drivers/mfd/cros_ec_acpi_gpe.c

   1 /*
   2  * ChromeOS EC multi-function device
   3  *
   4  * Copyright (C) 2017 Google, Inc
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * The ChromeOS EC multi function device is used to mux all the requests
  16  * to the EC device for its multiple features: keyboard controller,
  17  * battery charging and regulator control, firmware update.
  18  */
  19 #include <linux/acpi.h>
  20
  21 #define ACPI_LID_DEVICE      "LID0"
  22
  23 static int ec_wake_gpe = -EINVAL;
  24
  25 /*
  26  * This handler indicates to ACPI core that this GPE should stay enabled for
  27  * lid to work in suspend to idle path.
  28  */
  29 static u32 cros_ec_gpe_handler(acpi_handle gpe_device, u32 gpe_number,
  30                                void *data)
  31 {
  32         return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
  33 }
  34
  35 /*
  36  * Get ACPI GPE for LID0 device.
  37  */
  38 static int cros_ec_get_ec_wake_gpe(struct device *dev)
  39 {
  40         struct acpi_device *cros_acpi_dev;
  41         struct acpi_device *adev;
  42         acpi_handle handle;
  43         acpi_status status;
  44         int ret;
  45
  46         cros_acpi_dev = ACPI_COMPANION(dev);
  47
  48         if (!cros_acpi_dev || !cros_acpi_dev->parent ||
  49            !cros_acpi_dev->parent->handle)
  50                 return -EINVAL;
  51
  52         status = acpi_get_handle(cros_acpi_dev->parent->handle, ACPI_LID_DEVICE,
  53                                  &handle);
  54         if (ACPI_FAILURE(status))
  55                 return -EINVAL;
  56
  57         ret = acpi_bus_get_device(handle, &adev);
  58         if (ret)
  59                 return ret;
  60
  61         return adev->wakeup.gpe_number;
  62 }
  63
  64 int cros_ec_acpi_install_gpe_handler(struct device *dev)
  65 {
  66         acpi_status status;
  67
  68         ec_wake_gpe = cros_ec_get_ec_wake_gpe(dev);
  69
  70         if (ec_wake_gpe < 0)
  71                 return ec_wake_gpe;
  72
  73         status = acpi_install_gpe_handler(NULL, ec_wake_gpe,
  74                                           ACPI_GPE_EDGE_TRIGGERED,
  75                                           &cros_ec_gpe_handler, NULL);
  76         if (ACPI_FAILURE(status))
  77                 return -ENODEV;
  78
  79         dev_info(dev, "Initialized, GPE = 0x%x\n", ec_wake_gpe);
  80
  81         return 0;
  82 }
  83
  84 void cros_ec_acpi_remove_gpe_handler(void)
  85 {
  86         acpi_status status;
  87
  88         if (ec_wake_gpe < 0)
  89                 return;
  90
  91         status = acpi_remove_gpe_handler(NULL, ec_wake_gpe,
  92                                                  &cros_ec_gpe_handler);
  93         if (ACPI_FAILURE(status))
  94                 pr_err("failed to remove gpe handler\n");
  95 }
  96
  97 void cros_ec_acpi_clear_gpe(void)
  98 {
  99         if (ec_wake_gpe < 0)
 100                 return;
 101
 102         acpi_clear_gpe(NULL, ec_wake_gpe);
 103 }