From mboxrd@z Thu Jan  1 00:00:00 1970
From: eric@anholt.net (Eric Anholt)
Date: Tue, 21 Mar 2017 13:55:18 -0700
Subject: [PATCH v4 2/8] drm/stm: Add STM32 LTDC driver
In-Reply-To: <1489597334-16896-3-git-send-email-yannick.fertre@st.com>
References: <1489597334-16896-1-git-send-email-yannick.fertre@st.com>
 <1489597334-16896-3-git-send-email-yannick.fertre@st.com>
Message-ID: <87shm61hah.fsf@eliezer.anholt.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Yannick Fertre <yannick.fertre@st.com> writes:

> This controller provides output signals to interface directly a variety
> of LCD and TFT panels. These output signals are: RGB signals
> (up to 24bpp), vertical & horizontal synchronisations, data enable and
> the pixel clock.

I've got some feedback inline that hopefully helps cut some boilerplate
DRM code.  This looks like a complete driver, and some nice hardware as
far as modesetting goes.

If you're planning on going through drm-misc, I'd do another pass at
review so I could give an Ack.

> Change-Id: Ic1d6ade06ab7115c62e98dd21dc3981fb5948d1c
> Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
> ---
>  drivers/gpu/drm/Kconfig      |    3 +-
>  drivers/gpu/drm/Makefile     |    1 +
>  drivers/gpu/drm/stm/Kconfig  |   16 +
>  drivers/gpu/drm/stm/Makefile |    7 +
>  drivers/gpu/drm/stm/drv.c    |  232 +++++++
>  drivers/gpu/drm/stm/drv.h    |   22 +
>  drivers/gpu/drm/stm/ltdc.c   | 1422 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/stm/ltdc.h   |   22 +
>  8 files changed, 1724 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/stm/Kconfig
>  create mode 100644 drivers/gpu/drm/stm/Makefile
>  create mode 100644 drivers/gpu/drm/stm/drv.c
>  create mode 100644 drivers/gpu/drm/stm/drv.h
>  create mode 100644 drivers/gpu/drm/stm/ltdc.c
>  create mode 100644 drivers/gpu/drm/stm/ltdc.h
>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 78d7fc0..dd5762a 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -203,7 +203,6 @@ config DRM_VGEM
>  	  as used by Mesa's software renderer for enhanced performance.
>  	  If M is selected the module will be called vgem.
>  
> -
>  source "drivers/gpu/drm/exynos/Kconfig"
>  
>  source "drivers/gpu/drm/rockchip/Kconfig"
> @@ -246,6 +245,8 @@ source "drivers/gpu/drm/fsl-dcu/Kconfig"
>  
>  source "drivers/gpu/drm/tegra/Kconfig"
>  
> +source "drivers/gpu/drm/stm/Kconfig"
> +
>  source "drivers/gpu/drm/panel/Kconfig"
>  
>  source "drivers/gpu/drm/bridge/Kconfig"
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 59aae43..320fd86 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -81,6 +81,7 @@ obj-$(CONFIG_DRM_BOCHS) += bochs/
>  obj-$(CONFIG_DRM_VIRTIO_GPU) += virtio/
>  obj-$(CONFIG_DRM_MSM) += msm/
>  obj-$(CONFIG_DRM_TEGRA) += tegra/
> +obj-$(CONFIG_DRM_STM) += stm/
>  obj-$(CONFIG_DRM_STI) += sti/
>  obj-$(CONFIG_DRM_IMX) += imx/
>  obj-$(CONFIG_DRM_MEDIATEK) += mediatek/
> diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
> new file mode 100644
> index 0000000..8ef8a09
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/Kconfig
> @@ -0,0 +1,16 @@
> +config DRM_STM
> +	tristate "DRM Support for STMicroelectronics SoC Series"
> +	depends on DRM && (ARCH_STM32 || ARCH_MULTIPLATFORM)
> +	select DRM_KMS_HELPER
> +	select DRM_GEM_CMA_HELPER
> +	select DRM_KMS_CMA_HELPER
> +	select DRM_PANEL
> +	select VIDEOMODE_HELPERS
> +	select FB_PROVIDE_GET_FB_UNMAPPED_AREA
> +	default y
> +
> +	help
> +	  Enable support for the on-chip display controller on
> +	   STMicroelectronics STM32 MCUs.

Funny indentation here?

> +	  To compile this driver as a module, choose M here: the module
> +	  will be called stm-drm.
> diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
> new file mode 100644
> index 0000000..e114d45
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/Makefile
> @@ -0,0 +1,7 @@
> +ccflags-y := -Iinclude/drm
> +
> +stm-drm-y := \
> +	drv.o \
> +	ltdc.o
> +
> +obj-$(CONFIG_DRM_STM) += stm-drm.o
> diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
> new file mode 100644
> index 0000000..d5c46c5
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/drv.c
> @@ -0,0 +1,232 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <philippe.cornu@st.com>
> + *          Yannick Fertre <yannick.fertre@st.com>
> + *          Fabien Dessenne <fabien.dessenne@st.com>
> + *          Mickael Reulier <mickael.reulier@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#include <linux/component.h>
> +#include <linux/of_platform.h>
> +
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_fb_cma_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +
> +#include "drv.h"
> +#include "ltdc.h"
> +
> +#define DRIVER_NAME		"stm"
> +#define DRIVER_DESC		"STMicroelectronics SoC DRM"
> +#define DRIVER_DATE		"20170209"
> +#define DRIVER_MAJOR		1
> +#define DRIVER_MINOR		0
> +#define DRIVER_PATCH_LEVEL	0
> +
> +#define STM_MAX_FB_WIDTH		2048
> +#define STM_MAX_FB_HEIGHT	2048 /* same as width to handle orientation */
> +
> +static void drv_output_poll_changed(struct drm_device *ddev)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +
> +	drm_fbdev_cma_hotplug_event(priv->fbdev);
> +}
> +
> +static const struct drm_mode_config_funcs drv_mode_config_funcs = {
> +	.fb_create = drm_fb_cma_create,
> +	.output_poll_changed = drv_output_poll_changed,
> +	.atomic_check = drm_atomic_helper_check,
> +	.atomic_commit = drm_atomic_helper_commit,
> +};
> +
> +static const struct file_operations drv_driver_fops = {
> +	.owner = THIS_MODULE,
> +	.open = drm_open,
> +	.release = drm_release,
> +	.unlocked_ioctl = drm_ioctl,
> +	.compat_ioctl = drm_compat_ioctl,
> +	.poll = drm_poll,
> +	.read = drm_read,
> +	.mmap = drm_gem_cma_mmap,
> +	.get_unmapped_area = drm_gem_cma_get_unmapped_area,
> +};

This looks like almost a candidate for the new
DEFINE_DRM_GEM_CMA_FOPS().  Maybe that helper should conditionally add
the drm_gem_cma_get_unmapped_area reference on !MMU?

