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-rw-r--r--src/cpu/allwinner/a10/twi.c2
-rw-r--r--src/device/Kconfig10
-rw-r--r--src/device/Makefile.inc4
-rw-r--r--src/device/software_i2c.c345
-rw-r--r--src/include/device/i2c.h34
-rw-r--r--src/soc/nvidia/tegra/i2c.c2
-rw-r--r--src/soc/nvidia/tegra/i2c.h2
-rw-r--r--src/soc/nvidia/tegra/software_i2c.c96
-rw-r--r--src/soc/nvidia/tegra124/Makefile.inc3
-rw-r--r--src/soc/samsung/exynos5250/i2c.c2
-rw-r--r--src/soc/samsung/exynos5420/i2c.c2
11 files changed, 497 insertions, 5 deletions
diff --git a/src/cpu/allwinner/a10/twi.c b/src/cpu/allwinner/a10/twi.c
index 14e5ec7d9f..d6a0127803 100644
--- a/src/cpu/allwinner/a10/twi.c
+++ b/src/cpu/allwinner/a10/twi.c
@@ -215,7 +215,7 @@ static int i2c_write(unsigned bus, unsigned chip, unsigned addr,
* TODO: Rewite the i2c_transfer and supporting functions
*
*/
-int i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
{
struct i2c_seg *seg = segments;
diff --git a/src/device/Kconfig b/src/device/Kconfig
index bd2f34b618..67d01e077a 100644
--- a/src/device/Kconfig
+++ b/src/device/Kconfig
@@ -376,6 +376,16 @@ config PXE_ROM_ID
Under GNU/Linux you can run `lspci -nn` to list the IDs of your PCI devices.
+config SOFTWARE_I2C
+ bool "Enable I2C controller emulation in software"
+ default n
+ help
+ This config option will enable code to override the i2c_transfer
+ routine with a (simple) software emulation of the protocol. This may
+ be useful for debugging or on platforms where a driver for the real
+ I2C controller is not (yet) available. The platform code needs to
+ provide bindings to manually toggle I2C lines.
+
endmenu
menu "Display"
diff --git a/src/device/Makefile.inc b/src/device/Makefile.inc
index a7f336489d..7fdd9b587d 100644
--- a/src/device/Makefile.inc
+++ b/src/device/Makefile.inc
@@ -24,3 +24,7 @@ romstage-$(CONFIG_PCI) += pci_early.c
subdirs-y += oprom dram
ramstage-$(CONFIG_VGA_ROM_RUN) += pci_rom.c
+
+bootblock-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
+romstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
+ramstage-$(CONFIG_SOFTWARE_I2C) += software_i2c.c
diff --git a/src/device/software_i2c.c b/src/device/software_i2c.c
new file mode 100644
index 0000000000..6c9c200dc7
--- /dev/null
+++ b/src/device/software_i2c.c
@@ -0,0 +1,345 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#include <assert.h>
+#include <timer.h>
+#include <console/console.h>
+#include <device/i2c.h>
+
+/*
+ * The implementation is based on Wikipedia.
+ */
+
+#define DEBUG 0 /* Set to 1 for per-byte output */
+#define SPEW 0 /* Set to 1 for verbose bitwise/line-state output */
+#define DELAY_US 5 /* Default setup delay: 4us (+1 for timer inaccuracy) */
+#define TIMEOUT_US 50000 /* Maximum clock stretching time we want to allow */
+
+#define spew(...) do { if (SPEW) printk(BIOS_SPEW, ##__VA_ARGS__); } while (0)
+
+struct software_i2c_ops *software_i2c[SOFTWARE_I2C_MAX_BUS];
+
+/*
+ * Waits until either timeout_us have passed or (iff for_scl is set) until SCL
+ * goes high. Will report random line changes during the wait and return SCL.
