drivers/usb/typec/ucsi/ucsi_acpi.c

   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
  19 struct ucsi_acpi {
  20         struct device *dev;
  21         struct ucsi *ucsi;
  22         struct ucsi_ppm ppm;
  23         guid_t guid;
  24 };
  25
  26 static int ucsi_acpi_dsm(struct ucsi_acpi *ua, int func)
  27 {
  28         union acpi_object *obj;
  29
  30         obj = acpi_evaluate_dsm(ACPI_HANDLE(ua->dev), &ua->guid, 1, func,
  31                                 NULL);
  32         if (!obj) {
  33                 dev_err(ua->dev, "%s: failed to evaluate _DSM %d\n",
  34                         __func__, func);
  35                 return -EIO;
  36         }
  37
  38         ACPI_FREE(obj);
  39         return 0;
  40 }
  41
  42 static int ucsi_acpi_cmd(struct ucsi_ppm *ppm, struct ucsi_control *ctrl)
  43 {
  44         struct ucsi_acpi *ua = container_of(ppm, struct ucsi_acpi, ppm);
  45
  46         ppm->data->ctrl.raw_cmd = ctrl->raw_cmd;
  47
  48         return ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_WRITE);
  49 }
  50
  51 static int ucsi_acpi_sync(struct ucsi_ppm *ppm)
  52 {
  53         struct ucsi_acpi *ua = container_of(ppm, struct ucsi_acpi, ppm);
  54
  55         return ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_READ);
  56 }
  57
  58 static void ucsi_acpi_notify(acpi_handle handle, u32 event, void *data)
  59 {
  60         struct ucsi_acpi *ua = data;
  61
  62         ucsi_notify(ua->ucsi);
  63 }
  64
  65 static int ucsi_acpi_probe(struct platform_device *pdev)
  66 {
  67         struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
  68         struct ucsi_acpi *ua;
  69         struct resource *res;
  70         acpi_status status;
  71         int ret;
  72
  73         if (adev->dep_unmet)
  74                 return -EPROBE_DEFER;
  75
  76         ua = devm_kzalloc(&pdev->dev, sizeof(*ua), GFP_KERNEL);
  77         if (!ua)
  78                 return -ENOMEM;
  79
  80         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  81         if (!res) {
  82                 dev_err(&pdev->dev, "missing memory resource\n");
  83                 return -ENODEV;
  84         }
  85
  86         /* This will make sure we can use ioremap_nocache() */
  87         status = acpi_release_memory(ACPI_HANDLE(&pdev->dev), res, 1);
  88         if (ACPI_FAILURE(status))
  89                 return -ENOMEM;
  90
  91         /*
  92          * NOTE: The memory region for the data structures is used also in an
  93          * operation region, which means ACPI has already reserved it. Therefore
  94          * it can not be requested here, and we can not use
  95          * devm_ioremap_resource().
  96          */
  97         ua->ppm.data = devm_ioremap(&pdev->dev, res->start, resource_size(res));
  98         if (!ua->ppm.data)
  99                 return -ENOMEM;
 100
 101         if (!ua->ppm.data->version)
 102                 return -ENODEV;
 103
 104         ret = guid_parse(UCSI_DSM_UUID, &ua->guid);
 105         if (ret)
 106                 return ret;
 107
 108         ua->ppm.cmd = ucsi_acpi_cmd;
 109         ua->ppm.sync = ucsi_acpi_sync;
 110         ua->dev = &pdev->dev;
 111
 112         status = acpi_install_notify_handler(ACPI_HANDLE(&pdev->dev),
 113                                              ACPI_DEVICE_NOTIFY,
 114                                              ucsi_acpi_notify, ua);
 115         if (ACPI_FAILURE(status)) {
 116                 dev_err(&pdev->dev, "failed to install notify handler\n");
 117                 return -ENODEV;
 118         }
 119
 120         ua->ucsi = ucsi_register_ppm(&pdev->dev, &ua->ppm);
 121         if (IS_ERR(ua->ucsi)) {
 122                 acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev),
 123                                            ACPI_DEVICE_NOTIFY,
 124                                            ucsi_acpi_notify);
 125                 return PTR_ERR(ua->ucsi);
 126         }
 127
 128         platform_set_drvdata(pdev, ua);
 129
 130         return 0;
 131 }
 132
 133 static int ucsi_acpi_remove(struct platform_device *pdev)
 134 {
 135         struct ucsi_acpi *ua = platform_get_drvdata(pdev);
 136
 137         ucsi_unregister_ppm(ua->ucsi);
 138
 139         acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev), ACPI_DEVICE_NOTIFY,
 140                                    ucsi_acpi_notify);
 141
 142         return 0;
 143 }
 144
 145 static const struct acpi_device_id ucsi_acpi_match[] = {
 146         { "PNP0CA0", 0 },
 147         { },
 148 };
 149 MODULE_DEVICE_TABLE(acpi, ucsi_acpi_match);
 150
 151 static struct platform_driver ucsi_acpi_platform_driver = {
 152         .driver = {
 153                 .name = "ucsi_acpi",
 154                 .acpi_match_table = ACPI_PTR(ucsi_acpi_match),
 155         },
 156         .probe = ucsi_acpi_probe,
 157         .remove = ucsi_acpi_remove,
 158 };
 159
 160 module_platform_driver(ucsi_acpi_platform_driver);
 161
 162 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
 163 MODULE_LICENSE("GPL v2");
 164 MODULE_DESCRIPTION("UCSI ACPI driver");