Add SPI 25xx EEPROM support. (#8780)

1 files changed, 24 insertions, 5 deletions

diff --git a/docs/eeprom_driver.md b/docs/eeprom_driver.md
index 5a91a7c2da..188b95caa7 100644
--- a/docs/eeprom_driver.md
+++ b/docs/eeprom_driver.md
@@ -1,4 +1,4 @@
-# EEPROM Driver Configuration
+# EEPROM Driver Configuration :id=eeprom-driver-configuration
 
 The EEPROM driver can be swapped out depending on the needs of the keyboard, or whether extra hardware is present.
 
@@ -6,15 +6,20 @@ Driver                             | Description
 -----------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 `EEPROM_DRIVER = vendor` (default) | Uses the on-chip driver provided by the chip manufacturer. For AVR, this is provided by avr-libc. This is supported on ARM for a subset of chips -- STM32F3xx, STM32F1xx, and STM32F072xB will be emulated by writing to flash. STM32L0xx and STM32L1xx will use the onboard dedicated true EEPROM. Other chips will generally act as "transient" below.
 `EEPROM_DRIVER = i2c`              | Supports writing to I2C-based 24xx EEPROM chips. See the driver section below.
+`EEPROM_DRIVER = spi`              | Supports writing to SPI-based 25xx EEPROM chips. See the driver section below.
 `EEPROM_DRIVER = transient`        | Fake EEPROM driver -- supports reading/writing to RAM, and will be discarded when power is lost.
 
-## Vendor Driver Configuration
+## Vendor Driver Configuration :id=vendor-eeprom-driver-configuration
+
+#### STM32 L0/L1 Configuration :id=stm32l0l1-eeprom-driver-configuration
 
 !> Resetting EEPROM using an STM32L0/L1 device takes up to 1 second for every 1kB of internal EEPROM used.
 
-No configurable options are available.
+`config.h` override                 | Description                                                                                                              | Default Value
+------------------------------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------
+`#define STM32_ONBOARD_EEPROM_SIZE` | The size of the EEPROM to use, in bytes. Erase times can be high, so it's configurable here, if not using the default value. | Minimum required to cover base _eeconfig_ data, or `1024` if VIA is enabled.
 
-## I2C Driver Configuration
+## I2C Driver Configuration :id=i2c-eeprom-driver-configuration
 
 Currently QMK supports 24xx-series chips over I2C. As such, requires a working i2c_master driver configuration. You can override the driver configuration via your config.h:
 
@@ -41,7 +46,21 @@ MB85RC256V FRAM  | `#define EEPROM_I2C_MB85RC256V` | <https://www.adafruit.com/p
 
 ?> If you find that the EEPROM is not cooperating, ensure you've correctly shifted up your EEPROM address by 1. For example, the datasheet might state the address as `0b01010000` -- the correct value of `EXTERNAL_EEPROM_I2C_BASE_ADDRESS` needs to be `0b10100000`.
 
-## Transient Driver configuration
+## SPI Driver Configuration :id=spi-eeprom-driver-configuration
+
+Currently QMK supports 25xx-series chips over SPI. As such, requires a working spi_master driver configuration. You can override the driver configuration via your config.h:
+
+`config.h` override                            | Description                                                                          | Default Value
+-----------------------------------------------|--------------------------------------------------------------------------------------|--------------
+`#define EXTERNAL_EEPROM_SPI_SLAVE_SELECT_PIN` | SPI Slave select pin in order to inform that the EEPROM is currently being addressed | _none_
+`#define EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR`    | Clock divisor used to divide the peripheral clock to derive the SPI frequency        | `64`
+`#define EXTERNAL_EEPROM_BYTE_COUNT`           | Total size of the EEPROM in bytes                                                    | 8192
+`#define EXTERNAL_EEPROM_PAGE_SIZE`            | Page size of the EEPROM in bytes, as specified in the datasheet                      | 32
+`#define EXTERNAL_EEPROM_ADDRESS_SIZE`         | The number of bytes to transmit for the memory location within the EEPROM            | 2
+
+!> There's no way to determine if there is an SPI EEPROM actually responding. Generally, this will result in reads of nothing but zero.
+
+## Transient Driver configuration :id=transient-eeprom-driver-configuration
 
 The only configurable item for the transient EEPROM driver is its size: