Re: [PATCH 3/4] drm/tiny: add simple-dbi driver

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Hi

Am 03.08.21 um 03:25 schrieb Icenowy Zheng:
在 2021-08-02星期一的 17:08 +0200,Thomas Zimmermann写道:
Hi

Am 02.08.21 um 08:35 schrieb Icenowy Zheng:
Add a driver for generic MIPI DBI panels initialized with MIPI DCS
commands.

Currently a ST7789V-based panel is added to it. This panel has its
configuration pre-programmed into the controller, so no vendor-
specific
configuration is needed.

Signed-off-by: Icenowy Zheng <icenowy@xxxxxxxxxx>
---
   drivers/gpu/drm/tiny/Kconfig      |  12 ++
   drivers/gpu/drm/tiny/Makefile     |   1 +
   drivers/gpu/drm/tiny/simple-dbi.c | 244
++++++++++++++++++++++++++++++
   3 files changed, 257 insertions(+)
   create mode 100644 drivers/gpu/drm/tiny/simple-dbi.c

diff --git a/drivers/gpu/drm/tiny/Kconfig
b/drivers/gpu/drm/tiny/Kconfig
index d31be274a2bd..6cfc57b68a46 100644
--- a/drivers/gpu/drm/tiny/Kconfig
+++ b/drivers/gpu/drm/tiny/Kconfig
@@ -144,6 +144,18 @@ config TINYDRM_REPAPER
          If M is selected the module will be called repaper. +config TINYDRM_SIMPLE_DBI
+       tristate "DRM support for generic MIPI DBI panels"
+       depends on DRM && SPI
+       select DRM_KMS_HELPER
+       select DRM_KMS_CMA_HELPER
+       select DRM_MIPI_DBI
+       help
+         DRM driver for generic DBI panels that are MIPI DCS
compatible
+         and needs no vendor-specific setup commands.
+
+         If M is selected the module will be called simple-dbi.
+
   config TINYDRM_ST7586
         tristate "DRM support for Sitronix ST7586 display panels"
         depends on DRM && SPI
diff --git a/drivers/gpu/drm/tiny/Makefile
b/drivers/gpu/drm/tiny/Makefile
index e09942895c77..2553de651aa3 100644
--- a/drivers/gpu/drm/tiny/Makefile
+++ b/drivers/gpu/drm/tiny/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_TINYDRM_MI0283QT)                +=
mi0283qt.o
   obj-$(CONFIG_TINYDRM_REPAPER)         += repaper.o
   obj-$(CONFIG_TINYDRM_ST7586)          += st7586.o
   obj-$(CONFIG_TINYDRM_ST7735R)         += st7735r.o
+obj-$(CONFIG_TINYDRM_SIMPLE_DBI)       += simple-dbi.o
diff --git a/drivers/gpu/drm/tiny/simple-dbi.c
b/drivers/gpu/drm/tiny/simple-dbi.c
new file mode 100644
index 000000000000..2b207e43d500
--- /dev/null
+++ b/drivers/gpu/drm/tiny/simple-dbi.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DRM driver for display panels with configuration preset and
needs only
+ * standard MIPI DCS commands to bring up.
+ *
+ * Copyright (C) 2021 Sipeed
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/dma-buf.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_mipi_dbi.h>
+
+#define MIPI_DCS_ADDRESS_MODE_BGR              BIT(3)
+#define MIPI_DCS_ADDRESS_MODE_REVERSE          BIT(5)
+#define MIPI_DCS_ADDRESS_MODE_RTL              BIT(6)
+#define MIPI_DCS_ADDRESS_MODE_BTT              BIT(7)
+
+struct simple_dbi_cfg {
+       const struct drm_display_mode mode;
+       unsigned int left_offset;
+       unsigned int top_offset;
+       bool inverted;
+       bool write_only;
+       bool bgr;
+       bool right_to_left;
+       bool bottom_to_top;
+};
+
+struct simple_dbi_priv {
+       struct mipi_dbi_dev dbidev;     /* Must be first for
.release() */

Which release?