+ */
+static int __wait(unsigned bus, int timeout_us, int for_scl)
+{
+ int us;
+ int sda = software_i2c[bus]->get_sda(bus);
+ int scl = software_i2c[bus]->get_scl(bus);
+ struct mono_time start;
+ timer_monotonic_get(&start);
+
+ do {
+ int old_sda = sda;
+ int old_scl = scl;
+ struct rela_time diff = current_time_from(&start);
+ us = rela_time_in_microseconds(&diff);
+
+ if (old_sda != (sda = software_i2c[bus]->get_sda(bus)))
+ spew("[SDA transitioned to %d after %dus] ", sda, us);
+ if (old_scl != (scl = software_i2c[bus]->get_scl(bus)))
+ spew("[SCL transitioned to %d after %dus] ", scl, us);
+ } while (us < timeout_us && (!for_scl || !scl));
+
+ return scl;
+}
+
+/* Waits the default DELAY_US to allow line state to stabilize. */
+static void wait(unsigned bus)
+{
+ __wait(bus, DELAY_US, 0);
+}
+
+/* Waits until SCL goes high. Prints a contextual error message on timeout. */
+static int wait_for_scl(unsigned bus, const char *error_context)
+{
+ if (!__wait(bus, TIMEOUT_US, 1)) {
+ printk(BIOS_ERR, "software_i2c(%d): ERROR: Clock stretching "
+ "timeout %s!\n", bus, error_context);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int start_cond(unsigned bus)
+{
+ spew("software_i2c(%d): Sending start condition... ", bus);
+
+ /* SDA might not yet be high if repeated start. */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+
+ /* Might need to wait for clock stretching if repeated start. */
+ software_i2c[bus]->set_scl(bus, 1);
+ if (wait_for_scl(bus, "before start condition"))
+ return -1;
+ wait(bus); /* Repeated start setup time, minimum 4.7us */
+
+ if (!software_i2c[bus]->get_sda(bus)) {
+ printk(BIOS_ERR, "software_i2c(%d): Arbitration lost trying "
+ "to send start condition!\n", bus);
+ return -1;
+ }
+
+ /* SCL is high, transition SDA low as first part of start condition. */
+ software_i2c[bus]->set_sda(bus, 0);
+ wait(bus);
+ assert(software_i2c[bus]->get_scl(bus));
+
+ /* Pull SCL low to finish start condition (next pulse will be data). */
+ software_i2c[bus]->set_scl(bus, 0);
+
+ spew("Start condition transmitted!\n");
+ return 0;
+}
+
+static int stop_cond(unsigned bus)
+{
+ spew("software_i2c(%d): Sending stop condition... ", bus);
+
+ /* SDA is unknown, set it to low. SCL must be low. */
+ software_i2c[bus]->set_sda(bus, 0);
+ wait(bus);
+
+ /* Clock stretching */
+ assert(!software_i2c[bus]->get_scl(bus));
+ software_i2c[bus]->set_scl(bus, 1);
+ if (wait_for_scl(bus, "before stop condition"))
+ return -1;
+ wait(bus); /* Stop bit setup time, minimum 4us */
+
+ /* SCL is high, transition SDA high to signal stop condition. */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+ if (!software_i2c[bus]->get_sda(bus)) {
+ printk(BIOS_WARNING, "software_i2c(%d): WARNING: SDA low after "
+ "stop condition... access by another master or line "
+ "stuck from faulty slave?\n", bus);
+ /* Could theoretically happen with multi-master, so no -1. */
+ }
+
+ spew("Stop condition transmitted\n");
+ return 0;
+}
+
