i2c: i801: Fix missing Kconfig dependency

The original change adds usage of i2c_root_adapter(), which is
implemented in i2c-mux.c. Therefore we can't use the multiplexing
if I2C_I801=y and I2C_MUX=m.
Handling the dependencies in the code would become unnecessarily
complex, therefore create a new config symbol.

Fixes: 893fef0 ("i2c: i801: Call i2c_register_spd for muxed child segments")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404042206.MjAQC32x-lkp@intel.com/
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

Author: hkallweit

drivers/i2c/busses/Kconfig

@@ -163,6 +163,14 @@ config I2C_I801
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-i801.
 
+config I2C_I801_MUX
+	def_bool I2C_I801
+	depends on DMI && I2C_MUX_GPIO
+	depends on !(I2C_I801=y && I2C_MUX=m)
+	help
+	  Optional support for multiplexed SMBUS on certain systems with
+	  more than 8 memory slots.
+
 config I2C_ISCH
 	tristate "Intel SCH SMBus 1.0"
 	depends on PCI && HAS_IOPORT

drivers/i2c/busses/i2c-i801.c

@@ -120,7 +120,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/mutex.h>
 
-#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
+#ifdef CONFIG_I2C_I801_MUX
 #include <linux/gpio/machine.h>
 #include <linux/platform_data/i2c-mux-gpio.h>
 #endif
@@ -289,7 +289,7 @@ struct i801_priv {
 	int len;
 	u8 *data;
 
-#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
+#ifdef CONFIG_I2C_I801_MUX
 	struct platform_device *mux_pdev;
 	struct gpiod_lookup_table *lookup;
 	struct notifier_block mux_notifier_block;
@@ -1300,7 +1300,7 @@ static void i801_probe_optional_slaves(struct i801_priv *priv)
 		register_dell_lis3lv02d_i2c_device(priv);
 
 	/* Instantiate SPD EEPROMs unless the SMBus is multiplexed */
-#if IS_ENABLED(CONFIG_I2C_MUX_GPIO)
+#ifdef CONFIG_I2C_I801_MUX
 	if (!priv->mux_pdev)
 #endif
 		i2c_register_spd(&priv->adapter);
@@ -1310,7 +1310,7 @@ static void __init input_apanel_init(void) {}
 static void i801_probe_optional_slaves(struct i801_priv *priv) {}
 #endif	/* CONFIG_X86 && CONFIG_DMI */
 
-#if IS_ENABLED(CONFIG_I2C_MUX_GPIO) && defined CONFIG_DMI
+#ifdef CONFIG_I2C_I801_MUX
 static struct i801_mux_config i801_mux_config_asus_z8_d12 = {
 	.gpio_chip = "gpio_ich",
 	.values = { 0x02, 0x03 },