iwlwifi: mvm: add support for 32kHz external clock indication

In low power modes, the chip clock source for platform integrated
devices is 32kHz. It is generated internally and supplied by a crystal
oscillator. However using a 32kHz sourced from crystal oscillator
has high power penalty.

There is an option to get an external 32kHz clock from the platform. Past
experience shows that the reliability is platform dependent,
i.e. on some platforms it works good and on other it doesn’t.

Working from external clock will save 0.5 mW in sleep state, from overall
1.8mW that we have today, i.e. almost 30%.

Each OEM can enable or disable the use of the external 32kHz clock by
setting a BIOS configuration. In case the OEM configured to use 32kHz
external clock the driver will pass this indication to the FW.

Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
index 32d000cffe9f..405038ce98d6 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/acpi.c
@@ -6,6 +6,7 @@
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2017        Intel Deutschland GmbH
+ * Copyright (C) 2019 Intel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -26,6 +27,7 @@
  * BSD LICENSE
  *
  * Copyright(c) 2017        Intel Deutschland GmbH
+ * Copyright (C) 2019 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -205,3 +207,33 @@ out:
 	return dflt_pwr_limit;
 }
 IWL_EXPORT_SYMBOL(iwl_acpi_get_pwr_limit);
+
+int iwl_acpi_get_eckv(struct device *dev, u32 *extl_clk)
+{
+	union acpi_object *wifi_pkg, *data;
+	int ret;
+
+	data = iwl_acpi_get_object(dev, ACPI_ECKV_METHOD);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	wifi_pkg = iwl_acpi_get_wifi_pkg(dev, data, ACPI_ECKV_WIFI_DATA_SIZE);
+	if (IS_ERR(wifi_pkg)) {
+		ret = PTR_ERR(wifi_pkg);
+		goto out_free;
+	}
+
+	if (wifi_pkg->package.elements[1].type != ACPI_TYPE_INTEGER) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+
+	*extl_clk = wifi_pkg->package.elements[1].integer.value;
+
+	ret = 0;
+
+out_free:
+	kfree(data);
+	return ret;
+}
+IWL_EXPORT_SYMBOL(iwl_acpi_get_eckv);