From cbc29a2160d93f077098a022de3f8b8971ed85a2 Mon Sep 17 00:00:00 2001 From: Karthikeyan Ramasubramanian 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 Reviewed-on: https://review.coreboot.org/c/coreboot/+/45911 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh --- 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 (limited to 'src') 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 +#include + +#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 +#include +#include +#include +#include +#include +#include +#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 +}; -- cgit v1.2.3