time-keeping
>> +  capabilities of the hardware platform.
>> +
>> +  @param  Time                  A pointer to storage to receive a snapshot of
>> +                                the current time.
>> +  @param  Capabilities          An optional pointer to a buffer to receive the
>> +                                real time clock device's capabilities.
>> +
>> +  @retval EFI_SUCCESS           The operation completed successfully.
>> +  @retval EFI_INVALID_PARAMETER Time is NULL.
>> +  @retval EFI_DEVICE_ERROR      The time could not be retrieved due to hardware
>> +                                error.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +LibGetTime (
>> +  OUT EFI_TIME                *Time,
>> +  OUT EFI_TIME_CAPABILITIES   *Capabilities
>> +  )
>> +{
>> +  RTC_I2C_REQUEST             Op;
>> +  RTC_DATETIME                DateTime;
>> +  EFI_STATUS                  Status;
>> +  UINT8                       Reg;
>> +
>> +  if (Time == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (mI2cMaster == NULL) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  Reg = PCF8563_DATA_REG_OFFSET;
>> +
>> +  Op.OperationCount = 2;
>> +
>> +  Op.SetAddressOp.Flags = 0;
>> +  Op.SetAddressOp.LengthInBytes = 1;
>> +  Op.SetAddressOp.Buffer = &Reg;
>> +
>> +  Op.GetSetDateTimeOp.Flags = I2C_FLAG_READ;
>> +  Op.GetSetDateTimeOp.LengthInBytes = sizeof (RTC_DATETIME);
>> +  Op.GetSetDateTimeOp.Buffer = (VOID *)&DateTime;
>> +
>> +  Status = mI2cMaster->StartRequest (mI2cMaster, SLAVE_ADDRESS,
>> +                         (VOID *)&Op, NULL, NULL);
>> +  if (EFI_ERROR (Status)) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  Time->Second  = BcdToDecimal8 (DateTime.VL_seconds & PCF8563_SECONDS_MASK);
>> +  Time->Minute  = BcdToDecimal8 (DateTime.Minutes & PCF8563_MINUTES_MASK);
>> +  Time->Hour    = BcdToDecimal8 (DateTime.Hours & PCF8563_HOURS_MASK);
>> +  Time->Day     = BcdToDecimal8 (DateTime.Days & PCF8563_DAYS_MASK);
>> +  Time->Month   = BcdToDecimal8 (DateTime.Century_months & PCF8563_MONTHS_MASK);
>> +  Time->Year    = BcdToDecimal8 (DateTime.Years) + EPOCH_BASE;
>> +
>> +  if (DateTime.Century_months & PCF8563_CENTURY_MASK) {
>> +    Time->Year += 100;
>
> Guess we'd better retire all these platforms before the year 2100
> then... (Or, given EPOCH_BASE, is it 2070? (Or given EPOCH_BASE being
> set to 2000, is it 2200?))
>
> Could you add a small comment next to the EPOCH_BASE definition
> explaining the constrainst?
>

Well, ultimately it doesn't really matter, given that this IP treats
all years divisible by 4 as leap years, so regardless of which base we
choose, it is going to jump to 29/2/2100 no matter what.

So the EPOCH_BASE could even be 2016: UEFI fully owns the RTC so it
can do whatever it wants. 2000 just seemed the least arbitrary.

>> +  }
>> +
>> +  Time->Daylight  = EFI_TIME_ADJUST_DAYLIGHT;
>> +  Time->TimeZone  = 0; /* UTC */
>> +
>> +  if (Capabilities != NULL) {
>> +    Capabilities->Resolution = 1;
>> +    Capabilities->Accuracy = 0;
>> +    Capabilities->SetsToZero = TRUE;
>> +  }
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +
>> +/**
>> +  Sets the current local time and date information.
>> +
>> +  @param  Time                  A pointer to the current time.
>> +
>> +  @retval EFI_SUCCESS           The operation completed successfully.
>> +  @retval EFI_INVALID_PARAMETER A time field is out of range.
>> +  @retval EFI_DEVICE_ERROR      The time could not be set due due to hardware
>> +                                error.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +LibSetTime (
>> +  IN EFI_TIME                *Time
>> +  )
>> +{
>> +  RTC_I2C_REQUEST             Op;
>> +  RTC_DATETIME                DateTime;
>> +  EFI_STATUS                  Status;
>> +  UINT8                       Reg;
>> +
>> +  if (mI2cMaster == NULL) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +
>> +  DateTime.VL_seconds     = DecimalToBcd8 (Time->Second);
>> +  DateTime.Minutes        = DecimalToBcd8 (Time->Minute);
>> +  DateTime.Hours          = DecimalToBcd8 (Time->Hour);
>> +  DateTime.Days           = DecimalToBcd8 (Time->Day);
>> +  DateTime.Century_months = DecimalToBcd8 (Time->Month);
>> +  DateTime.Years          = DecimalToBcd8 (Time->Year % 100);
>> +  if (Time->Year >= EPOCH_BASE + 100) {
>> +    DateTime.Century_months |= PCF8563_CENTURY_MASK;
>
> Are you going to slap me if I ask for this to return error if
> Time->Year >= EPOCH_BASE + 200?
>

