drivers: i2c_dw: Remove hard-coded instance count assumption

Introduce a Kconfig variable that the SoC can set to indicate the
number of instances in Device Tree. This also fixes the accuracy of
the Elkhart Lake instance count where the code was previously assuming
up to 12 instances even though DT lists 15 nodes.

Signed-off-by: Johan Hedberg <[email protected]>

Author: Johan Hedberg

drivers/i2c/CMakeLists.txt

@@ -43,7 +43,9 @@ zephyr_library_sources_ifdef(CONFIG_I2C_STM32_V2
 
 if(CONFIG_I2C_DW)
   zephyr_library_sources(i2c_dw.c)
-  foreach(NUM RANGE 0 11)
+  math(EXPR max_index "${CONFIG_I2C_DW_MAX_INSTANCES} - 1")
+  foreach(NUM RANGE 0 ${max_index})
+    math(EXPR NEXT_NUM "${NUM} + 1")
     configure_file(
       i2c_dw_port_x.h
       ${PROJECT_BINARY_DIR}/include/generated/i2c_dw_port_${NUM}.h

drivers/i2c/Kconfig.dw

@@ -12,7 +12,17 @@ menuconfig I2C_DW
 	help
 	  Enable the Design Ware I2C driver
 
+if I2C_DW
+
 config I2C_DW_CLOCK_SPEED
 	int "Set the clock speed for I2C"
 	default 32
-	depends on I2C_DW
+
+config I2C_DW_MAX_INSTANCES
+	int "Maximum number of supported driver instances"
+	range 1 32
+	default 12
+	help
+	  The maximum number of supported driver instances in device tree.
+
+endif # I2C_DW

drivers/i2c/i2c_dw.c

@@ -665,50 +665,8 @@ static int i2c_dw_initialize(const struct device *dev)
 	return 0;
 }
 
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(0), okay)
+/* The instance-specific header files are chained together (each instance
+ * includes the next one, unless it's the last instance) so we only need to
+ * include the first instance.
+ */
 #include <i2c_dw_port_0.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(1), okay)
-#include <i2c_dw_port_1.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(2), okay)
-#include <i2c_dw_port_2.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(3), okay)
-#include <i2c_dw_port_3.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(4), okay)
-#include <i2c_dw_port_4.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(5), okay)
-#include <i2c_dw_port_5.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(6), okay)
-#include <i2c_dw_port_6.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(7), okay)
-#include <i2c_dw_port_7.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(8), okay)
-#include <i2c_dw_port_8.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(9), okay)
-#include <i2c_dw_port_9.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(10), okay)
-#include <i2c_dw_port_10.h>
-#endif
-
-#if DT_NODE_HAS_STATUS(DT_DRV_INST(11), okay)
-#include <i2c_dw_port_11.h>
-#endif

drivers/i2c/i2c_dw_port_x.h

@@ -6,6 +6,8 @@
  * This file is a template for cmake and is not meant to be used directly!
  */
 
+#if DT_NODE_HAS_STATUS(DT_DRV_INST(@NUM@), okay)
+
 static void i2c_config_@NUM@(const struct device *port);
 
 static const struct i2c_dw_rom_config i2c_config_dw_@NUM@ = {
@@ -82,3 +84,10 @@ static void i2c_config_@NUM@(const struct device *port)
 
 #endif
 }
+
+#endif /* DT_NODE_HAS_STATUS(DT_DRV_INST(@NUM@), okay) */
+
+/* Include subsequent instances */
+#if @NEXT_NUM@ < CONFIG_I2C_DW_MAX_INSTANCES
+#include <i2c_dw_port_@[email protected]>
+#endif

soc/x86/apollo_lake/Kconfig.defconfig

@@ -52,6 +52,10 @@ config I2C_DW
 	default y
 	depends on I2C
 
+config I2C_DW_MAX_INSTANCES
+	default 8
+	depends on I2C_DW
+
 config GPIO_INTEL_APL
 	default y
 	depends on GPIO

soc/x86/elkhart_lake/Kconfig.defconfig

@@ -52,6 +52,10 @@ config I2C_DW
 	default y
 	depends on I2C
 
+config I2C_DW_MAX_INSTANCES
+	default 15
+	depends on I2C_DW
+
 config UART_NS16550_MAX_INSTANCES
 	default 11
 	depends on UART_NS16550