> +
> +static void drv_lastclose(struct drm_device *ddev)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +
> +	DRM_DEBUG("%s\n", __func__);
> +
> +	drm_fbdev_cma_restore_mode(priv->fbdev);
> +}
> +
> +static struct drm_driver drv_driver = {
> +	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME |
> +			   DRIVER_ATOMIC,
> +	.lastclose = drv_lastclose,
> +	.name = DRIVER_NAME,
> +	.desc = DRIVER_DESC,
> +	.date = DRIVER_DATE,
> +	.major = DRIVER_MAJOR,
> +	.minor = DRIVER_MINOR,
> +	.patchlevel = DRIVER_PATCH_LEVEL,
> +	.fops = &drv_driver_fops,
> +	.dumb_create = drm_gem_cma_dumb_create,
> +	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
> +	.dumb_destroy = drm_gem_dumb_destroy,
> +	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> +	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> +	.gem_free_object_unlocked = drm_gem_cma_free_object,
> +	.gem_vm_ops = &drm_gem_cma_vm_ops,
> +	.gem_prime_export = drm_gem_prime_export,
> +	.gem_prime_import = drm_gem_prime_import,
> +	.gem_prime_get_sg_table = drm_gem_cma_prime_get_sg_table,
> +	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> +	.gem_prime_vmap = drm_gem_cma_prime_vmap,
> +	.gem_prime_vunmap = drm_gem_cma_prime_vunmap,
> +	.gem_prime_mmap = drm_gem_cma_prime_mmap,
> +	.enable_vblank = ltdc_crtc_enable_vblank,
> +	.disable_vblank = ltdc_crtc_disable_vblank,
> +};
> +
> +static int drv_load(struct drm_device *ddev)
> +{
> +	struct platform_device *pdev = to_platform_device(ddev->dev);
> +	struct drm_fbdev_cma *fbdev;
> +	struct stm_private *priv;
> +	int ret;
> +
> +	DRM_DEBUG("%s\n", __func__);
> +
> +	priv = devm_kzalloc(ddev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	ddev->dev_private = (void *)priv;
> +
> +	drm_mode_config_init(ddev);
> +
> +	/*
> +	 * set max width and height as default value.
> +	 * this value would be used to check framebuffer size limitation
> +	 * at drm_mode_addfb().
> +	 */
> +	ddev->mode_config.min_width = 0;
> +	ddev->mode_config.min_height = 0;
> +	ddev->mode_config.max_width = STM_MAX_FB_WIDTH;
> +	ddev->mode_config.max_height = STM_MAX_FB_HEIGHT;
> +	ddev->mode_config.funcs = &drv_mode_config_funcs;
> +
> +	ret = ltdc_load(ddev);
> +	if (ret)
> +		return ret;
> +
> +	drm_mode_config_reset(ddev);
> +	drm_kms_helper_poll_init(ddev);
> +
> +	if (ddev->mode_config.num_connector) {
> +		priv = ddev->dev_private;
> +		fbdev = drm_fbdev_cma_init(ddev, 16,
> +					   ddev->mode_config.num_connector);
> +		if (IS_ERR(fbdev)) {
> +			DRM_DEBUG("Warning: fails to create fbdev\n");
> +			fbdev = NULL;
> +		}
> +		priv->fbdev = fbdev;
> +	}
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	return 0;
> +}
> +
> +static void drv_unload(struct drm_device *ddev)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +
> +	DRM_DEBUG("%s\n", __func__);
> +
> +	ltdc_unload(ddev);
> +
> +	if (priv->fbdev) {
> +		drm_fbdev_cma_fini(priv->fbdev);
> +		priv->fbdev = NULL;
> +	}
> +
> +	drm_kms_helper_poll_fini(ddev);
> +	drm_vblank_cleanup(ddev);
> +	drm_mode_config_cleanup(ddev);
> +}
> +
> +static int stm_drm_platform_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct drm_device *ddev;
> +	int ret;
> +
> +	DRM_DEBUG("%s\n", __func__);
> +
> +	dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
> +
> +	ddev = drm_dev_alloc(&drv_driver, dev);
> +	if (IS_ERR(ddev))
> +		return PTR_ERR(ddev);
> +
> +	ret = drv_load(ddev);
> +	if (ret)
> +		goto err_unref;
> +
> +	ret = drm_dev_register(ddev, 0);
> +	if (ret)
> +		goto err_unref;
> +
> +	return 0;
> +
> +err_unref:
> +	drm_dev_unref(ddev);
> +
> +	return ret;
> +}
> +
> +static int stm_drm_platform_remove(struct platform_device *pdev)
> +{
> +	struct drm_device *ddev = platform_get_drvdata(pdev);
> +
> +	DRM_DEBUG("%s\n", __func__);
> +
> +	drm_dev_unregister(ddev);
> +	drv_unload(ddev);
> +	drm_dev_unref(ddev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id drv_dt_ids[] = {
> +	{ .compatible = "st,stm32-ltdc"},
> +	{ /* end node */ },
> +};
> +MODULE_DEVICE_TABLE(of, drv_dt_ids);
> +
> +static struct platform_driver stm_drm_platform_driver = {
> +	.probe = stm_drm_platform_probe,
> +	.remove = stm_drm_platform_remove,
> +	.driver = {
> +		.name = DRIVER_NAME,
> +		.of_match_table = drv_dt_ids,
> +	},
> +};
> +
> +module_platform_driver(stm_drm_platform_driver);
> +
> +MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");
> +MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
> +MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
> +MODULE_AUTHOR("Mickael Reulier <mickael.reulier@st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics ST DRM LTDC driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/gpu/drm/stm/drv.h b/drivers/gpu/drm/stm/drv.h
> new file mode 100644
> index 0000000..edff073
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/drv.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <philippe.cornu@st.com>
> + *          Yannick Fertre <yannick.fertre@st.com>
> + *          Fabien Dessenne <fabien.dessenne@st.com>
> + *          Mickael Reulier <mickael.reulier@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#ifndef _DRV_H_
> +#define _DRV_H_
> +
> +#include <drm/drmP.h>
> +
> +struct stm_private {
> +	struct ltdc *ltdc;
> +	struct drm_fbdev_cma *fbdev;
> +};
> +

Any reason not to just put the fbdev in ltdc and drop this struct?

