Add SPI 25xx EEPROM support. (#8780)

7 files changed, 368 insertions, 20 deletions

diff --git a/common_features.mk b/common_features.mk
index 50b1127dc6..bdc6f883eb 100644
--- a/common_features.mk
+++ b/common_features.mk
@@ -70,7 +70,7 @@ ifeq ($(strip $(POINTING_DEVICE_ENABLE)), yes)
     SRC += $(QUANTUM_DIR)/pointing_device.c
 endif
 
-VALID_EEPROM_DRIVER_TYPES := vendor custom transient i2c
+VALID_EEPROM_DRIVER_TYPES := vendor custom transient i2c spi
 EEPROM_DRIVER ?= vendor
 ifeq ($(filter $(EEPROM_DRIVER),$(VALID_EEPROM_DRIVER_TYPES)),)
   $(error EEPROM_DRIVER="$(EEPROM_DRIVER)" is not a valid EEPROM driver)
@@ -85,6 +85,11 @@ else
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
     QUANTUM_LIB_SRC += i2c_master.c
     SRC += eeprom_driver.c eeprom_i2c.c
+  else ifeq ($(strip $(EEPROM_DRIVER)), spi)
+    OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_SPI
+    COMMON_VPATH += $(DRIVER_PATH)/eeprom
+    QUANTUM_LIB_SRC += spi_master.c
+    SRC += eeprom_driver.c eeprom_spi.c
   else ifeq ($(strip $(EEPROM_DRIVER)), transient)
     OPT_DEFS += -DEEPROM_DRIVER -DEEPROM_TRANSIENT
     COMMON_VPATH += $(DRIVER_PATH)/eeprom
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:
 
diff --git a/drivers/eeprom/eeprom_driver.c b/drivers/eeprom/eeprom_driver.c
index 3835e5e9d0..6ce47faf7d 100644
--- a/drivers/eeprom/eeprom_driver.c
+++ b/drivers/eeprom/eeprom_driver.c
@@ -20,19 +20,19 @@
 #include "eeprom_driver.h"
 
 uint8_t eeprom_read_byte(const uint8_t *addr) {
-    uint8_t ret;
+    uint8_t ret = 0;
     eeprom_read_block(&ret, addr, 1);
     return ret;
 }
 
 uint16_t eeprom_read_word(const uint16_t *addr) {
-    uint16_t ret;
+    uint16_t ret = 0;
     eeprom_read_block(&ret, addr, 2);
     return ret;
 }
 
 uint32_t eeprom_read_dword(const uint32_t *addr) {
-    uint32_t ret;
+    uint32_t ret = 0;
     eeprom_read_block(&ret, addr, 4);
     return ret;
 }
diff --git a/drivers/eeprom/eeprom_i2c.c b/drivers/eeprom/eeprom_i2c.c
index 03dbc5e516..88be2be06f 100644
--- a/drivers/eeprom/eeprom_i2c.c
+++ b/drivers/eeprom/eeprom_i2c.c
@@ -50,7 +50,7 @@ static inline void init_i2c_if_required(void) {
 }
 
 static inline void fill_target_address(uint8_t *buffer, const void *addr) {
-    intptr_t p = (intptr_t)addr;
+    uintptr_t p = (uintptr_t)addr;
     for (int i = 0; i < EXTERNAL_EEPROM_ADDRESS_SIZE; ++i) {
         buffer[EXTERNAL_EEPROM_ADDRESS_SIZE - 1 - i] = p & 0xFF;
         p >>= 8;
@@ -60,11 +60,19 @@ static inline void fill_target_address(uint8_t *buffer, const void *addr) {
 void eeprom_driver_init(void) {}
 
 void eeprom_driver_erase(void) {
+#ifdef CONSOLE_ENABLE
+    uint32_t start = timer_read32();
+#endif
+
     uint8_t buf[EXTERNAL_EEPROM_PAGE_SIZE];
     memset(buf, 0x00, EXTERNAL_EEPROM_PAGE_SIZE);
-    for (intptr_t addr = 0; addr < EXTERNAL_EEPROM_BYTE_COUNT; addr += EXTERNAL_EEPROM_PAGE_SIZE) {
-        eeprom_write_block(buf, (void *)addr, EXTERNAL_EEPROM_PAGE_SIZE);
+    for (uint32_t addr = 0; addr < EXTERNAL_EEPROM_BYTE_COUNT; addr += EXTERNAL_EEPROM_PAGE_SIZE) {
+        eeprom_write_block(buf, (void *)(uintptr_t)addr, EXTERNAL_EEPROM_PAGE_SIZE);
     }
+
+#ifdef CONSOLE_ENABLE
+    dprintf("EEPROM erase took %ldms to complete\n", ((long)(timer_read32() - start)));
+#endif
 }
 
