// SPDX-License-Identifier: GPL-2.0+
/*
 * Serial multi-instantiate driver, pseudo driver to instantiate multiple
 * client devices from a single fwnode.
 *
 * Copyright 2018 Hans de Goede <hdegoede@redhat.com>
 */

#include <linux/acpi.h>
#include <linux/bits.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/spi/spi.h>
#include <linux/types.h>

#define IRQ_RESOURCE_TYPE       GENMASK(1, 0)
#define IRQ_RESOURCE_NONE       0
#define IRQ_RESOURCE_GPIO       1
#define IRQ_RESOURCE_APIC       2
#define IRQ_RESOURCE_AUTO   3
#define IRQ_RESOURCE_OPT        BIT(2)

enum smi_bus_type {
        SMI_I2C,
        SMI_SPI,
        SMI_AUTO_DETECT,
};

struct smi_instance {
        const char *type;
        unsigned int flags;
        int irq_idx;
};

struct smi_node {
        enum smi_bus_type bus_type;
        struct smi_instance instances[];
};

struct smi {
        int i2c_num;
        int spi_num;
        struct i2c_client **i2c_devs;
        struct spi_device **spi_devs;
};

static int smi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
                       const struct smi_instance *inst)
{
        int ret;

        switch (inst->flags & IRQ_RESOURCE_TYPE) {
        case IRQ_RESOURCE_AUTO:
                ret = acpi_dev_gpio_irq_get(adev, inst->irq_idx);
                if (ret > 0) {
                        dev_dbg(&pdev->dev, "Using gpio irq\n");
                        break;
                }
                ret = platform_get_irq(pdev, inst->irq_idx);
                if (ret > 0) {
                        dev_dbg(&pdev->dev, "Using platform irq\n");
                        break;
                }
                if (inst->flags & IRQ_RESOURCE_OPT) {
                        dev_dbg(&pdev->dev, "No irq\n");
                        return 0;
                }
                break;
        case IRQ_RESOURCE_GPIO:
                ret = acpi_dev_gpio_irq_get(adev, inst->irq_idx);
                break;
        case IRQ_RESOURCE_APIC:
                ret = platform_get_irq(pdev, inst->irq_idx);
                break;
        default:
                return 0;
        }
        if (ret < 0)
                return dev_err_probe(&pdev->dev, ret, "Error requesting irq at index %d\n",
                                     inst->irq_idx);

        return ret;
}

static void smi_devs_unregister(struct smi *smi)
{
#if IS_REACHABLE(CONFIG_I2C)
        while (smi->i2c_num--)
                i2c_unregister_device(smi->i2c_devs[smi->i2c_num]);
#endif

        if (IS_REACHABLE(CONFIG_SPI)) {
                while (smi->spi_num--)
                        spi_unregister_device(smi->spi_devs[smi->spi_num]);
        }
}

/**
 * smi_spi_probe - Instantiate multiple SPI devices from inst array
 * @pdev:       Platform device
 * @smi:        Internal struct for Serial multi instantiate driver
 * @inst_array: Array of instances to probe
 *
 * Returns the number of SPI devices instantiate, Zero if none is found or a negative error code.
 */
static int smi_spi_probe(struct platform_device *pdev, struct smi *smi,
                         const struct smi_instance *inst_array)
{
        struct device *dev = &pdev->dev;
        struct acpi_device *adev = ACPI_COMPANION(dev);
        struct spi_controller *ctlr;
        struct spi_device *spi_dev;
        char name[50];
        int i, ret, count;

        ret = acpi_spi_count_resources(adev);
        if (ret < 0)
                return ret;
        if (!ret)
                return -ENOENT;

        count = ret;

        smi->spi_devs = devm_kcalloc(dev, count, sizeof(*smi->spi_devs), GFP_KERNEL);
        if (!smi->spi_devs)
                return -ENOMEM;

        for (i = 0; i < count && inst_array[i].type; i++) {

                spi_dev = acpi_spi_device_alloc(NULL, adev, i);
                if (IS_ERR(spi_dev)) {
                        ret = dev_err_probe(dev, PTR_ERR(spi_dev), "failed to allocate SPI device %s from ACPI\n",
                                            dev_name(&adev->dev));
                        goto error;
                }

                ctlr = spi_dev->controller;

                strscpy(spi_dev->modalias, inst_array[i].type);

                ret = smi_get_irq(pdev, adev, &inst_array[i]);
                if (ret < 0) {
                        spi_dev_put(spi_dev);
                        goto error;
                }
                spi_dev->irq = ret;