> +#endif
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> new file mode 100644
> index 0000000..560375d
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -0,0 +1,1422 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <philippe.cornu@st.com>
> + *          Yannick Fertre <yannick.fertre@st.com>
> + *          Fabien Dessenne <fabien.dessenne@st.com>
> + *          Mickael Reulier <mickael.reulier@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/of_address.h>
> +#include <linux/of_graph.h>
> +#include <linux/reset.h>
> +
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_fb_cma_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_plane_helper.h>
> +
> +#include <video/videomode.h>
> +
> +#include "drv.h"
> +#include "ltdc.h"
> +
> +#define NB_CRTC 1
> +#define CRTC_MASK GENMASK(NB_CRTC - 1, 0)
> +
> +#define MAX_IRQ 4
> +
> +#define HWVER_10200 0x010200
> +#define HWVER_10300 0x010300
> +#define HWVER_20101 0x020101
> +
> +/*
> + * The address of some registers depends on the HW version: such registers have
> + * an extra offset specified with reg_ofs.
> + */
> +#define REG_OFS_NONE	0
> +#define REG_OFS_4	4 /* Insertion of "Layer Configuration 2" reg */
> +#define REG_OFS		(ltdc->caps.reg_ofs)
> +#define LAY_OFS		0x80	/* Register Offset between 2 layers */
> +
> +/* Global register offsets */
> +#define LTDC_IDR	0x0000 /* IDentification */
> +#define LTDC_LCR	0x0004 /* Layer Count */
> +#define LTDC_SSCR	0x0008 /* Synchronization Size Configuration */
> +#define LTDC_BPCR	0x000C /* Back Porch Configuration */
> +#define LTDC_AWCR	0x0010 /* Active Width Configuration */
> +#define LTDC_TWCR	0x0014 /* Total Width Configuration */
> +#define LTDC_GCR	0x0018 /* Global Control */
> +#define LTDC_GC1R	0x001C /* Global Configuration 1 */
> +#define LTDC_GC2R	0x0020 /* Global Configuration 2 */
> +#define LTDC_SRCR	0x0024 /* Shadow Reload Configuration */
> +#define LTDC_GACR	0x0028 /* GAmma Correction */
> +#define LTDC_BCCR	0x002C /* Background Color Configuration */
> +#define LTDC_IER	0x0034 /* Interrupt Enable */
> +#define LTDC_ISR	0x0038 /* Interrupt Status */
> +#define LTDC_ICR	0x003C /* Interrupt Clear */
> +#define LTDC_LIPCR	0x0040 /* Line Interrupt Position Configuration */
> +#define LTDC_CPSR	0x0044 /* Current Position Status */
> +#define LTDC_CDSR	0x0048 /* Current Display Status */
> +
> +/* Layer register offsets */
> +#define LTDC_L1LC1R	(0x0080)	   /* L1 Layer Configuration 1 */
> +#define LTDC_L1LC2R	(0x0084)	   /* L1 Layer Configuration 2 */
> +#define LTDC_L1CR	(0x0084 + REG_OFS) /* L1 Control */
> +#define LTDC_L1WHPCR	(0x0088 + REG_OFS) /* L1 Window Hor Position Config */
> +#define LTDC_L1WVPCR	(0x008C + REG_OFS) /* L1 Window Vert Position Config */
> +#define LTDC_L1CKCR	(0x0090 + REG_OFS) /* L1 Color Keying Configuration */
> +#define LTDC_L1PFCR	(0x0094 + REG_OFS) /* L1 Pixel Format Configuration */
> +#define LTDC_L1CACR	(0x0098 + REG_OFS) /* L1 Constant Alpha Config */
> +#define LTDC_L1DCCR	(0x009C + REG_OFS) /* L1 Default Color Configuration */
> +#define LTDC_L1BFCR	(0x00A0 + REG_OFS) /* L1 Blend Factors Configuration */
> +#define LTDC_L1FBBCR	(0x00A4 + REG_OFS) /* L1 FrameBuffer Bus Control */
> +#define LTDC_L1AFBCR	(0x00A8 + REG_OFS) /* L1 AuxFB Control */
> +#define LTDC_L1CFBAR	(0x00AC + REG_OFS) /* L1 Color FrameBuffer Address */
> +#define LTDC_L1CFBLR	(0x00B0 + REG_OFS) /* L1 Color FrameBuffer Length */
> +#define LTDC_L1CFBLNR	(0x00B4 + REG_OFS) /* L1 Color FrameBuffer Line Nb */
> +#define LTDC_L1AFBAR	(0x00B8 + REG_OFS) /* L1 AuxFB Address */
> +#define LTDC_L1AFBLR	(0x00BC + REG_OFS) /* L1 AuxFB Length */
> +#define LTDC_L1AFBLNR	(0x00C0 + REG_OFS) /* L1 AuxFB Line Number */
> +#define LTDC_L1CLUTWR	(0x00C4 + REG_OFS) /* L1 CLUT Write */
> +#define LTDC_L1YS1R	(0x00E0 + REG_OFS) /* L1 YCbCr Scale 1 */
> +#define LTDC_L1YS2R	(0x00E4 + REG_OFS) /* L1 YCbCr Scale 2 */
> +
> +/* Bit definitions */
> +#define SSCR_VSH	GENMASK(10, 0)	/* Vertical Synchronization Height */
> +#define SSCR_HSW	GENMASK(27, 16)	/* Horizontal Synchronization Width */
> +
> +#define BPCR_AVBP	GENMASK(10, 0)	/* Accumulated Vertical Back Porch */
> +#define BPCR_AHBP	GENMASK(27, 16)	/* Accumulated Horizontal Back Porch */
> +
> +#define AWCR_AAH	GENMASK(10, 0)	/* Accumulated Active Height */
> +#define AWCR_AAW	GENMASK(27, 16)	/* Accumulated Active Width */
> +
> +#define TWCR_TOTALH	GENMASK(10, 0)	/* TOTAL Height */
> +#define TWCR_TOTALW	GENMASK(27, 16)	/* TOTAL Width */
> +
> +#define GCR_LTDCEN	BIT(0)		/* LTDC ENable */
> +#define GCR_DEN		BIT(16)		/* Dither ENable */
> +#define GCR_PCPOL	BIT(28)		/* Pixel Clock POLarity */
> +#define GCR_DEPOL	BIT(29)		/* Data Enable POLarity */
> +#define GCR_VSPOL	BIT(30)		/* Vertical Synchro POLarity */
> +#define GCR_HSPOL	BIT(31)		/* Horizontal Synchro POLarity */
> +
> +#define GC1R_WBCH	GENMASK(3, 0)	/* Width of Blue CHannel output */
> +#define GC1R_WGCH	GENMASK(7, 4)	/* Width of Green Channel output */
> +#define GC1R_WRCH	GENMASK(11, 8)	/* Width of Red Channel output */
> +#define GC1R_PBEN	BIT(12)		/* Precise Blending ENable */
> +#define GC1R_DT		GENMASK(15, 14)	/* Dithering Technique */
> +#define GC1R_GCT	GENMASK(19, 17)	/* Gamma Correction Technique */
> +#define GC1R_SHREN	BIT(21)		/* SHadow Registers ENabled */
> +#define GC1R_BCP	BIT(22)		/* Background Colour Programmable */
> +#define GC1R_BBEN	BIT(23)		/* Background Blending ENabled */
> +#define GC1R_LNIP	BIT(24)		/* Line Number IRQ Position */
> +#define GC1R_TP		BIT(25)		/* Timing Programmable */
> +#define GC1R_IPP	BIT(26)		/* IRQ Polarity Programmable */
> +#define GC1R_SPP	BIT(27)		/* Sync Polarity Programmable */
> +#define GC1R_DWP	BIT(28)		/* Dither Width Programmable */
> +#define GC1R_STREN	BIT(29)		/* STatus Registers ENabled */
> +#define GC1R_BMEN	BIT(31)		/* Blind Mode ENabled */
> +
> +#define GC2R_EDCA	BIT(0)		/* External Display Control Ability  */
> +#define GC2R_STSAEN	BIT(1)		/* Slave Timing Sync Ability ENabled */
> +#define GC2R_DVAEN	BIT(2)		/* Dual-View Ability ENabled */
> +#define GC2R_DPAEN	BIT(3)		/* Dual-Port Ability ENabled */
> +#define GC2R_BW		GENMASK(6, 4)	/* Bus Width (log2 of nb of bytes) */
> +#define GC2R_EDCEN	BIT(7)		/* External Display Control ENabled */
> +
> +#define SRCR_IMR	BIT(0)		/* IMmediate Reload */
> +#define SRCR_VBR	BIT(1)		/* Vertical Blanking Reload */
> +
> +#define BCCR_BCBLACK	0x00		/* Background Color BLACK */
> +#define BCCR_BCBLUE	GENMASK(7, 0)	/* Background Color BLUE */
> +#define BCCR_BCGREEN	GENMASK(15, 8)	/* Background Color GREEN */
> +#define BCCR_BCRED	GENMASK(23, 16)	/* Background Color RED */
> +#define BCCR_BCWHITE	GENMASK(23, 0)	/* Background Color WHITE */
> +
> +#define IER_LIE		BIT(0)		/* Line Interrupt Enable */
> +#define IER_FUIE	BIT(1)		/* Fifo Underrun Interrupt Enable */
> +#define IER_TERRIE	BIT(2)		/* Transfer ERRor Interrupt Enable */
> +#define IER_RRIE	BIT(3)		/* Register Reload Interrupt enable */
> +
> +#define ISR_LIF		BIT(0)		/* Line Interrupt Flag */
> +#define ISR_FUIF	BIT(1)		/* Fifo Underrun Interrupt Flag */
> +#define ISR_TERRIF	BIT(2)		/* Transfer ERRor Interrupt Flag */
> +#define ISR_RRIF	BIT(3)		/* Register Reload Interrupt Flag */
> +
> +#define LXCR_LEN	BIT(0)		/* Layer ENable */
> +#define LXCR_COLKEN	BIT(1)		/* Color Keying Enable */
> +#define LXCR_CLUTEN	BIT(4)		/* Color Look-Up Table ENable */
> +
> +#define LXWHPCR_WHSTPOS	GENMASK(11, 0)	/* Window Horizontal StarT POSition */
> +#define LXWHPCR_WHSPPOS	GENMASK(27, 16)	/* Window Horizontal StoP POSition */
> +
> +#define LXWVPCR_WVSTPOS	GENMASK(10, 0)	/* Window Vertical StarT POSition */
> +#define LXWVPCR_WVSPPOS	GENMASK(26, 16)	/* Window Vertical StoP POSition */
> +
> +#define LXPFCR_PF	GENMASK(2, 0)	/* Pixel Format */
> +
> +#define LXCACR_CONSTA	GENMASK(7, 0)	/* CONSTant Alpha */
> +
> +#define LXBFCR_BF2	GENMASK(2, 0)	/* Blending Factor 2 */
> +#define LXBFCR_BF1	GENMASK(10, 8)	/* Blending Factor 1 */
> +
> +#define LXCFBLR_CFBLL	GENMASK(12, 0)	/* Color Frame Buffer Line Length */
> +#define LXCFBLR_CFBP	GENMASK(28, 16)	/* Color Frame Buffer Pitch in bytes */
> +
> +#define LXCFBLNR_CFBLN	GENMASK(10, 0)	 /* Color Frame Buffer Line Number */
> +
> +#define HSPOL_AL   0		/* Horizontal Sync POLarity Active Low */
> +#define VSPOL_AL   0		/* Vertical Sync POLarity Active Low */
> +#define DEPOL_AL   0		/* Data Enable POLarity Active Low */
> +#define PCPOL_IPC  0		/* Input Pixel Clock */
> +#define HSPOL_AH   GCR_HSPOL	/* Horizontal Sync POLarity Active High */
> +#define VSPOL_AH   GCR_VSPOL	/* Vertical Sync POLarity Active High */
> +#define DEPOL_AH   GCR_DEPOL	/* Data Enable POLarity Active High */
> +#define PCPOL_IIPC GCR_PCPOL	/* Inverted Input Pixel Clock */
> +#define CONSTA_MAX 0xFF		/* CONSTant Alpha MAX= 1.0 */
> +#define BF1_PAXCA  0x600	/* Pixel Alpha x Constant Alpha */
> +#define BF1_CA     0x400	/* Constant Alpha */
> +#define BF2_1PAXCA 0x007	/* 1 - (Pixel Alpha x Constant Alpha) */
> +#define BF2_1CA	   0x005	/* 1 - Constant Alpha */
> +
> +enum ltdc_pix_fmt {
> +	PF_NONE,
> +	/* RGB formats */
> +	PF_ARGB8888,    /* ARGB [32 bits] */
> +	PF_RGBA8888,    /* RGBA [32 bits] */
> +	PF_RGB888,      /* RGB [24 bits] */
> +	PF_RGB565,      /* RGB [16 bits] */
> +	PF_ARGB1555,    /* ARGB A:1 bit RGB:15 bits [16 bits] */
> +	PF_ARGB4444,    /* ARGB A:4 bits R/G/B: 4 bits each [16 bits] */
> +	/* Indexed formats */
> +	PF_L8,          /* Indexed 8 bits [8 bits] */
> +	PF_AL44,        /* Alpha:4 bits + indexed 4 bits [8 bits] */
> +	PF_AL88         /* Alpha:8 bits + indexed 8 bits [16 bits] */
> +};
> +
> +#define NB_PF           8       /* Max nb of HW pixel format */
> +
> +/* The index gives the encoding of the pixel format for an HW version */
> +static const enum ltdc_pix_fmt ltdc_pix_fmt_a0[NB_PF] = {
> +	PF_ARGB8888,	/* 0x00 */
> +	PF_RGB888,	/* 0x01 */
> +	PF_RGB565,	/* 0x02 */
> +	PF_ARGB1555,	/* 0x03 */
> +	PF_ARGB4444,	/* 0x04 */
> +	PF_L8,		/* 0x05 */
> +	PF_AL44,	/* 0x06 */
> +	PF_AL88		/* 0x07 */
> +};
> +
> +static const enum ltdc_pix_fmt ltdc_pix_fmt_a1[NB_PF] = {
> +	PF_ARGB8888,	/* 0x00 */
> +	PF_RGB888,	/* 0x01 */
> +	PF_RGB565,	/* 0x02 */
> +	PF_RGBA8888,	/* 0x03 */
> +	PF_AL44,	/* 0x04 */
> +	PF_L8,		/* 0x05 */
> +	PF_ARGB1555,	/* 0x06 */
> +	PF_ARGB4444	/* 0x07 */
> +};
> +
> +struct ltdc_caps {
> +	u32 hw_version;		/* hardware version */
> +	u32 nb_layers;		/* number of supported layers */
> +	u32 reg_ofs;		/* register offset for applicable regs */
> +	u32 bus_width;		/* bus width (32 or 64 bits) */
> +	const enum ltdc_pix_fmt *pix_fmt_hw; /* supported pixel formats */
> +};
> +
> +struct ltdc {
> +	struct drm_device *ddev;
> +	void __iomem *regs;
> +	struct clk *pixel_clk;	/* lcd pixel clock */
> +	struct drm_panel *panel;
> +	struct drm_pending_vblank_event *pending_event;
> +	u32 irq_status;
> +	u32 error_status;
> +	struct mutex err_lock;	/* protecting error_status */
> +	struct ltdc_caps caps;
> +	u32 clut[256];		/* color look up table */
> +};
> +
> +static inline u32 reg_read(void __iomem *base, u32 reg)
> +{
> +	return readl_relaxed(base + reg);
> +}
> +
> +static inline void reg_write(void __iomem *base, u32 reg, u32 val)
> +{
> +	writel_relaxed(val, base + reg);
> +}
> +
> +static inline void reg_set(void __iomem *base, u32 reg, u32 mask)
> +{
> +	reg_write(base, reg, reg_read(base, reg) | mask);
> +}
> +
> +static inline void reg_clear(void __iomem *base, u32 reg, u32 mask)
> +{
> +	reg_write(base, reg, reg_read(base, reg) & ~mask);
> +}
> +
> +static inline void reg_update_bits(void __iomem *base, u32 reg, u32 mask,
> +				   u32 val)
> +{
> +	reg_write(base, reg, (reg_read(base, reg) & ~mask) | val);
> +}
> +
> +static inline struct ltdc *crtc_to_ltdc(struct drm_crtc *crtc)
> +{
> +	return ((struct stm_private *)crtc->dev->dev_private)->ltdc;
> +}
> +
> +static inline struct ltdc *plane_to_ltdc(struct drm_plane *plane)
> +{
> +	return ((struct stm_private *)plane->dev->dev_private)->ltdc;
> +}
> +
> +static inline struct ltdc *encoder_to_ltdc(struct drm_encoder *encoder)
> +{
> +	return ((struct stm_private *)encoder->dev->dev_private)->ltdc;
> +}
> +
> +static inline struct ltdc *connector_to_ltdc(struct drm_connector *connector)
> +{
> +	return ((struct stm_private *)connector->dev->dev_private)->ltdc;
> +}
> +
> +static inline enum ltdc_pix_fmt to_ltdc_pixelformat(u32 drm_fmt)
> +{
> +	enum ltdc_pix_fmt pf;
> +
> +	switch (drm_fmt) {
> +	case DRM_FORMAT_ARGB8888:
> +	case DRM_FORMAT_XRGB8888:
> +		pf = PF_ARGB8888;
> +		break;
> +	case DRM_FORMAT_RGBA8888:
> +	case DRM_FORMAT_RGBX8888:
> +		pf = PF_RGBA8888;
> +		break;
> +	case DRM_FORMAT_RGB888:
> +		pf = PF_RGB888;
> +		break;
> +	case DRM_FORMAT_RGB565:
> +		pf = PF_RGB565;
> +		break;
> +	case DRM_FORMAT_ARGB1555:
> +	case DRM_FORMAT_XRGB1555:
> +		pf = PF_ARGB1555;
> +		break;
> +	case DRM_FORMAT_ARGB4444:
> +	case DRM_FORMAT_XRGB4444:
> +		pf = PF_ARGB4444;
> +		break;
> +	case DRM_FORMAT_C8:
> +		pf = PF_L8;
> +		break;
> +	default:
> +		pf = PF_NONE;
> +		break;
> +	/* Note: There are no DRM_FORMAT for AL44 and AL88 */
> +	}
> +
> +	return pf;
> +}
> +
> +static inline u32 to_drm_pixelformat(enum ltdc_pix_fmt pf)
> +{
> +	switch (pf) {
> +	case PF_ARGB8888:
> +		return DRM_FORMAT_ARGB8888;
> +	case PF_RGBA8888:
> +		return DRM_FORMAT_RGBA8888;
> +	case PF_RGB888:
> +		return DRM_FORMAT_RGB888;
> +	case PF_RGB565:
> +		return DRM_FORMAT_RGB565;
> +	case PF_ARGB1555:
> +		return DRM_FORMAT_ARGB1555;
> +	case PF_ARGB4444:
> +		return DRM_FORMAT_ARGB4444;
> +	case PF_L8:
> +		return DRM_FORMAT_C8;
> +	case PF_AL44: /* No DRM support */
> +	case PF_AL88: /* No DRM support */
> +	case PF_NONE:
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static struct drm_crtc *crtc_from_pipe(struct drm_device *ddev,
> +				       unsigned int pipe)
> +{
> +	struct drm_crtc *crtc;
> +
> +	list_for_each_entry(crtc, &ddev->mode_config.crtc_list, head) {
> +		if (pipe == drm_crtc_index(crtc))
> +			return crtc;
> +	}
> +
> +	return NULL;
> +}

