From d7bcac091c8c8e99588b25cbe5d95b5360f2f450 Mon Sep 17 00:00:00 2001
From: Sylvio Alves <sylvio.alves@espressif.com>
Date: Wed, 24 May 2023 11:18:52 -0300
Subject: [PATCH] drivers: spi: esp32: add option to handle lines state

SPI driver is current working for common SPI devices.
However, addressable LED like WS2812 requires MOSI line to be
default LOW during initialization. This PR adds such option.
This has no effect on common SPI operation.

Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>
---
 drivers/spi/spi_esp32_spim.c              | 13 +++++++++++++
 drivers/spi/spi_esp32_spim.h              |  1 +
 dts/bindings/spi/espressif,esp32-spi.yaml |  5 +++++
 3 files changed, 19 insertions(+)

diff --git a/drivers/spi/spi_esp32_spim.c b/drivers/spi/spi_esp32_spim.c
index 3a1a5dc244a..73ce992a1d2 100644
--- a/drivers/spi/spi_esp32_spim.c
+++ b/drivers/spi/spi_esp32_spim.c
@@ -265,6 +265,7 @@ static int IRAM_ATTR spi_esp32_configure(const struct device *dev,
 	struct spi_context *ctx = &data->ctx;
 	spi_hal_context_t *hal = &data->hal;
 	spi_hal_dev_config_t *hal_dev = &data->dev_config;
+	spi_dev_t *hw = hal->hw;
 	int freq;
 
 	if (spi_context_configured(ctx, spi_cfg)) {
@@ -347,6 +348,17 @@ static int IRAM_ATTR spi_esp32_configure(const struct device *dev,
 
 	spi_hal_setup_device(hal, hal_dev);
 
+	/* Workaround to handle default state of MISO and MOSI lines */
+#ifndef CONFIG_SOC_ESP32
+	if (cfg->line_idle_low) {
+		hw->ctrl.d_pol = 0;
+		hw->ctrl.q_pol = 0;
+	} else {
+		hw->ctrl.d_pol = 1;
+		hw->ctrl.q_pol = 1;
+	}
+#endif
+
 	/*
 	 * Workaround for ESP32S3 and ESP32C3 SoC. This dummy transaction is needed to sync CLK and
 	 * software controlled CS when SPI is in mode 3
@@ -505,6 +517,7 @@ static const struct spi_driver_api spi_api = {
 		.dma_host = DT_INST_PROP(idx, dma_host),	\
 		.cs_setup = DT_INST_PROP_OR(idx, cs_setup_time, 0), \
 		.cs_hold = DT_INST_PROP_OR(idx, cs_hold_time, 0), \
+		.line_idle_low = DT_INST_PROP(idx, line_idle_low), \
 	};	\
 		\
 	DEVICE_DT_INST_DEFINE(idx, &spi_esp32_init,	\
diff --git a/drivers/spi/spi_esp32_spim.h b/drivers/spi/spi_esp32_spim.h
index 8076904f56c..e60ca70c9be 100644
--- a/drivers/spi/spi_esp32_spim.h
+++ b/drivers/spi/spi_esp32_spim.h
@@ -38,6 +38,7 @@ struct spi_esp32_config {
 	int dma_host;
 	int cs_setup;
 	int cs_hold;
+	bool line_idle_low;
 };
 
 struct spi_esp32_data {
diff --git a/dts/bindings/spi/espressif,esp32-spi.yaml b/dts/bindings/spi/espressif,esp32-spi.yaml
index 910e8e92c68..5d25838ca6d 100644
--- a/dts/bindings/spi/espressif,esp32-spi.yaml
+++ b/dts/bindings/spi/espressif,esp32-spi.yaml
@@ -76,3 +76,8 @@ properties:
     description: |
       Chip select hold time setting, see TRF for SOC for details of
       timing applied.
+
+  line-idle-low:
+    type: boolean
+    description: |
+      Default MISO and MOSI pins GPIO level when idle. Defaults to high by default.