Actually, I think it would be better to treat the century bit as a
toggle, depending on whether (year % 200) >= 100


>> +  }
>> +
>> +  Reg = PCF8563_DATA_REG_OFFSET;
>> +
>> +  Op.OperationCount = 2;
>> +
>> +  Op.SetAddressOp.Flags = 0;
>> +  Op.SetAddressOp.LengthInBytes = 1;
>> +  Op.SetAddressOp.Buffer = &Reg;
>> +
>> +  Op.GetSetDateTimeOp.Flags = 0;
>> +  Op.GetSetDateTimeOp.LengthInBytes = sizeof (RTC_DATETIME);
>> +  Op.GetSetDateTimeOp.Buffer = (VOID *)&DateTime;
>> +
>> +  Status = mI2cMaster->StartRequest (mI2cMaster, SLAVE_ADDRESS,
>> +                         (VOID *)&Op, NULL, NULL);
>> +  if (EFI_ERROR (Status)) {
>> +    return EFI_DEVICE_ERROR;
>> +  }
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +
>> +/**
>> +  Returns the current wakeup alarm clock setting.
>> +
>> +  @param  Enabled               Indicates if the alarm is currently enabled or
>> +                                disabled.
>> +  @param  Pending               Indicates if the alarm signal is pending and
>> +                                requires acknowledgement.
>> +  @param  Time                  The current alarm setting.
>> +
>> +  @retval EFI_SUCCESS           The alarm settings were returned.
>> +  @retval EFI_INVALID_PARAMETER Any parameter is NULL.
>> +  @retval EFI_DEVICE_ERROR      The wakeup time could not be retrieved due to a
>> +                                hardware error.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +LibGetWakeupTime (
>> +  OUT BOOLEAN     *Enabled,
>> +  OUT BOOLEAN     *Pending,
>> +  OUT EFI_TIME    *Time
>> +  )
>> +{
>> +  return EFI_UNSUPPORTED;
>
> For now, unsupported by current platforms, or unsupportable by this
> RTC device?
>

Well, getting and setting the wakeup time should be fairly trivial to
implement, but I can't really test it on the hardware we have (the INT
line is not connected), so I didn't bother. I'll add a comment to that
effect.

>> +}
>> +
>> +
>> +/**
>> +  Sets the system wakeup alarm clock time.
>> +
>> +  @param  Enabled               Enable or disable the wakeup alarm.
>> +  @param  Time                  If Enable is TRUE, the time to set the wakeup
>> +                                alarm for.
>> +
>> +  @retval EFI_SUCCESS           If Enable is TRUE, then the wakeup alarm was
>> +                                enabled. If Enable is FALSE, then the wakeup
>> +                                alarm was disabled.
>> +  @retval EFI_INVALID_PARAMETER A time field is out of range.
>> +  @retval EFI_DEVICE_ERROR      The wakeup time could not be set due to a
>> +                                hardware error.
>> +  @retval EFI_UNSUPPORTED       A wakeup timer is not supported on this
>> +                                platform.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +LibSetWakeupTime (
>> +  IN BOOLEAN      Enabled,
>> +  OUT EFI_TIME    *Time
>> +  )
>> +{
>> +  return EFI_UNSUPPORTED;
>
> Same question.
>

Same answer. Trivial to implement, impossible to test fully atm
(especially because I fried my board today)