This looks like a duplicate of drm_crtc_from_index().

> +static irqreturn_t ltdc_irq_thread(int irq, void *arg)
> +{
> +	struct ltdc *ltdc = arg;
> +	struct drm_crtc *crtc = crtc_from_pipe(ltdc->ddev, 0);
> +
> +	/* Line IRQ : trigger the vblank event */
> +	if (ltdc->irq_status & ISR_LIF)
> +		drm_crtc_handle_vblank(crtc);
> +
> +	/* Save FIFO Underrun & Transfer Error status */
> +	mutex_lock(&ltdc->err_lock);
> +	if (ltdc->irq_status & ISR_FUIF)
> +		ltdc->error_status |= ISR_FUIF;
> +	if (ltdc->irq_status & ISR_TERRIF)
> +		ltdc->error_status |= ISR_TERRIF;
> +	mutex_unlock(&ltdc->err_lock);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t ltdc_irq(int irq, void *arg)
> +{
> +	struct ltdc *ltdc = arg;
> +
> +	/* Read & Clear the interrupt status */
> +	ltdc->irq_status = reg_read(ltdc->regs, LTDC_ISR);
> +	reg_write(ltdc->regs, LTDC_ICR, ltdc->irq_status);
> +
> +	return IRQ_WAKE_THREAD;
> +}

I'm curious, why a threaded irq here?  Can't you just use a spinlock for
err_lock and then move the thread body in here?

> +/*
> + * DRM_CRTC
> + */
> +
> +static void ltdc_crtc_load_lut(struct drm_crtc *crtc)
> +{
> +	struct ltdc *ltdc = crtc_to_ltdc(crtc);
> +	unsigned int i, lay;
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	for (lay = 0; lay < ltdc->caps.nb_layers; lay++)
> +		for (i = 0; i < 256; i++)
> +			reg_write(ltdc->regs, LTDC_L1CLUTWR + lay * LAY_OFS,
> +				  ltdc->clut[i]);
> +
> +	clk_disable(ltdc->pixel_clk);
> +}
> +
> +static void ltdc_crtc_enable(struct drm_crtc *crtc)
> +{
> +	struct ltdc *ltdc = crtc_to_ltdc(crtc);
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	/* Sets the background color value */
> +	reg_write(ltdc->regs, LTDC_BCCR, BCCR_BCBLACK);
> +
> +	/* Enable IRQ */
> +	reg_set(ltdc->regs, LTDC_IER, IER_RRIE | IER_FUIE | IER_TERRIE);
> +
> +	/* Immediately commit the planes */
> +	reg_set(ltdc->regs, LTDC_SRCR, SRCR_IMR);
> +
> +	/* Enable LTDC */
> +	reg_set(ltdc->regs, LTDC_GCR, GCR_LTDCEN);
> +
> +	drm_crtc_vblank_on(crtc);
> +}
> +
> +static void ltdc_crtc_disable(struct drm_crtc *crtc)
> +{
> +	struct ltdc *ltdc = crtc_to_ltdc(crtc);
> +	unsigned int i;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (!crtc->enabled) {
> +		DRM_DEBUG_DRIVER("already disabled\n");
> +		return;
> +	}
> +
> +	drm_crtc_vblank_off(crtc);
> +
> +	/* disable LTDC */
> +	reg_clear(ltdc->regs, LTDC_GCR, GCR_LTDCEN);
> +
> +	/* disable IRQ */
> +	reg_clear(ltdc->regs, LTDC_IER, IER_RRIE | IER_FUIE | IER_TERRIE);
> +
> +	/* disable layers */
> +	for (i = 0; i < ltdc->caps.nb_layers; i++)
> +		reg_clear(ltdc->regs, LTDC_L1CR + i * LAY_OFS, LXCR_LEN);

I think you're guaranteed that the layers have been disable()d.