+static int out_bit(unsigned bus, int bit)
+{
+ spew("software_i2c(%d): Sending a %d bit... ", bus, bit);
+
+ software_i2c[bus]->set_sda(bus, bit);
+ wait(bus);
+
+ if (bit && !software_i2c[bus]->get_sda(bus)) {
+ printk(BIOS_ERR, "software_i2c(%d): ERROR: SDA wedged low "
+ "by slave before clock pulse on transmit!\n", bus);
+ return -1;
+ }
+
+ /* Clock stretching */
+ assert(!software_i2c[bus]->get_scl(bus));
+ software_i2c[bus]->set_scl(bus, 1);
+ if (wait_for_scl(bus, "on transmit"))
+ return -1;
+ wait(bus);
+
+ if (bit && !software_i2c[bus]->get_sda(bus)) {
+ printk(BIOS_ERR, "software_i2c(%d): ERROR: SDA wedged low "
+ "by slave after clock pulse on transmit!\n", bus);
+ return -1;
+ }
+
+ assert(software_i2c[bus]->get_scl(bus));
+ software_i2c[bus]->set_scl(bus, 0);
+
+ spew("%d bit sent!\n", bit);
+ return 0;
+}
+
+static int in_bit(unsigned bus)
+{
+ int bit;
+
+ spew("software_i2c(%d): Receiving a bit... ", bus);
+
+ /* Let the slave drive data */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+
+ /* Clock stretching */
+ assert(!software_i2c[bus]->get_scl(bus));
+ software_i2c[bus]->set_scl(bus, 1);
+ if (wait_for_scl(bus, "on receive"))
+ return -1;
+
+ /* SCL is high, now data is valid */
+ bit = software_i2c[bus]->get_sda(bus);
+ wait(bus);
+ assert(software_i2c[bus]->get_scl(bus));
+ software_i2c[bus]->set_scl(bus, 0);
+
+ spew("Received a %d!\n", bit);
+
+ return bit;
+}
+
+/* Write a byte to I2C bus. Return 0 if ack by the slave. */
+static int out_byte(unsigned bus, u8 byte)
+{
+ unsigned bit;
+ int nack;
+
+ for (bit = 0; bit < 8; bit++)
+ if (out_bit(bus, (byte >> (7 - bit)) & 0x1) < 0)
+ return -1;
+
+ nack = in_bit(bus);
+
+ if (DEBUG && nack >= 0)
+ printk(BIOS_DEBUG, "software_i2c(%d): wrote byte 0x%02x, "
+ "received %s\n", bus, byte, nack ? "NAK" : "ACK");
+
+ return nack;
+}
+
+static int in_byte(unsigned bus, int ack)
+{
+ u8 byte = 0;
+ int i;
+ for (i = 0; i < 8; ++i) {
+ int bit = in_bit(bus);
+ if (bit < 0)
+ return -1;
+ byte = (byte << 1) | bit;
+ }
+
+ if (out_bit(bus, !ack) < 0)
+ return -1;
+
+ if (DEBUG)
+ printk(BIOS_DEBUG, "software_i2c(%d): read byte 0x%02x, "
+ "sent %s\n", bus, byte, ack ? "ACK" : "NAK");
+
+ return byte;
+}
+
+int software_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+{
+ int i;
+ struct i2c_seg *seg;
+
+ for (seg = segments; seg - segments < count; seg++) {
+ if (start_cond(bus) < 0)
+ return -1;
+ if (out_byte(bus, seg->chip << 1 | !!seg->read) < 0)
+ return -1;
+ for (i = 0; i < seg->len; i++) {
+ int ret;
+ if (seg->read) {
+ ret = in_byte(bus, i < seg->len - 1);
+ seg->buf[i] = (u8)ret;
+ } else {
+ ret = out_byte(bus, seg->buf[i]);
+ }
+ if (ret < 0)
+ return -1;
+ }
+ }
+ if (stop_cond(bus) < 0)
+ return -1;
+
+ return 0;
+}
+
+void software_i2c_wedge_ack(unsigned bus, u8 chip)
+{
+ int i;
+
+ /* Start a command to 'chip'... */
+ start_cond(bus);
+
+ /* Send the address bits but don't yet read the ACK. */
+ chip <<= 1;
+ for (i = 0; i < 8; ++i)
