ACPI: EC: make EC support compile-time conditional

The embedded controller code is mainly used on x86 laptops and cannot
work without PC style I/O port access.

Make this a user-visible configuration option that is default enabled
on x86 but otherwise disabled, and that can never be enabled unless
CONFIG_HAS_IOPORT is also available.

The empty stubs in internal.h help ignore the EC code in configurations
that don't support it. In order to see those stubs, the sbshc code also
has to include this header and drop duplicate declarations.

All the direct callers of ec_read/ec_write already had an x86
dependency and now also need to depend on APCI_EC.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patch.msgid.link/20241011061948.3211423-1-arnd@kernel.org
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: arndb

drivers/acpi/Kconfig

@@ -132,8 +132,17 @@ config ACPI_REV_OVERRIDE_POSSIBLE
 	  makes it possible to force the kernel to return "5" as the supported
 	  ACPI revision via the "acpi_rev_override" command line switch.
 
+config ACPI_EC
+	bool "Embedded Controller"
+	depends on HAS_IOPORT
+	default X86
+	help
+	  This driver handles communication with the microcontroller
+	  on many x86 laptops and other machines.
+
 config ACPI_EC_DEBUGFS
 	tristate "EC read/write access through /sys/kernel/debug/ec"
+	depends on ACPI_EC
 	help
 	  Say N to disable Embedded Controller /sys/kernel/debug interface
 
@@ -433,7 +442,7 @@ config ACPI_HOTPLUG_IOAPIC
 
 config ACPI_SBS
 	tristate "Smart Battery System"
-	depends on X86
+	depends on X86 && ACPI_EC
 	select POWER_SUPPLY
 	help
 	  This driver supports the Smart Battery System, another

drivers/acpi/Makefile

@@ -41,7 +41,7 @@ acpi-y				+= resource.o
 acpi-y				+= acpi_processor.o
 acpi-y				+= processor_core.o
 acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
-acpi-y				+= ec.o
+acpi-$(CONFIG_ACPI_EC)		+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-$(CONFIG_PCI)		+= pci_root.o pci_link.o pci_irq.o
 obj-$(CONFIG_ACPI_MCFG)		+= pci_mcfg.o

drivers/acpi/internal.h

@@ -215,6 +215,8 @@ extern struct acpi_ec *first_ec;
 /* External interfaces use first EC only, so remember */
 typedef int (*acpi_ec_query_func) (void *data);
 
+#ifdef CONFIG_ACPI_EC
+
 void acpi_ec_init(void);
 void acpi_ec_ecdt_probe(void);
 void acpi_ec_dsdt_probe(void);
@@ -231,6 +233,29 @@ void acpi_ec_flush_work(void);
 bool acpi_ec_dispatch_gpe(void);
 #endif
 
+#else
+
+static inline void acpi_ec_init(void) {}
+static inline void acpi_ec_ecdt_probe(void) {}
+static inline void acpi_ec_dsdt_probe(void) {}
+static inline void acpi_ec_block_transactions(void) {}
+static inline void acpi_ec_unblock_transactions(void) {}
+static inline int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
+			      acpi_handle handle, acpi_ec_query_func func,
+			      void *data)
+{
+	return -ENXIO;
+}
+static inline void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit) {}
+static inline void acpi_ec_register_opregions(struct acpi_device *adev) {}
+
+static inline void acpi_ec_flush_work(void) {}
+static inline bool acpi_ec_dispatch_gpe(void)
+{
+	return false;
+}
+
+#endif
 
 /*--------------------------------------------------------------------------
                                   Suspend/Resume

drivers/acpi/sbshc.c

@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include "sbshc.h"
+#include "internal.h"
 
 #define ACPI_SMB_HC_CLASS	"smbus_host_ctl"
 #define ACPI_SMB_HC_DEVICE_NAME	"ACPI SMBus HC"
@@ -236,12 +237,6 @@ static int smbus_alarm(void *context)
 	return 0;
 }
 
-typedef int (*acpi_ec_query_func) (void *data);
-
-extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
-			      acpi_handle handle, acpi_ec_query_func func,
-			      void *data);
-
 static int acpi_smbus_hc_add(struct acpi_device *device)
 {
 	int status;
@@ -278,8 +273,6 @@ static int acpi_smbus_hc_add(struct acpi_device *device)
 	return 0;
 }
 
-extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
-
 static void acpi_smbus_hc_remove(struct acpi_device *device)
 {
 	struct acpi_smb_hc *hc;

drivers/char/Kconfig

@@ -238,6 +238,7 @@ config APPLICOM
 config SONYPI
 	tristate "Sony Vaio Programmable I/O Control Device support"
 	depends on X86_32 && PCI && INPUT
+	depends on ACPI_EC || !ACPI
 	help
 	  This driver enables access to the Sony Programmable I/O Control
 	  Device which can be found in many (all ?) Sony Vaio laptops.

