platform/chrome: cros_ec_lpc: Register the driver if ACPI entry is missing.

Web:        https://git.kernel.org/torvalds/c/5f454bdf63536d7d0142be3cbb9e83899a199ec8
Commit:     5f454bdf63536d7d0142be3cbb9e83899a199ec8
Parent:     d3b56c566d4ba8cae688baf3cca94425d57ea783
Refname:    refs/heads/master
Author:     Enric Balletbo i Serra <[email protected]>
AuthorDate: Fri Dec 1 14:42:21 2017 +0100
Committer:  Benson Leung <[email protected]>
CommitDate: Sun Dec 17 14:04:21 2017 -0800

    platform/chrome: cros_ec_lpc: Register the driver if ACPI entry is missing.
    
    Commit 12278dc7c572 ("platform/chrome: cros_ec_lpc: Add support for
    GOOG004 ACPI device") added support when the firmware reports the ACPI
    device, there are some firmwares though that doesn't report this device
    but have it. In such cases we need to instantiate the driver explicitly
    if it is not instantiated through ACPI.
    
    Fixes: 12278dc7c572 ("platform/chrome: cros_ec_lpc: Add support for GOOG004 ACPI device")
    Signed-off-by: Guenter Roeck <[email protected]>
    Signed-off-by: Enric Balletbo i Serra <[email protected]>
    Signed-off-by: Thierry Escande <[email protected]>
    Reviewed-by: Gwendal Grignou <[email protected]>
    Signed-off-by: Benson Leung <[email protected]>
---
 drivers/platform/chrome/cros_ec_lpc.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 87e9747d229a..47ace9938952 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -35,6 +35,9 @@
 #define DRV_NAME "cros_ec_lpcs"
 #define ACPI_DRV_NAME "GOOG0004"
 
+/* True if ACPI device is present */
+static bool cros_ec_lpc_acpi_device_found;
+
 static int ec_response_timed_out(void)
 {
 	unsigned long one_second = jiffies + HZ;
@@ -393,9 +396,21 @@ static struct platform_driver cros_ec_lpc_driver = {
 	.remove = cros_ec_lpc_remove,
 };
 
+static struct platform_device cros_ec_lpc_device = {
+	.name = DRV_NAME
+};
+
+static acpi_status cros_ec_lpc_parse_device(acpi_handle handle, u32 level,
+					    void *context, void **retval)
+{
+	*(bool *)context = true;
+	return AE_CTRL_TERMINATE;
+}
+
 static int __init cros_ec_lpc_init(void)
 {
 	int ret;
+	acpi_status status;
 
 	if (!dmi_check_system(cros_ec_lpc_dmi_table)) {
 		pr_err(DRV_NAME ": unsupported system.\n");
@@ -412,11 +427,28 @@ static int __init cros_ec_lpc_init(void)
 		return ret;
 	}
 
-	return 0;
+	status = acpi_get_devices(ACPI_DRV_NAME, cros_ec_lpc_parse_device,
+				  &cros_ec_lpc_acpi_device_found, NULL);
+	if (ACPI_FAILURE(status))
+		pr_warn(DRV_NAME ": Looking for %s failed\n", ACPI_DRV_NAME);
+
+	if (!cros_ec_lpc_acpi_device_found) {
+		/* Register the device, and it'll get hooked up automatically */
+		ret = platform_device_register(&cros_ec_lpc_device);
+		if (ret) {
+			pr_err(DRV_NAME ": can't register device: %d\n", ret);
+			platform_driver_unregister(&cros_ec_lpc_driver);
+			cros_ec_lpc_reg_destroy();
+		}
+	}
+
+	return ret;
 }
 
 static void __exit cros_ec_lpc_exit(void)
 {
+	if (!cros_ec_lpc_acpi_device_found)
+		platform_device_unregister(&cros_ec_lpc_device);
 	platform_driver_unregister(&cros_ec_lpc_driver);
 	cros_ec_lpc_reg_destroy();
 }
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