+ out_bit(bus, (chip >> (7 - i)) & 0x1);
+
+ /* Let the slave drive it's ACK but keep the clock high forever. */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+ software_i2c[bus]->set_scl(bus, 1);
+ wait_for_scl(bus, "on wedge_ack()");
+
+ printk(BIOS_INFO, "software_i2c(%d): wedged address write on slave "
+ "ACK. SDA %d, SCL %d\n", bus, software_i2c[bus]->get_sda(bus),
+ software_i2c[bus]->get_scl(bus));
+}
+
+void software_i2c_wedge_read(unsigned bus, u8 chip, u8 reg, int bits)
+{
+ int i;
+
+ /* Start a command to 'chip'... */
+ start_cond(bus);
+ out_byte(bus, chip << 1);
+ /* ...for register 'reg'. */
+ out_byte(bus, reg);
+
+ /* Start a read command... */
+ start_cond(bus);
+ out_byte(bus, chip << 1 | 1);
+
+ /* Read bit_count bits and stop */
+ for (i = 0; i < bits; ++i)
+ in_bit(bus);
+
+ /* Let the slave drive SDA but keep the clock high forever. */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+ software_i2c[bus]->set_scl(bus, 1);
+ wait_for_scl(bus, "on wedge_read()");
+
+ printk(BIOS_INFO, "software_i2c(%d): wedged data read after %d bits. "
+ "SDA %d, SCL %d\n", bus, bits, software_i2c[bus]->get_sda(bus),
+ software_i2c[bus]->get_scl(bus));
+}
+
+void software_i2c_wedge_write(unsigned bus, u8 chip, u8 reg, int bits)
+{
+ int i;
+
+ /* Start a command to 'chip'... */
+ start_cond(bus);
+ out_byte(bus, chip << 1);
+
+ /* Write bit_count register bits and stop */
+ for (i = 0; i < bits; ++i)
+ out_bit(bus, (reg >> (7 - i)) & 0x1);
+
+ /* Pretend to write another 1 bit but keep the clock high forever. */
+ software_i2c[bus]->set_sda(bus, 1);
+ wait(bus);
+ software_i2c[bus]->set_scl(bus, 1);
+ wait_for_scl(bus, "on wedge_write()");
+
+ printk(BIOS_INFO, "software_i2c(%d): wedged data write after %d bits. "
+ "SDA %d, SCL %d\n", bus, bits, software_i2c[bus]->get_sda(bus),
+ software_i2c[bus]->get_scl(bus));
+}
diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h
index da9d1bcb3c..c1f2a2103a 100644
--- a/src/include/device/i2c.h
+++ b/src/include/device/i2c.h
@@ -31,7 +31,39 @@ struct i2c_seg
int len;
};
-int i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
+
+#define SOFTWARE_I2C_MAX_BUS 10 /* increase as necessary */
+
+struct software_i2c_ops {
+ void (*set_sda)(unsigned bus, int high);
+ void (*set_scl)(unsigned bus, int high);
+ int (*get_sda)(unsigned bus);
+ int (*get_scl)(unsigned bus);
+};
+
+extern struct software_i2c_ops *software_i2c[];
+
+int software_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
+void software_i2c_wedge_ack(unsigned bus, u8 chip);
+void software_i2c_wedge_read(unsigned bus, u8 chip, u8 reg, int bit_count);
+void software_i2c_wedge_write(unsigned bus, u8 chip, u8 reg, int bit_count);
+
+/*
+ * software_i2c is supposed to be a debug feature. It's usually not compiled in,
+ * but when it is it can be dynamically enabled at runtime for certain busses.
+ * Need this ugly stub to arbitrate since I2C device drivers hardcode
+ * 'i2c_transfer()' as their entry point.
