From cbc29a2160d93f077098a022de3f8b8971ed85a2 Mon Sep 17 00:00:00 2001
From: Karthikeyan Ramasubramanian <kramasub@google.com>
Date: Wed, 30 Sep 2020 17:04:15 -0600
Subject: drivers/i2c: Add chip driver for GPIO based I2C multiplexer
Add identifiers in ACPI tables for GPIO based I2C multiplexer. The
multiplexer device defines the GPIO resource used to select the
adapter/bus lines. The multiplexer adapter device defines the address
to select the adapter/client 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 waddledee to OS. Ensure that the ACPI identifiers
are added for I2C devices multiplexed using I2C MUX under the
appropriate scope. Here is the output SSDT:
Scope (\_SB.PCI0.I2C3)
{
Device (MUX0)
{
Name (_HID, "PRP0001") // _HID: Hardware ID
Method (_STA, 0, NotSerialized) // _STA: Status
{
Return (0x0F)
}
Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
{
GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
"\\_SB.PCI0.GPIO", 0x00, ResourceConsumer, ,
)
{ // Pin list
0x0125
}
})
Name (_DSD, Package (0x02) // _DSD: Device-Specific Data
{
ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device Properties for _DSD */,
Package (0x02)
{
Package (0x02)
{
"compatible",
"i2c-mux-gpio"
},
Package (0x02)
{
"mux-gpios",
Package (0x04)
{
\_SB.PCI0.I2C3.MUX0,
Zero,
Zero,
Zero
}
}
}
})
}
}
Change-Id: Ib371108cc6043c133681066bf7bf4b2e00771e8b
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45911
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
---
src/drivers/i2c/gpiomux/Kconfig | 6 +++
src/drivers/i2c/gpiomux/Makefile.inc | 1 +
src/drivers/i2c/gpiomux/mux/Makefile.inc | 1 +
src/drivers/i2c/gpiomux/mux/chip.h | 17 +++++++
src/drivers/i2c/gpiomux/mux/mux.c | 82 ++++++++++++++++++++++++++++++++
5 files changed, 107 insertions(+)
create mode 100644 src/drivers/i2c/gpiomux/Kconfig
create mode 100644 src/drivers/i2c/gpiomux/Makefile.inc
create mode 100644 src/drivers/i2c/gpiomux/mux/Makefile.inc
create mode 100644 src/drivers/i2c/gpiomux/mux/chip.h
create mode 100644 src/drivers/i2c/gpiomux/mux/mux.c
diff --git a/src/drivers/i2c/gpiomux/Kconfig b/src/drivers/i2c/gpiomux/Kconfig
new file mode 100644
index 0000000000..f09a641eb7
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/Kconfig
@@ -0,0 +1,6 @@
+config DRIVERS_I2C_GPIO_MUX
+ bool
+ default n
+ depends on HAVE_ACPI_TABLES
+ help
+ When enabled, add identifiers in ACPI tables for GPIO based I2C multiplexer.
diff --git a/src/drivers/i2c/gpiomux/Makefile.inc b/src/drivers/i2c/gpiomux/Makefile.inc
new file mode 100644
index 0000000000..fec8d5b00f
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/Makefile.inc
@@ -0,0 +1 @@
+subdirs-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += mux
diff --git a/src/drivers/i2c/gpiomux/mux/Makefile.inc b/src/drivers/i2c/gpiomux/mux/Makefile.inc
new file mode 100644
index 0000000000..e51f706eda
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/mux/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_I2C_GPIO_MUX) += mux.c
diff --git a/src/drivers/i2c/gpiomux/mux/chip.h b/src/drivers/i2c/gpiomux/mux/chip.h
new file mode 100644
index 0000000000..9906b258db
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/mux/chip.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __I2C_GPIOMUX_MUX_CHIP_H__
+#define __I2C_GPIOMUX_MUX_CHIP_H__
+
+#include <acpi/acpi_device.h>
+#include <types.h>
+
+#define MAX_NUM_MUX_GPIOS 4
+
+struct drivers_i2c_gpiomux_mux_config {
+ /* GPIOs used to select the mux lines */
+ uint32_t mux_gpio_count;
+ struct acpi_gpio mux_gpio[MAX_NUM_MUX_GPIOS];
+};
+
+#endif /* __I2C_GPIOMUX_MUX_CHIP_H__ */
diff --git a/src/drivers/i2c/gpiomux/mux/mux.c b/src/drivers/i2c/gpiomux/mux/mux.c
new file mode 100644
index 0000000000..66c8cc5cc3
--- /dev/null
+++ b/src/drivers/i2c/gpiomux/mux/mux.c
@@ -0,0 +1,82 @@
+/* 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_mux_acpi_name(const struct device *dev)
+{
+ static char name[ACPI_NAME_BUFFER_SIZE];
+
+ snprintf(name, ACPI_NAME_BUFFER_SIZE, "MUX%01.1X", dev->path.generic.id);
+ return name;
+}
+
+static void i2c_gpiomux_mux_fill_ssdt(const struct device *dev)
+{
+ const char *scope = acpi_device_scope(dev);
+ const char *path = acpi_device_path(dev);
+ struct drivers_i2c_gpiomux_mux_config *config = config_of(dev);
+ struct acpi_dp *dsd = NULL;
+ const char *compat_string = "i2c-mux-gpio";
+ struct acpi_gpio_res_params param[MAX_NUM_MUX_GPIOS];
+ int i;
+
+ if (!dev->enabled || !scope || !path)
+ return;
+
+ /* Device */
+ acpigen_write_scope(scope);
+ acpigen_write_device(acpi_device_name(dev));
+ acpigen_write_name_string("_HID", ACPI_DT_NAMESPACE_HID);
+ acpigen_write_STA(acpi_device_status(dev));
+
+ /* Resources */
+ acpigen_write_name("_CRS");
+ acpigen_write_resourcetemplate_header();
+ for (i = 0; i < config->mux_gpio_count; i++) {
+ acpi_device_write_gpio(&config->mux_gpio[i]);
+ param[i].ref = path;
+ param[i].index = i;
+ param[i].pin = 0;
+ param[i].active_low = config->mux_gpio[i].active_low;
+ }
+ acpigen_write_resourcetemplate_footer();
+
+ /* DSD */
+ dsd = acpi_dp_new_table("_DSD");
+ acpi_dp_add_string(dsd, "compatible", compat_string);
+ acpi_dp_add_gpio_array(dsd, "mux-gpios", param, config->mux_gpio_count);
+ acpi_dp_write(dsd);
+
+ 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_mux_ops = {
+ .read_resources = noop_read_resources,
+ .set_resources = noop_set_resources,
+ .scan_bus = scan_static_bus,
+ .acpi_name = i2c_gpiomux_mux_acpi_name,
+ .acpi_fill_ssdt = i2c_gpiomux_mux_fill_ssdt,
+};
+
+static void i2c_gpiomux_mux_enable(struct device *dev)
+{
+ if (!dev)
+ return;
+
+ dev->ops = &i2c_gpiomux_mux_ops;
+}
+
+struct chip_operations drivers_i2c_gpiomux_mux_ops = {
+ CHIP_NAME("I2C GPIO MUX Device")
+ .enable_dev = i2c_gpiomux_mux_enable
+};
--
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