> +	/* immediately commit disable of layers before switching off LTDC */
> +	reg_set(ltdc->regs, LTDC_SRCR, SRCR_IMR);
> +
> +	clk_disable(ltdc->pixel_clk);
> +
> +	if (crtc->state->event && !crtc->state->active) {
> +		spin_lock_irq(&crtc->dev->event_lock);
> +		drm_crtc_send_vblank_event(crtc, crtc->state->event);
> +		spin_unlock_irq(&crtc->dev->event_lock);
> +
> +		crtc->state->event = NULL;
> +	}

Instead of this block here, on pl111 I just made the "if
(drm_crtc_vblank_get(crtc) == 0)" in the CRTC atomic_flush() also check
for crtc->state->active before starting to arm.

> +}
> +
> +static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
> +				 const struct drm_display_mode *mode,
> +				 struct drm_display_mode *adjusted_mode)
> +{
> +	DRM_DEBUG_DRIVER("\n");
> +	/* accept the provided drm_display_mode, do not fix it up */
> +
> +	return true;
> +}

If you don't do anything in this function, it can be dropped.

> +static u32 ltdc_get_paddr(struct drm_framebuffer *fb, int x, int y)
> +{
> +	struct drm_gem_cma_object *cma_obj;
> +	unsigned int pixsize;
> +	u32 paddr;
> +
> +	cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
> +	if (IS_ERR(cma_obj)) {
> +		DRM_ERROR("Can't get CMA GEM object for fb\n");
> +		return 0;
> +	}
> +
> +	pixsize = drm_format_plane_cpp(fb->format->format, 0);
> +	paddr = (u32)cma_obj->paddr + fb->offsets[0];
> +	paddr += (x * pixsize) + (y * fb->pitches[0]);
> +
> +	return paddr;
> +}

Having just written this function for pl111, one of us should probably
put a generic copy in drm_fb_cma_helper.  No need to do so for getting
your driver in, though.

> +static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
> +{
> +	struct ltdc *ltdc = crtc_to_ltdc(crtc);
> +	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> +	struct videomode vm;
> +	int rate = mode->clock * 1000;
> +	u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
> +	u32 total_width, total_height;
> +	u32 val;
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	drm_display_mode_to_videomode(mode, &vm);
> +
> +	DRM_DEBUG_DRIVER("CRTC:%d mode:%s\n", crtc->base.id, mode->name);
> +	DRM_DEBUG_DRIVER("Video mode: %dx%d", vm.hactive, vm.vactive);
> +	DRM_DEBUG_DRIVER(" hfp %d hbp %d hsl %d vfp %d vbp %d vsl %d\n",
> +			 vm.hfront_porch, vm.hback_porch, vm.hsync_len,
> +			 vm.vfront_porch, vm.vback_porch, vm.vsync_len);
> +
> +	/* Convert video timings to ltdc timings */
> +	hsync = vm.hsync_len - 1;
> +	vsync = vm.vsync_len - 1;
> +	accum_hbp = hsync + vm.hback_porch;
> +	accum_vbp = vsync + vm.vback_porch;
> +	accum_act_w = accum_hbp + vm.hactive;
> +	accum_act_h = accum_vbp + vm.vactive;
> +	total_width = accum_act_w + vm.hfront_porch;
> +	total_height = accum_act_h + vm.vfront_porch;
> +
> +	if (clk_set_rate(ltdc->pixel_clk, rate) < 0) {
> +		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> +		return;
> +	}
> +
> +	/* Configures the HS, VS, DE and PC polarities. */
> +	val = HSPOL_AL | HSPOL_AL | DEPOL_AL | PCPOL_IPC;
> +
> +	if (vm.flags & DISPLAY_FLAGS_HSYNC_HIGH)
> +		val |= HSPOL_AH;
> +
> +	if (vm.flags & DISPLAY_FLAGS_VSYNC_HIGH)
> +		val |= VSPOL_AH;
> +
> +	if (vm.flags & DISPLAY_FLAGS_DE_HIGH)
> +		val |= DEPOL_AH;
> +
> +	if (vm.flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
> +		val |= PCPOL_IIPC;
> +
> +	reg_update_bits(ltdc->regs, LTDC_GCR,
> +			GCR_HSPOL | GCR_VSPOL | GCR_DEPOL | GCR_PCPOL, val);
> +
> +	/* Set Synchronization size */
> +	val = (hsync << 16) | vsync;
> +	reg_update_bits(ltdc->regs, LTDC_SSCR, SSCR_VSH | SSCR_HSW, val);
> +
> +	/* Set Accumulated Back porch */
> +	val = (accum_hbp << 16) | accum_vbp;
> +	reg_update_bits(ltdc->regs, LTDC_BPCR, BPCR_AVBP | BPCR_AHBP, val);
> +
> +	/* Set Accumulated Active Width */
> +	val = (accum_act_w << 16) | accum_act_h;
> +	reg_update_bits(ltdc->regs, LTDC_AWCR, AWCR_AAW | AWCR_AAH, val);
> +
> +	/* Set total width & height */
> +	val = (total_width << 16) | total_height;
> +	reg_update_bits(ltdc->regs, LTDC_TWCR, TWCR_TOTALH | TWCR_TOTALW, val);
> +
> +	reg_write(ltdc->regs, LTDC_LIPCR, (accum_act_h + 1));
> +
> +	clk_disable(ltdc->pixel_clk);
> +}
> +
> +static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
> +				   struct drm_crtc_state *old_crtc_state)
> +{
> +	struct ltdc *ltdc = crtc_to_ltdc(crtc);
> +	struct drm_pending_vblank_event *event = crtc->state->event;
> +
> +	DRM_DEBUG_ATOMIC("\n");
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	/* Commit shadow registers = update planes at next vblank */
> +	reg_set(ltdc->regs, LTDC_SRCR, SRCR_VBR);
> +
> +	if (event) {
> +		crtc->state->event = NULL;
> +
> +		spin_lock_irq(&crtc->dev->event_lock);
> +		if (drm_crtc_vblank_get(crtc) == 0)
> +			drm_crtc_arm_vblank_event(crtc, event);
> +		else
> +			drm_crtc_send_vblank_event(crtc, event);
> +		spin_unlock_irq(&crtc->dev->event_lock);
> +	}
> +
> +	clk_disable(ltdc->pixel_clk);
> +}
> +
> +static struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
> +	.load_lut = ltdc_crtc_load_lut,
> +	.enable = ltdc_crtc_enable,
> +	.disable = ltdc_crtc_disable,
> +	.mode_fixup = ltdc_crtc_mode_fixup,
> +	.mode_set_nofb = ltdc_crtc_mode_set_nofb,
> +	.atomic_flush = ltdc_crtc_atomic_flush,
> +};
> +
> +int ltdc_crtc_enable_vblank(struct drm_device *ddev, unsigned int pipe)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +	struct ltdc *ltdc = priv->ltdc;
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return -EINVAL;
> +	}
> +
> +	DRM_DEBUG_DRIVER("\n");
> +	reg_set(ltdc->regs, LTDC_IER, IER_LIE);
> +
> +	clk_disable(ltdc->pixel_clk);
> +
> +	return 0;
> +}
> +
> +void ltdc_crtc_disable_vblank(struct drm_device *ddev, unsigned int pipe)
> +{
> +	struct drm_crtc *crtc = crtc_from_pipe(ddev, pipe);
> +	struct stm_private *priv = ddev->dev_private;
> +	struct ltdc *ltdc = priv->ltdc;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	reg_clear(ltdc->regs, LTDC_IER, IER_LIE);
> +
> +	if (ltdc->pending_event) {
> +		drm_crtc_vblank_put(crtc);
> +		ltdc->pending_event = NULL;
> +	}
> +
> +	clk_disable(ltdc->pixel_clk);
> +}

Note that instead of looking up the crtc from its index, you could move
these hooks from the dev to the enable/disable_vblank in drm_crtc_funcs.

> +static struct drm_crtc_funcs ltdc_crtc_funcs = {
> +	.destroy = drm_crtc_cleanup,
> +	.set_config = drm_atomic_helper_set_config,
> +	.page_flip = drm_atomic_helper_page_flip,
> +	.reset = drm_atomic_helper_crtc_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> +};
> +
> +/*
> + * DRM_PLANE
> + */
> +
> +static int ltdc_plane_atomic_check(struct drm_plane *plane,
> +				   struct drm_plane_state *state)
> +{
> +	struct drm_framebuffer *fb = state->fb;
> +	u32 src_x, src_y, src_w, src_h;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (!fb)
> +		return 0;
> +
> +	/* convert src_ from 16:16 format */
> +	src_x = state->src_x >> 16;
> +	src_y = state->src_y >> 16;
> +	src_w = state->src_w >> 16;
> +	src_h = state->src_h >> 16;
> +
> +	/* Reject scaling */
> +	if ((src_w != state->crtc_w) || (src_h != state->crtc_h)) {
> +		DRM_ERROR("Scaling is not supported");
> +		return -EINVAL;
> +	}
> +
> +	if (!ltdc_get_paddr(fb, src_x, src_y)) {
> +		DRM_ERROR("Cannot get fb address\n");
> +		return -EFAULT;
> +	}

I don't think this call can fail.

