diff --git a/docs/spi_driver.md b/docs/spi_driver.md
index e2b5b140b7..c170bf1dfc 100644
--- a/docs/spi_driver.md
+++ b/docs/spi_driver.md
@@ -18,7 +18,24 @@ You may use more than one slave select pin, not just the `SS` pin. This is usefu
## ChibiOS/ARM Configuration
-ARM support for this driver is not ready yet. Check back later!
+You'll need to determine which pins can be used for SPI -- as an example, STM32 parts generally have multiple SPI peripherals, labeled SPI1, SPI2, SPI3 etc.
+
+To enable SPI, modify your board's `halconf.h` to enable SPI - both `HAL_USE_SPI` and `SPI_USE_WAIT` should be `TRUE`, and `SPI_SELECT_MODE` should be `SPI_SELECT_MODE_PAD`.
+Then, modify your board's `mcuconf.h` to enable the SPI peripheral you've chosen -- in the case of using SPI2, modify `STM32_SPI_USE_SPI2` to be `TRUE`.
+
+As per the AVR configuration, you may select any other standard GPIO as a slave select pin, and can be supplied to `spi_start()`.
+
+Configuration-wise, you'll need to set up the peripheral as per your MCU's datasheet -- the defaults match the pins for a Proton-C, i.e. STM32F303.
+
+`config.h` override | Description | Default Value
+----------------------------|---------------------------------------------------------------|--------------
+`#define SPI_DRIVER` | SPI peripheral to use - SPI1 => `SPID1`, SPI2 => `SPID2` etc. | `SPID2`
+`#define SPI_SCK_PIN` | The pin to use for the SCK | `B13`
+`#define SPI_SCK_PAL_MODE` | The alternate function mode for the SCK pin | `5`
+`#define SPI_MOSI_PIN` | The pin to use for the MOSI | `B15`
+`#define SPI_MOSI_PAL_MODE` | The alternate function mode for the MOSI pin | `5`
+`#define SPI_MISO_PIN` | The pin to use for the MISO | `B14`
+`#define SPI_MISO_PAL_MODE` | The alternate function mode for the MISO pin | `5`
## Functions
diff --git a/drivers/chibios/spi_master.c b/drivers/chibios/spi_master.c
new file mode 100644
index 0000000000..552ac663c1
--- /dev/null
+++ b/drivers/chibios/spi_master.c
@@ -0,0 +1,137 @@
+/* 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 3 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "spi_master.h"
+#include "quantum.h"
+#include "timer.h"
+
+static pin_t currentSlavePin = NO_PIN;
+static SPIConfig spiConfig = {false, NULL, 0, 0, 0, 0};
+
+__attribute__((weak)) void spi_init(void) {
+ // Try releasing special pins for a short time
+ palSetPadMode(PAL_PORT(SPI_SCK_PIN), PAL_PAD(SPI_SCK_PIN), PAL_MODE_INPUT);
+ palSetPadMode(PAL_PORT(SPI_MOSI_PIN), PAL_PAD(SPI_MOSI_PIN), PAL_MODE_INPUT);
+ palSetPadMode(PAL_PORT(SPI_MISO_PIN), PAL_PAD(SPI_MISO_PIN), PAL_MODE_INPUT);
+
+ chThdSleepMilliseconds(10);
+#if defined(USE_GPIOV1)
+ palSetPadMode(PAL_PORT(SPI_SCK_PIN), PAL_PAD(SPI_SCK_PIN), PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+ palSetPadMode(PAL_PORT(SPI_MOSI_PIN), PAL_PAD(SPI_MOSI_PIN), PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+ palSetPadMode(PAL_PORT(SPI_MISO_PIN), PAL_PAD(SPI_MISO_PIN), PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+#else
+ palSetPadMode(PAL_PORT(SPI_SCK_PIN), PAL_PAD(SPI_SCK_PIN), PAL_MODE_ALTERNATE(SPI_SCK_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
+ palSetPadMode(PAL_PORT(SPI_MOSI_PIN), PAL_PAD(SPI_MOSI_PIN), PAL_MODE_ALTERNATE(SPI_MOSI_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
+ palSetPadMode(PAL_PORT(SPI_MISO_PIN), PAL_PAD(SPI_MISO_PIN), PAL_MODE_ALTERNATE(SPI_MISO_PAL_MODE) | PAL_STM32_OTYPE_PUSHPULL | PAL_STM32_OSPEED_HIGHEST);
+#endif
+}
+
+bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
+ if (currentSlavePin != NO_PIN || slavePin == NO_PIN) {
+ return false;
+ }
+
+ uint16_t roundedDivisor = 2;
+ while (roundedDivisor < divisor) {
+ roundedDivisor <<= 1;
+ }
+
+ if (roundedDivisor < 2 || roundedDivisor > 256) {
+ return false;
+ }
+
+ spiConfig.cr1 = 0;
