Add I2C and SPI drivers from example design

Signed-off-by: gatecat <[email protected]>

Author: gatecat

chipflow_lib/software/drivers/i2c.c

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+#include "i2c.h"
+
+void i2c_init(volatile i2c_regs_t *i2c, uint32_t divider) {
+	i2c->divider = divider;
+}
+
+void i2c_start(volatile i2c_regs_t *i2c) {
+	i2c->action = (1<<1);
+	while (i2c->status & 0x1)
+		;
+}
+
+int i2c_write(volatile i2c_regs_t *i2c, uint8_t data) {
+	i2c->send_data = data;
+	while (i2c->status & 0x1)
+		;
+	return (i2c->status & 0x2) != 0; // check ACK
+}
+
+uint8_t i2c_read(volatile i2c_regs_t *i2c) {
+	i2c->action = (1<<3);
+	while (i2c->status & 0x1)
+		;
+	return i2c->receive_data;
+}
+
+void i2c_stop(volatile i2c_regs_t *i2c) {
+	i2c->action = (1<<2);
+	while (i2c->status & 0x1)
+		;
+}

chipflow_lib/software/drivers/i2c.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+#ifndef I2C_H
+#define I2C_H
+
+#include <stdint.h>
+
+typedef struct {
+	uint32_t divider;
+	uint32_t action;
+	uint32_t send_data;
+	uint32_t receive_data;
+	uint32_t status;
+} i2c_regs_t;
+
+void i2c_init(volatile i2c_regs_t *i2c, uint32_t divider);
+void i2c_start(volatile i2c_regs_t *i2c);
+int i2c_write(volatile i2c_regs_t *i2c, uint8_t data);
+uint8_t i2c_read(volatile i2c_regs_t *i2c);
+void i2c_stop(volatile i2c_regs_t *i2c);
+
+#endif

chipflow_lib/software/drivers/spi.c

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+#include "spi.h"
+
+void spi_init(volatile spi_regs_t *spi, uint32_t divider) {
+	spi->divider = divider;
+    spi->config = 0x02; // CS=0, SCK_EDGE=1, SCK_IDLE=0
+}
+
+uint32_t spi_xfer(volatile spi_regs_t *spi, uint32_t data, uint32_t width, bool deselect) {
+    spi->config = ((width - 1) << 3) | 0x06; // CS=1, SCK_EDGE=1, SCK_IDLE=0
+    spi->send_data = data << (32U - width);
+    while (!(spi->status & 0x1)) // wait for rx full
+        ;
+   	if (deselect) {
+    	spi->config = ((width - 1) << 3) | 0x02; // CS=0, SCK_EDGE=1, SCK_IDLE=0
+    }
+    return spi->receive_data;
+}

chipflow_lib/software/drivers/spi.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+#ifndef SPI_H
+#define SPI_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct {
+	uint32_t config;
+	uint32_t divider;
+	uint32_t send_data;
+	uint32_t receive_data;
+	uint32_t status;
+} spi_regs_t;
+
+void spi_init(volatile spi_regs_t *spi, uint32_t divider);
+uint32_t spi_xfer(volatile spi_regs_t *spi, uint32_t data, uint32_t width, bool deselect);
+
+#endif