> +	return 0;
> +}
> +
> +static void ltdc_plane_atomic_update(struct drm_plane *plane,
> +				     struct drm_plane_state *oldstate)
> +{
> +	struct ltdc *ltdc = plane_to_ltdc(plane);
> +	struct drm_plane_state *state = plane->state;
> +	struct drm_framebuffer *fb = state->fb;
> +	u32 lofs = plane->index * LAY_OFS;
> +	u32 x0 = state->crtc_x;
> +	u32 x1 = state->crtc_x + state->crtc_w - 1;
> +	u32 y0 = state->crtc_y;
> +	u32 y1 = state->crtc_y + state->crtc_h - 1;
> +	u32 src_x, src_y, src_w, src_h;
> +	u32 val, pitch_in_bytes, line_length, paddr, ahbp, avbp, bpcr;
> +	enum ltdc_pix_fmt pf;
> +
> +	if (!state->crtc || !fb) {
> +		DRM_DEBUG_DRIVER("fb or crtc NULL");
> +		return;
> +	}
> +
> +	/* convert src_ from 16:16 format */
> +	src_x = state->src_x >> 16;
> +	src_y = state->src_y >> 16;
> +	src_w = state->src_w >> 16;
> +	src_h = state->src_h >> 16;
> +
> +	DRM_DEBUG_DRIVER(
> +		"plane:%d fb:%d (%dx%d)@(%d,%d) -> (%dx%d)@(%d,%d)\n",
> +		plane->base.id, fb->base.id,
> +		src_w, src_h, src_x, src_y,
> +		state->crtc_w, state->crtc_h, state->crtc_x, state->crtc_y);
> +
> +	bpcr = reg_read(ltdc->regs, LTDC_BPCR);
> +	ahbp = (bpcr & BPCR_AHBP) >> 16;
> +	avbp = bpcr & BPCR_AVBP;
> +
> +	/* Configures the horizontal start and stop position */
> +	val = ((x1 + 1 + ahbp) << 16) + (x0 + 1 + ahbp);
> +	reg_update_bits(ltdc->regs, LTDC_L1WHPCR + lofs,
> +			LXWHPCR_WHSTPOS | LXWHPCR_WHSPPOS, val);
> +
> +	/* Configures the vertical start and stop position */
> +	val = ((y1 + 1 + avbp) << 16) + (y0 + 1 + avbp);
> +	reg_update_bits(ltdc->regs, LTDC_L1WVPCR + lofs,
> +			LXWVPCR_WVSTPOS | LXWVPCR_WVSPPOS, val);
> +
> +	/* Specifies the pixel format */
> +	pf = to_ltdc_pixelformat(fb->format->format);
> +	for (val = 0; val < NB_PF; val++)
> +		if (ltdc->caps.pix_fmt_hw[val] == pf)
> +			break;
> +
> +	if (val == NB_PF) {
> +		DRM_ERROR("Pixel format %.4s not supported\n",
> +			  (char *)&fb->format->format);
> +		val = 0; /* set by default ARGB 32 bits */
> +	}
> +	reg_update_bits(ltdc->regs, LTDC_L1PFCR + lofs, LXPFCR_PF, val);
> +
> +	/* Configures the color frame buffer pitch in bytes & line length */
> +	pitch_in_bytes = fb->pitches[0];
> +	line_length = drm_format_plane_cpp(fb->format->format, 0) *
> +		      (x1 - x0 + 1) + (ltdc->caps.bus_width >> 3) - 1;
> +	val = ((pitch_in_bytes << 16) | line_length);
> +	reg_update_bits(ltdc->regs, LTDC_L1CFBLR + lofs,
> +			LXCFBLR_CFBLL | LXCFBLR_CFBP, val);
> +
> +	/* Specifies the constant alpha value */
> +	val = CONSTA_MAX;
> +	reg_update_bits(ltdc->regs, LTDC_L1CACR + lofs,
> +			LXCACR_CONSTA, val);
> +
> +	/* Specifies the blending factors */
> +	val = BF1_PAXCA | BF2_1PAXCA;
> +	reg_update_bits(ltdc->regs, LTDC_L1BFCR + lofs,
> +			LXBFCR_BF2 | LXBFCR_BF1, val);
> +
> +	/* Configures the frame buffer line number */
> +	val = y1 - y0 + 1;
> +	reg_update_bits(ltdc->regs, LTDC_L1CFBLNR + lofs,
> +			LXCFBLNR_CFBLN, val);
> +
> +	/* Sets the FB address */
> +	paddr = ltdc_get_paddr(fb, src_x, src_y);
> +	DRM_DEBUG_DRIVER("fb: phys 0x%08x", paddr);
> +	reg_write(ltdc->regs, LTDC_L1CFBAR + lofs, paddr);
> +
> +	/* Enable layer and CLUT if needed */
> +	val = fb->format->format == DRM_FORMAT_C8 ? LXCR_CLUTEN : 0;
> +	val |= LXCR_LEN;
> +	reg_update_bits(ltdc->regs, LTDC_L1CR + lofs,
> +			LXCR_LEN | LXCR_CLUTEN, val);
> +
> +	mutex_lock(&ltdc->err_lock);
> +	if (ltdc->error_status & ISR_FUIF) {
> +		DRM_DEBUG_DRIVER("Fifo underrun\n");
> +		ltdc->error_status &= ~ISR_FUIF;
> +	}
> +	if (ltdc->error_status & ISR_TERRIF) {
> +		DRM_DEBUG_DRIVER("Transfer error\n");
> +		ltdc->error_status &= ~ISR_TERRIF;
> +	}
> +	mutex_unlock(&ltdc->err_lock);
> +}
> +
> +static void ltdc_plane_atomic_disable(struct drm_plane *plane,
> +				      struct drm_plane_state *oldstate)
> +{
> +	struct ltdc *ltdc = plane_to_ltdc(plane);
> +	u32 lofs = plane->index * LAY_OFS;
> +
> +	if (!oldstate->crtc) {
> +		DRM_DEBUG_DRIVER("drm plane:%d not enabled\n", plane->base.id);
> +		return;
> +	}

I believe you're guaranteed that it was enabled when the disable is called.

> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return;
> +	}
> +
> +	/* disable layer */
> +	reg_clear(ltdc->regs, LTDC_L1CR + lofs, LXCR_LEN);
> +
> +	clk_disable(ltdc->pixel_clk);
> +
> +	DRM_DEBUG_DRIVER("CRTC:%d plane:%d\n",
> +			 oldstate->crtc->base.id, plane->base.id);
> +}
> +
> +static void ltdc_plane_destroy(struct drm_plane *plane)
> +{
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	drm_plane_helper_disable(plane);
> +	drm_plane_cleanup(plane);
> +}

Hmm.  I would assume that a plane has been disabled at the point that
destroy is called, so that you wouldn't even need this wrapper function.

