The Display Pixel Interface is a configurable-width video-only
unidirectional parallel bus standard that defines video formats and
signaling for panel devices.

This driver implements support for simple DPI panels with no runtime
configuration capabilities (GPIOs- and/or regulators-based control can
be implemented later when needed) and exposes it as a display entity.
The panel native video mode is passed to the driver through platform
data or device tree properties.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 drivers/video/display/Kconfig     |  10 ++
 drivers/video/display/Makefile    |   1 +
 drivers/video/display/panel-dpi.c | 207 ++++++++++++++++++++++++++++++++++++++
 include/video/panel-dpi.h         |  24 +++++
 4 files changed, 242 insertions(+)
 create mode 100644 drivers/video/display/panel-dpi.c
 create mode 100644 include/video/panel-dpi.h

diff --git a/drivers/video/display/Kconfig b/drivers/video/display/Kconfig
index f7532c1..bce09d6 100644
--- a/drivers/video/display/Kconfig
+++ b/drivers/video/display/Kconfig
@@ -9,4 +9,14 @@ config DISPLAY_MIPI_DBI
        tristate
        default n

+config DISPLAY_PANEL_DPI
+       tristate "DPI (Parallel) Display Panels"
+       ---help---
+         Support for simple digital (parallel) pixel interface panels. Those
+         panels receive pixel data through a parallel bus and have no control
+         bus.
+
+         If you are in doubt, say N. To compile this driver as a module, choose
+         M here; the module will be called panel-dpi.
+
 endif # DISPLAY_CORE
diff --git a/drivers/video/display/Makefile b/drivers/video/display/Makefile
index 59022d2..31c017b 100644
--- a/drivers/video/display/Makefile
+++ b/drivers/video/display/Makefile
@@ -2,3 +2,4 @@ display-y                                       := 
display-core.o \
                                                   display-notifier.o
 obj-$(CONFIG_DISPLAY_CORE)                     += display.o
 obj-$(CONFIG_DISPLAY_MIPI_DBI)                 += mipi-dbi-bus.o
+obj-$(CONFIG_DISPLAY_PANEL_DPI)                        += panel-dpi.o
diff --git a/drivers/video/display/panel-dpi.c 
b/drivers/video/display/panel-dpi.c
new file mode 100644
index 0000000..b1ecf6d
--- /dev/null
+++ b/drivers/video/display/panel-dpi.c
@@ -0,0 +1,207 @@
+/*
+ * DPI Display Panel
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <video/display.h>
+#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
+#include <video/panel-dpi.h>
+#include <video/videomode.h>
+
+struct panel_dpi {
+       struct display_entity entity;
+
+       unsigned int width;
+       unsigned int height;
+       struct videomode mode;
+};
+
+static inline struct panel_dpi *to_panel_dpi(struct display_entity *e)
+{
+       return container_of(e, struct panel_dpi, entity);
+}
+
+static const struct display_entity_interface_params panel_dpi_params = {
+       .type = DISPLAY_ENTITY_INTERFACE_DPI,
+};
+
+static int panel_dpi_set_state(struct display_entity *entity,
+                              enum display_entity_state state)
+{
+       struct media_pad *source;
+
+       source = media_entity_remote_pad(&entity->entity.pads[0]);
+       if (source == NULL)
+               return -EPIPE;
+
+       switch (state) {
+       case DISPLAY_ENTITY_STATE_OFF:
+       case DISPLAY_ENTITY_STATE_STANDBY:
+               display_entity_set_stream(to_display_entity(source->entity),
+                                         source->index,
+                                         DISPLAY_ENTITY_STREAM_STOPPED);
+               break;
+
+       case DISPLAY_ENTITY_STATE_ON:
+               display_entity_set_stream(to_display_entity(source->entity),
+                                         source->index,
+                                         DISPLAY_ENTITY_STREAM_CONTINUOUS);
+               break;
+       }
+
+       return 0;
+}
+
+static int panel_dpi_get_modes(struct display_entity *entity, unsigned int 
port,
+                              const struct videomode **modes)
+{
+       struct panel_dpi *panel = to_panel_dpi(entity);
+
+       *modes = &panel->mode;
+       return 1;
+}
+
+static int panel_dpi_get_size(struct display_entity *entity,
+                             unsigned int *width, unsigned int *height)
+{
+       struct panel_dpi *panel = to_panel_dpi(entity);