                snprintf(name, sizeof(name), "%s-%s-%s.%d", dev_name(&ctlr->dev), dev_name(dev),
                         inst_array[i].type, i);
                spi_dev->dev.init_name = name;

                ret = spi_add_device(spi_dev);
                if (ret) {
                        dev_err_probe(&ctlr->dev, ret, "failed to add SPI device %s from ACPI\n",
                                      dev_name(&adev->dev));
                        spi_dev_put(spi_dev);
                        goto error;
                }

                dev_dbg(dev, "SPI device %s using chip select %u", name,
                        spi_get_chipselect(spi_dev, 0));

                smi->spi_devs[i] = spi_dev;
                smi->spi_num++;
        }

        if (smi->spi_num < count) {
                dev_dbg(dev, "Error finding driver, idx %d\n", i);
                ret = -ENODEV;
                goto error;
        }

        dev_info(dev, "Instantiated %d SPI devices.\n", smi->spi_num);

        return 0;
error:
        smi_devs_unregister(smi);

        return ret;
}

/**
 * smi_i2c_probe - Instantiate multiple I2C devices from inst array
 * @pdev:       Platform device
 * @smi:        Internal struct for Serial multi instantiate driver
 * @inst_array: Array of instances to probe
 *
 * Returns the number of I2C devices instantiate, Zero if none is found or a negative error code.
 */
static int smi_i2c_probe(struct platform_device *pdev, struct smi *smi,
                         const struct smi_instance *inst_array)
{
        struct i2c_board_info board_info = {};
        struct device *dev = &pdev->dev;
        struct acpi_device *adev = ACPI_COMPANION(dev);
        char name[32];
        int i, ret, count;

        ret = i2c_acpi_client_count(adev);
        if (ret < 0)
                return ret;
        if (!ret)
                return -ENOENT;

        count = ret;

        smi->i2c_devs = devm_kcalloc(dev, count, sizeof(*smi->i2c_devs), GFP_KERNEL);
        if (!smi->i2c_devs)
                return -ENOMEM;

        for (i = 0; i < count && inst_array[i].type; i++) {
                memset(&board_info, 0, sizeof(board_info));
                strscpy(board_info.type, inst_array[i].type);
                snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst_array[i].type, i);
                board_info.dev_name = name;

                ret = smi_get_irq(pdev, adev, &inst_array[i]);
                if (ret < 0)
                        goto error;
                board_info.irq = ret;

                smi->i2c_devs[i] = i2c_acpi_new_device(dev, i, &board_info);
                if (IS_ERR(smi->i2c_devs[i])) {
                        ret = dev_err_probe(dev, PTR_ERR(smi->i2c_devs[i]),
                                            "Error creating i2c-client, idx %d\n", i);
                        goto error;
                }
                smi->i2c_num++;
        }
        if (smi->i2c_num < count) {
                dev_dbg(dev, "Error finding driver, idx %d\n", i);
                ret = -ENODEV;
                goto error;
        }

        dev_info(dev, "Instantiated %d I2C devices.\n", smi->i2c_num);

        return 0;
error:
        smi_devs_unregister(smi);

        return ret;
}

static int smi_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct smi_node *node;
        struct smi *smi;
        int ret;

        node = device_get_match_data(dev);
        if (!node) {
                dev_dbg(dev, "Error ACPI match data is missing\n");
                return -ENODEV;
        }

        smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
        if (!smi)
                return -ENOMEM;

        platform_set_drvdata(pdev, smi);

        switch (node->bus_type) {
        case SMI_I2C:
                if (IS_REACHABLE(CONFIG_I2C))
                        return smi_i2c_probe(pdev, smi, node->instances);

                return -ENODEV;
        case SMI_SPI:
                if (IS_REACHABLE(CONFIG_SPI))
                        return smi_spi_probe(pdev, smi, node->instances);

                return -ENODEV;
        case SMI_AUTO_DETECT:
                /*
                 * For backwards-compatibility with the existing nodes I2C
                 * is checked first and if such entries are found ONLY I2C
                 * devices are created. Since some existing nodes that were
                 * already handled by this driver could also contain unrelated
                 * SpiSerialBus nodes that were previously ignored, and this
                 * preserves that behavior.
                 */
                if (IS_REACHABLE(CONFIG_I2C)) {
                        ret = smi_i2c_probe(pdev, smi, node->instances);
                        if (ret != -ENOENT)
                                return ret;
                }

                if (IS_REACHABLE(CONFIG_SPI))
                        return smi_spi_probe(pdev, smi, node->instances);