> +
> +static struct drm_plane_funcs ltdc_plane_funcs = {
> +	.update_plane = drm_atomic_helper_update_plane,
> +	.disable_plane = drm_atomic_helper_disable_plane,
> +	.destroy = ltdc_plane_destroy,
> +	.set_property = drm_atomic_helper_plane_set_property,
> +	.reset = drm_atomic_helper_plane_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
> +};
> +
> +static const struct drm_plane_helper_funcs ltdc_plane_helper_funcs = {
> +	.atomic_check = ltdc_plane_atomic_check,
> +	.atomic_update = ltdc_plane_atomic_update,
> +	.atomic_disable = ltdc_plane_atomic_disable,
> +};
> +
> +static struct drm_plane *ltdc_plane_create(struct drm_device *ddev,
> +					   enum drm_plane_type type)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +	unsigned long possible_crtcs = CRTC_MASK;
> +	struct device *dev = ddev->dev;
> +	struct ltdc *ltdc = priv->ltdc;
> +	struct drm_plane *plane;
> +	unsigned int i, nb_fmt = 0;
> +	u32 formats[NB_PF];
> +	u32 drm_fmt;
> +	int ret;
> +
> +	/* Get supported pixel formats */
> +	for (i = 0; i < NB_PF; i++) {
> +		drm_fmt = to_drm_pixelformat(ltdc->caps.pix_fmt_hw[i]);
> +		if (!drm_fmt)
> +			continue;
> +		formats[nb_fmt++] = drm_fmt;
> +	}
> +
> +	plane = devm_kzalloc(dev, sizeof(*plane), GFP_KERNEL);
> +	if (!plane)
> +		return 0;
> +
> +	ret = drm_universal_plane_init(ddev, plane, possible_crtcs,
> +				       &ltdc_plane_funcs, formats, nb_fmt,
> +				       type, NULL);
> +	if (ret < 0)
> +		return 0;
> +
> +	drm_plane_helper_add(plane, &ltdc_plane_helper_funcs);
> +
> +	DRM_DEBUG_DRIVER("plane:%d created\n", plane->base.id);
> +
> +	return plane;
> +}
> +
> +static void ltdc_plane_destroy_all(struct ltdc *ltdc)
> +{
> +	struct drm_plane *plane, *plane_temp;
> +
> +	list_for_each_entry_safe(plane, plane_temp,
> +				 &ltdc->ddev->mode_config.plane_list, head)
> +		drm_plane_cleanup(plane);
> +}
> +
> +static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +	struct ltdc *ltdc = priv->ltdc;
> +	struct drm_plane *primary, *overlay;
> +	unsigned int i;
> +	int res;
> +
> +	primary = ltdc_plane_create(ddev, DRM_PLANE_TYPE_PRIMARY);
> +	if (!primary) {
> +		DRM_ERROR("Can not create primary plane\n");
> +		return -EINVAL;
> +	}
> +
> +	res = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
> +					&ltdc_crtc_funcs, NULL);
> +	if (res) {
> +		DRM_ERROR("Can not initialize CRTC\n");
> +		goto cleanup;
> +	}
> +
> +	drm_crtc_helper_add(crtc, &ltdc_crtc_helper_funcs);
> +
> +	DRM_DEBUG_DRIVER("CRTC:%d created\n", crtc->base.id);
> +
> +	/* Add planes. Note : the first layer is used by primary plane */
> +	for (i = 1; i < ltdc->caps.nb_layers; i++) {
> +		overlay = ltdc_plane_create(ddev, DRM_PLANE_TYPE_OVERLAY);
> +		if (!overlay) {
> +			res = -ENOMEM;
> +			DRM_ERROR("Can not create overlay plane %d\n", i);
> +			goto cleanup;
> +		}
> +	}
> +
> +	return 0;
> +
> +cleanup:
> +	ltdc_plane_destroy_all(ltdc);
> +	return res;
> +}
> +
> +/*
> + * DRM_ENCODER
> + */
> +
> +static void ltdc_rgb_encoder_enable(struct drm_encoder *encoder)
> +{
> +	struct ltdc *ltdc = encoder_to_ltdc(encoder);
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	drm_panel_prepare(ltdc->panel);
> +	drm_panel_enable(ltdc->panel);
> +}
> +
> +static void ltdc_rgb_encoder_disable(struct drm_encoder *encoder)
> +{
> +	struct ltdc *ltdc = encoder_to_ltdc(encoder);
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	drm_panel_disable(ltdc->panel);
> +	drm_panel_unprepare(ltdc->panel);
> +}
> +
> +static const struct drm_encoder_helper_funcs ltdc_rgb_encoder_helper_funcs = {
> +	.enable = ltdc_rgb_encoder_enable,
> +	.disable = ltdc_rgb_encoder_disable,
> +};
> +
> +static const struct drm_encoder_funcs ltdc_rgb_encoder_funcs = {
> +	.destroy = drm_encoder_cleanup,
> +};
> +
> +static struct drm_encoder *ltdc_rgb_encoder_create(struct drm_device *ddev)
> +{
> +	struct drm_encoder *encoder;
> +
> +	encoder = devm_kzalloc(ddev->dev, sizeof(*encoder), GFP_KERNEL);
> +	if (!encoder)
> +		return NULL;
> +
> +	encoder->possible_crtcs = CRTC_MASK;
> +	encoder->possible_clones = 0; /* No cloning support */
> +
> +	drm_encoder_init(ddev, encoder, &ltdc_rgb_encoder_funcs,
> +			 DRM_MODE_ENCODER_LVDS, NULL);
> +
> +	drm_encoder_helper_add(encoder, &ltdc_rgb_encoder_helper_funcs);
> +
> +	DRM_DEBUG_DRIVER("RGB encoder:%d created\n", encoder->base.id);
> +
> +	return encoder;
> +}
> +
> +static struct drm_encoder *ltdc_rgb_encoder_find(struct drm_device *ddev)
> +{
> +	struct drm_encoder *encoder;
> +
> +	list_for_each_entry(encoder, &ddev->mode_config.encoder_list, head) {
> +		if (encoder->encoder_type == DRM_MODE_ENCODER_LVDS)
> +			return encoder;
> +	}
> +
> +	return NULL;
> +}
> +
> +static int ltdc_create_encoders(struct ltdc *ltdc)
> +{
> +	struct drm_device *ddev = ltdc->ddev;
> +	struct drm_encoder *encoder;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (ltdc->panel) {
> +		encoder = ltdc_rgb_encoder_create(ddev);
> +		if (!encoder)
> +			return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static void ltdc_destroy_encoders(struct ltdc *ltdc)
> +{
> +	struct drm_encoder *encoder, *encoder_temp;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	list_for_each_entry_safe(encoder, encoder_temp,
> +				 &ltdc->ddev->mode_config.encoder_list, head)
> +		drm_encoder_cleanup(encoder);
> +}
> +
> +/*
> + * DRM_CONNECTOR
> + */
> +
> +static int ltdc_rgb_connector_get_modes(struct drm_connector *connector)
> +{
> +	struct ltdc *ltdc = connector_to_ltdc(connector);
> +	int ret = 0;
> +
> +	dev_dbg(ltdc->ddev->dev, "%s\n", __func__);
> +
> +	if (ltdc->panel)
> +		ret = drm_panel_get_modes(ltdc->panel);
> +
> +	return ret < 0 ? 0 : ret;
> +}
> +
> +/* Set a tolerance of 20% on pixel clock */
> +#define CLK_TOLERANCE_PCT 20
> +
> +static enum drm_mode_status
> +ltdc_rgb_connector_mode_valid(struct drm_connector *connector,
> +			      struct drm_display_mode *mode)
> +{
> +	struct ltdc *ltdc = connector_to_ltdc(connector);
> +	unsigned long rate = mode->clock * 1000;
> +	long rate_min = rate - (rate * CLK_TOLERANCE_PCT) / 100;
> +	long rate_max = rate;
> +	long rounded_rate;
> +
> +	rounded_rate = clk_round_rate(ltdc->pixel_clk, rate);
> +
> +	DRM_DEBUG_DRIVER("Target rate = %ld => available rate = %ld\n",
> +			 rate, rounded_rate);
> +
> +	if (rounded_rate < rate_min)
> +		return MODE_CLOCK_LOW;
> +
> +	if (rounded_rate > rate_max)
> +		return MODE_CLOCK_HIGH;
> +
> +	if (!rate)
> +		return MODE_BAD;
> +
> +	return MODE_OK;
> +}

I like that you've got a tolerance on your clocks here.

Something interesting that I read recently: mode_valid doesn't actually
limit whether userspace can set a mode on the hw, it just filters modes
coming back from your get_modes().  Unless the core starts doing this,
you might be interested in calling this function from the CRTC's
mode_fixup().

> +static struct drm_connector_helper_funcs ltdc_rgb_connector_helper_funcs = {
> +	.get_modes = ltdc_rgb_connector_get_modes,
> +	.mode_valid = ltdc_rgb_connector_mode_valid,
> +};
> +
> +static enum drm_connector_status
> +ltdc_rgb_connector_detect(struct drm_connector *connector, bool force)
> +{
> +	struct ltdc *ltdc = connector_to_ltdc(connector);
> +	int ret = 0;
> +
> +	if (ltdc->panel) {
> +		ret = drm_panel_attach(ltdc->panel, connector);
> +		if (!ret || ret == -EBUSY) {
> +			DRM_DEBUG_DRIVER("connector status connected");
> +			return connector_status_connected;
> +		}
> +	}
> +	DRM_DEBUG_DRIVER("connector status disconnected");
> +
> +	return connector_status_disconnected;
> +}

In vc4 and other drivers I've looked at, we drm_panel_attach at load
time, so detect is just return ltdc->panel ? connected : disconnected.

