generic.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <acpi/acpi_device.h>
#include <acpi/acpigen.h>
#include <console/console.h>
#include <device/i2c_simple.h>
#include <device/device.h>
#include <device/path.h>
#include <gpio.h>
#include <string.h>
#include "chip.h"
 
#if CONFIG(HAVE_ACPI_TABLES)
 
static bool i2c_generic_add_gpios_to_crs(struct drivers_i2c_generic_config *cfg)
{
        /*
         * Return false if:
         * 1. Request to explicitly disable export of GPIOs in CRS, or
         * 2. Both reset and enable GPIOs are not provided.
         */
        if (cfg->disable_gpio_export_in_crs ||
            ((cfg->reset_gpio.pin_count == 0) &&
             (cfg->enable_gpio.pin_count == 0)))
                return false;
 
        return true;
}
 
static int i2c_generic_write_gpio(struct acpi_gpio *gpio, int *curr_index)
{
        int ret = -1;
 
        if (gpio->pin_count == 0)
                return ret;
 
        acpi_device_write_gpio(gpio);
        ret = *curr_index;
        (*curr_index)++;
 
        return ret;
}
 
void i2c_generic_fill_ssdt(const struct device *dev,
                        void (*callback)(const struct device *dev),
                        struct drivers_i2c_generic_config *config)
{
        const char *scope = acpi_device_scope(dev);
        struct acpi_i2c i2c = {
                .address = dev->path.i2c.device,
                .mode_10bit = dev->path.i2c.mode_10bit,
                .speed = config->speed ? : I2C_SPEED_FAST,
                .resource = scope,
        };
        struct acpi_dp *dsd = NULL;
        int curr_index = 0;
        int reset_gpio_index = -1, enable_gpio_index = -1, irq_gpio_index = -1;
        const char *path = acpi_device_path(dev);
 
        if (!scope)
                return;
 
        if (!config->hid) {
                printk(BIOS_ERR, "%s: ERROR: HID required\n", dev_path(dev));
                return;
        }
 
        /* Device */
        acpigen_write_scope(scope);
        acpigen_write_device(acpi_device_name(dev));
        acpigen_write_name_string("_HID", config->hid);
        if (config->cid)
                acpigen_write_name_string("_CID", config->cid);
        acpigen_write_name_integer("_UID", config->uid);
        if (config->desc)
                acpigen_write_name_string("_DDN", config->desc);
        acpigen_write_STA(acpi_device_status(dev));
 
        /* Resources */
        acpigen_write_name("_CRS");
        acpigen_write_resourcetemplate_header();
        acpi_device_write_i2c(&i2c);
 
        /* Use either Interrupt() or GpioInt() */
        if (config->irq_gpio.pin_count)
                irq_gpio_index = i2c_generic_write_gpio(&config->irq_gpio,
                                                        &curr_index);
        else
                acpi_device_write_interrupt(&config->irq);
 
        if (i2c_generic_add_gpios_to_crs(config) == true) {
                reset_gpio_index = i2c_generic_write_gpio(&config->reset_gpio,
                                                        &curr_index);
                enable_gpio_index = i2c_generic_write_gpio(&config->enable_gpio,
                                                        &curr_index);
        }
        acpigen_write_resourcetemplate_footer();
 
        /* Wake capabilities */
        if (config->wake) {
                acpigen_write_name_integer("_S0W", ACPI_DEVICE_SLEEP_D3_HOT);
                acpigen_write_PRW(config->wake, 3);
        }
 
        /* DSD */
        if (config->probed || config->property_count || config->compat_string ||
            (reset_gpio_index != -1) ||
            (enable_gpio_index != -1) || (irq_gpio_index != -1)) {
                dsd = acpi_dp_new_table("_DSD");
                if (config->compat_string)
                        acpi_dp_add_string(dsd, "compatible",
                                           config->compat_string);
                if (config->probed)
                        acpi_dp_add_integer(dsd, "linux,probed", 1);
                if (irq_gpio_index != -1)
                        acpi_dp_add_gpio(dsd, "irq-gpios", path,
                                         irq_gpio_index, 0,
                                         config->irq_gpio.active_low);
                if (reset_gpio_index != -1)
                        acpi_dp_add_gpio(dsd, "reset-gpios", path,
                                        reset_gpio_index, 0,
                                        config->reset_gpio.active_low);
                if (enable_gpio_index != -1)
                        acpi_dp_add_gpio(dsd, "enable-gpios", path,
                                        enable_gpio_index, 0,
                                        config->enable_gpio.active_low);
                /* Add generic property list */
                acpi_dp_add_property_list(dsd, config->property_list,
                                          config->property_count);
                acpi_dp_write(dsd);
        }
 
        /* Power Resource */
        if (config->has_power_resource) {
                const struct acpi_power_res_params power_res_params = {
                        &config->reset_gpio,
                        config->reset_delay_ms,
                        config->reset_off_delay_ms,
                        &config->enable_gpio,
                        config->enable_delay_ms,
                        config->enable_off_delay_ms,
                        &config->stop_gpio,
                        config->stop_delay_ms,
                        config->stop_off_delay_ms
                };
                acpi_device_add_power_res(&power_res_params);
        }
 
        /* Callback if any. */
        if (callback)
                callback(dev);
 
        acpigen_pop_len(); /* Device */
        acpigen_pop_len(); /* Scope */
 
        printk(BIOS_INFO, "%s: %s at %s\n", path,
               config->desc ? : dev->chip_ops->name, dev_path(dev));
}
 
static void i2c_generic_fill_ssdt_generator(const struct device *dev)
{
        i2c_generic_fill_ssdt(dev, NULL, dev->chip_info);
}
 
/* Use name specified in config or build one from I2C address */
static const char *i2c_generic_acpi_name(const struct device *dev)
{
        struct drivers_i2c_generic_config *config = dev->chip_info;
        static char name[5];
 
        if (config->name)
                return config->name;
 
        snprintf(name, sizeof(name), "D%03.3X", dev->path.i2c.device);
        name[4] = '\0';
        return name;
}
#endif
 
static struct device_operations i2c_generic_ops = {
        .read_resources         = noop_read_resources,
        .set_resources          = noop_set_resources,
#if CONFIG(HAVE_ACPI_TABLES)
        .acpi_name              = i2c_generic_acpi_name,
        .acpi_fill_ssdt         = i2c_generic_fill_ssdt_generator,
#endif
};
 
static void i2c_generic_enable(struct device *dev)
{
        struct drivers_i2c_generic_config *config = dev->chip_info;
 
        if (!config)
                return;
 
        /* Check if device is present by reading GPIO */
        if (config->device_present_gpio) {
                int present = gpio_get(config->device_present_gpio);
                present ^= config->device_present_gpio_invert;
 
                printk(BIOS_INFO, "%s is %spresent\n",
                       dev->chip_ops->name, present ? "" : "not ");
 
                if (!present) {
                        dev->enabled = 0;
                        return;
                }
        }
 
        dev->ops = &i2c_generic_ops;
 
        /* Name the device as per description provided in devicetree */
        if (config->desc)
                dev->name = config->desc;
}
 
struct chip_operations drivers_i2c_generic_ops = {
        CHIP_NAME("I2C Device")
        .enable_dev = i2c_generic_enable
};