linux/drivers/usb/typec/ucsi/ucsi_acpi.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * UCSI ACPI driver
   4 *
   5 * Copyright (C) 2017, Intel Corporation
   6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
   7 */
   8
   9#include <linux/platform_device.h>
  10#include <linux/module.h>
  11#include <linux/acpi.h>
  12
  13#include "ucsi.h"
  14
  15#define UCSI_DSM_UUID           "6f8398c2-7ca4-11e4-ad36-631042b5008f"
  16#define UCSI_DSM_FUNC_WRITE     1
  17#define UCSI_DSM_FUNC_READ      2
  18
  19struct ucsi_acpi {
  20        struct device *dev;
  21        struct ucsi *ucsi;
  22        void __iomem *base;
  23        struct completion complete;
  24        unsigned long flags;
  25        guid_t guid;
  26};
  27
  28static int ucsi_acpi_dsm(struct ucsi_acpi *ua, int func)
  29{
  30        union acpi_object *obj;
  31
  32        obj = acpi_evaluate_dsm(ACPI_HANDLE(ua->dev), &ua->guid, 1, func,
  33                                NULL);
  34        if (!obj) {
  35                dev_err(ua->dev, "%s: failed to evaluate _DSM %d\n",
  36                        __func__, func);
  37                return -EIO;
  38        }
  39
  40        ACPI_FREE(obj);
  41        return 0;
  42}
  43
  44static int ucsi_acpi_read(struct ucsi *ucsi, unsigned int offset,
  45                          void *val, size_t val_len)
  46{
  47        struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
  48        int ret;
  49
  50        ret = ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_READ);
  51        if (ret)
  52                return ret;
  53
  54        memcpy(val, (const void __force *)(ua->base + offset), val_len);
  55
  56        return 0;
  57}
  58
  59static int ucsi_acpi_async_write(struct ucsi *ucsi, unsigned int offset,
  60                                 const void *val, size_t val_len)
  61{
  62        struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
  63
  64        memcpy((void __force *)(ua->base + offset), val, val_len);
  65
  66        return ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_WRITE);
  67}
  68
  69static int ucsi_acpi_sync_write(struct ucsi *ucsi, unsigned int offset,
  70                                const void *val, size_t val_len)
  71{
  72        struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
  73        int ret;
  74
  75        set_bit(COMMAND_PENDING, &ua->flags);
  76
  77        ret = ucsi_acpi_async_write(ucsi, offset, val, val_len);
  78        if (ret)
  79                goto out_clear_bit;
  80
  81        if (!wait_for_completion_timeout(&ua->complete, 60 * HZ))
  82                ret = -ETIMEDOUT;
  83
  84out_clear_bit:
  85        clear_bit(COMMAND_PENDING, &ua->flags);
  86
  87        return ret;
  88}
  89
  90static const struct ucsi_operations ucsi_acpi_ops = {
  91        .read = ucsi_acpi_read,
  92        .sync_write = ucsi_acpi_sync_write,
  93        .async_write = ucsi_acpi_async_write
  94};
  95
  96static void ucsi_acpi_notify(acpi_handle handle, u32 event, void *data)
  97{
  98        struct ucsi_acpi *ua = data;
  99        u32 cci;
 100        int ret;
 101
 102        ret = ucsi_acpi_read(ua->ucsi, UCSI_CCI, &cci, sizeof(cci));
 103        if (ret)
 104                return;
 105
 106        if (UCSI_CCI_CONNECTOR(cci))
 107                ucsi_connector_change(ua->ucsi, UCSI_CCI_CONNECTOR(cci));
 108
 109        if (test_bit(COMMAND_PENDING, &ua->flags) &&
 110            cci & (UCSI_CCI_ACK_COMPLETE | UCSI_CCI_COMMAND_COMPLETE))
 111                complete(&ua->complete);
 112}
 113
 114static int ucsi_acpi_probe(struct platform_device *pdev)
 115{
 116        struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 117        struct ucsi_acpi *ua;
 118        struct resource *res;
 119        acpi_status status;
 120        int ret;
 121
 122        if (adev->dep_unmet)
 123                return -EPROBE_DEFER;
 124
 125        ua = devm_kzalloc(&pdev->dev, sizeof(*ua), GFP_KERNEL);
 126        if (!ua)
 127                return -ENOMEM;
 128
 129        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 130        if (!res) {
 131                dev_err(&pdev->dev, "missing memory resource\n");
 132                return -ENODEV;
 133        }
 134
 135        /* This will make sure we can use ioremap() */
 136        status = acpi_release_memory(ACPI_HANDLE(&pdev->dev), res, 1);
 137        if (ACPI_FAILURE(status))
 138                return -ENOMEM;
 139
 140        /*
 141         * NOTE: The memory region for the data structures is used also in an
 142         * operation region, which means ACPI has already reserved it. Therefore
 143         * it can not be requested here, and we can not use
 144         * devm_ioremap_resource().
 145         */
 146        ua->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 147        if (!ua->base)
 148                return -ENOMEM;
 149
 150        ret = guid_parse(UCSI_DSM_UUID, &ua->guid);
 151        if (ret)
 152                return ret;
 153
 154        init_completion(&ua->complete);
 155        ua->dev = &pdev->dev;
 156
 157        ua->ucsi = ucsi_create(&pdev->dev, &ucsi_acpi_ops);
 158        if (IS_ERR(ua->ucsi))
 159                return PTR_ERR(ua->ucsi);
 160
 161        ucsi_set_drvdata(ua->ucsi, ua);
 162
 163        status = acpi_install_notify_handler(ACPI_HANDLE(&pdev->dev),
 164                                             ACPI_DEVICE_NOTIFY,
 165                                             ucsi_acpi_notify, ua);
 166        if (ACPI_FAILURE(status)) {
 167                dev_err(&pdev->dev, "failed to install notify handler\n");
 168                ucsi_destroy(ua->ucsi);
 169                return -ENODEV;
 170        }
 171
 172        ret = ucsi_register(ua->ucsi);
 173        if (ret) {
 174                acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev),
 175                                           ACPI_DEVICE_NOTIFY,
 176                                           ucsi_acpi_notify);
 177                ucsi_destroy(ua->ucsi);
 178                return ret;
 179        }
 180
 181        platform_set_drvdata(pdev, ua);
 182
 183        return 0;
 184}
 185
 186static int ucsi_acpi_remove(struct platform_device *pdev)
 187{
 188        struct ucsi_acpi *ua = platform_get_drvdata(pdev);
 189
 190        ucsi_unregister(ua->ucsi);
 191        ucsi_destroy(ua->ucsi);
 192
 193        acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev), ACPI_DEVICE_NOTIFY,
 194                                   ucsi_acpi_notify);
 195
 196        return 0;
 197}
 198
 199static const struct acpi_device_id ucsi_acpi_match[] = {
 200        { "PNP0CA0", 0 },
 201        { },
 202};
 203MODULE_DEVICE_TABLE(acpi, ucsi_acpi_match);
 204
 205static struct platform_driver ucsi_acpi_platform_driver = {
 206        .driver = {
 207                .name = "ucsi_acpi",
 208                .acpi_match_table = ACPI_PTR(ucsi_acpi_match),
 209        },
 210        .probe = ucsi_acpi_probe,
 211        .remove = ucsi_acpi_remove,
 212};
 213
 214module_platform_driver(ucsi_acpi_platform_driver);
 215
 216MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
 217MODULE_LICENSE("GPL v2");
 218MODULE_DESCRIPTION("UCSI ACPI driver");
 219