5 files changed, 139 insertions, 0 deletions
diff --git a/src/drivers/i2c/pca9538/Kconfig b/src/drivers/i2c/pca9538/Kconfig
new file mode 100644
index 0000000000..558332be3d
--- /dev/null
+++ b/src/drivers/i2c/pca9538/Kconfig
@@ -0,0 +1,5 @@
+config DRIVERS_I2C_PCA9538
+	bool
+	default n
+	help
+	  Enable support for I2C I/O expander PCA9538.
diff --git a/src/drivers/i2c/pca9538/Makefile.inc b/src/drivers/i2c/pca9538/Makefile.inc
new file mode 100644
index 0000000000..8b7fa2546e
--- /dev/null
+++ b/src/drivers/i2c/pca9538/Makefile.inc
@@ -0,0 +1,5 @@
+ramstage-$(CONFIG_DRIVERS_I2C_PCA9538) += pca9538.c
+
+ifeq ($(CONFIG_DRIVERS_I2C_PCA9538),y)
+CFLAGS_common += -Isrc/drivers/i2c/pca9538
+endif
diff --git a/src/drivers/i2c/pca9538/chip.h b/src/drivers/i2c/pca9538/chip.h
new file mode 100644
index 0000000000..9c60aab226
--- /dev/null
+++ b/src/drivers/i2c/pca9538/chip.h
@@ -0,0 +1,21 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Siemens AG
+ *
+ * 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.
+ */
+
+
+struct drivers_i2c_pca9538_config {
+	unsigned char in_out;	/* Use bit as input(1) or output (0). */
+	unsigned char invert;	/* If a bit is 1, the input will be inverted. */
+	unsigned char out_val;	/* Initial output value to drive. */
+};
diff --git a/src/drivers/i2c/pca9538/pca9538.c b/src/drivers/i2c/pca9538/pca9538.c
new file mode 100644
index 0000000000..30e3b47acf
--- /dev/null
+++ b/src/drivers/i2c/pca9538/pca9538.c
@@ -0,0 +1,70 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Siemens AG
+ *
+ * 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.
+ */
+
+#include <device/i2c_bus.h>
+#include <device/device.h>
+#include <console/console.h>
+#include "pca9538.h"
+#include "chip.h"
+
+/* This function can be used from outside the chip driver to read input. */
+uint8_t pca9538_read_input(void)
+{
+	struct device *dev = pca9538_get_dev();
+
+	if (!dev)
+		return 0;
+	else
+		return (uint8_t)(i2c_dev_readb_at(dev, INPUT_REG));
+}
+
+/* This function can be used from outside the chip driver to set output. */
+void pca9538_set_output(uint8_t val)
+{
+	struct device *dev = pca9538_get_dev();
+
+	if (dev)
+		i2c_dev_writeb_at(dev, OUTPUT_REG, val);
+}
+
+static void pca9538_init(struct device *dev)
+{
+	struct drivers_i2c_pca9538_config *config = dev->chip_info;
+
+	if (!config)
+		return;
+	/* Set up registers as requested in devicetree. */
+	i2c_dev_writeb_at(dev, INPUT_INVERT_REG, config->invert);
+	i2c_dev_writeb_at(dev, OUTPUT_REG, config->out_val);
+	i2c_dev_writeb_at(dev, IO_CONFIG_REG, config->in_out);
+}
+
+static struct device_operations pca9538_ops = {
+	.read_resources		= DEVICE_NOOP,
+	.set_resources		= DEVICE_NOOP,
+	.enable_resources	= DEVICE_NOOP,
+	.init			= pca9538_init,
+	.final			= DEVICE_NOOP
+};
+
+static void pca9538_enable(struct device *dev)
+{
+	dev->ops = &pca9538_ops;
+}
+
+struct chip_operations drivers_i2c_pca9538_ops = {
+	CHIP_NAME("PCA9538")
+	.enable_dev = pca9538_enable
+};
diff --git a/src/drivers/i2c/pca9538/pca9538.h b/src/drivers/i2c/pca9538/pca9538.h
new file mode 100644
index 0000000000..6db95be646
--- /dev/null
+++ b/src/drivers/i2c/pca9538/pca9538.h
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2018 Siemens AG
+ *
+ * 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.
+ */
+
+#ifndef _I2C_PCA9538_H_
+#define _I2C_PCA9538_H_
+
+#include <types.h>
+#include <device/device.h>
+
+/* Register layout */
+#define INPUT_REG		0x00
+#define OUTPUT_REG		0x01
+#define INPUT_INVERT_REG	0x02
+#define IO_CONFIG_REG		0x03
+
+/* Provide some functions to read input and write output values. */
+uint8_t pca9538_read_input(void);
+void pca9538_set_output(uint8_t val);
+/*
+ * Provide a way to get the right device structure for the I/O expander.
+ * The user of this driver has to provide this function if read/write of I/O
+ * values on the I/O expander is needed.
+ */
+struct device *pca9538_get_dev(void);
+
+#endif /* _I2C_PCA9538_H_ */