From 3f199180414445d4157a80f505dbf48d00d02fca Mon Sep 17 00:00:00 2001
From: Johann Fischer <j.fischer@phytec.de>
Date: Mon, 11 May 2020 16:29:47 +0200
Subject: [PATCH] drivers: ssd16xx: add temperature sensor support

Appropriate WS can be loaded automatically if
the display controller has integrated temperature
sensor or an external sensor is connected.

Signed-off-by: Johann Fischer <j.fischer@phytec.de>
---
 .../waveshare_epaper_gdeh0154a07.overlay      |  1 +
 drivers/display/ssd16xx.c                     | 26 ++++++++++++++++---
 dts/bindings/display/solomon,ssd16xx.yaml     |  9 +++++++
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/boards/shields/waveshare_epaper/waveshare_epaper_gdeh0154a07.overlay b/boards/shields/waveshare_epaper/waveshare_epaper_gdeh0154a07.overlay
index 15872e9482c..7e0ae2b35f5 100644
--- a/boards/shields/waveshare_epaper/waveshare_epaper_gdeh0154a07.overlay
+++ b/boards/shields/waveshare_epaper/waveshare_epaper_gdeh0154a07.overlay
@@ -24,5 +24,6 @@
 		sdv = [41 a8 32];
 		vcom = <0x00>;
 		border-waveform = <0x05>;
+		tssv = <0x80>;
 	};
 };
diff --git a/drivers/display/ssd16xx.c b/drivers/display/ssd16xx.c
index b1acd2537d0..59f52f764a5 100644
--- a/drivers/display/ssd16xx.c
+++ b/drivers/display/ssd16xx.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 PHYTEC Messtechnik GmbH
+ * Copyright (c) 2018-2020 PHYTEC Messtechnik GmbH
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -22,7 +22,7 @@ LOG_MODULE_REGISTER(ssd16xx);
 #include <display/cfb.h>
 
 /**
- * SSD1673, SSD1608 compatible EPD controller driver.
+ * SSD1673, SSD1608, SSD1681, ILI3897 compatible EPD controller driver.
  */
 
 #define SSD16XX_SPI_FREQ DT_INST_PROP(0, spi_max_frequency)
@@ -435,9 +435,28 @@ static int ssd16xx_clear_cntlr_mem(struct device *dev, uint8_t ram_cmd,
 static inline int ssd16xx_load_ws_from_otp(struct device *dev)
 {
 	struct ssd16xx_data *driver = dev->driver_data;
-	int16_t t = (SSD16XX_DEFAULT_TR_VALUE * SSD16XX_TR_SCALE_FACTOR);
 	uint8_t tmp[2];
 
+#if DT_INST_NODE_HAS_PROP(0, tssv)
+	/*
+	 * Controller has an integrated temperature sensor or external
+	 * temperature sensor is connected to the controller.
+	 */
+	LOG_INF("Select and load WS from OTP");
+
+	tmp[0] = DT_INST_PROP(0, tssv);
+	if (ssd16xx_write_cmd(driver,
+			      SSD16XX_CMD_TSENSOR_SELECTION,
+			      tmp, 1)) {
+		return -EIO;
+	}
+
+	driver->update_cmd |= SSD16XX_CTRL2_LOAD_LUT |
+			      SSD16XX_CTRL2_LOAD_TEMPERATURE;
+
+	return 0;
+#else
+	int16_t t = (SSD16XX_DEFAULT_TR_VALUE * SSD16XX_TR_SCALE_FACTOR);
 
 	LOG_INF("Load default WS (25 degrees Celsius) from OTP");
 
@@ -477,6 +496,7 @@ static inline int ssd16xx_load_ws_from_otp(struct device *dev)
 	driver->update_cmd |= SSD16XX_CTRL2_LOAD_LUT;
 
 	return 0;
+#endif
 }
 
 static int ssd16xx_load_ws_initial(struct device *dev)
diff --git a/dts/bindings/display/solomon,ssd16xx.yaml b/dts/bindings/display/solomon,ssd16xx.yaml
index 6ceec4684c3..97ab09042ad 100644
--- a/dts/bindings/display/solomon,ssd16xx.yaml
+++ b/dts/bindings/display/solomon,ssd16xx.yaml
@@ -92,3 +92,12 @@ properties:
     lut-default:
       type: uint8-array
       required: false
+
+    tssv:
+      type: int
+      required: false
+      description: Temperature Sensor Selection Value
+
+        Display controller can have integrated temperature sensor or
+        an external temperature sensor is connected to the controller.
+        The value selects which sensor should be used.