drivers/hwmon/Kconfig

@@ -1752,7 +1752,7 @@ source "drivers/hwmon/occ/Kconfig"
 
 config SENSORS_OXP
 	tristate "OneXPlayer EC fan control"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on X86
 	help
 		If you say yes here you get support for fan readings and control over
@@ -2592,6 +2592,7 @@ config SENSORS_ASUS_WMI
 config SENSORS_ASUS_EC
 	tristate "ASUS EC Sensors"
 	depends on X86
+	depends on ACPI_EC
 	help
 	  If you say yes here you get support for the ACPI embedded controller
 	  hardware monitoring interface found in ASUS motherboards. The driver

drivers/platform/x86/Kconfig

@@ -52,6 +52,7 @@ config WMI_BMOF
 config HUAWEI_WMI
 	tristate "Huawei WMI laptop extras driver"
 	depends on ACPI_BATTERY
+	depends on ACPI_EC
 	depends on ACPI_WMI
 	depends on INPUT
 	select INPUT_SPARSEKMAP
@@ -147,7 +148,7 @@ config YT2_1380
 
 config ACERHDF
 	tristate "Acer Aspire One temperature and fan driver"
-	depends on ACPI && THERMAL
+	depends on ACPI_EC && THERMAL
 	select THERMAL_GOV_BANG_BANG
 	help
 	  This is a driver for Acer Aspire One netbooks. It allows to access
@@ -186,6 +187,7 @@ config ACER_WMI
 	depends on SERIO_I8042
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
+	depends on ACPI_EC
 	depends on ACPI_WMI
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on HWMON
@@ -334,7 +336,7 @@ config MERAKI_MX100
 
 config EEEPC_LAPTOP
 	tristate "Eee PC Hotkey Driver"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
@@ -503,7 +505,7 @@ config SENSORS_HDAPS
 
 config THINKPAD_ACPI
 	tristate "ThinkPad ACPI Laptop Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_BATTERY
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
@@ -682,15 +684,15 @@ config MEEGOPAD_ANX7428
 
 config MSI_EC
 	tristate "MSI EC Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_BATTERY
 	help
 	  This driver allows various MSI laptops' functionalities to be
 	  controlled from userspace, including battery charge threshold.
 
 config MSI_LAPTOP
 	tristate "MSI Laptop Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL
@@ -796,15 +798,15 @@ config SAMSUNG_LAPTOP
 
 config SAMSUNG_Q10
 	tristate "Samsung Q10 Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	select BACKLIGHT_CLASS_DEVICE
 	help
 	  This driver provides support for backlight control on Samsung Q10
 	  and related laptops, including Dell Latitude X200.
 
 config ACPI_TOSHIBA
 	tristate "Toshiba Laptop Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_BATTERY
 	depends on ACPI_WMI
 	select LEDS_CLASS
@@ -904,7 +906,7 @@ config ACPI_CMPC
 
 config COMPAL_LAPTOP
 	tristate "Compal (and others) Laptop Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL
@@ -949,7 +951,7 @@ config PANASONIC_LAPTOP
 
 config SONY_LAPTOP
 	tristate "Sony Laptop Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on INPUT
@@ -972,7 +974,7 @@ config SONYPI_COMPAT
 
 config SYSTEM76_ACPI
 	tristate "System76 ACPI Driver"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_BATTERY
 	depends on HWMON
 	depends on INPUT

drivers/platform/x86/dell/Kconfig

@@ -194,6 +194,7 @@ config DELL_WMI
 config DELL_WMI_PRIVACY
 	bool "Dell WMI Hardware Privacy Support"
 	depends on DELL_WMI
+	depends on ACPI_EC
 	help
 	  This option adds integration with the "Dell Hardware Privacy"
 	  feature of Dell laptops to the dell-wmi driver.

drivers/platform/x86/hp/Kconfig

@@ -37,6 +37,7 @@ config HP_ACCEL
 config HP_WMI
 	tristate "HP WMI extras"
 	default m
+	depends on ACPI_EC
 	depends on ACPI_WMI
 	depends on INPUT
 	depends on RFKILL || RFKILL = n

drivers/platform/x86/intel/Kconfig

@@ -62,7 +62,7 @@ config INTEL_INT0002_VGPIO
 
 config INTEL_OAKTRAIL
 	tristate "Intel Oaktrail Platform Extras"
-	depends on ACPI
+	depends on ACPI_EC
 	depends on ACPI_VIDEO || ACPI_VIDEO=n
 	depends on RFKILL && BACKLIGHT_CLASS_DEVICE && ACPI
 	help