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From: Thomas Zimmermann <tzimmermann@suse.de>
To: Icenowy Zheng <icenowy@sipeed.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Rob Herring <robh+dt@kernel.org>
Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] drm/tiny: add simple-dbi driver
Date: Tue, 3 Aug 2021 10:21:34 +0200	[thread overview]
Message-ID: <4825d604-668e-38bc-96c8-dc86ed782a10@suse.de> (raw)
In-Reply-To: <f69afa7ac2984c5145f38c037a06668b9e08fe44.camel@sipeed.com>


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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@sipeed.com>
>>> ---
>>>    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@aosc.io>");
>>> +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@suse.de>

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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  parent reply	other threads:[~2021-08-03  8:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02  6:35 [PATCH 0/4] Add simple-dbi tinydrm driver Icenowy Zheng
2021-08-02  6:35 ` [PATCH 1/4] dt-bindings: vendor-prefixes: add Zhishengxin Icenowy Zheng
2021-08-06 21:44   ` Rob Herring
2021-08-02  6:35 ` [PATCH 2/4] dt-bindings: display: add binding for simple-dbi panels Icenowy Zheng
2021-08-06 21:46   ` Rob Herring
2021-08-02  6:35 ` [PATCH 3/4] drm/tiny: add simple-dbi driver Icenowy Zheng
2021-08-02  9:02   ` kernel test robot
2021-08-02 15:08   ` Thomas Zimmermann
     [not found]     ` <f69afa7ac2984c5145f38c037a06668b9e08fe44.camel@sipeed.com>
2021-08-03  8:21       ` Thomas Zimmermann [this message]
2021-08-02  6:35 ` [PATCH 4/4] MAINTAINERS: " Icenowy Zheng

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