alto2: Use callback for reading keyboard (nw)

src/devices/cpu/alto2/a2kbd.cpp

@@ -16,21 +16,7 @@
  */
 READ16_MEMBER( alto2_cpu_device::kbd_ad_r )
 {
-	uint16_t data = 0177777;
+	uint16_t data = m_kb_read_callback(offset & 3);
-	switch (offset & 3) {
-	case 0:
-		data = machine().root_device().ioport("ROW0")->read();
-		break;
-	case 1:
-		data = machine().root_device().ioport("ROW1")->read();
-		break;
-	case 2:
-		data = machine().root_device().ioport("ROW2")->read();
-		break;
-	case 3:
-		data = machine().root_device().ioport("ROW3")->read();
-		break;
-	}
 	m_kbd.matrix[offset & 03] = data;
 	if (!machine().side_effects_disabled()) {
 		LOG((this,LOG_KBD,2,"    read KBDAD+%o (%#o)\n", offset & 3, data));

src/devices/cpu/alto2/alto2cpu.cpp

@@ -127,6 +127,7 @@ void alto2_cpu_device::iomem_map(address_map &map)
 
 alto2_cpu_device::alto2_cpu_device(const machine_config& mconfig, const char* tag, device_t* owner, uint32_t clock) :
 	cpu_device(mconfig, ALTO2, tag, owner, clock),
+	m_kb_read_callback(*this),
 	m_ucode_config("ucode", ENDIANNESS_BIG, 32, 12, -2 ),
 	m_const_config("const", ENDIANNESS_BIG, 16,  8, -1 ),
 	m_iomem_config("iomem", ENDIANNESS_BIG, 16, 17, -1 ),
@@ -813,6 +814,8 @@ device_memory_interface::space_config_vector alto2_cpu_device::memory_space_conf
 
 void alto2_cpu_device::device_start()
 {
+	m_kb_read_callback.resolve_safe(0177777);
+
 	// get a pointer to the IO address space
 	m_iomem = &space(2);
 

src/devices/cpu/alto2/alto2cpu.h

@@ -185,6 +185,8 @@ public:
 	alto2_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
 	~alto2_cpu_device();
 
+	auto kb_read_callback() { return m_kb_read_callback.bind(); }
+
 	//! driver interface to set diablo_hd_device
 	void set_diablo(int unit, diablo_hd_device* ptr);
 
@@ -244,6 +246,8 @@ private:
 
 	void fatal(int level, const char *format, ...);
 
+	devcb_read16 m_kb_read_callback;
+
 	address_space_config m_ucode_config;
 	address_space_config m_const_config;
 	address_space_config m_iomem_config;

src/mame/drivers/alto2.cpp

@@ -20,14 +20,7 @@ public:
 		driver_device(mconfig, type, tag),
 		m_maincpu(*this, "maincpu"),
 		m_speaker(*this, "speaker"),
-		m_io_row0(*this, "ROW0"),
+		m_io_row(*this, "ROW%u", 0U),
-		m_io_row1(*this, "ROW1"),
-		m_io_row2(*this, "ROW2"),
-		m_io_row3(*this, "ROW3"),
-		m_io_row4(*this, "ROW4"),
-		m_io_row5(*this, "ROW5"),
-		m_io_row6(*this, "ROW6"),
-		m_io_row7(*this, "ROW7"),
 		m_io_config(*this, "CONFIG")
 	{ }
 
@@ -38,17 +31,13 @@ public:
 	void alto2_const_map(address_map &map);
 	void alto2_iomem_map(address_map &map);
 	void alto2_ucode_map(address_map &map);
+
 protected:
+	u16 kb_r(offs_t offset);
+
 	required_device<alto2_cpu_device> m_maincpu;
 	required_device<speaker_sound_device> m_speaker;
-	required_ioport m_io_row0;
+	required_ioport_array<8> m_io_row;
-	required_ioport m_io_row1;
-	required_ioport m_io_row2;
-	required_ioport m_io_row3;
-	required_ioport m_io_row4;
-	required_ioport m_io_row5;
-	required_ioport m_io_row6;
-	required_ioport m_io_row7;
 	optional_ioport m_io_config;
 	static const device_timer_id TIMER_VBLANK = 0;
 	emu_timer* m_vblank_timer;
@@ -254,6 +243,11 @@ static INPUT_PORTS_START( alto2 )
 	PORT_DIPSETTING( 0374, "ID 374")   PORT_DIPSETTING( 0375, "ID 375")
 INPUT_PORTS_END
 
+u16 alto2_state::kb_r(offs_t offset)
+{
+	return m_io_row[offset]->read();
+}
+
 /* ROM */
 ROM_START( alto2 )
 	// dummy region for the maincpu - this is not used in any way
@@ -289,6 +283,7 @@ void alto2_state::alto2(machine_config &config)
 	m_maincpu->set_addrmap(AS_PROGRAM, &alto2_state::alto2_ucode_map);
 	m_maincpu->set_addrmap(AS_DATA, &alto2_state::alto2_const_map);
 	m_maincpu->set_addrmap(AS_IO, &alto2_state::alto2_iomem_map);
+	m_maincpu->kb_read_callback().set(FUNC(alto2_state::kb_r));
 
 	// Video hardware
 	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));