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Diffstat (limited to 'drivers/platform/x86/nvidia-wmi-ec-backlight.c')
-rw-r--r--drivers/platform/x86/nvidia-wmi-ec-backlight.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/drivers/platform/x86/nvidia-wmi-ec-backlight.c b/drivers/platform/x86/nvidia-wmi-ec-backlight.c
new file mode 100644
index 0000000000..1b572c90c7
--- /dev/null
+++ b/drivers/platform/x86/nvidia-wmi-ec-backlight.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/acpi.h>
+#include <linux/backlight.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_data/x86/nvidia-wmi-ec-backlight.h>
+#include <linux/types.h>
+#include <linux/wmi.h>
+#include <acpi/video.h>
+
+static bool force;
+module_param(force, bool, 0444);
+MODULE_PARM_DESC(force, "Force loading (disable acpi_backlight=xxx checks");
+
+/**
+ * wmi_brightness_notify() - helper function for calling WMI-wrapped ACPI method
+ * @w: Pointer to the struct wmi_device identified by %WMI_BRIGHTNESS_GUID
+ * @id: The WMI method ID to call (e.g. %WMI_BRIGHTNESS_METHOD_LEVEL or
+ * %WMI_BRIGHTNESS_METHOD_SOURCE)
+ * @mode: The operation to perform on the method (e.g. %WMI_BRIGHTNESS_MODE_SET
+ * or %WMI_BRIGHTNESS_MODE_GET)
+ * @val: Pointer to a value passed in by the caller when @mode is
+ * %WMI_BRIGHTNESS_MODE_SET, or a value passed out to caller when @mode
+ * is %WMI_BRIGHTNESS_MODE_GET or %WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL.
+ *
+ * Returns 0 on success, or a negative error number on failure.
+ */
+static int wmi_brightness_notify(struct wmi_device *w, enum wmi_brightness_method id, enum wmi_brightness_mode mode, u32 *val)
+{
+ struct wmi_brightness_args args = {
+ .mode = mode,
+ .val = 0,
+ .ret = 0,
+ };
+ struct acpi_buffer buf = { (acpi_size)sizeof(args), &args };
+ acpi_status status;
+
+ if (id < WMI_BRIGHTNESS_METHOD_LEVEL ||
+ id >= WMI_BRIGHTNESS_METHOD_MAX ||
+ mode < WMI_BRIGHTNESS_MODE_GET || mode >= WMI_BRIGHTNESS_MODE_MAX)
+ return -EINVAL;
+
+ if (mode == WMI_BRIGHTNESS_MODE_SET)
+ args.val = *val;
+
+ status = wmidev_evaluate_method(w, 0, id, &buf, &buf);
+ if (ACPI_FAILURE(status)) {
+ dev_err(&w->dev, "EC backlight control failed: %s\n",
+ acpi_format_exception(status));
+ return -EIO;
+ }
+
+ if (mode != WMI_BRIGHTNESS_MODE_SET)
+ *val = args.ret;
+
+ return 0;
+}
+
+static int nvidia_wmi_ec_backlight_update_status(struct backlight_device *bd)
+{
+ struct wmi_device *wdev = bl_get_data(bd);
+
+ return wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+ WMI_BRIGHTNESS_MODE_SET,
+ &bd->props.brightness);
+}
+
+static int nvidia_wmi_ec_backlight_get_brightness(struct backlight_device *bd)
+{
+ struct wmi_device *wdev = bl_get_data(bd);
+ u32 level;
+ int ret;
+
+ ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+ WMI_BRIGHTNESS_MODE_GET, &level);
+ if (ret < 0)
+ return ret;
+
+ return level;
+}
+
+static const struct backlight_ops nvidia_wmi_ec_backlight_ops = {
+ .update_status = nvidia_wmi_ec_backlight_update_status,
+ .get_brightness = nvidia_wmi_ec_backlight_get_brightness,
+};
+
+static int nvidia_wmi_ec_backlight_probe(struct wmi_device *wdev, const void *ctx)
+{
+ struct backlight_properties props = {};
+ struct backlight_device *bdev;
+ int ret;
+
+ /* drivers/acpi/video_detect.c also checks that SOURCE == EC */
+ if (!force && acpi_video_get_backlight_type() != acpi_backlight_nvidia_wmi_ec)
+ return -ENODEV;
+
+ /*
+ * Identify this backlight device as a firmware device so that it can
+ * be prioritized over any exposed GPU-driven raw device(s).
+ */
+ props.type = BACKLIGHT_FIRMWARE;
+
+ ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+ WMI_BRIGHTNESS_MODE_GET_MAX_LEVEL,
+ &props.max_brightness);
+ if (ret)
+ return ret;
+
+ ret = wmi_brightness_notify(wdev, WMI_BRIGHTNESS_METHOD_LEVEL,
+ WMI_BRIGHTNESS_MODE_GET, &props.brightness);
+ if (ret)
+ return ret;
+
+ bdev = devm_backlight_device_register(&wdev->dev,
+ "nvidia_wmi_ec_backlight",
+ &wdev->dev, wdev,
+ &nvidia_wmi_ec_backlight_ops,
+ &props);
+ return PTR_ERR_OR_ZERO(bdev);
+}
+
+static const struct wmi_device_id nvidia_wmi_ec_backlight_id_table[] = {
+ { .guid_string = WMI_BRIGHTNESS_GUID },
+ { }
+};
+MODULE_DEVICE_TABLE(wmi, nvidia_wmi_ec_backlight_id_table);
+
+static struct wmi_driver nvidia_wmi_ec_backlight_driver = {
+ .driver = {
+ .name = "nvidia-wmi-ec-backlight",
+ },
+ .probe = nvidia_wmi_ec_backlight_probe,
+ .id_table = nvidia_wmi_ec_backlight_id_table,
+};
+module_wmi_driver(nvidia_wmi_ec_backlight_driver);
+
+MODULE_AUTHOR("Daniel Dadap <ddadap@nvidia.com>");
+MODULE_DESCRIPTION("NVIDIA WMI EC Backlight driver");
+MODULE_LICENSE("GPL");