i2s_machine_dev.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <acpi/acpi_device.h>
#include <acpi/acpigen.h>
#include <device/device.h>
#include <string.h>
#include "chip.h"
#include <console/console.h>
 
#define AMD_I2S_ACPI_DESC       "I2S machine driver"
 
static void i2s_machine_dev_fill_crs_dsd(const char *path,
                                        const struct acpi_gpio *dmic_select_gpio)
{
        struct acpi_dp *dsd;
 
        /* Resources */
        acpigen_write_name("_CRS");
        acpigen_write_resourcetemplate_header();
        acpi_device_write_gpio(dmic_select_gpio);
        acpigen_write_resourcetemplate_footer();
 
        dsd = acpi_dp_new_table("_DSD");
        /*
         * This GPIO is used to select DMIC0 or DMIC1 by the kernel driver. It does not
         * really have a polarity since low and high control the selection of DMIC and
         * hence does not have an active polarity.
         * Kernel driver does not use the polarity field and instead treats the GPIO
         * selection as follows:
         * Set low (0) = Select DMIC0
         * Set high (1) = Select DMIC1
         */
        acpi_dp_add_gpio(dsd, "dmic-gpios", path,
                         0,  /* Index = 0 (There is a single GPIO entry in _CRS). */
                         0,  /* Pin = 0 (There is a single pin in the GPIO resource). */
                         0); /* Active low = 0 (Kernel driver does not use active polarity). */
        acpi_dp_write(dsd);
}
 
static void i2s_machine_dev_fill_ssdt(const struct device *dev)
{
        const char *scope = acpi_device_scope(dev);
        const struct acpi_gpio *dmic_select_gpio;
        const struct drivers_amd_i2s_machine_dev_config *cfg;
        const char *path = acpi_device_path(dev);
 
        cfg = config_of(dev);
 
        dmic_select_gpio = &cfg->dmic_select_gpio;
 
        if (scope == NULL) {
                printk(BIOS_ERR, "%s: ERROR: ACPI I2S scope not found\n", dev_path(dev));
                return;
        }
 
        if (cfg->hid == NULL) {
                printk(BIOS_ERR, "%s: ERROR: HID required\n", dev_path(dev));
                return;
        }
 
        acpigen_write_scope(scope); /* Scope */
        acpigen_write_device(acpi_device_name(dev)); /* Device */
        acpigen_write_name_string("_HID", cfg->hid);
        acpigen_write_name_integer("_UID", cfg->uid);
        acpigen_write_name_string("_DDN", AMD_I2S_ACPI_DESC);
 
        acpigen_write_STA(acpi_device_status(dev));
 
        if (dmic_select_gpio->pin_count)
                i2s_machine_dev_fill_crs_dsd(path, dmic_select_gpio);
 
        acpigen_pop_len(); /* Device */
        acpigen_pop_len(); /* Scope */
 
        printk(BIOS_INFO, "%s: %s at %s\n", path, AMD_I2S_ACPI_DESC, dev_path(dev));
}
 
static const char *i2s_machine_dev_acpi_name(const struct device *dev)
{
        static char name[5];
        snprintf(name, sizeof(name), "I2S%X", dev->path.generic.id);
        return name;
}
 
static struct device_operations i2s_machine_dev_ops = {
        .read_resources         = noop_read_resources,
        .set_resources          = noop_set_resources,
        .acpi_name              = i2s_machine_dev_acpi_name,
        .acpi_fill_ssdt         = i2s_machine_dev_fill_ssdt,
};
 
static void i2s_machine_dev_enable(struct device *dev)
{
        dev->ops = &i2s_machine_dev_ops;
}
 
struct chip_operations drivers_amd_i2s_machine_dev_ops = {
        CHIP_NAME("AMD I2S Machine Device")
        .enable_dev = i2s_machine_dev_enable
};