[PATCH v2 4/6] drm/tinydrm/mipi-dbi: Add poweron-reset functions

[Noralf Trønnes]

Split out common poweron-reset functionality.

Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
---
 drivers/gpu/drm/tinydrm/mi0283qt.c | 20 ++----------
 drivers/gpu/drm/tinydrm/mipi-dbi.c | 63 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/tinydrm/st7586.c   |  9 ++----
 drivers/gpu/drm/tinydrm/st7735r.c  |  8 ++---
 include/drm/tinydrm/mipi-dbi.h     |  2 ++
 5 files changed, 73 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
index c69a4d958f24..2a78bcd35045 100644
--- a/drivers/gpu/drm/tinydrm/mi0283qt.c
+++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
@@ -49,31 +49,17 @@
 
 static int mi0283qt_init(struct mipi_dbi *mipi)
 {
-	struct tinydrm_device *tdev = &mipi->tinydrm;
-	struct device *dev = tdev->drm->dev;
 	u8 addr_mode;
 	int ret;
 
 	DRM_DEBUG_KMS("\n");
 
-	ret = regulator_enable(mipi->regulator);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "Failed to enable regulator %d\n", ret);
+	ret = mipi_dbi_poweron_conditional_reset(mipi);
+	if (ret < 0)
 		return ret;
-	}
-
-	/* Avoid flicker by skipping setup if the bootloader has done it */
-	if (mipi_dbi_display_is_on(mipi))
+	if (ret > 0)
 		return 0;
 
-	mipi_dbi_hw_reset(mipi);
-	ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
-		regulator_disable(mipi->regulator);
-		return ret;
-	}
-
 	msleep(20);
 
 	mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index ecc5c81a93ac..eea6803ff223 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -463,6 +463,7 @@ bool mipi_dbi_display_is_on(struct mipi_dbi *mipi)
 
 	val &= ~DCS_POWER_MODE_RESERVED_MASK;
 
+	/* The poweron/reset value is 08h DCS_POWER_MODE_DISPLAY_NORMAL_MODE */
 	if (val != (DCS_POWER_MODE_DISPLAY |
 	    DCS_POWER_MODE_DISPLAY_NORMAL_MODE | DCS_POWER_MODE_SLEEP_MODE))
 		return false;
@@ -473,6 +474,68 @@ bool mipi_dbi_display_is_on(struct mipi_dbi *mipi)
 }
 EXPORT_SYMBOL(mipi_dbi_display_is_on);
 
+static int mipi_dbi_por_conditional(struct mipi_dbi *mipi, bool cond)
+{
+	struct device *dev = mipi->tinydrm.drm->dev;
+	int ret;
+
+	if (mipi->regulator) {
+		ret = regulator_enable(mipi->regulator);
+		if (ret) {
+			DRM_DEV_ERROR(dev, "Failed to enable regulator (%d)\n", ret);
+			return ret;
+		}
+	}
+
+	if (cond && mipi_dbi_display_is_on(mipi))
+		return 1;
+
+	mipi_dbi_hw_reset(mipi);
+	ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "Failed to send reset command (%d)\n", ret);
+		if (mipi->regulator)
+			regulator_disable(mipi->regulator);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * mipi_dbi_poweron_reset - MIPI DBI poweron and reset
+ * @mipi: MIPI DBI structure
+ *
+ * This function enables the regulator if used and does a hardware and software
+ * reset.
+ *
+ * Returns:
+ * Zero on success, or a negative error code.
+ */
+int mipi_dbi_poweron_reset(struct mipi_dbi *mipi)
+{
+	return mipi_dbi_por_conditional(mipi, false);
+}
+EXPORT_SYMBOL(mipi_dbi_poweron_reset);
+
+/**
+ * mipi_dbi_poweron_conditional_reset - MIPI DBI poweron and conditional reset
+ * @mipi: MIPI DBI structure
+ *
+ * This function enables the regulator if used and if the display is off, it
+ * does a hardware and software reset. If mipi_dbi_display_is_on() determines
+ * that the display is on, no reset is performed.
+ *
+ * Returns:
+ * Zero if the controller was reset, 1 if the display was already on, or a
+ * negative error code.
+ */
+int mipi_dbi_poweron_conditional_reset(struct mipi_dbi *mipi)
+{
+	return mipi_dbi_por_conditional(mipi, true);
+}
+EXPORT_SYMBOL(mipi_dbi_poweron_conditional_reset);
+
 #if IS_ENABLED(CONFIG_SPI)
 
 /**
diff --git a/drivers/gpu/drm/tinydrm/st7586.c b/drivers/gpu/drm/tinydrm/st7586.c
index 9fd4423c8e70..a6396ef9cc4a 100644
--- a/drivers/gpu/drm/tinydrm/st7586.c
+++ b/drivers/gpu/drm/tinydrm/st7586.c
@@ -179,19 +179,16 @@ static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 {
 	struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 	struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
-	struct device *dev = tdev->drm->dev;
 	int ret;
 	u8 addr_mode;
 
 	DRM_DEBUG_KMS("\n");
 
-	mipi_dbi_hw_reset(mipi);
-	ret = mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
+	ret = mipi_dbi_poweron_reset(mipi);
+	if (ret)
 		return;
-	}
 
+	mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
 	mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
 
 	msleep(10);
diff --git a/drivers/gpu/drm/tinydrm/st7735r.c b/drivers/gpu/drm/tinydrm/st7735r.c
index 1f38e15da676..650257ad0193 100644
--- a/drivers/gpu/drm/tinydrm/st7735r.c
+++ b/drivers/gpu/drm/tinydrm/st7735r.c
@@ -46,13 +46,9 @@ static void jd_t18003_t01_pipe_enable(struct drm_simple_display_pipe *pipe,
 
 	DRM_DEBUG_KMS("\n");
 
-	mipi_dbi_hw_reset(mipi);
-
-	ret = mipi_dbi_command(mipi, MIPI_DCS_SOFT_RESET);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
+	ret = mipi_dbi_poweron_reset(mipi);
+	if (ret)
 		return;
-	}
 
 	msleep(150);
 
diff --git a/include/drm/tinydrm/mipi-dbi.h b/include/drm/tinydrm/mipi-dbi.h
index 6441d9a9161a..795a4a2205bb 100644
--- a/include/drm/tinydrm/mipi-dbi.h
+++ b/include/drm/tinydrm/mipi-dbi.h
@@ -73,6 +73,8 @@ void mipi_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
 void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe);
 void mipi_dbi_hw_reset(struct mipi_dbi *mipi);
 bool mipi_dbi_display_is_on(struct mipi_dbi *mipi);
+int mipi_dbi_poweron_reset(struct mipi_dbi *mipi);
+int mipi_dbi_poweron_conditional_reset(struct mipi_dbi *mipi);
 u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len);
 
 int mipi_dbi_command_read(struct mipi_dbi *mipi, u8 cmd, u8 *val);
-- 
2.14.2