 void eeprom_read_block(void *buf, const void *addr, size_t len) {
@@ -72,8 +80,8 @@ void eeprom_read_block(void *buf, const void *addr, size_t len) {
     fill_target_address(complete_packet, addr);
 
     init_i2c_if_required();
-    i2c_transmit(EXTERNAL_EEPROM_I2C_ADDRESS((intptr_t)addr), complete_packet, EXTERNAL_EEPROM_ADDRESS_SIZE, 100);
-    i2c_receive(EXTERNAL_EEPROM_I2C_ADDRESS((intptr_t)addr), buf, len, 100);
+    i2c_transmit(EXTERNAL_EEPROM_I2C_ADDRESS((uintptr_t)addr), complete_packet, EXTERNAL_EEPROM_ADDRESS_SIZE, 100);
+    i2c_receive(EXTERNAL_EEPROM_I2C_ADDRESS((uintptr_t)addr), buf, len, 100);
 
 #ifdef DEBUG_EEPROM_OUTPUT
     dprintf("[EEPROM R] 0x%04X: ", ((int)addr));
@@ -85,14 +93,14 @@ void eeprom_read_block(void *buf, const void *addr, size_t len) {
 }
 
 void eeprom_write_block(const void *buf, void *addr, size_t len) {
-    uint8_t  complete_packet[EXTERNAL_EEPROM_ADDRESS_SIZE + EXTERNAL_EEPROM_PAGE_SIZE];
-    uint8_t *read_buf    = (uint8_t *)buf;
-    intptr_t target_addr = (intptr_t)addr;
+    uint8_t   complete_packet[EXTERNAL_EEPROM_ADDRESS_SIZE + EXTERNAL_EEPROM_PAGE_SIZE];
+    uint8_t * read_buf    = (uint8_t *)buf;
+    uintptr_t target_addr = (uintptr_t)addr;
 
     init_i2c_if_required();
     while (len > 0) {
-        intptr_t page_offset  = target_addr % EXTERNAL_EEPROM_PAGE_SIZE;
-        int      write_length = EXTERNAL_EEPROM_PAGE_SIZE - page_offset;
+        uintptr_t page_offset  = target_addr % EXTERNAL_EEPROM_PAGE_SIZE;
+        int       write_length = EXTERNAL_EEPROM_PAGE_SIZE - page_offset;
         if (write_length > len) {
             write_length = len;
         }
@@ -110,7 +118,7 @@ void eeprom_write_block(const void *buf, void *addr, size_t len) {
         dprintf("\n");
 #endif  // DEBUG_EEPROM_OUTPUT
 
-        i2c_transmit(EXTERNAL_EEPROM_I2C_ADDRESS((intptr_t)addr), complete_packet, EXTERNAL_EEPROM_ADDRESS_SIZE + write_length, 100);
+        i2c_transmit(EXTERNAL_EEPROM_I2C_ADDRESS((uintptr_t)addr), complete_packet, EXTERNAL_EEPROM_ADDRESS_SIZE + write_length, 100);
         wait_ms(EXTERNAL_EEPROM_WRITE_TIME);
 