+ */
+static inline int i2c_transfer(unsigned bus, struct i2c_seg *segments,
+ int count)
+{
+ if (CONFIG_SOFTWARE_I2C)
+ if (bus < SOFTWARE_I2C_MAX_BUS && software_i2c[bus])
+ return software_i2c_transfer(bus, segments, count);
+
+ return platform_i2c_transfer(bus, segments, count);
+}
/*
* Read a raw chunk of data in one segment and one frame.
diff --git a/src/soc/nvidia/tegra/i2c.c b/src/soc/nvidia/tegra/i2c.c
index 6c269cfaed..555d0318c1 100644
--- a/src/soc/nvidia/tegra/i2c.c
+++ b/src/soc/nvidia/tegra/i2c.c
@@ -180,7 +180,7 @@ static int i2c_transfer_segment(unsigned bus, unsigned chip, int restart,
return 0;
}
-int i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
{
struct i2c_seg *seg = segments;
diff --git a/src/soc/nvidia/tegra/i2c.h b/src/soc/nvidia/tegra/i2c.h
index 6347fff8ad..4b1bddd2af 100644
--- a/src/soc/nvidia/tegra/i2c.h
+++ b/src/soc/nvidia/tegra/i2c.h
@@ -23,6 +23,8 @@
#include <stdint.h>
void i2c_init(unsigned bus);
+void tegra_software_i2c_init(unsigned bus);
+void tegra_software_i2c_disable(unsigned bus);
enum {
/* Word 0 */
diff --git a/src/soc/nvidia/tegra/software_i2c.c b/src/soc/nvidia/tegra/software_i2c.c
new file mode 100644
index 0000000000..b50fb4f654
--- /dev/null
+++ b/src/soc/nvidia/tegra/software_i2c.c
@@ -0,0 +1,96 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2014 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#include <device/i2c.h>
+#include <soc/nvidia/tegra124/gpio.h>
+#include <soc/nvidia/tegra124/pinmux.h>
+
+#include "i2c.h"
+
+static struct {
+ int pinmux_func;
+ gpio_t sda;
+ gpio_t scl;
+} pins[] = {
+ [0]{.pinmux_func = PINMUX_GEN1_I2C_SCL_FUNC_I2C1,
+ .sda = GPIO(C5), .scl = GPIO(C4)},
+ [1]{.pinmux_func = PINMUX_GEN2_I2C_SCL_FUNC_I2C2,
+ .sda = GPIO(T6), .scl = GPIO(T5)},
+ [2]{.pinmux_func = PINMUX_CAM_I2C_SCL_FUNC_I2C3,
+ .sda = GPIO(BB2), .scl = GPIO(BB1)},
+ [3]{.pinmux_func = PINMUX_DDC_SCL_FUNC_I2C4,
+ .sda = GPIO(V5), .scl = GPIO(V4)},
+ [4]{.pinmux_func = PINMUX_PWR_I2C_SCL_FUNC_I2CPMU,
+ .sda = GPIO(Z7), .scl = GPIO(Z6)},
+};
+
+static void tegra_set_sda(unsigned bus, int high)
+{
+ if (high)
+ gpio_input_pullup(pins[bus].sda);
+ else
+ gpio_output(pins[bus].sda, 0);
+}
+
+static void tegra_set_scl(unsigned bus, int high)
+{
+ if (high)
+ gpio_input_pullup(pins[bus].scl);
+ else
+ gpio_output(pins[bus].scl, 0);
+}
+
+static int tegra_get_sda(unsigned bus)
+{
+ return gpio_get_in_value(pins[bus].sda);
+}
+
+static int tegra_get_scl(unsigned bus)
+{
+ return gpio_get_in_value(pins[bus].scl);
+}
+
+static struct software_i2c_ops tegra_ops = {
+ .set_sda = tegra_set_sda,
+ .set_scl = tegra_set_scl,
+ .get_sda = tegra_get_sda,
