// SPDX-License-Identifier: GPL-2.0-only
/*
 * dptf_pch_fivr:  DPTF PCH FIVR Participant driver
 * Copyright (c) 2020, Intel Corporation.
 */

#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

struct pch_fivr_resp {
        u64 status;
        u64 result;
};

static int pch_fivr_read(acpi_handle handle, char *method, struct pch_fivr_resp *fivr_resp)
{
        struct acpi_buffer resp = { sizeof(struct pch_fivr_resp), fivr_resp};
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        struct acpi_buffer format = { sizeof("NN"), "NN" };
        union acpi_object *obj;
        acpi_status status;
        int ret = -EFAULT;

        status = acpi_evaluate_object(handle, method, NULL, &buffer);
        if (ACPI_FAILURE(status))
                return ret;

        obj = buffer.pointer;
        if (!obj || obj->type != ACPI_TYPE_PACKAGE)
                goto release_buffer;

        status = acpi_extract_package(obj, &format, &resp);
        if (ACPI_FAILURE(status))
                goto release_buffer;

        if (fivr_resp->status)
                goto release_buffer;

        ret = 0;

release_buffer:
        ACPI_FREE(buffer.pointer);
        return ret;
}

/*
 * Presentation of attributes which are defined for INTC10xx
 * They are:
 * freq_mhz_low_clock : Set PCH FIVR switching freq for
 *                      FIVR clock 19.2MHz and 24MHz
 * freq_mhz_high_clock : Set PCH FIVR switching freq for
 *                      FIVR clock 38.4MHz
 */
#define PCH_FIVR_SHOW(name, method) \
static ssize_t name##_show(struct device *dev,\
                           struct device_attribute *attr,\
                           char *buf)\
{\
        struct acpi_device *acpi_dev = dev_get_drvdata(dev);\
        struct pch_fivr_resp fivr_resp;\
        int status;\
\
        status = pch_fivr_read(acpi_dev->handle, #method, &fivr_resp);\
        if (status)\
                return status;\
\
        return sprintf(buf, "%llu\n", fivr_resp.result);\
}

#define PCH_FIVR_STORE(name, method) \
static ssize_t name##_store(struct device *dev,\
                            struct device_attribute *attr,\
                            const char *buf, size_t count)\
{\
        struct acpi_device *acpi_dev = dev_get_drvdata(dev);\
        acpi_status status;\
        u32 val;\
\
        if (kstrtouint(buf, 0, &val) < 0)\
                return -EINVAL;\
\
        status = acpi_execute_simple_method(acpi_dev->handle, #method, val);\
        if (ACPI_SUCCESS(status))\
                return count;\
\
        return -EINVAL;\
}

PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
PCH_FIVR_SHOW(ssc_clock_info, GEMI)
PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)

static DEVICE_ATTR_RW(freq_mhz_low_clock);
static DEVICE_ATTR_RW(freq_mhz_high_clock);
static DEVICE_ATTR_RO(ssc_clock_info);
static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
static DEVICE_ATTR_RO(fivr_switching_fault_status);

static struct attribute *fivr_attrs[] = {
        &dev_attr_freq_mhz_low_clock.attr,
        &dev_attr_freq_mhz_high_clock.attr,
        &dev_attr_ssc_clock_info.attr,
        &dev_attr_fivr_switching_freq_mhz.attr,
        &dev_attr_fivr_switching_fault_status.attr,
        NULL
};

static const struct attribute_group pch_fivr_attribute_group = {
        .attrs = fivr_attrs,
        .name = "pch_fivr_switch_frequency"
};

static int pch_fivr_add(struct platform_device *pdev)
{
        struct acpi_device *acpi_dev;
        unsigned long long ptype;
        acpi_status status;
        int result;

        acpi_dev = ACPI_COMPANION(&(pdev->dev));
        if (!acpi_dev)
                return -ENODEV;

        status = acpi_evaluate_integer(acpi_dev->handle, "PTYP", NULL, &ptype);
        if (ACPI_FAILURE(status) || ptype != 0x05)
                return -ENODEV;

        result = sysfs_create_group(&pdev->dev.kobj,
                                    &pch_fivr_attribute_group);
        if (result)
                return result;

        platform_set_drvdata(pdev, acpi_dev);

        return 0;
}

static void pch_fivr_remove(struct platform_device *pdev)
{
        sysfs_remove_group(&pdev->dev.kobj, &pch_fivr_attribute_group);
}

static const struct acpi_device_id pch_fivr_device_ids[] = {
        {"INTC1045", 0},
        {"INTC1049", 0},
        {"INTC1064", 0},
        {"INTC106B", 0},
        {"INTC10A3", 0},
        {"INTC10D7", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, pch_fivr_device_ids);

static struct platform_driver pch_fivr_driver = {
        .probe = pch_fivr_add,
        .remove = pch_fivr_remove,
        .driver = {
                .name = "dptf_pch_fivr",
                .acpi_match_table = pch_fivr_device_ids,
        },
};

module_platform_driver(pch_fivr_driver);

MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ACPI DPTF PCH FIVR driver");