Ah, some copy-n-paste waste.

Will drop this in v2.


+       const struct simple_dbi_cfg *cfg;
+};
+
+static void simple_dbi_pipe_enable(struct drm_simple_display_pipe
*pipe,
+                               struct drm_crtc_state *crtc_state,
+                               struct drm_plane_state
*plane_state)
+{
+       struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe-
crtc.dev);
+       struct simple_dbi_priv *priv = container_of(dbidev,
+                                                   struct
simple_dbi_priv,
+                                                   dbidev);
+       struct mipi_dbi *dbi = &dbidev->dbi;
+       int ret, idx;
+       u8 addr_mode = 0x00;
+
+       if (!drm_dev_enter(pipe->crtc.dev, &idx))
+               return;
+
+       DRM_DEBUG_KMS("\n");

I'm not a friend of such debugging statements. If you absolutely want
to
keep it, rather use drm_dbg_kms().

Should be copy-n-paste waste too.


+
+       ret = mipi_dbi_poweron_reset(dbidev);
+       if (ret)
+               goto out_exit;
+
+       mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+       msleep(5);
+
+       /* Currently tinydrm supports 16bit only now */
+       mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT,
+                        MIPI_DCS_PIXEL_FMT_16BIT);
+
+       if (priv->cfg->inverted)
+               mipi_dbi_command(dbi, MIPI_DCS_ENTER_INVERT_MODE);
+       else
+               mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
+
+       if (priv->cfg->bgr)
+               addr_mode |= MIPI_DCS_ADDRESS_MODE_BGR;
+
+       if (priv->cfg->right_to_left)
+               addr_mode |= MIPI_DCS_ADDRESS_MODE_RTL;
+
+       if (priv->cfg->bottom_to_top)
+               addr_mode |= MIPI_DCS_ADDRESS_MODE_BTT;
+
+       switch (dbidev->rotation) {
+       default:
+               break;
+       case 90:
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_REVERSE;
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_RTL;
+               break;
+       case 180:
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_RTL;
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_BTT;
+               break;
+       case 270:
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_REVERSE;
+               addr_mode ^= MIPI_DCS_ADDRESS_MODE_BTT;
+               break;
+       }
+
+       mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE,
addr_mode);
+
+       mipi_dbi_command(dbi, MIPI_DCS_ENTER_NORMAL_MODE);
+
+       mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+
+       mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
+out_exit:
+       drm_dev_exit(idx);
+}
+
+static const struct drm_simple_display_pipe_funcs
simple_dbi_pipe_funcs = {
+       .enable         = simple_dbi_pipe_enable,
+       .disable        = mipi_dbi_pipe_disable,
+       .update         = mipi_dbi_pipe_update,
+       .prepare_fb     = drm_gem_simple_display_pipe_prepare_fb,
+};
+
+static const struct simple_dbi_cfg zsx154_b1206_cfg = {
+       .mode           = { DRM_SIMPLE_MODE(240, 240, 28, 28) },
+       .inverted       = true,
+       .write_only     = true,
+};
+
+DEFINE_DRM_GEM_CMA_FOPS(simple_dbi_fops);
+
+static const struct drm_driver simple_dbi_driver = {
+       .driver_features        = DRIVER_GEM | DRIVER_MODESET |
DRIVER_ATOMIC,
+       .fops                   = &simple_dbi_fops,
+       DRM_GEM_CMA_DRIVER_OPS_VMAP,
+       .debugfs_init           = mipi_dbi_debugfs_init,
+       .name                   = "simple-dbi",
+       .desc                   = "Generic MIPI-DCS compatible DBI
panel",
+       .date                   = "20210723",
+       .major                  = 1,
+       .minor                  = 0,
+};
+
+static const struct of_device_id simple_dbi_of_match[] = {
+       { .compatible = "zsx,zsx154-b1206", .data =
&zsx154_b1206_cfg },
+       { },
+}
+MODULE_DEVICE_TABLE(of, simple_dbi_of_match);
+
+static int simple_dbi_probe(struct spi_device *spi)
+{
+       struct device *dev = &spi->dev;
+       const struct simple_dbi_cfg *cfg;
+       struct mipi_dbi_dev *dbidev;
+       struct simple_dbi_priv *priv;
+       struct drm_device *drm;
+       struct mipi_dbi *dbi;
+       struct gpio_desc *dc;
+       u32 rotation = 0;
+       int ret;
+
+       cfg = device_get_match_data(&spi->dev);
+       if (!cfg)
+               cfg = (void *)spi_get_device_id(spi)->driver_data;
+
+       priv = devm_drm_dev_alloc(dev, &simple_dbi_driver,
+                                 struct simple_dbi_priv,
dbidev.drm);
+       if (IS_ERR(priv))
+               return PTR_ERR(priv);
+
+       dbidev = &priv->dbidev;
+       priv->cfg = cfg;
+
+       dbi = &dbidev->dbi;
+       drm = &dbidev->drm;
+
+       dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(dbi->reset))
+               return dev_err_probe(dev, PTR_ERR(dbi->reset),
"Failed to get reset GPIO\n");
+
+       dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
+       if (IS_ERR(dc))
+               return dev_err_probe(dev, PTR_ERR(dc), "Failed to
get D/C GPIO\n");
+
+       dbidev->backlight = devm_of_find_backlight(dev);
+       if (IS_ERR(dbidev->backlight))
+               return PTR_ERR(dbidev->backlight);
+
+       device_property_read_u32(dev, "rotation", &rotation);
+
+       ret = mipi_dbi_spi_init(spi, dbi, dc);
+       if (ret)
+               return ret;
+
+       if (cfg->write_only)
+               dbi->read_commands = NULL;
+
+       ret = mipi_dbi_dev_init(dbidev, &simple_dbi_pipe_funcs,
&cfg->mode,
+                               rotation);
+       if (ret)
+               return ret;
+
+       drm_mode_config_reset(drm);
+
+       ret = drm_dev_register(drm, 0);
+       if (ret)
+               return ret;
+
+       spi_set_drvdata(spi, drm);