+
+ if (lsbFirst) {
+ spiConfig.cr1 |= SPI_CR1_LSBFIRST;
+ }
+
+ switch (mode) {
+ case 0:
+ break;
+ case 1:
+ spiConfig.cr1 |= SPI_CR1_CPHA;
+ break;
+ case 2:
+ spiConfig.cr1 |= SPI_CR1_CPOL;
+ break;
+ case 3:
+ spiConfig.cr1 |= SPI_CR1_CPHA | SPI_CR1_CPOL;
+ break;
+ }
+
+ switch (roundedDivisor) {
+ case 2:
+ break;
+ case 4:
+ spiConfig.cr1 |= SPI_CR1_BR_0;
+ break;
+ case 8:
+ spiConfig.cr1 |= SPI_CR1_BR_1;
+ break;
+ case 16:
+ spiConfig.cr1 |= SPI_CR1_BR_1 | SPI_CR1_BR_0;
+ break;
+ case 32:
+ spiConfig.cr1 |= SPI_CR1_BR_2;
+ break;
+ case 64:
+ spiConfig.cr1 |= SPI_CR1_BR_2 | SPI_CR1_BR_0;
+ break;
+ case 128:
+ spiConfig.cr1 |= SPI_CR1_BR_2 | SPI_CR1_BR_1;
+ break;
+ case 256:
+ spiConfig.cr1 |= SPI_CR1_BR_2 | SPI_CR1_BR_1 | SPI_CR1_BR_0;
+ break;
+ }
+
+ currentSlavePin = slavePin;
+ spiConfig.ssport = PAL_PORT(slavePin);
+ spiConfig.sspad = PAL_PAD(slavePin);
+
+ setPinOutput(slavePin);
+ spiStart(&SPI_DRIVER, &spiConfig);
+ spiSelect(&SPI_DRIVER);
+
+ return true;
+}
+
+spi_status_t spi_write(uint8_t data) { return spi_transmit(&data, 1); }
+
+spi_status_t spi_read(void) {
+ uint8_t data = 0;
+ spi_receive(&data, 1);
+ return data;
+}
+
+spi_status_t spi_transmit(const uint8_t *data, uint16_t length) {
+ spiSend(&SPI_DRIVER, length, data);
+ return SPI_STATUS_SUCCESS;
+}
+
+spi_status_t spi_receive(uint8_t *data, uint16_t length) {
+ spiReceive(&SPI_DRIVER, length, data);
+ return SPI_STATUS_SUCCESS;
+}
+
+void spi_stop(void) {
+ if (currentSlavePin != NO_PIN) {
+ spiUnselect(&SPI_DRIVER);
+ spiStop(&SPI_DRIVER);
+ currentSlavePin = NO_PIN;
+ }
+}
diff --git a/drivers/chibios/spi_master.h b/drivers/chibios/spi_master.h
new file mode 100644
index 0000000000..0c18587c95
--- /dev/null
+++ b/drivers/chibios/spi_master.h
@@ -0,0 +1,78 @@
+/* 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 3 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 <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <ch.h>
+#include <hal.h>
+#include <quantum.h>
+
+#ifndef SPI_DRIVER
+# define SPI_DRIVER SPID2
+#endif
+
+#ifndef SPI_SCK_PIN
+# define SPI_SCK_PIN B13
+#endif
+
+#ifndef SPI_SCK_PAL_MODE
+# define SPI_SCK_PAL_MODE 5
+#endif
+
+#ifndef SPI_MOSI_PIN
+# define SPI_MOSI_PIN B15
+#endif
+
+#ifndef SPI_MOSI_PAL_MODE
+# define SPI_MOSI_PAL_MODE 5
+#endif
+
+#ifndef SPI_MISO_PIN
+# define SPI_MISO_PIN B14
+#endif
+
+#ifndef SPI_MISO_PAL_MODE
+# define SPI_MISO_PAL_MODE 5
+#endif
+
+typedef int16_t spi_status_t;
+
+#define SPI_STATUS_SUCCESS (0)
+#define SPI_STATUS_ERROR (-1)
+#define SPI_STATUS_TIMEOUT (-2)
+
+#define SPI_TIMEOUT_IMMEDIATE (0)
+#define SPI_TIMEOUT_INFINITE (0xFFFF)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+void spi_init(void);
+
+bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor);
+
+spi_status_t spi_write(uint8_t data);
+
+spi_status_t spi_read(void);
+
+spi_status_t spi_transmit(const uint8_t *data, uint16_t length);
+
+spi_status_t spi_receive(uint8_t *data, uint16_t length);
+
+void spi_stop(void);
+#ifdef __cplusplus
+}
+#endif
diff --git a/quantum/stm32/halconf.h b/quantum/stm32/halconf.h
index 106f0f5755..533803a25f 100644
--- a/quantum/stm32/halconf.h
+++ b/quantum/stm32/halconf.h
@@ -156,7 +156,7 @@
* @brief Enables the SPI subsystem.
*/
# if !defined(HAL_USE_SPI) || defined(__DOXYGEN__)
-# define HAL_USE_SPI FALSE
+# define HAL_USE_SPI TRUE
# endif
/**
diff --git a/quantum/stm32/mcuconf.h b/quantum/stm32/mcuconf.h
index ca4ad7b515..71994a98e0 100644
--- a/quantum/stm32/mcuconf.h
+++ b/quantum/stm32/mcuconf.h
@@ -227,7 +227,7 @@
* SPI driver system settings.
*/
#define STM32_SPI_USE_SPI1 FALSE
-#define STM32_SPI_USE_SPI2 FALSE
+#define STM32_SPI_USE_SPI2 TRUE
#define STM32_SPI_USE_SPI3 FALSE
#define STM32_SPI_SPI1_DMA_PRIORITY 1
#define STM32_SPI_SPI2_DMA_PRIORITY 1