                return -ENODEV;
        default:
                return -EINVAL;
        }
}

static void smi_remove(struct platform_device *pdev)
{
        struct smi *smi = platform_get_drvdata(pdev);

        smi_devs_unregister(smi);
}

static const struct smi_node bsg1160_data = {
        .instances = {
                { "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
                { "bmc150_magn" },
                { "bmg160" },
                {}
        },
        .bus_type = SMI_I2C,
};

static const struct smi_node bsg2150_data = {
        .instances = {
                { "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
                { "bmc150_magn" },
                /* The resources describe a 3th client, but it is not really there. */
                { "bsg2150_dummy_dev" },
                {}
        },
        .bus_type = SMI_I2C,
};

static const struct smi_node int3515_data = {
        .instances = {
                { "tps6598x", IRQ_RESOURCE_APIC, 0 },
                { "tps6598x", IRQ_RESOURCE_APIC, 1 },
                { "tps6598x", IRQ_RESOURCE_APIC, 2 },
                { "tps6598x", IRQ_RESOURCE_APIC, 3 },
                {}
        },
        .bus_type = SMI_I2C,
};

static const struct smi_node cs35l41_hda = {
        .instances = {
                { "cs35l41-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l41-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l41-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l41-hda", IRQ_RESOURCE_AUTO, 0 },
                {}
        },
        .bus_type = SMI_AUTO_DETECT,
};

static const struct smi_node cs35l54_hda = {
        .instances = {
                { "cs35l54-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l54-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l54-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l54-hda", IRQ_RESOURCE_AUTO, 0 },
                /* a 5th entry is an alias address, not a real device */
                { "cs35l54-hda_dummy_dev" },
                {}
        },
        .bus_type = SMI_AUTO_DETECT,
};

static const struct smi_node cs35l56_hda = {
        .instances = {
                { "cs35l56-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l56-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l56-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l56-hda", IRQ_RESOURCE_AUTO, 0 },
                /* a 5th entry is an alias address, not a real device */
                { "cs35l56-hda_dummy_dev" },
                {}
        },
        .bus_type = SMI_AUTO_DETECT,
};

static const struct smi_node cs35l57_hda = {
        .instances = {
                { "cs35l57-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l57-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l57-hda", IRQ_RESOURCE_AUTO, 0 },
                { "cs35l57-hda", IRQ_RESOURCE_AUTO, 0 },
                /* a 5th entry is an alias address, not a real device */
                { "cs35l57-hda_dummy_dev" },
                {}
        },
        .bus_type = SMI_AUTO_DETECT,
};

static const struct smi_node tas2781_hda = {
        .instances = {
                { "tas2781-hda", IRQ_RESOURCE_AUTO | IRQ_RESOURCE_OPT, 0 },
                { "tas2781-hda", IRQ_RESOURCE_AUTO | IRQ_RESOURCE_OPT, 0 },
                { "tas2781-hda", IRQ_RESOURCE_AUTO | IRQ_RESOURCE_OPT, 0 },
                { "tas2781-hda", IRQ_RESOURCE_AUTO | IRQ_RESOURCE_OPT, 0 },
                {}
        },
        .bus_type = SMI_AUTO_DETECT,
};

/*
 * Note new device-ids must also be added to ignore_serial_bus_ids in
 * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
 */
static const struct acpi_device_id smi_acpi_ids[] = {
        { "BSG1160", (unsigned long)&bsg1160_data },
        { "BSG2150", (unsigned long)&bsg2150_data },
        { "CSC3551", (unsigned long)&cs35l41_hda },
        { "CSC3554", (unsigned long)&cs35l54_hda },
        { "CSC3556", (unsigned long)&cs35l56_hda },
        { "CSC3557", (unsigned long)&cs35l57_hda },
        { "INT3515", (unsigned long)&int3515_data },
        { "TXNW2781", (unsigned long)&tas2781_hda },
        /* Non-conforming _HID for Cirrus Logic already released */
        { "CLSA0100", (unsigned long)&cs35l41_hda },
        { "CLSA0101", (unsigned long)&cs35l41_hda },
        { }
};
MODULE_DEVICE_TABLE(acpi, smi_acpi_ids);

static struct platform_driver smi_driver = {
        .driver = {
                .name = "Serial bus multi instantiate pseudo device driver",
                .acpi_match_table = smi_acpi_ids,
        },
        .probe = smi_probe,
        .remove = smi_remove,
};
module_platform_driver(smi_driver);

MODULE_DESCRIPTION("Serial multi instantiate pseudo device driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");