hw-gpio: consolidate platform gems into ports/ directories

Move hw-esp32-gpio and hw-rp2040-gpio into hw-gpio/ports/esp32/
and hw-gpio/ports/rp2040/ using the new ports build system.

Co-authored-by: Claude <noreply@anthropic.com>

mrbgems/hw-esp32-gpio/mrbgem.rake

@@ -1,7 +0,0 @@
-MRuby::Gem::Specification.new('hw-esp32-gpio') do |spec|
-  spec.license = 'MIT'
-  spec.author  = 'mruby developers'
-  spec.summary = 'GPIO HAL for ESP32'
-
-  spec.add_dependency 'hw-gpio'
-end

mrbgems/hw-gpio/README.md

@@ -6,26 +6,27 @@ It is designed for embedded platforms such as ESP32 and RP2040.
 
 ## Architecture
 
-- **hw-gpio** (this gem) - Ruby API, C bindings, and HAL function declarations
-- **hw-esp32-gpio** - HAL implementation for ESP32 (using ESP-IDF GPIO driver)
-- **hw-rp2040-gpio** - HAL implementation for RP2040 (using Pico SDK)
+Platform-specific HAL implementations are in `ports/` directories:
 
-The platform gems depend on hw-gpio, so you only need to specify the
-platform gem in your build configuration.
+- `ports/esp32/` - ESP32 using ESP-IDF GPIO driver
+- `ports/rp2040/` - RP2040 using Pico SDK
+
+The build system automatically compiles matching port sources based
+on `conf.ports` setting.
 
 ## Build Configuration
 
 ```ruby
 # For ESP32
 MRuby::CrossBuild.new('esp32') do |conf|
-  # ...
-  conf.gem "#{root}/mrbgems/hw-esp32-gpio"
+  conf.ports :esp32
+  conf.gem core: 'hw-gpio'
 end
 
 # For RP2040
 MRuby::CrossBuild.new('rp2040') do |conf|
-  # ...
-  conf.gem "#{root}/mrbgems/hw-rp2040-gpio"
+  conf.ports :rp2040
+  conf.gem core: 'hw-gpio'
 end
 ```
 
@@ -121,9 +122,9 @@ GPIO.open_drain_at(pin)     # enable open-drain
 
 ## HAL Interface
 
-To add support for a new platform, create a gem (e.g., `hw-myboard-gpio`)
-that depends on `hw-gpio` and implements the following C functions
-declared in `<mruby/gpio.h>`:
+To add support for a new platform, create a `ports/<name>/`
+directory and implement the following C functions declared in
+`<mruby/gpio.h>`:
 
 ```c
 void mrb_gpio_init(uint8_t pin);
@@ -135,13 +136,8 @@ int  mrb_gpio_read(uint8_t pin);
 void mrb_gpio_write(uint8_t pin, uint8_t val);
 ```
 
-The `flags` parameter for `mrb_gpio_set_dir()` uses the bitmask
-constants defined in the header (`MRB_GPIO_IN`, `MRB_GPIO_OUT`,
-`MRB_GPIO_HIGH_Z`).
-
-The gem must also provide empty `mrb_<gemname>_gem_init()` and
-`mrb_<gemname>_gem_final()` functions (with hyphens replaced by
-underscores).
+The port sources are compiled automatically when the build
+configuration includes a matching `conf.ports` tag.
 
 ## License
 

mrbgems/hw-gpio/ports/esp32/gpio.c

@@ -48,8 +48,3 @@ mrb_gpio_write(uint8_t pin, uint8_t val)
 {
   gpio_set_level(pin, val);
 }
-
-#include <mruby.h>
-
-void mrb_hw_esp32_gpio_gem_init(mrb_state *mrb) {}
-void mrb_hw_esp32_gpio_gem_final(mrb_state *mrb) {}

mrbgems/hw-gpio/ports/rp2040/gpio.c

@@ -49,8 +49,3 @@ mrb_gpio_write(uint8_t pin, uint8_t val)
 {
   gpio_put(pin, val == 1);
 }
-
-#include <mruby.h>
-
-void mrb_hw_rp2040_gpio_gem_init(mrb_state *mrb) {}
-void mrb_hw_rp2040_gpio_gem_final(mrb_state *mrb) {}

mrbgems/hw-rp2040-gpio/mrbgem.rake

@@ -1,7 +0,0 @@
-MRuby::Gem::Specification.new('hw-rp2040-gpio') do |spec|
-  spec.license = 'MIT'
-  spec.author  = 'mruby developers'
-  spec.summary = 'GPIO HAL for RP2040'
-
-  spec.add_dependency 'hw-gpio'
-end