>> +}
>> +
>> +STATIC
>> +VOID
>> +DriverRegistrationEvent (
>> +  IN  EFI_EVENT       Event,
>> +  IN  VOID            *Context
>> +  )
>> +{
>> +  EFI_HANDLE                Handle[2];
>> +  UINTN                     BufferSize;
>> +  EFI_STATUS                Status;
>> +  EFI_I2C_MASTER_PROTOCOL   *I2cMaster;
>> +  UINTN                     BusFrequency;
>> +
>> +  //
>> +  // Try to connect the newly registered driver to our handle.
>> +  //
>> +  do {
>> +    BufferSize = sizeof (EFI_HANDLE);
>> +    Status = gBS->LocateHandle (ByRegisterNotify,
>> +                                &gEfiDriverBindingProtocolGuid,
>> +                                mDriverEventRegistration,
>> +                                &BufferSize,
>> +                                Handle);
>> +    if (EFI_ERROR (Status)) {
>> +      if (Status != EFI_NOT_FOUND) {
>> +        DEBUG ((DEBUG_WARN, "%a: gBS->LocateHandle () returned %r\n",
>> +          __FUNCTION__, Status));
>> +      }
>> +      break;
>> +    }
>> +
>> +    //
>> +    // Check if we can connect our handle to this driver.
>> +    //
>> +    Handle[1] = NULL;
>> +    Status = gBS->ConnectController (mI2cMasterHandle, Handle, NULL, FALSE);
>> +    if (EFI_ERROR (Status)) {
>> +      continue;
>> +    }
>> +
>> +    DEBUG ((DEBUG_INFO, "%a: found I2C master!\n", __FUNCTION__));
>> +
>> +    gBS->CloseEvent (Event);
>> +
>> +    Status = gBS->OpenProtocol (mI2cMasterHandle, &gEfiI2cMasterProtocolGuid,
>> +                    (VOID **)&I2cMaster, gImageHandle, NULL,
>> +                    EFI_OPEN_PROTOCOL_EXCLUSIVE);
>> +    ASSERT_EFI_ERROR (Status);
>> +
>> +    Status = I2cMaster->Reset (I2cMaster);
>> +    if (EFI_ERROR (Status)) {
>> +      DEBUG ((DEBUG_ERROR, "%a: I2CMaster->Reset () failed - %r\n",
>> +        __FUNCTION__, Status));
>> +      break;
>> +    }
>> +
>> +    BusFrequency = FixedPcdGet16 (PcdI2cBusFrequency);
>> +    Status = I2cMaster->SetBusFrequency (I2cMaster, &BusFrequency);
>> +    if (EFI_ERROR (Status)) {
>> +      DEBUG ((DEBUG_ERROR, "%a: I2CMaster->SetBusFrequency () failed - %r\n",
>> +        __FUNCTION__, Status));
>> +      break;
>> +    }
>> +
>> +    mI2cMaster = I2cMaster;
>> +    break;
>> +  } while (TRUE);
>> +}
>> +
>> +/**
>> +  Fixup internal data so that EFI can be call in virtual mode.
>> +  Call the passed in Child Notify event and convert any pointers in
>> +  lib to virtual mode.
>> +
>> +  @param[in]    Event   The Event that is being processed
>> +  @param[in]    Context Event Context
>> +**/
>> +VOID
>> +EFIAPI
>> +LibRtcVirtualNotifyEvent (
>> +  IN EFI_EVENT        Event,
>> +  IN VOID             *Context
>> +  )
>> +{
>> +  EfiConvertPointer (0x0, (VOID **)&mI2cMaster);
>> +}
>> +
>> +/**
>> +  Library entry point
>> +
>> +  @param  ImageHandle           Handle that identifies the loaded image.
>> +  @param  SystemTable           System Table for this image.
>> +
>> +  @retval EFI_SUCCESS           The operation completed successfully.
>> +
>> +**/
>> +EFI_STATUS
>> +EFIAPI
>> +LibRtcInitialize (
>> +  IN EFI_HANDLE                            ImageHandle,
>> +  IN EFI_SYSTEM_TABLE                      *SystemTable
>> +  )
>> +{
>> +  EFI_STATUS          Status;
>> +  UINTN               BufferSize;
>> +
>> +  //
>> +  // Find the handle that marks the controller
>> +  // that will provide the I2C master protocol.
>> +  //
>> +  BufferSize = sizeof (EFI_HANDLE);
>> +  Status = gBS->LocateHandle (ByProtocol,
>> +                  &gPcf8563RealTimeClockLibI2cMasterProtolGuid, NULL,
>> +                  &BufferSize, &mI2cMasterHandle);
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  //
>> +  // Register a protocol registration notification callback on the driver
>> +  // binding protocol so we can attempt to connect our I2C master to it
>> +  // as soon as it appears.
>> +  //
>> +  EfiCreateProtocolNotifyEvent (
>> +    &gEfiDriverBindingProtocolGuid,
>> +    TPL_CALLBACK,
>> +    DriverRegistrationEvent,
>> +    NULL,
>> +    &mDriverEventRegistration);
>> +
>> +  //
>> +  // Register for the virtual address change event
>> +  //
>> +  Status = gBS->CreateEventEx (EVT_NOTIFY_SIGNAL, TPL_NOTIFY,
>> +                  LibRtcVirtualNotifyEvent, NULL,
>> +                  &gEfiEventVirtualAddressChangeGuid,
>> +                  &mRtcVirtualAddrChangeEvent);
>> +  ASSERT_EFI_ERROR (Status);
>> +
>> +  return EFI_SUCCESS;
>> +}
>> diff --git a/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.dec b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.dec
>> new file mode 100644
>> index 000000000000..bc8fc60c0602
>> --- /dev/null
>> +++ b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.dec
>> @@ -0,0 +1,29 @@
>> +#/** @file
>> +#
>> +#  Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>
>> +#
>> +#  This program and the accompanying materials
>> +#  are licensed and made available under the terms and conditions of the BSD License
>> +#  which accompanies this distribution. The full text of the license may be found at
>> +#  http://opensource.org/licenses/bsd-license.php
>> +#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
>> +#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>> +#
>> +#
>> +#**/
>> +
>> +[Defines]
>> +  DEC_SPECIFICATION              = 0x0001001A
>> +  PACKAGE_NAME                   = Pcf8563RealTimeClockLib
>> +  PACKAGE_GUID                   = 44d63668-c86b-446a-b303-f3a5176702aa
>> +  PACKAGE_VERSION                = 0.1
>> +
>> +[Guids]
>> +  gPcf8563RealTimeClockLibTokenSpaceGuid = { 0xaaf5b169, 0x93a0, 0x4d60, { 0xba, 0xe4, 0x06, 0x07, 0x92, 0x8e, 0x63, 0xdd }}
>> +
>> +[Protocols]
>> +  gPcf8563RealTimeClockLibI2cMasterProtolGuid = { 0xa6af18ae, 0x3bd5, 0x4af9, { 0xbb, 0x6a, 0xdb, 0x85, 0x07, 0x62, 0x81, 0x38 }}
>> +
>> +[PcdsFixedAtBuild]
>> +  gPcf8563RealTimeClockLibTokenSpaceGuid.PcdI2cSlaveAddress|0x51|UINT8|0x00000001
>> +  gPcf8563RealTimeClockLibTokenSpaceGuid.PcdI2cBusFrequency|400|UINT16|0x00000002
>
> Could you add a comment clarifying unit?
>

