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-rw-r--r--drivers/eeprom/eeprom_i2c.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/drivers/eeprom/eeprom_i2c.c b/drivers/eeprom/eeprom_i2c.c
new file mode 100644
index 0000000000..03dbc5e516
--- /dev/null
+++ b/drivers/eeprom/eeprom_i2c.c
@@ -0,0 +1,120 @@
+/* Copyright 2019 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 i2c 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 "i2c_master.h"
+#include "eeprom.h"
+#include "eeprom_i2c.h"
+
+// #define DEBUG_EEPROM_OUTPUT
+
+#ifdef DEBUG_EEPROM_OUTPUT
+# include "print.h"
+#endif // DEBUG_EEPROM_OUTPUT
+
+static inline void init_i2c_if_required(void) {
+ static int done = 0;
+ if (!done) {
+ i2c_init();
+ done = 1;
+ }
+}
+
+static inline void fill_target_address(uint8_t *buffer, const void *addr) {
+ intptr_t p = (intptr_t)addr;
+ for (int i = 0; i < EXTERNAL_EEPROM_ADDRESS_SIZE; ++i) {
+ buffer[EXTERNAL_EEPROM_ADDRESS_SIZE - 1 - i] = p & 0xFF;
+ p >>= 8;
+ }
+}
+
+void eeprom_driver_init(void) {}
+
+void eeprom_driver_erase(void) {
+ 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);
+ }
+}
+
+void eeprom_read_block(void *buf, const void *addr, size_t len) {
+ uint8_t complete_packet[EXTERNAL_EEPROM_ADDRESS_SIZE];
+ 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);
+
+#ifdef DEBUG_EEPROM_OUTPUT
+ dprintf("[EEPROM R] 0x%04X: ", ((int)addr));
+ for (size_t i = 0; i < len; ++i) {
+ dprintf(" %02X", (int)(((uint8_t *)buf)[i]));
+ }
+ dprintf("\n");
+#endif // DEBUG_EEPROM_OUTPUT
+}
+
+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;
+
+ 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;
+ if (write_length > len) {
+ write_length = len;
+ }
+
+ fill_target_address(complete_packet, (const void *)target_addr);
+ for (uint8_t i = 0; i < write_length; i++) {
+ complete_packet[EXTERNAL_EEPROM_ADDRESS_SIZE + i] = read_buf[i];
+ }
+
+#ifdef DEBUG_EEPROM_OUTPUT
+ dprintf("[EEPROM W] 0x%04X: ", ((int)target_addr));
+ for (uint8_t i = 0; i < write_length; i++) {
+ dprintf(" %02X", (int)(read_buf[i]));
+ }
+ dprintf("\n");
+#endif // DEBUG_EEPROM_OUTPUT
+
+ i2c_transmit(EXTERNAL_EEPROM_I2C_ADDRESS((intptr_t)addr), complete_packet, EXTERNAL_EEPROM_ADDRESS_SIZE + write_length, 100);
+ wait_ms(EXTERNAL_EEPROM_WRITE_TIME);
+
+ read_buf += write_length;
+ target_addr += write_length;
+ len -= write_length;
+ }
+}