+
+       *width = panel->width;
+       *height = panel->height;
+       return 0;
+}
+
+static int panel_dpi_get_params(struct display_entity *entity,
+                               unsigned int port,
+                               struct display_entity_interface_params *params)
+{
+       *params = panel_dpi_params;
+       return 0;
+}
+
+static const struct display_entity_control_ops panel_dpi_control_ops = {
+       .set_state = panel_dpi_set_state,
+       .get_modes = panel_dpi_get_modes,
+       .get_size = panel_dpi_get_size,
+       .get_params = panel_dpi_get_params,
+};
+
+static const struct display_entity_ops panel_dpi_ops = {
+       .ctrl = &panel_dpi_control_ops,
+};
+
+static int panel_dpi_remove(struct platform_device *pdev)
+{
+       struct panel_dpi *panel = platform_get_drvdata(pdev);
+
+       display_entity_remove(&panel->entity);
+       display_entity_cleanup(&panel->entity);
+
+       return 0;
+}
+
+static int panel_dpi_parse_pdata(struct panel_dpi *panel,
+                                struct platform_device *pdev)
+{
+       const struct panel_dpi_platform_data *pdata = pdev->dev.platform_data;
+       struct device_node *np = pdev->dev.of_node;
+       int ret;
+
+       if (pdata) {
+               panel->width = pdata->width;
+               panel->height = pdata->height;
+               panel->mode = *pdata->mode;
+       } else if (IS_ENABLED(CONFIG_OF) && np) {
+               /* Width and height are optional. */
+               of_property_read_u32(np, "width-mm", &panel->width);
+               of_property_read_u32(np, "height-mm", &panel->height);
+
+               ret = of_get_videomode(np, &panel->mode, OF_USE_NATIVE_MODE);
+               if (ret < 0)
+                       return ret;
+       } else {
+               dev_err(&pdev->dev, "no platform data\n");
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int panel_dpi_probe(struct platform_device *pdev)
+{
+       struct panel_dpi *panel;
+       int ret;
+
+       panel = devm_kzalloc(&pdev->dev, sizeof(*panel), GFP_KERNEL);
+       if (panel == NULL)
+               return -ENOMEM;
+
+       ret = panel_dpi_parse_pdata(panel, pdev);
+       if (ret < 0)
+               return ret;
+
+       panel->entity.dev = &pdev->dev;
+       panel->entity.ops = &panel_dpi_ops;
+       strlcpy(panel->entity.name, "panel-dpi", sizeof(panel->entity.name));
+
+       ret = display_entity_init(&panel->entity, 1, 0);
+       if (ret < 0)
+               return ret;
+
+       ret = display_entity_add(&panel->entity);
+       if (ret < 0)
+               return ret;
+
+       platform_set_drvdata(pdev, panel);
+
+       return 0;
+}
+
+static const struct dev_pm_ops panel_dpi_dev_pm_ops = {
+};
+
+static struct platform_device_id panel_dpi_id_table[] = {
+       { "panel-dpi", 0 },
+       { },
+};
+MODULE_DEVICE_TABLE(platform, panel_dpi_id_table);
+
+#ifdef CONFIG_OF
+static struct of_device_id panel_dpi_of_id_table[] = {
+       { .compatible = "panel-dpi", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, panel_dpi_of_id_table);
+#endif
+
+static struct platform_driver panel_dpi_driver = {
+       .probe = panel_dpi_probe,
+       .remove = panel_dpi_remove,
+       .id_table = panel_dpi_id_table,
+       .driver = {
+               .name = "panel-dpi",
+               .owner = THIS_MODULE,
+               .pm = &panel_dpi_dev_pm_ops,
+               .of_match_table = of_match_ptr(panel_dpi_of_id_table),
+       },
+};
+
+module_platform_driver(panel_dpi_driver);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart at ideasonboard.com>");
+MODULE_DESCRIPTION("DPI Display Panel");
+MODULE_LICENSE("GPL");
diff --git a/include/video/panel-dpi.h b/include/video/panel-dpi.h
new file mode 100644
index 0000000..af85d5b
--- /dev/null
+++ b/include/video/panel-dpi.h
@@ -0,0 +1,24 @@
+/*
+ * DPI Display Panel
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __PANEL_DPI_H__
+#define __PANEL_DPI_H__
+
+struct videomode;
+
+struct panel_dpi_platform_data {
+       unsigned long width;            /* Panel width in mm */
+       unsigned long height;           /* Panel height in mm */
+       const struct videomode *mode;
+};
+
+#endif /* __PANEL_DPI_H__ */
-- 
1.8.1.5

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