JustOS/linux-6.13/sound/soc/sdca/sdca_functions.c

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2024 Intel Corporation

/*
 * The MIPI SDCA specification is available for public downloads at
 * https://www.mipi.org/mipi-sdca-v1-0-download
 */

#include <linux/acpi.h>
#include <linux/soundwire/sdw.h>
#include <sound/sdca.h>
#include <sound/sdca_function.h>

static int patch_sdca_function_type(struct device *dev,
				    u32 interface_revision,
				    u32 *function_type,
				    const char **function_name)
{
	unsigned long function_type_patch = 0;

	/*
	 * Unfortunately early SDCA specifications used different indices for Functions,
	 * for backwards compatibility we have to reorder the values found
	 */
	if (interface_revision >= 0x0801)
		goto skip_early_draft_order;

	switch (*function_type) {
	case 1:
		function_type_patch = SDCA_FUNCTION_TYPE_SMART_AMP;
		break;
	case 2:
		function_type_patch = SDCA_FUNCTION_TYPE_SMART_MIC;
		break;
	case 3:
		function_type_patch = SDCA_FUNCTION_TYPE_SPEAKER_MIC;
		break;
	case 4:
		function_type_patch = SDCA_FUNCTION_TYPE_UAJ;
		break;
	case 5:
		function_type_patch = SDCA_FUNCTION_TYPE_RJ;
		break;
	case 6:
		function_type_patch = SDCA_FUNCTION_TYPE_HID;
		break;
	default:
		dev_warn(dev, "%s: SDCA version %#x unsupported function type %d, skipped\n",
			 __func__, interface_revision, *function_type);
		return -EINVAL;
	}

skip_early_draft_order:
	if (function_type_patch)
		*function_type = function_type_patch;

	/* now double-check the values */
	switch (*function_type) {
	case SDCA_FUNCTION_TYPE_SMART_AMP:
		*function_name = SDCA_FUNCTION_TYPE_SMART_AMP_NAME;
		break;
	case SDCA_FUNCTION_TYPE_SMART_MIC:
		*function_name = SDCA_FUNCTION_TYPE_SMART_MIC_NAME;
		break;
	case SDCA_FUNCTION_TYPE_UAJ:
		*function_name = SDCA_FUNCTION_TYPE_UAJ_NAME;
		break;
	case SDCA_FUNCTION_TYPE_HID:
		*function_name = SDCA_FUNCTION_TYPE_HID_NAME;
		break;
	case SDCA_FUNCTION_TYPE_SIMPLE_AMP:
	case SDCA_FUNCTION_TYPE_SIMPLE_MIC:
	case SDCA_FUNCTION_TYPE_SPEAKER_MIC:
	case SDCA_FUNCTION_TYPE_RJ:
	case SDCA_FUNCTION_TYPE_IMP_DEF:
		dev_warn(dev, "%s: found unsupported SDCA function type %d, skipped\n",
			 __func__, *function_type);
		return -EINVAL;
	default:
		dev_err(dev, "%s: found invalid SDCA function type %d, skipped\n",
			__func__, *function_type);
		return -EINVAL;
	}

	dev_info(dev, "%s: found SDCA function %s (type %d)\n",
		 __func__, *function_name, *function_type);

	return 0;
}

static int find_sdca_function(struct acpi_device *adev, void *data)
{
	struct fwnode_handle *function_node = acpi_fwnode_handle(adev);
	struct sdca_device_data *sdca_data = data;
	struct device *dev = &adev->dev;
	struct fwnode_handle *control5; /* used to identify function type */
	const char *function_name;
	u32 function_type;
	int func_index;
	u64 addr;
	int ret;

	if (sdca_data->num_functions >= SDCA_MAX_FUNCTION_COUNT) {
		dev_err(dev, "%s: maximum number of functions exceeded\n", __func__);
		return -EINVAL;
	}

	/*
	 * The number of functions cannot exceed 8, we could use
	 * acpi_get_local_address() but the value is stored as u64 so
	 * we might as well avoid casts and intermediate levels
	 */
	ret = acpi_get_local_u64_address(adev->handle, &addr);
	if (ret < 0)
		return ret;

	if (!addr) {
		dev_err(dev, "%s: no addr\n", __func__);
		return -ENODEV;
	}

	/*
	 * Extracting the topology type for an SDCA function is a
	 * convoluted process.
	 * The Function type is only visible as a result of a read
	 * from a control. In theory this would mean reading from the hardware,
	 * but the SDCA/DisCo specs defined the notion of "DC value" - a constant
	 * represented with a DSD subproperty.
	 * Drivers have to query the properties for the control
	 * SDCA_CONTROL_ENTITY_0_FUNCTION_TOPOLOGY (0x05)
	 */
	control5 = fwnode_get_named_child_node(function_node,
					       "mipi-sdca-control-0x5-subproperties");
	if (!control5)
		return -ENODEV;

	ret = fwnode_property_read_u32(control5, "mipi-sdca-control-dc-value",
				       &function_type);

	fwnode_handle_put(control5);

	if (ret < 0) {
		dev_err(dev, "%s: the function type can only be determined from ACPI information\n",
			__func__);
		return ret;
	}

	ret = patch_sdca_function_type(dev, sdca_data->interface_revision,
				       &function_type, &function_name);
	if (ret < 0)
		return ret;

	/* store results */
	func_index = sdca_data->num_functions;
	sdca_data->sdca_func[func_index].adr = addr;
	sdca_data->sdca_func[func_index].type = function_type;
	sdca_data->sdca_func[func_index].name = function_name;
	sdca_data->num_functions++;

	return 0;
}

void sdca_lookup_functions(struct sdw_slave *slave)
{
	struct device *dev = &slave->dev;
	struct acpi_device *adev = to_acpi_device_node(dev->fwnode);

	if (!adev) {
		dev_info(dev, "No matching ACPI device found, ignoring peripheral\n");
		return;
	}
	acpi_dev_for_each_child(adev, find_sdca_function, &slave->sdca_data);
}
EXPORT_SYMBOL_NS(sdca_lookup_functions, "SND_SOC_SDCA");

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("SDCA library");