         read_buf += write_length;
diff --git a/drivers/eeprom/eeprom_spi.c b/drivers/eeprom/eeprom_spi.c
new file mode 100644
index 0000000000..e10aaf14c8
--- /dev/null
+++ b/drivers/eeprom/eeprom_spi.c
@@ -0,0 +1,231 @@
+/* Copyright 2020 Nick Brassel (tzarc)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+/*
+    Note that the implementations of eeprom_XXXX_YYYY on AVR are normally
+    provided by avr-libc. The same functions are reimplemented below and are
+    rerouted to the external SPI equivalent.
+
+    Seemingly, as this is compiled from within QMK, the object file generated
+    during the build overrides the avr-libc implementation during the linking
+    stage.
+
+    On other platforms such as ARM, there are no provided implementations, so
+    there is nothing to override during linkage.
+*/
+
+#include "wait.h"
+#include "spi_master.h"
+#include "eeprom.h"
+#include "eeprom_spi.h"
+
+#define CMD_WREN 6
+#define CMD_WRDI 4
+#define CMD_RDSR 5
+#define CMD_WRSR 1
+#define CMD_READ 3
+#define CMD_WRITE 2
+
+#define SR_WIP 0x01
+
+// #define DEBUG_EEPROM_OUTPUT
+
+#ifndef EXTERNAL_EEPROM_SPI_TIMEOUT
+#    define EXTERNAL_EEPROM_SPI_TIMEOUT 100
+#endif
+
+#ifdef CONSOLE_ENABLE
+#    include "print.h"
+#endif  // CONSOLE_ENABLE
+
+static void init_spi_if_required(void) {
+    static int done = 0;
+    if (!done) {
+        spi_init();
+        done = 1;
+    }
+}
+
+static bool spi_eeprom_start(void) { return spi_start(EXTERNAL_EEPROM_SPI_SLAVE_SELECT_PIN, EXTERNAL_EEPROM_SPI_LSBFIRST, EXTERNAL_EEPROM_SPI_MODE, EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR); }
+
+static spi_status_t spi_eeprom_wait_while_busy(int timeout) {
+    uint32_t     deadline = timer_read32() + timeout;
+    spi_status_t response;
+    do {
+        spi_write(CMD_RDSR);
+        response = spi_read();
+        if (timer_read32() >= deadline) {
+            return SPI_STATUS_TIMEOUT;
+        }
+    } while (response & SR_WIP);
+    return SPI_STATUS_SUCCESS;
+}
+
+static void spi_eeprom_transmit_address(uintptr_t addr) {
+    uint8_t buffer[EXTERNAL_EEPROM_ADDRESS_SIZE];
+
+    for (int i = 0; i < EXTERNAL_EEPROM_ADDRESS_SIZE; ++i) {
+        buffer[EXTERNAL_EEPROM_ADDRESS_SIZE - 1 - i] = addr & 0xFF;
+        addr >>= 8;
+    }
+
+    spi_transmit(buffer, EXTERNAL_EEPROM_ADDRESS_SIZE);
+}
+
+//----------------------------------------------------------------------------------------------------------------------
+
+void eeprom_driver_init(void) {}
+
+void eeprom_driver_erase(void) {
+#ifdef CONSOLE_ENABLE
+    uint32_t start = timer_read32();
+#endif
+
+    uint8_t buf[EXTERNAL_EEPROM_PAGE_SIZE];
+    memset(buf, 0x00, EXTERNAL_EEPROM_PAGE_SIZE);
+    for (uint32_t addr = 0; addr < EXTERNAL_EEPROM_BYTE_COUNT; addr += EXTERNAL_EEPROM_PAGE_SIZE) {
+        eeprom_write_block(buf, (void *)(uintptr_t)addr, EXTERNAL_EEPROM_PAGE_SIZE);
+    }
+
+#ifdef CONSOLE_ENABLE
+    dprintf("EEPROM erase took %ldms to complete\n", ((long)(timer_read32() - start)));
+#endif
+}
+
+void eeprom_read_block(void *buf, const void *addr, size_t len) {
+    init_spi_if_required();
+
+    //-------------------------------------------------
+    // Wait for the write-in-progress bit to be cleared
+    bool res = spi_eeprom_start();
+    if (!res) {
+        dprint("failed to start SPI for WIP check\n");
+        memset(buf, 0, len);
+        return;
+    }
+
+    spi_status_t response = spi_eeprom_wait_while_busy(EXTERNAL_EEPROM_SPI_TIMEOUT);
+    spi_stop();
+    if (response == SPI_STATUS_TIMEOUT) {
+        dprint("SPI timeout for WIP check\n");
+        memset(buf, 0, len);
+        return;
+    }
+
+    //-------------------------------------------------
+    // Perform read
+    res = spi_eeprom_start();
+    if (!res) {
+        dprint("failed to start SPI for read\n");
+        memset(buf, 0, len);
+        return;
+    }
+
+    spi_write(CMD_READ);
+    spi_eeprom_transmit_address((uintptr_t)addr);
+    spi_receive(buf, len);
+
+#ifdef DEBUG_EEPROM_OUTPUT
+    dprintf("[EEPROM R] 0x%08lX: ", ((uint32_t)(uintptr_t)addr));
+    for (size_t i = 0; i < len; ++i) {
+        dprintf(" %02X", (int)(((uint8_t *)buf)[i]));
+    }
+    dprintf("\n");
+#endif  // DEBUG_EEPROM_OUTPUT
+
+    spi_stop();
+}
+
+void eeprom_write_block(const void *buf, void *addr, size_t len) {
+    init_spi_if_required();
+
+    bool      res;
+    uint8_t * read_buf    = (uint8_t *)buf;
+    uintptr_t target_addr = (uintptr_t)addr;
+
+    while (len > 0) {
+        uintptr_t page_offset  = target_addr % EXTERNAL_EEPROM_PAGE_SIZE;