AFAIK dev files are being created during drm_dev_register(). It's
probably safer to set the drvdata before.

Okay, thanks.


+
+       drm_fbdev_generic_setup(drm, 0);
+
+       return 0;
+}
+
+static int simple_dbi_remove(struct spi_device *spi)
+{
+       struct drm_device *drm = spi_get_drvdata(spi);
+
+       drm_dev_unplug(drm);
+       drm_atomic_helper_shutdown(drm);
+
+       return 0;
+}
+
+static void simple_dbi_shutdown(struct spi_device *spi)
+{
+       drm_atomic_helper_shutdown(spi_get_drvdata(spi));
+}
+
+static struct spi_driver simple_dbi_spi_driver = {
+       .driver = {
+               .name = "simple-dbi",
+               .of_match_table = simple_dbi_of_match,
+       },
+       .probe = simple_dbi_probe,
+       .remove = simple_dbi_remove,
+       .shutdown = simple_dbi_shutdown,
+};
+module_spi_driver(simple_dbi_spi_driver);
+
+MODULE_DESCRIPTION("Simple DBI panel DRM driver");
+MODULE_AUTHOR("Icenowy Zheng <icenowy@xxxxxxx>");
+MODULE_LICENSE("GPL");


Trailing blank line. (?)

Ah I do not know what happened, I just `git format-patch` and then `git
send-email`.

At least I have no trailing blank line in the file inside patch :-)

No problem. Could have been my email client.

After you cleaned up the patch as you outlined above, you can add

Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

to the patch. I don't have much insight into the MIPI code. Maybe ask for someone else's review as well.

Best regards
Thomas



Best regards
Thomas




--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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