Yep, and actually this is wrong. It should be in Hz not kHz

>> diff --git a/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.inf b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.inf
>> new file mode 100644
>> index 000000000000..e1e001162144
>> --- /dev/null
>> +++ b/Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.inf
>> @@ -0,0 +1,52 @@
>> +#/** @file
>> +#
>> +#  Copyright (c) 2017, Linaro, Ltd. All rights reserved.<BR>
>> +#
>> +#  This program and the accompanying materials
>> +#  are licensed and made available under the terms and conditions of the BSD License
>> +#  which accompanies this distribution. The full text of the license may be found at
>> +#  http://opensource.org/licenses/bsd-license.php
>> +#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
>> +#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>> +#
>> +#
>> +#**/
>> +
>> +[Defines]
>> +  INF_VERSION                    = 0x0001001A
>> +  BASE_NAME                      = Pcf8563RealTimeClockLib
>> +  FILE_GUID                      = 1e3d33f3-a671-4116-bd81-6b435296c1e0
>> +  MODULE_TYPE                    = DXE_DRIVER
>> +  VERSION_STRING                 = 1.0
>> +  LIBRARY_CLASS                  = RealTimeClockLib
>> +
>> +[Sources.common]
>> +  Pcf8563RealTimeClockLib.c
>> +
>> +[Packages]
>> +  MdePkg/MdePkg.dec
>> +  EmbeddedPkg/EmbeddedPkg.dec
>> +  Silicon/NXP/Library/Pcf8563RealTimeClockLib/Pcf8563RealTimeClockLib.dec
>> +
>> +[LibraryClasses]
>> +  BaseMemoryLib
>> +  DebugLib
>> +  IoLib
>> +  UefiBootServicesTableLib
>> +  UefiLib
>> +  UefiRuntimeLib
>> +
>> +[Guids]
>> +  gEfiEventVirtualAddressChangeGuid
>> +
>> +[Protocols]
>> +  gEfiDriverBindingProtocolGuid                   ## CONSUMES
>> +  gEfiI2cMasterProtocolGuid                       ## CONSUMES
>> +  gPcf8563RealTimeClockLibI2cMasterProtolGuid     ## CONSUMES
>> +
>> +[FixedPcd]
>> +  gPcf8563RealTimeClockLibTokenSpaceGuid.PcdI2cSlaveAddress
>> +  gPcf8563RealTimeClockLibTokenSpaceGuid.PcdI2cBusFrequency
>> +
>> +[Depex]
>> +  gPcf8563RealTimeClockLibI2cMasterProtolGuid
>> --
>> 2.11.0
>>