+ .get_scl = tegra_get_scl,
+};
+
+void tegra_software_i2c_init(unsigned bus)
+{
+ software_i2c[bus] = &tegra_ops;
+
+ /* Initialize bus to idle state. */
+ tegra_set_sda(bus, 1);
+ tegra_set_scl(bus, 1);
+}
+
+void tegra_software_i2c_disable(unsigned bus)
+{
+ software_i2c[bus] = NULL;
+
+ /* Return pins to I2C controller. */
+ pinmux_set_config(pins[bus].sda >> GPIO_PINMUX_SHIFT,
+ pins[bus].pinmux_func | PINMUX_INPUT_ENABLE);
+ pinmux_set_config(pins[bus].scl >> GPIO_PINMUX_SHIFT,
+ pins[bus].pinmux_func | PINMUX_INPUT_ENABLE);
+ gpio_set_mode(pins[bus].sda, GPIO_MODE_SPIO);
+ gpio_set_mode(pins[bus].scl, GPIO_MODE_SPIO);
+}
diff --git a/src/soc/nvidia/tegra124/Makefile.inc b/src/soc/nvidia/tegra124/Makefile.inc
index c7b2e16c4b..792bb9992b 100644
--- a/src/soc/nvidia/tegra124/Makefile.inc
+++ b/src/soc/nvidia/tegra124/Makefile.inc
@@ -11,6 +11,7 @@ bootblock-y += power.c
bootblock-y += spi.c
bootblock-y += ../tegra/gpio.c
bootblock-y += ../tegra/i2c.c
+bootblock-$(CONFIG_SOFTWARE_I2C) += ../tegra/software_i2c.c
bootblock-y += ../tegra/pingroup.c
bootblock-y += ../tegra/pinmux.c
bootblock-y += ../tegra/apbmisc.c
@@ -32,6 +33,7 @@ romstage-y += sdram_lp0.c
romstage-y += spi.c
romstage-y += ../tegra/gpio.c
romstage-y += ../tegra/i2c.c
+romstage-$(CONFIG_SOFTWARE_I2C) += ../tegra/software_i2c.c
romstage-y += ../tegra/pinmux.c
romstage-y += timer.c
romstage-$(CONFIG_CONSOLE_SERIAL) += uart.c
@@ -51,6 +53,7 @@ ramstage-y += spi.c
ramstage-y += dp.c
ramstage-y += ../tegra/gpio.c
ramstage-y += ../tegra/i2c.c
+ramstage-$(CONFIG_SOFTWARE_I2C) += ../tegra/software_i2c.c
ramstage-y += ../tegra/pinmux.c
ramstage-y += ../tegra/usb.c
ramstage-y += timer.c
diff --git a/src/soc/samsung/exynos5250/i2c.c b/src/soc/samsung/exynos5250/i2c.c
index d5d83b393a..1e526d633a 100644
--- a/src/soc/samsung/exynos5250/i2c.c
+++ b/src/soc/samsung/exynos5250/i2c.c
@@ -237,7 +237,7 @@ static int i2c_recv_buf(struct i2c_regs *regs, uint8_t *data, int len)
return 0;
}
-int i2c_transfer(unsigned bus, struct i2c_seg *segments, int seg_count)
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int seg_count)
{
struct s3c24x0_i2c_bus *i2c = &i2c_busses[bus];
struct i2c_regs *regs = i2c->regs;
diff --git a/src/soc/samsung/exynos5420/i2c.c b/src/soc/samsung/exynos5420/i2c.c
index b79f9144a9..49875d79ed 100644
--- a/src/soc/samsung/exynos5420/i2c.c
+++ b/src/soc/samsung/exynos5420/i2c.c
@@ -633,7 +633,7 @@ static int i2c_recv_buf(struct i2c_regs *regs, uint8_t *data, int len)
return 0;
}
-int i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
{
struct i2c_bus *i2c = &i2c_busses[bus];
if (i2c->is_highspeed)