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authorKarthikeyan Ramasubramanian <kramasub@google.com>2020-10-07 12:42:44 -0600
committerPatrick Georgi <pgeorgi@google.com>2020-10-19 06:57:52 +0000
commitbf089d2a6286eae4e25b7cb51e92633ae39252d4 (patch)
treeed5f1cf60b5fcdace8731cd819023e9ac9c17e82 /src/drivers
parentcbc29a2160d93f077098a022de3f8b8971ed85a2 (diff)
downloadcoreboot-bf089d2a6286eae4e25b7cb51e92633ae39252d4.tar.xz
drivers/i2c/gpiomux: Add chip driver for multiplexed I2C bus
This chip driver adds ACPI identifiers for multiplexed I2C bus that are selected using GPIO. The multiplexed bus device defines the address to select the I2C lines. These ACPI identifiers are consumed by the i2c-mux-gpio kernel driver: https://www.kernel.org/doc/html/latest/i2c/muxes/i2c-mux-gpio.html BUG=b:169444894 TEST=Build and boot to OS in waddledee. Ensure that the ACPI identifiers are added in appropriate context. Scope (\_SB.PCI0.I2C3.MUX0) { Device (MXA0) { Method (_STA, 0, NotSerialized) // _STA: Status { Return (0x0F) } Name (_ADR, Zero) // _ADR: Address } } Scope (\_SB.PCI0.I2C3.MUX0) { Device (MXA1) { Method (_STA, 0, NotSerialized) // _STA: Status { Return (0x0F) } Name (_ADR, One) // _ADR: Address } } Change-Id: If8b983bc8ce212ce05fe6b7f01a6d9092468e582 Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/46144 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Furquan Shaikh <furquan@google.com>
Diffstat (limited to 'src/drivers')
-rw-r--r--src/drivers/i2c/gpiomux/Makefile.inc1
-rw-r--r--src/drivers/i2c/gpiomux/bus/Makefile.inc1
-rw-r--r--src/drivers/i2c/gpiomux/bus/bus.c60
-rw-r--r--src/drivers/i2c/gpiomux/bus/chip.h9
4 files changed, 71 insertions, 0 deletions
diff --git a/src/drivers/i2c/gpiomux/Makefile.inc b/src/drivers/i2c/gpiomux/Makefile.inc
index fec8d5b00f..5c328cba40 100644
--- a/src/drivers/i2c/gpiomux/Makefile.inc
+++ b/src/drivers/i2c/gpiomux/Makefile.inc
@@ -1 +1,2 @@
subdirs-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += mux
+subdirs-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += bus
diff --git a/src/drivers/i2c/gpiomux/bus/Makefile.inc b/src/drivers/i2c/gpiomux/bus/Makefile.inc
new file mode 100644
index 0000000000..1c462dc094
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/bus/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += bus.c
diff --git a/src/drivers/i2c/gpiomux/bus/bus.c b/src/drivers/i2c/gpiomux/bus/bus.c
new file mode 100644
index 0000000000..66aef8e8c0
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/bus/bus.c
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <device/path.h>
+#include <stdlib.h>
+#include <string.h>
+#include "chip.h"
+
+static const char *i2c_gpiomux_bus_acpi_name(const struct device *dev)
+{
+ static char name[ACPI_NAME_BUFFER_SIZE];
+
+ snprintf(name, ACPI_NAME_BUFFER_SIZE, "MXA%01.1X", dev->path.generic.id);
+ return name;
+}
+
+static void i2c_gpiomux_bus_fill_ssdt(const struct device *dev)
+{
+ const char *scope = acpi_device_scope(dev);
+ const char *path = acpi_device_path(dev);
+
+ if (!dev || !dev->enabled || !scope || !path)
+ return;
+
+ /* Device */
+ acpigen_write_scope(scope);
+ acpigen_write_device(acpi_device_name(dev));
+
+ acpigen_write_STA(acpi_device_status(dev));
+ acpigen_write_ADR(dev->path.generic.id);
+
+ acpigen_pop_len(); /* Device */
+ acpigen_pop_len(); /* Scope */
+
+ printk(BIOS_INFO, "%s: %s at %s\n", path, dev->chip_ops->name, dev_path(dev));
+}
+
+static struct device_operations i2c_gpiomux_bus_ops = {
+ .read_resources = noop_read_resources,
+ .set_resources = noop_set_resources,
+ .scan_bus = scan_static_bus,
+ .acpi_name = i2c_gpiomux_bus_acpi_name,
+ .acpi_fill_ssdt = i2c_gpiomux_bus_fill_ssdt,
+};
+
+static void i2c_gpiomux_bus_enable(struct device *dev)
+{
+ if (!dev)
+ return;
+
+ dev->ops = &i2c_gpiomux_bus_ops;
+}
+
+struct chip_operations drivers_i2c_gpiomux_bus_ops = {
+ CHIP_NAME("I2C GPIO MUX Bus Device")
+ .enable_dev = i2c_gpiomux_bus_enable
+};
diff --git a/src/drivers/i2c/gpiomux/bus/chip.h b/src/drivers/i2c/gpiomux/bus/chip.h
new file mode 100644
index 0000000000..2baf334a6c
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/bus/chip.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __I2C_GPIOMUX_BUS_CHIP_H__
+#define __I2C_GPIOMUX_BUS_CHIP_H__
+
+struct drivers_i2c_gpiomux_bus_config {
+};
+
+#endif /* __I2C_GPIOMUX_BUS_CHIP_H__ */