add RA8875 Touch Support (#606)

* implemented `lgfx::Touch_RA8875` touch functionality

src/lgfx/v1/touch/Touch_RA8875.cpp

@@ -0,0 +1,130 @@
+/*----------------------------------------------------------------------------/
+  Lovyan GFX - Graphics library for embedded devices.
+
+Original Source:
+ https://github.com/lovyan03/LovyanGFX/
+
+Licence:
+ [FreeBSD](https://github.com/lovyan03/LovyanGFX/blob/master/license.txt)
+
+Author:
+ [lovyan03](https://twitter.com/lovyan03)
+
+Contributors:
+ [ciniml](https://github.com/ciniml)
+ [mongonta0716](https://github.com/mongonta0716)
+ [tobozo](https://github.com/tobozo)
+/----------------------------------------------------------------------------*/
+#include "Touch_RA8875.hpp"
+
+#include "../../internal/algorithm.h"
+#include "../platforms/common.hpp"
+
+namespace lgfx
+{
+ inline namespace v1
+ {
+//----------------------------------------------------------------------------
+
+  bool Touch_RA8875::init(void)
+  {
+    _inited = false;
+
+    lgfx::gpio_hi(_cfg.pin_cs);
+    lgfx::pinMode(_cfg.pin_cs, lgfx::pin_mode_t::output);
+    if (!lgfx::spi::init(_cfg.spi_host, _cfg.pin_sclk, _cfg.pin_miso, _cfg.pin_mosi).has_value()) return false;
+
+    // enable Touch Panel
+    // RA8875_TPCR0: RA8875_TPCR0_ENABLE | RA8875_TPCR0_WAIT_4096CLK | RA8875_TPCR0_WAKEENABLE | adcClk
+    writeRegister8(0x70, 0x80 | 0x30 | 0x08 | 0x04); // 10mhz max!
+
+    // Set Auto Mode
+    // RA8875_TPCR1, RA8875_TPCR1_AUTO | RA8875_TPCR1_DEBOUNCE
+    writeRegister8(0x71, 0x00 | 0x04);
+
+    // Enable TP INT
+    // ToDo: you might want to mask the other bits of the register
+    writeRegister8(0xF0, 0x04);
+
+    delay(2);
+    writeRegister8(0xF1, 0x04); // clear interrupt
+
+    _inited = true;
+    return true;
+  }
+
+  uint_fast8_t Touch_RA8875::getTouchRaw(touch_point_t* tp, uint_fast8_t count)
+  {
+    if (!_inited || count == 0) return 0;   // ToDo: figure what count does
+
+    // what does it do??
+    // if (_cfg.pin_int >= 0 && lgfx::gpio_in(_cfg.pin_int))
+    // {
+    //   return 0;
+    // }
+
+    uint16_t tx, ty;
+    uint8_t temp, interrupt_reg;
+
+    tx = readRegister8(0x72); // RA8875_TPXH
+    ty = readRegister8(0x73); // RA8875_TPYH 
+    temp = readRegister8(0x74); // RA8875_TPXYL
+    interrupt_reg = readRegister8(0xF1);  // INTC2
+
+    tx <<= 2;
+    ty <<= 2;
+    tx |= temp & 0x03;        // get the bottom x bits
+    ty |= (temp >> 2) & 0x03; // get the bottom y bits
+
+    if(interrupt_reg & (1 << 2)){   // touch interrupt has been triggered
+      tp->x = tx;
+      tp->y = ty;
+      tp->size = 1;
+    }else{
+      tp->x = 0;
+      tp->y = 0;
+      tp->size = 0;
+    }    
+
+    writeRegister8(0xF1, 0x04); // clear interrupt
+
+    return tp->size ? 1 : 0;
+  }
+
+  uint8_t Touch_RA8875::readRegister8(uint8_t reg)
+  {
+    if (isSPI()) {
+      uint8_t tmp[3] = {0x80, reg, 0x40};
+      uint8_t res = 0;
+
+      spi::beginTransaction(_cfg.spi_host, _cfg.freq);
+      lgfx::gpio_lo(_cfg.pin_cs);
+
+      spi::writeBytes(_cfg.spi_host, tmp, 3);
+      spi::readBytes(_cfg.spi_host, &res, 1);
+
+      spi::endTransaction(_cfg.spi_host);
+      lgfx::gpio_hi(_cfg.pin_cs);
+
+      return res;
+    }
+    return 0;
+  }
+
+  void Touch_RA8875::writeRegister8(uint8_t reg, uint8_t data)
+  {
+    if (isSPI()) {
+      uint8_t tmp[4] = {0x80, reg, 0x00, data };
+
+      spi::beginTransaction(_cfg.spi_host, _cfg.freq);
+      lgfx::gpio_lo(_cfg.pin_cs);
+
+      spi::writeBytes(_cfg.spi_host, tmp, 4);
+
+      spi::endTransaction(_cfg.spi_host);
+      lgfx::gpio_hi(_cfg.pin_cs);
+    }
+  }
+//----------------------------------------------------------------------------
+ }
+}

src/lgfx/v1/touch/Touch_RA8875.hpp

@@ -0,0 +1,53 @@
+/*----------------------------------------------------------------------------/
+  Lovyan GFX - Graphics library for embedded devices.
+
+Original Source:
+ https://github.com/lovyan03/LovyanGFX/
+
+Licence:
+ [FreeBSD](https://github.com/lovyan03/LovyanGFX/blob/master/license.txt)
+
+Author:
+ [lovyan03](https://twitter.com/lovyan03)
+
+Contributors:
+ [ciniml](https://github.com/ciniml)
+ [mongonta0716](https://github.com/mongonta0716)
+ [tobozo](https://github.com/tobozo)
+/----------------------------------------------------------------------------*/
+#pragma once
+
+#include "../Touch.hpp"
+
+namespace lgfx
+{
+ inline namespace v1
+ {
+//----------------------------------------------------------------------------
+
+  struct Touch_RA8875 : public ITouch
+  {
+    Touch_RA8875(void)
+    {
+      _cfg.freq = 1000000;
+      _cfg.x_min = 300;
+      _cfg.x_max = 3900;
+      _cfg.y_min = 400;
+      _cfg.y_max = 3900;
+    }
+
+    bool init(void) override;
+
+    void wakeup(void) override {}
+    void sleep(void) override {}
+
+    uint_fast8_t getTouchRaw(touch_point_t* tp, uint_fast8_t count) override;
+
+  private:
+    uint8_t readRegister8(uint8_t reg);
+    void writeRegister8(uint8_t reg, uint8_t data);
+  };
+
+//----------------------------------------------------------------------------
+ }
+}

src/lgfx/v1_init.hpp

@@ -66,4 +66,4 @@ Original Source:
 #include "v1/touch/Touch_STMPE610.hpp"
 #include "v1/touch/Touch_TT21xxx.hpp"
 #include "v1/touch/Touch_XPT2046.hpp"
-
+#include "v1/touch/Touch_RA8875.hpp"