From bf089d2a6286eae4e25b7cb51e92633ae39252d4 Mon Sep 17 00:00:00 2001 From: Karthikeyan Ramasubramanian Date: Wed, 7 Oct 2020 12:42:44 -0600 Subject: 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 Reviewed-on: https://review.coreboot.org/c/coreboot/+/46144 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh --- src/drivers/i2c/gpiomux/Makefile.inc | 1 + src/drivers/i2c/gpiomux/bus/Makefile.inc | 1 + src/drivers/i2c/gpiomux/bus/bus.c | 60 ++++++++++++++++++++++++++++++++ src/drivers/i2c/gpiomux/bus/chip.h | 9 +++++ 4 files changed, 71 insertions(+) create mode 100644 src/drivers/i2c/gpiomux/bus/Makefile.inc create mode 100644 src/drivers/i2c/gpiomux/bus/bus.c create mode 100644 src/drivers/i2c/gpiomux/bus/chip.h (limited to 'src/drivers') 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 +#include +#include +#include +#include +#include +#include +#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__ */ -- cgit v1.2.3