+        int       write_length = EXTERNAL_EEPROM_PAGE_SIZE - page_offset;
+        if (write_length > len) {
+            write_length = len;
+        }
+
+        //-------------------------------------------------
+        // Wait for the write-in-progress bit to be cleared
+        res = spi_eeprom_start();
+        if (!res) {
+            dprint("failed to start SPI for WIP check\n");
+            return;
+        }
+
+        spi_status_t response = spi_eeprom_wait_while_busy(EXTERNAL_EEPROM_SPI_TIMEOUT);
+        spi_stop();
+        if (response == SPI_STATUS_TIMEOUT) {
+            dprint("SPI timeout for WIP check\n");
+            return;
+        }
+
+        //-------------------------------------------------
+        // Enable writes
+        res = spi_eeprom_start();
+        if (!res) {
+            dprint("failed to start SPI for write-enable\n");
+            return;
+        }
+
+        spi_write(CMD_WREN);
+        spi_stop();
+
+        //-------------------------------------------------
+        // Perform the write
+        res = spi_eeprom_start();
+        if (!res) {
+            dprint("failed to start SPI for write\n");
+            return;
+        }
+
+#ifdef DEBUG_EEPROM_OUTPUT
+        dprintf("[EEPROM W] 0x%08lX: ", ((uint32_t)(uintptr_t)target_addr));
+        for (size_t i = 0; i < write_length; i++) {
+            dprintf(" %02X", (int)(uint8_t)(read_buf[i]));
+        }
+        dprintf("\n");
+#endif  // DEBUG_EEPROM_OUTPUT
+
+        spi_write(CMD_WRITE);
+        spi_eeprom_transmit_address(target_addr);
+        spi_transmit(read_buf, write_length);
+        spi_stop();
+
+        read_buf += write_length;
+        target_addr += write_length;
+        len -= write_length;
+    }
+
+    //-------------------------------------------------
+    // Disable writes
+    res = spi_eeprom_start();
+    if (!res) {
+        dprint("failed to start SPI for write-disable\n");
+        return;
+    }
+
+    spi_write(CMD_WRDI);
+    spi_stop();
+}
diff --git a/drivers/eeprom/eeprom_spi.h b/drivers/eeprom/eeprom_spi.h
new file mode 100644
index 0000000000..282c603565
--- /dev/null
+++ b/drivers/eeprom/eeprom_spi.h
@@ -0,0 +1,80 @@
+/* Copyright 2020 Nick Brassel (tzarc)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+/*
+    The slave select pin of the EEPROM.
+    This needs to be a normal GPIO pin_t value, such as A7.
+*/
+#ifndef EXTERNAL_EEPROM_SPI_SLAVE_SELECT_PIN
+#    error "No chip select pin defined -- missing EXTERNAL_EEPROM_SPI_SLAVE_SELECT_PIN"
+#endif
+
+/*
+    The clock divisor for SPI to ensure that the MCU is within the
+    specifications of the EEPROM chip. Generally this will be PCLK divided by
+    the intended divisor -- check your clock settings and the datasheet of
+    your EEPROM.
+*/
+#ifndef EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR
+#    ifdef __AVR__
+#        define EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR 8
+#    else
+#        define EXTERNAL_EEPROM_SPI_CLOCK_DIVISOR 64
+#    endif
+#endif
+
+/*
+    The SPI mode to communicate with the EEPROM.
+*/
+#ifndef EXTERNAL_EEPROM_SPI_MODE
+#    define EXTERNAL_EEPROM_SPI_MODE 0
+#endif
+
+/*
+    Whether or not the SPI communication between the MCU and EEPROM should be
+    LSB-first.
+*/
+#ifndef EXTERNAL_EEPROM_SPI_LSBFIRST
+#    define EXTERNAL_EEPROM_SPI_LSBFIRST false
+#endif
+
+/*
+    The total size of the EEPROM, in bytes. The EEPROM datasheet will usually
+    specify this value in kbits, and will require conversion to bytes.
+*/
+#ifndef EXTERNAL_EEPROM_BYTE_COUNT
+#    define EXTERNAL_EEPROM_BYTE_COUNT 8192
+#endif
+
+/*
+    The page size in bytes of the EEPROM, as specified in the datasheet.
+*/
+#ifndef EXTERNAL_EEPROM_PAGE_SIZE
+#    define EXTERNAL_EEPROM_PAGE_SIZE 32
+#endif
+
+/*
+    The address size in bytes of the EEPROM. For EEPROMs with <=256 bytes, this
+    will likely be 1. For EEPROMs >256 and <=65536, this will be 2. For EEPROMs
+    >65536, this will likely need to be 4.
+
+    As expected, consult the datasheet for specifics of your EEPROM.
+*/
+#ifndef EXTERNAL_EEPROM_ADDRESS_SIZE
+#    define EXTERNAL_EEPROM_ADDRESS_SIZE 2
+#endif
diff --git a/keyboards/handwired/onekey/keymaps/eep_rst/keymap.c b/keyboards/handwired/onekey/keymaps/eep_rst/keymap.c
new file mode 100644
index 0000000000..adb8e4cd2f
--- /dev/null
+++ b/keyboards/handwired/onekey/keymaps/eep_rst/keymap.c
@@ -0,0 +1,5 @@
+#include QMK_KEYBOARD_H
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+  LAYOUT( EEP_RST )
+};