linux-kernel - [PATCH v3 3/5] drm/mipi-dbi: Make bits per word configurable for pixel transfers

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Message-Id: <20240603-panel-mipi-dbi-rgb666-v3-3-59ed53ca73da@tronnes.org>
Date: Mon, 03 Jun 2024 13:21:34 +0200
From: Noralf Trønnes via B4 Relay <devnull+noralf.tronnes.org@...nel.org>
To: Neil Armstrong <neil.armstrong@...aro.org>, 
 Jessica Zhang <quic_jesszhan@...cinc.com>, Sam Ravnborg <sam@...nborg.org>, 
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
 Conor Dooley <conor+dt@...nel.org>, David Lechner <david@...hnology.com>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Kamlesh Gurudasani <kamlesh.gurudasani@...il.com>, 
 Tommaso Merciai <tommaso.merciai@...rulasolutions.com>, 
 Noralf Trønnes <noralf@...nnes.org>
Subject: [PATCH v3 3/5] drm/mipi-dbi: Make bits per word configurable for
 pixel transfers

From: Noralf Trønnes <noralf@...nnes.org>

This prepares for supporting other pixel formats than RGB565.

Signed-off-by: Noralf Trønnes <noralf@...nnes.org>
---
 drivers/gpu/drm/drm_mipi_dbi.c | 14 ++++++++++----
 include/drm/drm_mipi_dbi.h     |  5 +++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
index fa8aba6dc81c..77f8a828d6e0 100644
--- a/drivers/gpu/drm/drm_mipi_dbi.c
+++ b/drivers/gpu/drm/drm_mipi_dbi.c
@@ -1079,7 +1079,7 @@ static int mipi_dbi_typec1_command_read(struct mipi_dbi *dbi, u8 *cmd,
 static int mipi_dbi_typec1_command(struct mipi_dbi *dbi, u8 *cmd,
 				   u8 *parameters, size_t num)
 {
-	unsigned int bpw = (*cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
+	unsigned int bpw = 8;
 	int ret;
 
 	if (mipi_dbi_command_is_read(dbi, *cmd))
@@ -1091,6 +1091,9 @@ static int mipi_dbi_typec1_command(struct mipi_dbi *dbi, u8 *cmd,
 	if (ret || !num)
 		return ret;
 
+	if (*cmd == MIPI_DCS_WRITE_MEMORY_START)
+		bpw = dbi->write_memory_bpw;
+
 	return mipi_dbi_spi1_transfer(dbi, 1, parameters, num, bpw);
 }
 
@@ -1184,8 +1187,8 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *dbi, u8 *cmd,
 	if (ret || !num)
 		return ret;
 
-	if (*cmd == MIPI_DCS_WRITE_MEMORY_START && !dbi->swap_bytes)
-		bpw = 16;
+	if (*cmd == MIPI_DCS_WRITE_MEMORY_START)
+		bpw = dbi->write_memory_bpw;
 
 	spi_bus_lock(spi->controller);
 	gpiod_set_value_cansleep(dbi->dc, 1);
@@ -1256,12 +1259,15 @@ int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *dbi,
 
 	dbi->spi = spi;
 	dbi->read_commands = mipi_dbi_dcs_read_commands;
+	dbi->write_memory_bpw = 16;
 
 	if (dc) {
 		dbi->command = mipi_dbi_typec3_command;
 		dbi->dc = dc;
-		if (!spi_is_bpw_supported(spi, 16))
+		if (!spi_is_bpw_supported(spi, 16)) {
+			dbi->write_memory_bpw = 8;
 			dbi->swap_bytes = true;
+		}
 	} else {
 		dbi->command = mipi_dbi_typec1_command;
 		dbi->tx_buf9_len = SZ_16K;
diff --git a/include/drm/drm_mipi_dbi.h b/include/drm/drm_mipi_dbi.h
index e8e0f8d39f3a..b36596efdcc3 100644
--- a/include/drm/drm_mipi_dbi.h
+++ b/include/drm/drm_mipi_dbi.h
@@ -56,6 +56,11 @@ struct mipi_dbi {
 	 */
 	struct spi_device *spi;
 
+	/**
+	 * @write_memory_bpw: Bits per word used on a MIPI_DCS_WRITE_MEMORY_START transfer
+	 */
+	unsigned int write_memory_bpw;
+
 	/**
 	 * @dc: Optional D/C gpio.
 	 */

-- 
2.45.1