From b0ec24bc9eb8552c335d4d62250b13e5015157e4 Mon Sep 17 00:00:00 2001
From: Gunar Schorcht <gunar@schorcht.net>
Date: Fri, 14 Jul 2023 00:59:22 +0200
Subject: [PATCH] drivers/st7735: add MCU 8080 8-/16-bit parallel mode support

---
 drivers/include/st77xx.h               | 14 +++++++--
 drivers/st77xx/include/st77xx_params.h | 40 +++++++++++++++++++++++---
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/drivers/include/st77xx.h b/drivers/include/st77xx.h
index f88b711a0a73..eb755ed55376 100644
--- a/drivers/include/st77xx.h
+++ b/drivers/include/st77xx.h
@@ -22,8 +22,18 @@
  * @ref lcd_params_t::cntrl or as macro @ref ST77XX_PARAM_CNTRL if the
  * default parameter set @ref ST77XX_PARAMS is used.
  *
- * The driver uses the SPI serial interface to communicate with the display
- * controller.
+ * The driver communicates with the device either via an
+ *
+ * - SPI serial interface (if module `lcd_spi` enabled) or an
+ * - MCU 8080 8-/16-bit parallel interface (if module `lcd_parallel` or
+ *   module `lcd_parallel_16` is enabled).
+ *
+ * Usually the device driver is used either for a single display with SPI serial
+ * interface or for a display with parallel MCU 8080 8-/16-bit parallel
+ * interface. However, the device driver can also be used simultaneously for
+ * multiple displays with different interfaces if several of the `lcd_spi`,
+ * `lcd_parallel` and `lcd_parallel_16bit` modules are enabled at the same time.
+ * In this case, please refer to the notes in @ref lcd_params_t.
  *
  * The device requires colors to be send in big endian RGB-565 format. The
  * @ref CONFIG_LCD_LE_MODE compile time option can switch this, but only use this
diff --git a/drivers/st77xx/include/st77xx_params.h b/drivers/st77xx/include/st77xx_params.h
index e3b2ab7b309a..37508059cf4a 100644
--- a/drivers/st77xx/include/st77xx_params.h
+++ b/drivers/st77xx/include/st77xx_params.h
@@ -137,14 +137,46 @@ extern "C" {
 #define ST77XX_PARAM_OFFSET_Y       0               /**< Vertival offset */
 #endif
 
+#if MODULE_LCD_SPI || DOXYGEN
+/** Default interface params if SPI serial interface is enabled */
+#define ST77XX_PARAM_IF_SPI         .spi = ST77XX_PARAM_SPI, \
+                                    .spi_clk = ST77XX_PARAM_SPI_CLK, \
+                                    .spi_mode = ST77XX_PARAM_SPI_MODE,
+#else
+#define ST77XX_PARAM_IF_SPI
+#endif
+
+#if MODULE_LCD_PARALLEL || DOXYGEN
+/** Default interface params if MCU 8080 8-bit parallel interface is enabled */
+#define ST77XX_PARAM_IF_PAR         .d0_pin = ST77XX_PARAM_D0, \
+                                    .d1_pin = ST77XX_PARAM_D1, \
+                                    .d2_pin = ST77XX_PARAM_D2, \
+                                    .d3_pin = ST77XX_PARAM_D3, \
+                                    .d4_pin = ST77XX_PARAM_D4, \
+                                    .d5_pin = ST77XX_PARAM_D5, \
+                                    .d6_pin = ST77XX_PARAM_D6, \
+                                    .d7_pin = ST77XX_PARAM_D7, \
+                                    .wrx_pin = ST77XX_PARAM_WRX, \
+                                    .rdx_pin = ST77XX_PARAM_RDX,
+#else
+#define ST77XX_PARAM_IF_PAR
+#endif
+
 /**
  * @brief   Default params
+ *
+ * @note The default parameter set defined here can only be used if a single
+ *       ST77xx display and only one interface mode is used. If multiple
+ *       ST77xx displays are used or if multiple interface modes are enabled
+ *       by the modules `lcd_spi`, lcd_parallel and `lcd_parallel_16bit`, a user
+ *       defined parameter set @ref ST77XX_PARAMS has to be defined. In the
+ *       latter case @ref lcd_params_t::spi must then be set to @ref SPI_UNDEF
+ *       for displays with MCU 8080 8-/16-bit parallel interfaces.
  */
 #ifndef ST77XX_PARAMS
 #define ST77XX_PARAMS              {  .cntrl = ST77XX_PARAM_CNTRL, \
-                                      .spi = ST77XX_PARAM_SPI, \
-                                      .spi_clk = ST77XX_PARAM_SPI_CLK, \
-                                      .spi_mode = ST77XX_PARAM_SPI_MODE, \
+                                      ST77XX_PARAM_IF_SPI \
+                                      ST77XX_PARAM_IF_PAR \
                                       .cs_pin = ST77XX_PARAM_CS, \
                                       .dcx_pin = ST77XX_PARAM_DCX, \
                                       .rst_pin = ST77XX_PARAM_RST, \
@@ -156,7 +188,7 @@ extern "C" {
                                       .offset_x = ST77XX_PARAM_OFFSET_X, \
                                       .offset_y = ST77XX_PARAM_OFFSET_Y, \
                                     }
-#endif
+#endif /* ST77XX_PARAMS */
 /** @} */
 
 /**