> +static void ltdc_rgb_connector_destroy(struct drm_connector *connector)
> +{
> +	struct ltdc *ltdc = connector_to_ltdc(connector);
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	if (ltdc->panel)
> +		drm_panel_detach(ltdc->panel);
> +	drm_connector_cleanup(connector);
> +}
> +
> +static const struct drm_connector_funcs ltdc_rgb_connector_funcs = {
> +	.dpms = drm_atomic_helper_connector_dpms,
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.detect = ltdc_rgb_connector_detect,
> +	.destroy = ltdc_rgb_connector_destroy,
> +	.reset = drm_atomic_helper_connector_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +};
> +
> +struct drm_connector *ltdc_rgb_connector_create(struct drm_device *ddev)
> +{
> +	struct drm_connector *connector;
> +	int err;
> +
> +	connector = devm_kzalloc(ddev->dev, sizeof(*connector), GFP_KERNEL);
> +	if (!connector) {
> +		DRM_ERROR("Failed to allocate connector\n");
> +		return NULL;
> +	}
> +
> +	connector->polled = DRM_CONNECTOR_POLL_HPD;
> +
> +	err = drm_connector_init(ddev, connector, &ltdc_rgb_connector_funcs,
> +				 DRM_MODE_CONNECTOR_LVDS);
> +	if (err) {
> +		DRM_ERROR("Failed to initialize connector\n");
> +		return NULL;
> +	}
> +
> +	drm_connector_helper_add(connector, &ltdc_rgb_connector_helper_funcs);
> +
> +	DRM_DEBUG_DRIVER("RGB connector:%d created\n", connector->base.id);
> +
> +	return connector;
> +}
> +
> +static int ltdc_get_caps(struct ltdc *ltdc)
> +{
> +	u32 bus_width_log2, lcr, gc2r;
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return -EINVAL;
> +	}
> +
> +	/* at least 1 layer must be managed */
> +	lcr = reg_read(ltdc->regs, LTDC_LCR);
> +
> +	ltdc->caps.nb_layers = max_t(int, lcr, 1);
> +
> +	/* set data bus width */
> +	gc2r = reg_read(ltdc->regs, LTDC_GC2R);
> +	bus_width_log2 = (gc2r & GC2R_BW) >> 4;
> +	ltdc->caps.bus_width = 8 << bus_width_log2;
> +	ltdc->caps.hw_version = reg_read(ltdc->regs, LTDC_IDR);
> +
> +	clk_disable(ltdc->pixel_clk);
> +
> +	switch (ltdc->caps.hw_version) {
> +	case HWVER_10200:
> +	case HWVER_10300:
> +		ltdc->caps.reg_ofs = REG_OFS_NONE;
> +		ltdc->caps.pix_fmt_hw = ltdc_pix_fmt_a0;
> +		break;
> +	case HWVER_20101:
> +		ltdc->caps.reg_ofs = REG_OFS_4;
> +		ltdc->caps.pix_fmt_hw = ltdc_pix_fmt_a1;
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
> +{
> +	struct device *dev = ddev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct device_node *entity, *port = NULL;
> +	struct drm_panel *panel = NULL;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	/*
> +	 * Parse ltdc node to get remote port and find RGB panel / HDMI slave
> +	 * If a dsi or a bridge (hdmi, lvds...) is connected to ltdc,
> +	 * a remote port & RGB panel will not be found.
> +	 */
> +	for_each_endpoint_of_node(np, entity) {
> +		if (!of_device_is_available(entity))
> +			continue;
> +
> +		port = of_graph_get_remote_port_parent(entity);
> +		if (port) {
> +			panel = of_drm_find_panel(port);
> +			of_node_put(port);
> +			if (panel) {
> +				DRM_DEBUG_DRIVER("remote panel %s\n",
> +						 port->full_name);
> +			} else {
> +				DRM_DEBUG_DRIVER("panel missing\n");
> +				of_node_put(entity);
> +			}
> +		}
> +	}
> +
> +	return panel;
> +}
> +
> +int ltdc_load(struct drm_device *ddev)
> +{
> +	struct platform_device *pdev = to_platform_device(ddev->dev);
> +	struct stm_private *priv = ddev->dev_private;
> +	struct device *dev = ddev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct drm_encoder *encoder;
> +	struct drm_connector *connector = NULL;
> +	struct drm_crtc *crtc;
> +	struct reset_control *rstc;
> +	struct resource res;
> +	struct ltdc *ltdc;
> +	int irq, ret, i;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	ltdc = devm_kzalloc(dev, sizeof(*ltdc), GFP_KERNEL);
> +	if (!ltdc) {
> +		DRM_ERROR("Cannot allocate memory for ltdc\n");
> +		return -ENOMEM;
> +	}
> +
> +	ltdc->panel = ltdc_get_panel(ddev);
> +	if (!ltdc->panel)
> +		return -EPROBE_DEFER;
> +
> +	ltdc->ddev = ddev;
> +	priv->ltdc = ltdc;
> +
> +	rstc = of_reset_control_get(np, NULL);
> +
> +	mutex_init(&ltdc->err_lock);
> +
> +	ltdc->pixel_clk = devm_clk_get(dev, "lcd");
> +	if (IS_ERR(ltdc->pixel_clk)) {
> +		DRM_ERROR("Unable to get lcd clock\n");
> +		return -ENODEV;
> +	}
> +
> +	if (clk_prepare(ltdc->pixel_clk)) {
> +		DRM_ERROR("Unable to prepare pixel clock\n");
> +		return -ENODEV;
> +	}
> +
> +	if (of_address_to_resource(np, 0, &res)) {
> +		DRM_ERROR("Unable to get resource\n");
> +		return -ENODEV;
> +	}
> +
> +	ltdc->regs = devm_ioremap_resource(dev, &res);
> +	if (IS_ERR(ltdc->regs)) {
> +		DRM_ERROR("Unable to get ltdc registers\n");
> +		return PTR_ERR(ltdc->regs);
> +	}
> +
> +	for (i = 0; i < MAX_IRQ; i++) {
> +		irq = platform_get_irq(pdev, i);
> +		if (irq < 0)
> +			continue;
> +
> +		ret = devm_request_threaded_irq(dev, irq, ltdc_irq,
> +						ltdc_irq_thread, IRQF_ONESHOT,
> +						dev_name(dev), ltdc);
> +		if (ret) {
> +			DRM_ERROR("Failed to register LTDC interrupt\n");
> +			return ret;
> +		}
> +	}

Up to four IRQs that call the same irq handler with the same args?  That
seems suspicious.

> +
> +	if (!IS_ERR(rstc))
> +		reset_control_deassert(rstc);
> +
> +	if (clk_enable(ltdc->pixel_clk)) {
> +		DRM_ERROR("failed to enable pixel clock\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Disable interrupts */
> +	reg_clear(ltdc->regs, LTDC_IER,
> +		  IER_LIE | IER_RRIE | IER_FUIE | IER_TERRIE);
> +
> +	clk_disable(ltdc->pixel_clk);
> +
> +	ret = ltdc_get_caps(ltdc);
> +	if (ret) {
> +		DRM_ERROR("hardware identifier (0x%08x) not supported!\n",
> +			  ltdc->caps.hw_version);
> +		return ret;
> +	}
> +
> +	DRM_INFO("ltdc hw version 0x%08x - ready\n", ltdc->caps.hw_version);
> +
> +	if (ltdc_create_encoders(ltdc)) {
> +		DRM_ERROR("Failed to create encoders\n");
> +		return -EINVAL;
> +	}
> +
> +	if (ltdc->panel) {
> +		encoder = ltdc_rgb_encoder_find(ddev);
> +		if (!encoder) {
> +			DRM_ERROR("Failed to find RGB encoder\n");
> +			ret = -EINVAL;
> +			goto err_encoder;
> +		}
> +
> +		connector = ltdc_rgb_connector_create(ddev);
> +		if (!connector) {
> +			DRM_ERROR("Failed to create RGB connector\n");
> +			ret = -EINVAL;
> +			goto err_encoder;
> +		}
> +
> +		ret = drm_mode_connector_attach_encoder(connector, encoder);
> +		if (ret) {
> +			DRM_ERROR("Failed to attach connector to encoder\n");
> +			goto err_connector;
> +		}
> +	}
> +
> +	crtc = devm_kzalloc(dev, sizeof(*crtc), GFP_KERNEL);
> +	if (!crtc) {
> +		DRM_ERROR("Failed to allocate crtc\n");
> +		ret = -ENOMEM;
> +		goto err_connector;
> +	}
> +
> +	ret = ltdc_crtc_init(ddev, crtc);
> +	if (ret) {
> +		DRM_ERROR("Failed to init crtc\n");
> +		goto err_connector;
> +	}
> +
> +	ret = drm_vblank_init(ddev, NB_CRTC);
> +	if (ret) {
> +		DRM_ERROR("Failed calling drm_vblank_init()\n");
> +		goto err_vblank;
> +	}
> +
> +	/* Allow usage of vblank without having to call drm_irq_install */
> +	ddev->irq_enabled = 1;
> +
> +	return 0;
> +
> +err_vblank:
> +	ltdc_plane_destroy_all(ltdc);
> +err_connector:
> +	ltdc_rgb_connector_destroy(connector);
> +err_encoder:
> +	ltdc_destroy_encoders(ltdc);

In pl111, I just call drm_mode_config_cleanup here and in the unload,
which will call the objects' destroy functions for you.

> +
> +	return ret;
> +}
> +
> +void ltdc_unload(struct drm_device *ddev)
> +{
> +	struct stm_private *priv = ddev->dev_private;
> +	struct ltdc *ltdc = priv->ltdc;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	drm_vblank_cleanup(ddev);
> +	ltdc_plane_destroy_all(ltdc);
> +	ltdc_destroy_encoders(ltdc);
> +	clk_unprepare(ltdc->pixel_clk);
> +}
> +
> +MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");
> +MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
> +MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
> +MODULE_AUTHOR("Mickael Reulier <mickael.reulier@st.com>");
> +MODULE_DESCRIPTION("STMicroelectronics ST DRM LTDC driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> new file mode 100644
> index 0000000..d1f9e35
> --- /dev/null
> +++ b/drivers/gpu/drm/stm/ltdc.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <philippe.cornu@st.com>
> + *          Yannick Fertre <yannick.fertre@st.com>
> + *          Fabien Dessenne <fabien.dessenne@st.com>
> + *          Mickael Reulier <mickael.reulier@st.com>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#ifndef _LTDC_H_
> +#define _LTDC_H_
> +
> +#include <drm/drmP.h>
> +
> +int ltdc_crtc_enable_vblank(struct drm_device *dev, unsigned int pipe);
> +void ltdc_crtc_disable_vblank(struct drm_device *dev, unsigned int pipe);
> +int ltdc_load(struct drm_device *ddev);
> +void ltdc_unload(struct drm_device *ddev);
> +
> +#endif
> -- 
> 1.9.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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